ISSN:0144-557X    

DOI:10.1039/AP98017FX037

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

455 ANALYTICAL DIVISIOK DIARY October, 1980 Anglo-Dutch Symposium on Quantitative Organic Analysis A Joint Symposium organised by the Analytical Chemistry Section of the Royal Netherlands Chemical Society and the Analytical Division of The Royal Society of Chemistry will be held at the Leeuwenhorst Congress Centre, N oo rd w i j kerhou t, The Net her lands Thursday and Friday, April 23 and 24,1981 The Plenary Lectures at the Symposium will be given by Professor A. de Leenheer, Ghent University, Belgium, Mr. D. C. M. Squirrell, ICI Plastics Division, Welwyn Garden City, Hertfordshire, Mr. D. T. Coker, Esso Europe Incorporated, Esso Research Centre, Abingdon, Oxfordshire, Professor D. Betteridge, University College of Swansea and Mr. D. van Houwelingen, AKZO, Arnhem. There will also be three Keynote Lectures delivered by Dr. G. G. Skellern, University of Strathclyde, Glasgow and Drs. J. Bax and J. P. C. M. van Dongen of Shell, Amsterdam. If you wish to present a paper or poster, send the title and a 40-50 word summary as soon as possible to either Dr. J. D. R. Thomas, Department of Chemistry, UWIST, King Edward VII Avenue, Cardiff, CFI 3NU or Dr. B. Griepink, c/o Analytical Chemistry Laboratory, Croesestraat 77A, 3522 AD Utrecht, The Netherlands. Requests for information about the Symposium should be addressed to Miss P. E. Hutchinson, Secretary of the Analytical Division, The Royal Society of Chemistry, Burlington House, London, W1 V OBN.

ISSN:0144-557X    

DOI:10.1039/AP98017BX039

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

ANPRDI 17(10) 399-456 (1980) I SSN 01 44-557X October 1980 Hon. Secretary P. G. W. Cobb Analvtical Proceedinas Proceedings of the Analytical Division of The Royal Society of Chemistry AD President L. S . Bark Hon. Treasurer J. K. Foreman Hon. Assistant Secretary D. I. Coomber. O.B.E. Hon. Publicity and Public Relations Officer Dr. A. Townshend, Department of Chemistry, University of Hull, Hull, HU6 7RX Secretary Miss P. E. Hutchinson Editor, Analyst and Analytical Proceedings P. C. Weston Assistant Editors Mrs. J. Brew, R. W. Hazell, R. A. Young Publication of Analytical Proceedings is the responsi- bility of the Analyst Publications Committee: J. M. Ottaway (Chairman) W. H. C. Shaw H. J. Cluley D. Simpson 'P. Gray J. M. Skinner J. N. Miller A. Townshend G. E. Penketh "P.C. Weston T. B. Pierce J. Whitehead "Ex officio members All editorial matter should be addressed to: The Editor, Analytical Proceedings, The Royal Society of Chemistry, Burlington House, Piccadilly, London, W1 V OBN. Telephone 01 -734 9864. Telex 268001. Advertisements: Advertising Department, The Royal Society of Chemistry, Burlington House, Piccadilly, London, W1 V OBN. Telephone 01 -734 9864. @ The Royal Society of Chemistry 1980 Professor L. E. Smythe The Analyst's new Regional Advisory Editor for Australia is Professor L. E. Smythe. Lloyd Smythe was born in Suva, Fiji, in 1922 and studied chemistry a t the Universities of Sydney and Tasmania (PhD) (MSc). His career as a lecturer started a t the former university in 1945, although he later moved to the University of Tasmania to take up a post as Senior Lecturer, following a short spell as a research chemist in Fiji.In 1955, Dr. Smythe became the Corday Morgan Commonwealth Research Fellow of the Chemical Society and continued his work a t Cambridge University with Emeleus and on attachment to AERE Harwell with A. A. Smales. On returning to Australia he became Senior Principal Research Scientist of the Chemistry Division of the Australian Atomic Energy Commission and was made Chief of the Division in 1967. He occupied his present post as Foundation Professor of Analytical Chemistry at the University of New South Wales in 1968, running the only department of its kind in the 20 Australian universities. Undergraduate courses are offered in analytical chemistry in the latter 2 years of a bachelor degree, and these can be followed with Honours (fourth year research), MSc (research), MChem (formal study course) and PhD (research) courses. 399400 FIFTH INTERNATIONAL SAC CONFERENCE Anal. Proc. member of the Editorial Board of Analytical Royal Australian Chemical Institute and was Letters and the Advisory Board of Talanta. its Federal President in 1970. His research Another of his interests is wine, and he is a interests are analytical atomic spectroscopy Chevalier, Confrerie des Chevaliers du Tastevin. (particularly furnace atomisation) and trace Lloyd Smythe is married, with one daughter. element investigations, He has been the His hobbies, apart from drinking wine, are golf, author of about 160 papers, reports and swimming and tennis. patents during the past 20 years and is a Professor Smythe has been very active in the

ISSN:0144-557X    

DOI:10.1039/AP9801700399

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

400 FIFTH INTERNATIONAL SAC CONFERENCE Anal. Proc. SAC 80-Fifth International SAC Conference, Lancaster, July 1980 The Fifth SAC Conference, held on the modern campus of the University of Lancaster just south of the English Lake District, was attended by 425 delegates from over 30 countries. A welcoming reception was given by the President of the RSC Analytical Division, Professor Ronald Belcher, in the Nuffield Theatre on Sunday, July 20th, and this began a week of events that seemed once again to maintain the success and enjoyment of earlier conferences in the series. The formal Opening Ceremony took place in the Great Hall on the Monday morning. Mr. J. W. Ogleby, Chairman of the Local Com- mittee, first introduced the Mayor of Lancaster, Councillor A. C. Bryning, who welcomed delegates on behalf of the City of Lancaster.Welcoming speeches were also delivered by the Vice-Chancellor of Lancaster University, Pro- fessor P. A. Reynolds; the President of the Analytical Division, Professor R. Belcher ; and the Chairman of the SAC 80 Steering Committee, Dr. W. H. C. Shaw. In addition, the President of the IUPAC Analytical Division, Dr. T. S. West, gave a short address on behalf of IUPAC, which was sponsoring the Conference. delivered by Professor T. P. Whitehead, entitled “Assessing the Analytical Quality of the Clinical Laboratory.” The other Plenary Lectures were delivered on the Tuesday, Thursday and Friday and were as follows : “Analytical Instrumenta- tion for the 1980s,” by Professor H. V. Malm- stadt ; “Plasma Spectroscopy Comes of Age,” by Dr.S. Greenfield; and “Moral Ageing of Analytical Methods,” by Professor G. M. Baiulescu. All four Plenary Lectures will be published in full in the November issue of The Analyst. Professor R. Belcher with the Mayor of Lancaster, Councillor A . c. Bryning, and the Mayoress at the reception before the Confeyence Banquet. Dr. T. S. West speaking at the Opening Ceremony. (R-L) Professor J . C. Bevington, Professor P. A . Reynolds, Professor R. Belcher, Councillor A . C. Bryning, Dr. T . S . West, Dr. W . H . C. Shaw and A complete scientific Programme covering MY. G . B. Crump. virtually all aspects of analytical chemistry occupied three days, with three simultaneous streams of half-hour lectures giving a total of the first of the four Plenary Lectures was about 90 papers.In addition, about 60 papers Immediately after the Opening Ceremony,401 Octo bey, 1980 FIFTH INTERNATIONAL SAC CONFERENCE were presented in Poster Sessions throughout the week. It is expected that many of these papers will appear as extended summaries in Analytical Proceedings, and that some will be submitted for publication in The Analyst in the usual way. Professor L. S. Bark (R) with Professor R. Belcher and Mrs. Bark at the reception before the Conference Banquet. Throughout the Conference a trade exhibition was mounted in two laboratories. There appeared to be considerable interest in the stands, and attendances were helped by serving refreshments to delegates in the exhibition areas. As usual at SAC Conferences, a compre- hensive social programme for all delegates was arranged, together with various visits to places of interest in the surrounding area for accom- panying persons.The Wednesday was devoted to all-day visits for all delegates, including Lake Windermere, the Roman Forts and Hadrian’s Wall, Bowes Museum and Raby Castle, a “Wordsworth Visit” and Levens Hall and Cartmel Priory. Unfortunately, this was the one day of the week marred by bad weather, the remaining days being sunny exceptions to a generally abysmal summer in the UK. Several scientific visits were also arranged, including British Nuclear Fuels (Windscale), Glaxo and Storeys. Each evening except Wednesday a social function took place. On Monday a Wine Reception was held by invitation of the Vice- Chancellor of Lancaster University, followed by a party given by the North-West Region of the Analytical Division.Tuesday was com- pleted by a Civic Reception at Lancaster Town On the Tuesday and Thursday afternoons, informal Group Discussions, open to all delegates, were organised by some of the specialist subject and technique groups of the Analytical Division. The Automatic Methods Group held a session on “Exploiting Microprocessors for Graphical Display,” the Joint Pharmaceutical Analysis Group on “Some Analytical Aspects of Environ- mental Control in the Pharmaceutical Industry,” the Chromatography and Electro- phoresis Group on “Whither Chromatography,” the Analytical Methods Committee on “Can We Believe the Result We Get?,” the Electro- analytical Group on “Electroanalysis-Where Next ?,” and the Atomic Spectroscopy Group on “ICPs and Other Developments.” Also on the Tuesday and Thursday, Work- shop Sessions were held throughout the day, in which delegates could see and discuss practical demonstrations of participants’ latest laboratory work.The topics included flow injection analysis, the acquisition and processing of analytical data with low-cost computers, a MECA detector for HPLC, an automated sedi- mentation balance, cheap and simple hydride generation AAS and square-wave wavelength modulation for atomic spectrometry. Professor K. J . Morgan proposing the toast of the City of Lancaster at the Conference Banquet. On the left of the photograph i s Mrs. Morgan and on the right Mrs. Reynolds. Hall, followed by a concert in the Ashton Hall by the celebrated pianist John Ogden.Thurs- day saw the traditional and excellent Conference Banquet at the University. The toast of Her Majesty the Queen, the Duke of Lancaster, was proposed by Professor R. Belcher. The toast of the City of Lancaster was proposed by402 SAFETY I N ANALYTICAL LABORATORIES Anal. Proc. Professor K. J . Morgan, and the response was by the Mayor, who proposed the toast of the Analytical Division. Professor Belcher replied and proposed the toast of the guests, to which Professor H. V. Malmstadt replied. Finally, as the Thursday coincided with the AGM of the Royal Society of Chemistry, the Divisional Presidencies changed on that day, so that Professor L. S. Bark was due to take over from Professor Belcher. A t the end of the dinner, therefore, Professor Belcher handed over the gold Presidential Badge, bearing the likeness of Theophilus Redwood, the first President, and received a replica in return. SAC 80 ended on the Friday with a “Lan- cashire Evening” at the University, where a traditional meal and entertainment were pro- vided. This gave a very lively and informal ending to what had proved to be, once again, Professor R, Belcher (L) handing over the Analytical Division Presidential Badge to the new President, a most and enjoyab1e SAC Con- Professor L. S . Bark. ference.

ISSN:0144-557X    

DOI:10.1039/AP9801700400

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

402 SAFETY I N ANALYTICAL LABORATORIES Anal. Proc. Safety in Analytical Laboratories This article is the fifth in a series of reports on aspects of safety of particular interest to analytical chemists. I t is hoped that these articles will provide a forum for further discussion, and correspondence on the individual articles and on all safety matters is invited. This series is written by outside contributors and views expressed in the articles are not necessarily those of the Royal Society of Chemistry. Health and Safety Aspects of Analytical Atomic Absorption W. J. Price Pye Unicam Limited, York Street, Cambridge, C B 1 2PX Introduction The practice of atomic-absorption analysis involves materials and techniques, which, if not properly handled and controlled, incur certain risks to health and safety.Supervisors and operators therefore need to be aware of these hazards, which arise in three main areas: the use of gases that form combustible mixtures; hazards associated with electrical and elec- tronic apparatus; and the handling of samples and solvents, which themselves are, or readily form, toxicologically active or chemically dangerous compounds. The emphasis in all Health and Safety legislation is on reduction of risk as far as is reasonably practical, both by control of hazards and by training of operatives. To the instrument manufacturer, control of hazards implies, of course, that the instrument should be designed with the safety of the operator in mind. Responsibility for the training of opera- tives is shared by management, supervisors and the operators themselves.Combustible Gases Dangers stem from the use of combustion flames. The fuel and oxidant gases are pre- mixed in order to achieve a homogeneous flame of laminar flow. Some of the gas mixtures in use are summarised in Table I. Under certain conditions of misuse, therefore, it is possible for the pre-mixed gases in the spray chamber to be ignited and cause an explosion. There are thus two principal considerations : firstly to prevent the explosion happening, a responsi- bility shared by designer and user, andOctober, 1980 SAFETY IN ANALYTICAL LABORATORIES 403 secondly to minimise the risk of injury (and damage) if the explosion unfortunately should occur. TABLE I GAS MIXTURES USED IN ATOMIC-ABSORPTION SPECTROPHOTOMETRY Temperature/ Oxidant-fuel K Air -propane .. 2200 Air - acetylene . . 2450 N,O - acetylene . . 3200 Air - hydrogen . . 2300 N,O - hydrogen . . 2900 N,O -propane . . 2900 Flame speed/ cms-l* 45 160 285 320 380 250 * For references see Price, W. J., “Spectro- chemical Analysis by Atomic Absorption,” Heyden, London, 1979, p. 29. Manufacturers design their atomic-absorption instruments to allow for a good margin of error on the part of the operators. Therefore, in general, if the instrument is being used in accordance with manufacturer’s instructions it is highly unlikely that any trouble will ensue. Safety in Operation The different gas mixtures employed burn with different flame propagation velocities (Table I). Provided, therefore, that the gas velocity through the burner slot is greater than the flame propagation velocity, the flame will not burn back into the burner shell and spray chamber and cause an explosion.From this fact several conclusions follow. (2) The operator must use the right burner, i.e., one designed to provide an adequate gas velocity. To ensure this, even when the flame is being extinguished, each gas should flow through the burner at a velocity greater than flame propagation. (ii) In lighting the flame, the oxidant must be turned on first; in extinguishing, the fuel must be turned off first. (22;) If the flame appears to start to fail, the gases should be turned up, not down. (in) The flame should never be extinguished by turning both gases down at the same time. The above apply to mixtures in which air is the oxidant.Where dinitrogen oxide is the oxidant, the burning velocities are higher, so burner slot dimensions are smaller. Although the principles still apply, most manufacturers arrange for the flames to be ignited with air as the oxidant, and to change oxidants (which requires an increase in fuel flow) while the flame is burning. Further points to check before operation of the atomic-absorption instrument are that the liquid trap in the spray chamber has been filled with the correct solvent (or that incom- patible solvents or solutions are not mixed, causing a precipitate and thus a potential blockage), that all gas pipe joints are leak-free and that the burner is clean and free from deposits. Carbon deposited by the dinitrogen oxide - acetylene flame should on no account be moved while the flame is in operation, as incandescent particles can drop through the slot and ignite the mixture in the burner shell, causing an explosion.Designing for Safe Operation The above are mostly precautions the operator should take to avoid atomic- absorption instrument explosions. The manu- facturer should, of course, have designed the instrument so that there is minimum risk. For example, the burner slot should be such that for each gas employed in each gas mixture, the minimum flow-rate should be at least 20% greater than the effective flame propagation velocity in the slot, both in case one gas should fail during operation and for safety in extinguishing. Another contribution both to safety and to the operator’s peace of mind is the automatic “gas box.” In brief this is a device that automatically adjusts oxidant and fuel gas pressures prior to lighting the flames and controls the pressure during changeover between mixtures and on extinguishing.It is also often interlocked with burners so that flames cannot be ignited unless pressures are correct and a suitable burner is in place, and will auto- matically go into a safe shut-down routine should any supply (oxidant, fuel or mains electricity) fail. A flame sensor should also be connected to the box so that operations are shut down should the flame for any reason become extinguished. Unless extremely com- plex and costly, the gas box is unlikely to be totally fool-proof. It should be regarded as an aid to a busy operator so that he may be as certain as is reasonably practical that minor errors on his part, or failure of some part of the system, will not have serious consequences.A further point on the burner itself is that this should be so designed that it can be lifted off the burner stem while hot without the operator burning his fingers. Similarly, if parts of the electrothermal-atomisation furnace have to be touched, these should be subject to cooling like the tube holders. Design for safety also includes features whereby risk of damage and injury are mini- mised in case of an explosion. A safety disc404 SAFETY I N ANALYTICAL LABORATORIES Anal. Proc. should be fitted a t the rear of the spray chamber. This is designed to rupture before the burner or spray chamber themselves explode and parts (including the nebuliser) are projected in dangerous directions.The burner compartment is usually of strong construction so that damage is not transmitted to other parts of the instrument. Clearly, an instru- ment fitted with a door having a strong catch affords protection to the operator. The door should have a window of dark ultraviolet absorbing safety glass or perspex so that the flame can be observed in safety. A further advantage of a properly designed door is that it would help to reduce the noise of an explosion within the instrument. Five and explosion caused by gas leakage All piping within the instrument should be of rigid stainless steel with properly sealed joints. The exception to this is the flexible plastic pipe to the burner, which is metal shielded, and which is readily visible.The system should be factory tested to pressures well above operating pressures, e.g., 55 p.s.i.g. (3.75 bar) for the air and dinitrogen oxide lines and 25 p.s.i.g. (1.7 bar) for the acetylene line (but not, of course, with acetylene itself). The regular servicing procedure should include either bubble or leak check on piping and joints. In this way the user can be as certain as is reasonably possible that no gas leakage will occur inside the instrument, causing a potentially explosive build-up of gas. The flame lifts off the burner when an explosion occurs, and the flame sensor mentioned above would then cause the gases to be turned off. This is a vital safety point because much more damage can be caused by fires that result from the con- tinued supply of acetylene after an explosion than is caused by the explosion itself.Visual safety The safety door mentioned earlier gives the operator protection against ultraviolet and strong visible radiation from hot flames. Similarly, it should not be possible for the operator to see the hot electrothermal-atomisa- tion tube directly. He should also be warned against looking a t it by means of an aluminium foil dentists’ mirror, a common practice in alignment, when the tube is at high tempera- ture. Gas Supply Systems The methods of supplying acetylene to the point of use either by pipe or by cylinder are a t present governed by Order in Council No. 30 and the Compressed Acetylene Order of 1947. These are based upon out-dated laws formu- lated in about 1897 when acetylene was classi- fied as an explosive gas within the meaning of the Explosive Act of 1875, i.e., it could explode spontaneously under pressure in the absence of oxygen, probably because it was produced in a much less pure form than it is today.Existing legislation therefore still defines acetylene gas a t pressures greater than 9 p.s.i. (0.62 bar) above atmospheric as being an explosive gas. This means that it should not be delivered to an atomic-absorption instru- ment, e.g., from a cylinder, a t pressures higher than this, and that if a piped system is employed, which almost certainly would have to operate a t such higher pressures, a special licence has to be obtained. A working party of the Health and Safety Executive, representing the CBI, TUC and professional bodies, recently proposed that acetylene a t pressures between 9 and 22 p.s.i.(0.62-1.5 bar) should be classified as a flam- mable gas, and that its use should be allowed up to 22 p.s.i. (1.5 bar) provided that the installation conforms to the Health and Safety Executive’s famous “21 points” and that they are notified of the installation. The provisions of the 21 points cover every use of acetylene, not just atomic absorption. There is also a strong feeling that the lower limit of 9 p.s.i. (0.62 bar) at which the regulations come into force should be raised to 15 p.s.i. (1.03 bar), and therefore individual approval would not be necessary. Reasons for raising the lower limit are : (i) It is now established that acetylene will not detonate at pressures below 15 p.s.i.in pipework of 25 mm or less diameter. (ii) Legal standards overseas generally place no restriction on the use of acetylene below 15 p.s.i. (iii) As the legal position in the UK is thus out of step with EEC practice it is restrictive to open trade. ( i v ) Most atomic-absorption instruments in fact operate a t just over 9 p.s.i., and full compli- ance with the 21 point standard is unduly restricting and expensive. As a result, responsibility for codes of regula- tions affecting the use of acetylene at pressures below 1-5 bar has now been passed from HM Explosives Inspectorate to the HSE working party on flammable gases. Nevertheless, the changes outlined will still presumably require a new Order in Council. The following provisions, which are relevant405 October, 1980 SAFETY I N ANALYTICAL LABORATORIES to atomic-absorption installations, are con- densed from the 21 points.(i) Acetylene must be stored in cylinders of design approved by the Secretary of State (hopefully all British companies’ acetylene cylinders are, but some imported ones may not be). (ii) A quantity of highly flammable materials must not be kept, nor more than 21 used, within 3 m of a pipe containing acetylene a t or above 9 p.s.i. or within 5 m of the apparatus. (iii) Cylinders connected to a permanent system operating between 9 and 22 p.s.i. may not be kept in a working building. (This means that if pipework or the instrument contains acetylene at more than 9 p.s.i. the cylinder must be outside the laboratory.) (iv) The structure of the building where acetylene cylinders are connected into the system is strictly controlled as far as design, access and electrical gear are concerned.(v) Both the positioning and materials used for construction of pipework and connections are strictly controlled. The pressure regulation system (limiting to not more than 22 p.s.i.) must be close to the cylinder(s) and has to be certified annually. (vi) Flashback arrestors have to be fitted within 1 m of the regulator and within 1 m of the outlet, and there must be a manually operated isolating valve near the instrument as well as an effective non-return valve. ( v i i ) Acetylene pipelines must be clearly identified as such and must be tested a t an over-pressure of 50 p.s.i.on installation, on modification and annually. An anomaly of the 21-point standard is that the majority of cylinder “manifolds” installed by professional companies in continuous supply systems could thereby be made illegal, for these operate up to the full cylinder pressure of 225 p.s.i. (15.5 bar). It is expected that this would be resolved by defining a minimum design standard for manifold systems in the amendment of existing legislation. Electrical Safety Electrical risks in atomic-absorption instru- ments are the same as those created in other electrical or electronic instrumentation. Most atomic-absorption equipment is in Class 1, i.e., it relies upon an earth connection for electrical safety. The outer case and accessible con- ductive parts likely to become live in the event of a fault should be bonded electrically to the protective earth terminal.An earthing efficiency check and insulation breakdown test are mandatory on every instru- ment following manufacture, and it is recom- mended that these checks be repeated periodically, e.g., after the annual service. Where electrical hazards exist in compart- ments of an instrument, it is standard practice that these should be accessible only by use of a tool (not a coin!). Anyone making access to such a compartment should be trained to be able to recognise and avoid these hazards. At the present time there are still no recognised international standards specifically referring to laboratory instrumentation, though the standard IEC 348 1978 for electrical measuring apparatus is applicable.National standards exist in some countries, e.g., the Underwriters Laboratory Standards for general conformity in the USA. It is clear that proliferation of standards covering the same field is of little help either to the manufacturer or to the user. This has been recognised by the International Electrotechnical Commission, which is actively engaged in the generation of a unified standard specification covering most professional laboratory instrumentation. Health Risks Some of these have already been mentioned but are included again here for completeness. Combustion Products The main risk to health is from the com- bustion products of dinitrogen oxide, which always contain the other oxides of nitrogen and which are therefore comparatively more dangerous.Acetylene itself is mainly an asphyxiate. Samples and Sample Solutions The use of organic compounds containing halogens, particularly chlorine, in or as the solvent is quite common. As well as tri- chloroacetic acid, used for de-proteinisation, chloroform and carbon tetrachloride may well be used in solvent extraction, both in flame and in electrothermal-atomisation methods. In the flame, phosgene (carbon oxychloride) and similar compounds are produced. In electro- thermal atomisation the solvents, though in much smaller amounts, are vaporised un- changed. Many elemental vapours, especially beryllium, cadmium, lead, mercury, platinum, thallium, etc., are well known to be exceedingly toxic. Exceptional care must therefore be taken when such elements form part of the sample matrix, e.g., beryllium - copper or magnox alloys, yellow pigments, solders, etc.Anal.PYOC. 406 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Fume Extraction In these instances, both in flame and electro- thermal-atomisation methods, the use of very efficient fume extraction systems is essential. The efficiency of the system when used with electrothermal atomisation is particularly important because in this situation extraction is not aided by the powerful convection effects associated with the flame. It would be expected that fume extraction would always be provided for flame atomic absorption (because of the possibility of use of dinitrogen oxide) and it should be considered essential if toxic elements are being measured, as the concentration of these could build up to dangerous levels in a small laboratory.Although desirable with electrothermal- atomisation methods, particularly with organic matrices that give rise to unpleasant odours, fume extraction may not be considered to be so essential because actual amounts of such elements are exceedingly small; e.g., a 1 p.p.b. (parts per lo9) concentration of a toxic element in a 20-pl sample is 2Opg in absolute terms, i.e., 1 ng if totalled over 50 samples and standards. The TLV for beryllium compounds is Z ~ g m - ~ , i.e., a factor of a t least 2 000 times greater. But for mercury, where 20 ml of prepared sample solution containing 1 ,ug ml-l of mercury, i.e., 20,ug, might be used in the cold-vapour method, the TLV is 0.05 mg ~ n - ~ , i.e., the equivalent of the mercury content of only 2 or 3 such samples, and proper extraction should be installed. Incidentally, a t normal breathing rate, 2 1 min-l, an operator will inspire rather less than 1 m3 of the laboratory atmosphere in a working day. Chemical Technique The risks involved in the preparation of solutions and standards for atomic absorption are the same as in the performance of analytical chemistry in general. The actual amount of handling can, of course, be reduced by use of an auto-sampler. Hollow-cathode Lamps A minor risk, but one that should neverthe- less be appreciated, occurs if the glass envelope of certain hollow-cathode lamps is broken. The metal from the cathode usually appears in the inner glass surface in a very finely divided form. The danger exists particularly with such elements as mercury, beryllium, cadmium, etc. “Demountable” lamps are not in frequent use in routine laboratories but, if this use is contemplated, care should be taken to ensure that the exhaust gas from the pumping down system is vented outside the laboratory.

ISSN:0144-557X    

DOI:10.1039/AP9801700402

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

406 Anal. PYOC. POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Inorganic and Organic Pollutants in the Troposphere and Natural Waters The following are summaries of seven of the papers presented at an Interdivisional Meeting organised in conjunction with the Microchemical Methods and Electroanalytical Groups and held on September 26-28th, 1979, at the Queen’s University, Belfast. Summaries of eleven other papers presented at the meeting appeared in the September issue of AnaZyticaZ Proceed- ings (p. 348). Removal of Dyes from Water Using Adsorption Techniques G. McKay and M. S. Otterburn Department of Industrial Chemistry, The Queen’s University of Belfast, Belfast, BT9 5AG, Northern Ireland The ability of several materials to adsorb dyes has been considered, and methods of con- tacting liquid effluents by batch, fixed-bed and fluidised-bed systems have been studied.Equilibrium Studies and Simplified Economic Model A series of isotherms have been measured to determine the adsorption capacity of two classes of dye on various adsorbents. All the experiments were undertaken using similar conditions and an adsorbent particle size range between 150 and 250pm. The two dyes used were Telon Blue ANL (BAY) (CI Acid Blue 25) and Astrazone Blue FRR (BAY) (CI Basic Blue 69).October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 407 The maximum equilibrium adsorption capacity of each adsorbent was measured ( X / M mg of dye per gram of adsorbent) and the values were used to assess the amount of adsorbent required to remove 1 kg of dye.The amounts have been used as a basis for costing the adsorption process. The relative costs of adsorbents are shown in Table I together with adsorption costs of removing 1 kg of dye. Wood, being the cheapest material, was taken as a standard, having a comparative cost of unity per kilogram. TABLE I RELATIVE COSTS OF ADSORBENTS Relative X / M valueslmg dye g-1 Adsorbent material cost Acid dye Basic dye adsorbent ‘_---h---- 7 Wood . . . . .. 1.0 54 120 Peat . . . . . . . . 4.0 99 660 Fuller’s earth . . . . 66 36 827 Carbon . . .. .. 100 83 985 200 Diatomaceous earth . . 50 Silica . . . . ,. . . 150 23 35 . . . . 182 96 - Alumina . . - Relative cost to remove 1 kg of dye Acid dye Basic dye 1 .o 1.0 2.1 0.7 9.8 10 6.4 12 35 512 10 30 ‘_-d-_-7 - - Table I shows that peat adsorbs the largest amount of acid dye, followed by alumina, carbon, wood, fuller’s earth and silica.In economic terms the order changes, with wood being the cheapest, followed closely by peat, with carbon being 65 times more expensive. For the basic dye all the adsorbents show a high adsorptive capacity; decolorising carbon, fuller’s earth and peat are capable of adsorbing almost their own mass of dye. Peat is the cheapest adsorbent system, closely followed by wood. I t should be emphasised that in this model no account was taken of contact time data and regeneration costs. Single-stage Batch Adsorption An effluent to be treated contains G g of water, and the dye concentration in water is to be reduced from C, to C, g g-l. The adsorbent, L g, is added and the solute dye increases from Xo (X,, = 0 for pure, fresh adsorbent) to XI g of dye per gram of adsorbent.The ratio of adsorbent to effluent solution may be obtained1 from equation (1) if the isotherm follows the Freundlich isotherm: where K and n are the Freundlich constants. Equation (1) permits the analytical calculation of the adsorbent to solution ratio for a given change in solution concentration. A series of plots are shown in Fig. 1 for various adsorbents, using an initial dye concentration of 200 mg 1-1 and a C,/C, ratio of 0.9. The data may be used to predict the design of single-stage batch adsorbers and the economics are dictated by the results in the previous section. There are, however, certain disadvantages with batch adsorption, namely : (a) the time required for the adsorbent and liquid to come to substantial equilibrium is large, (b) the plant items include an agitated tank and a filter press, which are expensive, and (c) additional time is required for the filtration process.Unsteady-state Fixed-bed Studies Many equations have been derived for correlating the service time of a fixed adsorption bed with operating variables. The bed depth service time (BDST) model2 states that the service time of a column can be related to a number of process variables, and at 50% break- through this relationship is given by the equation408 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. . . * * (2) to.5 = - = constant x H .. .. COU where to.5 = service time at 50% breakthrough; No = adsorption capacity; u = linear flow-rate; H = bed depth; and Co = initial dye concentration.Table I1 shows the results for the adsorption of Acid Blue 25 on carbon, peat and wood, where the samples were taken at a bed height of 20 cm and at 50% breakthrough. Conse- quently, for a fixed dye velocity carbon removes more dye than peat and wood. However, based on the relative costs of the adsorbents, in order of lowest costs the choice becomes wood, peat and carbon, respectively. TABLE I1 ADSORPTION OF ACID BLUE 25 ON DIFFERENT ADSORBENTS Comparative cost I Volume of dye Per kg of To remove 1 kg Adsorbent treated/l kg-l adsorbent of Acid Blue 25 Carbon . . .. 610 100 10 Peat . . .. 140 4.00 1.70 Wood . . .. 60 1.00 1 .oo Fluidised-bed Studies In wastewater treatment systems, it is advantageous to keep the particle size as small as possible, so that high rates of adsorption may be achieved. Column operation, in which the dye solution to be treated flows upwards through an expanded bed of the particulate adsorbent, i.e., a fluidised bed, is one method of taking advantage of small particle size.The apparatus for fixed-bed and fluidised-bed studies has been described previously.3 The adsorption of Basic Blue 69 on Sorbsil silica has been studied in a fluidised bed using a particle size range 500-710pm. Fig. 2 shows plots of the volume of dye treated to 50% breakthrough against bed mass for batch, fixed-bed and fluidised-bed processes. A plot of RDST at 50% breakthrough against bed height should be a straight line. However, Fig.2 0 100 Masslg 200 Fig. 1. Volume of CI Acid Blue 25 treated against mass of various absorbents: A, peat; B, alumina; C , carbon; I), wood; E, fuller’s earth; and F, silica. 100 200 Bed masslg Fig. 2 . Volume of dye treated against bed inass €or 60% breakthrough. Broken line, batch studies. o., e, Fixed-bed studies: A, A, fluidised-bed studies. u : A, 50; R, 75; C, 100; D, 790; E, 1266; and F, 1400 ml min-I.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 409 shows that the plots are curved for fixed-bed studies using dye velocities of 50, 75 and 100 ml min-1. The points of intersection for fixed and fluidised beds at dye velocities of 50, 75 and 100 ml min-1 correspond to silica bed masses of 130, 150 and 220 g, respectively. The fluidised-bed results are linear and show that much lower volumes of dye may be treated under these conditions owing to much greater dye velocities. Although high mass transfer rates are attained in fluidised beds the major problems associated with them are controlling plant-scale operations and the relatively high velocities required to achieve fluidisation.The latter fact means the spent silica has reached only a fraction of its equilibrium adsorption capacity. References 1. 2 . 3. Treybal, K. E., “Mass Transfer Operations,” McGraw-Hill, New York, 1969. Hutchins, R. A., Chew,. Eng., 1973, 80, 133. Poots, V. J. P., McKay, G., and Healy, J. J., Water Res., 1976, 10, 1061. Spectrochemical Analysis of Environmental Pollutants in Agricultural Materials A. M. Ure ilfacaulay Institute for Soil Research, Craigiebuckler, Aberdeen, A B 9 2Q J Public discussion of the impact of pollution on human health and welfare is not usually dominated by agricultural implications.It is necessary to remind ourselves of the importance of soil, derived from geological formations, which ultimately provides the principal source of all the elements required for life and with the sea constitutes the main sink for pollution materials. I t is in the soil, which supplies both nutrient and pollutant elements to plant and animal, that most of the long-term effects of pollution will be seen. What then are the elements with which we must be concerned in our examination of the agricultural environment? Firstly, there are the elements that have been shown to be essential for some form of plant or animal life and health.In addition to the universal constituents carbon, hydrogen, nitrogen and oxygen, the essential elements include B, Ca, C1, Co, Cr, Cu, F, Fe, I, K, Mg, Mn, Mo, Na, Ni, P, S, Se, Si, Sn, V and Zn. Many of these elements in excess show toxic effects on plant growth or animal health, for example B, Cu, F, Mn, Mo, Ni, Se and Zn; indeed, most elements in sufficient excess can have deleterious effects on health. The toxic properties of elements such as As, Be, Cd, Hg, Pb, Sb and T1 are well known. Other elements, such as Al, Ag, Au, Ba, Bi, Br, Cs, Ge, Li, Rb, Sr, Ti and W, have potential biological significance ; for example, even the normally innocuous element A1 can, in water, be toxic to fish,l in the blood-stream to man2 and under very acidic con- ditions to most plant^,^ while Au, Bi and Li have pharmaceutical uses.A wide range of elements must, therefore, be considered and multi-element analytical techniques should be available for survey and monitoring purposes. For such surveys and for base-line studies there is much to recommend d.c. arc optical emission spectrography (OES), a technique rarely used by environmentalists in the UK, but used for many years in agricultural laboratories in Scotland and Ireland. It is economical and versatile and provides wide element coverage, which includes many of the biologically important elements. I t is sufficiently accurate and sensitive for monitoring pollution and, while it can be made more rapid and precise with direct-reading spectrometer instrumentation, the cost of the additional sophistication is considerable and, for many purposes, unjustified.This technique uses410 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. solid samples, e.g., soil, rock, ignited sewage sludge, ashed plant or biological material, and has the advantage of much greater freedom from contamination and dilution problems contingent on the use of sample dissolution techniques necessary for many other spectro- chemical methods such as atomic-absorption spectrometry. Another multi-element tech- nique, more sensitive and with much wider elemental coverage, is spark-source mass spectrometry (SSMS). This again uses powdered samples mixed with a conducting material such as pure graphite or aluminium powder to form a sample electrode.With this technique, using an AEI MS 702R instrument, and supplementing the SSMS analyses with those for a few major and trace elements by other methods, about 60 elements can be determined directly in a soil or sewage sludge sample with detection limits in the range 0.01-1 mg kg-1 and a precision of &10-15%.4 An example of such a comprehensive analysis of a European sewage sludge is given in Table I. TABLE I COMPREHENSIVE ANALYSIS OF A EUROPEAN SEWAGE SLUDGE (40.6% LOSS ON IGNITION) BY SPARK-SOURCE MASS SPECTROMETRY (SSMS) , D.C. ARC OPTICAL-EMISSION SPECTROGRAPHY (OES) AND X-RAY FLUORESCENCE SPECTROMETRY (XRF) Major element contents as oxides by XRF, % r+------7 SIO, 21.00 TiO, 0.31 3.05 Fez03 1.24 MnO 0.01 2.88 ?:: 13.82 Na,O ND K,O 0.04 p 2 0 5 7.25 so3 0.91 Kesults as yo or mg kg-l air-dry material.Trace element contents by SSMS or OES/mg kg-l AG- Au B Ba Be Bi Cd Ce c1 co Cr 25 40 1100 6 21 9 10 1800 6 190 0.9 c u Er F Ga Gd Ho La Lu Mn Mo DY 450 0.5 0.2 420 6 0.9 0.05 8 0.04 120 3 Nb Nd 0 s P b Pd P r Pt Rb Re Sb s c 4 3 0.1 190 0.01 0.9 0.06 24 0.03 6 0.7 ~~ Sn Sr Th T1 Tm U V w Y Yb Zn 7 ___ 130 390 1 0.04 0.09 1 20 8 6 0.3 4 000 Turning to the sources of pollution of importance in an agricultural context, perhaps the principal one is a consequence of the effort to improve water quality and to treat sewage before discharge into a river or the sea. Current methods of treatment leave a solid or liquid residue that is often applied to agricultural land as a source of organic matter and some essential nutrients.Unfortunately, many of the toxic metals are in this way presented in concentrated form to the soil with actual and potential hazards, both short and long term, to plant and animal. While sewage sludges are very variable in their composition, depending on the types of industry in the area, comparison of a typical sludge and soil composition5 shows that elements such as B, Cd, Cr, Cu, Hg, Ni, Pb and Zn can be present in considerable amounts in sewage sludges. Other waste materials are sometimes applied to soils, e.g., municipal composts, which can have high levels of elements such as Be and fuel or fly ashes that are often high in B and Mo. Agricultural operations themselves provide inputs of pollutants as well as beneficial elements.Fertilisers, manures and certain pesticides, etc., can make a significant cumulative contribution to the soil of the trace elements present in them as impurities. Phosphatic fertilisers can, for example, contain 50 mg kg-l of Cd, 200 mg kg-l of Cr and 100 mg kg-1 of Pb, and lime may contain 500 mg kg-1 of Mn. Pig slurry from intensive pig production units and pot ale residues from malt whisky distilleries, both normally disposed of to land, can contain upwards of 500mg kg-l of Cu. Many Scottish vegetable garden soils have elevated mercury contents from soot that may contain 10 mg kg-l of Hg and more particu- larly from the perennial use of 4% calomel dust as a fungicide in the cabbage patch. The atmospheric deposition of heavy metals such as Pb, especially in urban situations, can pollute broad-leaved vegetables such as lettuce, while atmospheric fluoride contamina- tion from aluminium smelters is deleterious both for forestry and for animal health.The damaging effects of sulphur dioxide on plant growth and on human health have receivedOctober, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 411 much attention. Indeed, with the reduction of atmospheric sulphur dioxide levels an important input of sulphur and perhaps of selenium to agricultural land may be lost. The greatest contributor to the atmospheric aerosol is the sea,6 but this contribution is not necessarily representative of the oceanic composition but may reflect preferential concentration processes, physical and biologi~al,~~~ at the surface of the sea.Significant beneficial inputs of elements such as K, Cu, I, Mg, Se and Zn may arise from this source. So far only the total contents of elements in soils and sludges have been considered, but the availability of polluting elements to plants is dependent not only on the total content but on a variety of factors, soil drainage, pH, soil type, plant species, climate, agricultural practice and on the chemical form of the elements. While the assessment of plant uptake can be made by analysis of plant materials, it is often preferable to use a soil assessment of availability, as plant contents vary appreciably with species, stage of growth, season and plant part. The availability of an element to the plant can be assessed by means of various empirically derived soil extractants whose extracting performance have been correlated with plant uptake.In the short term, the analysis of soil extracts is, therefore, useful in assessing the impact of pollution while the longer term aspects require monitoring of the total soil contents of the pollutant elements. In 0.5 M acetic acid extracts of soils, flame atomic-absorption spectro- metry (AAS) is sufficiently sensitive for the determination of only a few trace elements, Co, Ni, Mn and Zn without or with only a small pre-concentration. EDTA (0.05 M) extracts can provide concentrations of Cd, Cu, Mn, Pb and Zn measurable by flame AAS and these extracts give a useful assessment for some of these elements. As most laboratories have access to AAS methods of analysis, solution methods for deter- mining total contents of heavy metal pollutants in sewage sludges and sludge-treated or contaminated soils are essential. For this purpose, aqua regia digestion is one of the most convenient methods for the preparation of these samples.Analysis of such digests will not provide true total contents, as silicate-bound elements will not be dissolved. While this defect could be important in soil analysis for some purposes, it is not, however, a major disadvantage for. the assessment of the extent of contamination as few pollutants will be present, or added to the soil, in silicate-combined forms. The aqua regia digestion procedure adopted at the Macaulay Institute takes 0.25 g of ignited sewage sludge or 1 g of unignited soil to dryness six times with 10 ml of aqua regia (re-distilled nitric acid - 6 M hydrochloric acid, 1 + 3) on a water-bath with the final residue again taken to dryness with 10 ml of 6 M hydrochloric acid and dissolved in 50 ml (sludge) or 25 ml (soil) of 0.06 M hydrochloric acid for analysis by AAS.Pressure digestion systems using PTFE-lined stainless-steel bombs can also be used and are more rapid and give slightly more efficient extraction. These bomb procedures are generally limited to sample sizes of a few hundred milligrams and they are, moreover, expensive if batch analyses are required. For multi-element analysis dry- ashing methods are preferred because the problems of contamination by chemical reagents are minimised. Only a few elements, such as As, Hg and Se, are lost by volatilisation from plant and similar materials, such as sludges, when ashed at 450 "C.Low-temperature ashing techniques, using R.F.-excited oxygen, have been advocated, but the method is slow and Se, Hg and even Cr can be lost by volatilisation, so it offers little advantage over con- ventional dry-ashing methods. Standard wet-ashing or oxidative digestion procedures using perchloric acid in combination with other acids such as nitric acid or nitric acid- sulphuric acid can be used for plants and sewage sludges, but losses of volatile Cr species and precipitation problems with samples having high potassium contents (low perchlorate solubility) can occur with these procedures. Sulphuric acid digestion methods are un- desirable if Pb is to be determined or if the alkaline earth metal contents are high.Wet- digestion procedures for the determination of mercury by cold-vapour, reduction - aeration AAS usually involve a low-temperature (50 "C) digestion with nitric acid - sulphuric acid followed by overnight oxidation with potassium permanganate. For this and other volatile elements oxygen-flask combustion methods can also be used. These are based on the Schoniger flask method but, for both Hg and Se, the platinum sample basket must be replaced with a silica boat, and an oxidative collecting solution used, if quantitative recoveries are to be obtained. Following this procedure Se can be determined by converting to Se(1V) with Not all inputs from the atmosphere are, however, damaging. Plant materials require wet or dry ashing before analysis.POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Anal.Proc. 412 hydrochloric acid, complexing with 2,3-diaminonaphthalene (DAN) and extracting the Se complex with dekalin for analysis by molecular fluorimetry. There are so many recent advances in spectrochemical techniques which have relevance to the analysis of environmental and agricultural materials that only a brief and selective review can be made here. One of the most important of these is the use of electrothermal atomisers in AAS. Various types exist, graphite furnace, carbon rod, tantalum ribbon and metallic filament atomisers, all of which in some measure possess certain advantages over conventional flame methods. These are (1) small sample size, typically 5-100 pl; (2) detection limits 2 or 3 orders of magnitude better; (3) viscous and even solid samples in favourable instances can be used; and (4) ashing, drying and atomising the sample can be performed directly in the furnace without recourse to prior chemical treatment. The last possibility has been realised for sewage sludge in practicegJO by making use of mechanically homogenised samples pipetted into a graphite furnace atomiser where the elements Cd, Cr, Cu, Ni, Pb and Zn are determined directly by AAS with results that are in excellent agree- ment with conventional flame AAS determination in digested samples.I t is important to remember, however, that the high sensitivity of the furnace technique is accompanied by greater interference effects from the sample matrix and a much greater dependence on the chemical form of the elements.Analysis by electrothermal atomiser methods require, therefore, not only a much better understanding of the chemistry of the atomising process but also a considerably longer time for the development of a reliable analytical method. It appears sensible to make use of conventional flame methods in the first instance where these are practicable and to resort to furnace methods only when the sample size or sensitivity criteria necessitate it. In some instances, however, with furnace techniques interferences may be so great, or so complex to interpret, that a pre-concentration or separation stage is necessary to eliminate them. Such a procedure has been adopted at the Macaulay Institute for the simultaneous routine determination of cadmium by atomic fluorescence and of lead by AAS in solutions of ashed plant materials. A solvent extraction of Pb and Cd from the plant ash solution by dithizone in chloroform provides a chloroform solution of the metal dithizonates, which is pipetted directly on to a carbon rod atomiser, where it is dried, ashed and atomised for analysis.For elements such as As, Bi, Pb, Sb, Se and Sn, which form gaseous hydrides, a sensitive analytical technique is available in which the hydrides formed by reduction in a reaction vessel are passed into a flame, a flame-heated or an electrically heated furnace tube where the atoms formed by thermal decomposition of the hydride are available for determination by AAS. The method is more sensitive than graphite furnace method+ for As and Se, for example, and has much greater freedom from matrix interference effects.Interference effects do, however, existlz and the interference of Cu and Ni in the determination of Se can be severe enough to require masking or prior separation in many samples of agricultural interest . For many years AAS has been the most popular method for trace element determinations, but recently it has come under challenge from atomic-emission spectrometry (AES) with the increasing realisation of the advantages of simultaneous multi-element analysis offered by the inductively coupled argon plasma (ICP) as an emission source. Superficially it resembles AAS in that it uses solution samples nebulised into a flame-like plasma. Complete com- mercial instruments, incorporating the source and multi-element direct-reading spectrometer, are available.The published detection limits are impressive and, like those for electro- thermal atomiser AAS, are in the nanograms per millilitre range. At the Macaulay Institute a 5-kW Radyne source has been coupled to a scanning monochromator and a large quartz spectrograph to investigate the properties of the system, to establish and identify the spectral lines produced and to quantify the interference effects. Most of the published detection limits are for single-analyte solutions and may not be achieved in the analysis of complex samples such as soil extracts. Generally the technique does, however, offer the possibility that some trace elements may be determinable directly in soil extracts or solutions of plant material without pre- concentration and a few successful applications to this type of sample are now being made.13 In comparing this multi-element method with some of the other multi-element spectro- chemical techniques already considered here, which use samples in solid form, it should be remembered that dissolution of a sample must introduce a dilution of the trace elementOctober, 1980 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS 413 concentration.It is instructive, therefore, to compare detection limits for both solution and solid sample techniques taking this factor into account (Table 11). It can be seen that, despite the excellent detection limits offered by furnace AAS and ICP AES in solution, when the not unrealistic dilution factor of 1000 (0.1% mfV) is taken into account, the superiority of these techniques over even classical d.c.arc spectrographic analysis is minimal, while with respect to SSMS they are inferior. It is important, therefore, in choosing an analytical technique that manufacturers’ detection limit data, based often on single analyte solutions, should be regarded critically and the use of solid sample multi-element methods adopted where appropriate. TABLE I1 COMPARISON OF DETECTION LIMITS FOR SOLID SAMPLES BY VARIOUS SPECTROCHEMICAL METHODS Flame atomic absorption (FAAS), flame atomic emission (FAES), graphite furnace atomic absorption (GFAAS) , inductively coupled plasma emission (ICP), d.c. arc optical-emission spectrography (OES) and spark-source mass spectrometry (SSMS).Average detection limits for elements of Period 4 of Periodic Table, viz., Na, Ca, Ti, V, Cr, Mn. Fe, Co, Ni, Cu, Zn, Ge, As (Na substituted for K and Sc; Se, Br omitted as data not available for all methods). FAAS FAES GFAAS ICP OES SSMS r \ Solution sampleslpg ml-l A r In solution . . . . 0.022 1.57 1.66 x 0.79 x - - Solid samples/pg g-l r 1 In solid, 1% m/V . . 2.2 157 0.17 0.08 4.0 0.1 In solid, 0.1% m/V . . 22 1570 1.7 0.8 4.0 0.1 Another type of plasma emission spectrometer available commercially in which the plasma is produced by an arc discharge in a stream of argon has been applied to the direct determina- tion of Al, Fe, Mn, Ni, V and Zn at concentrations of about 0.05 pg 1-1 in natural water.14 A technique which, with development, may have application in water analysis is that of atom-trapping AAS.l5 This uses a water-cooled silica tube in an air - acetylene flame to trap metal atoms, or their precursors in the flame, from solutions nebulised in the normal way.After a period of collection, the trapped metal is released into the flame by switching off the cooling water to the trap and determined by AAS. For elements such as Cu, Zn, Au, Pb and Cd this technique offers appreciable improvements in sensitivity. Lastly, in addition to the analysis of elemental forms of pollutant, work is in progress at the Macaulay Institute on the measurement of atmospheric sulphur dioxide by a remote- sensing technique using differential absorption with a laser source.16 This technique, known as LIDAR (light detection and ranging) is capable of detection limits for sulphur dioxide of about 10 parts per lo9 at ranges of a few kilometres and has applications to other gaseous pollutants such as the oxides of nitrogen.The author gratefully acknowledges the assistance of Dr. D. C. Bain, Department of Mineral Soils of the Macaulay Institute, with XRF analyses. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. References Freeman, R. A., and Everhart, W. H., Trans. Am. Fish. SOG., 1971, 4, 644. Alfrey, A. C., Le Gendre, G. R., and Kaehny, W. D., N . Engl. J . Med., 1976, 294, 184. Fay, C. D., Chaney, R. L., and White, M. C., Annu. Rev. Plant Physiol., 1978, 29, 511. Ure, A. M., and Bacon, J. R., Analyst, 1978, 103, 807. Berrow, M. L., and Webber, J., J . Sci. Food Agric., 1972, 23, 93.Robinson, H., and Robbins, H., Stanford Res. Inst. Rep., SRI 8507, 1971. Van Grieken, R. E.. Johansson, T. B., and Winchester, J. W.. J . Rech. Atmos., 1974, 8, 611. Duce, R. A.. Quinn, J. G., Olney, C. E., Piotrowicz, S. R., Ray, B. J., and Wade, T. L., Science, Lester, J. N., Sci. Total Environ., 1977, 8, 153. Stoveland, S., Sci. Total Environ., 1978, 9, 263. Brodie, K. G., Int. Lab., 1979, 8, 40. 1972, 176, 161.414 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. 12. 13. 14. 15. 16. Smith, A. E., Analyst, 1975, 100, 300. Dalquist, R. L., and Knoll, J. W., Appl. Spectrosc., 1978, 32, 1. Reednick, J., Am. Lab., March 1979, 53. Khalighie, J., Ure, A. M., and West, T. S., Anal. Chim. Acta, 1979, 107, 191. Morrisson, A. R., and Sharp, B. L., Proc.Anal. Div. Chem. Soc., 1979, 16, 23. Organochlorine Pesticide Pollution in Northern Ireland David 6. Harper Department of Agricultural and Food Chemistry, The Queen’s University of Belfast, and Department of Agri- culture ( N I ) , Newforge Lane, Belfast, Northern Ireland The major problem as regards pollution of the global environment by pesticides has been caused by the organochlorine (OC) pesticides, e.g., DDT [ l ,l-bis(p-chloropheny1)-2,2,2- trichloroethane] , HCH (hexachlorocyclohexane) and the chlorinated cyclodienes such as dieldrin. These compounds are heavily chlorinated and highly lipid soluble and hence are not readily attacked by bacteria or leached from the soil. Such characteristics render them exceptionally persistent in the environment. Moreover, partioning between aqueous and lipid phases in successive organisms leads to concentration of the compounds as they move up the food chain.This phenomenon was responsible for the disastrous effects observed on certain species of wildlife in the 1960s and represented a potential threat to man through contamination of his food. In response to public concern severe restrictions were placed on the use of many OC insecticides and maximum residue limits were introduced for many foods by certain countries, particularly the USA. Consequently, a gradual fall in residue levels has been observed in many Western countries in recent years. In Northern Ireland the Department of Agriculture has monitored OC residues in both animal products and the environment since 1972 and a summary of the results is given below.Meat The mean levels of OC residues in various classes of meat in 1978 are compared with those in 1972 in Table I. Both DDT and dieldrin concentrations have declined over the years to barely detectable levels. Dieldrin, which was widely used in sheep dip prior to 1969, has fallen particularly sharply. However, residues of HCH, the only OC insecticide that has not been severely restricted in usage, not only show little evidence of decline in pig and sheep meat but have actually increased in cattle meat 7-fold since 1972. HCH residues in meat are mainly in the form of the non-insecticidal cc-isomer, a possible source of which is suggested below. TABLE I MEAN PESTICIDE LEVELS I N MEAT I N NORTHERN IRELAND-1972 AND 1978 Concentration, p.p.m.on a fat basis 7+ & & Meat 1972 1978 1972 1978 1972 1978 Cattle. . . . 0.049 0.383 0.033 0.008 0.097 0.001 Sheep. . . . 0.317 0.141 0.138 0.004 0.020 0.002 Pig . . . . 0.048 0.041 0.028 0.002 0.095 0.010 r h \ Total HCH Dieldrin DDT Dairy Products Examination of OC residues in butter from a number of creameries in Northern Ireland over an extended period revealed pronounced seasonal fluctuations in the concentration of HCH residues, although little consistent change was noted in other OC residues (Fig. 1 ) . l Unusually high HCH concentrations occurred in January and early February and anotherOctober, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 415 smaller time of present at the Oct. Dec. Feb. Apr. Jun. Aug. Oct. Dec. Feb.Apr. Jun. Nov. Jan. Mar. May Jul. Sept. Nov. Jan. Mar. May -4 .- 1973 1974 1975 Date of butter manufacture Fig. 1. Seasonal variations in the organochlorine pesticide residue content of butter from a creamery in County Tyrone: A, total concentration of HCH isomers; and B, total DDT concentra- tion. A number of factors could be responsible for the elevated HCH levels found. Contamina- tion at the creamery during processing by careless use of insecticide was excluded by the observation that butter produced in a creamery possessed similar levels of HCH on a fat basis to milk arriving at the creamery. Also, the predominance of the a-isomer mitigated against casual contamination, as only lindane (HCH with an y-isomer content of 299%) is used for insecticidal purposes in such situations.High HCH levels in winter feed for dairy cattle could be responsible for the seasonal increase in HCH concentrations in dairy products, but analysis of typical winter feedstuffs gave no indication of elevated HCH residues. Another factor that might lead to the appearance of HCH residues in milk fat is the external treatment of dairy cattle with HCH-based veterinary preparations, which could be ingested or absorbed through the skin. The use of such insecticides is common for the control of lice, mange and other ectoparasites. Lice do not usually become apparent on animals until they have been housed indoors for about 2 months. As cattle are usually housed in mid-October in Northern Ireland, treatment for infection would probably begin in mid-December.This period coincides with the rapid rise in HCH levels in butter. A t the time of the survey there was no restriction on the isomeric composition of HCH for veterinary use in the UK, so the possibility that technical HCH, i.e., HCH containing a large proportion of or-HCH, was being marketed for veterinary use was investigated. Analysis of the two leading brands of louse powder sold in Ulster demonstrated that one of the products was indeed technical HCH. Of a total HCH content in the preparation of 5.24y0, only 0.81% was y-HCH, the remainder consisting of a- and other isomers of HCH. The seasonal province-wide contamination of dairy products in late winter by a-HCH can be attributed entirely to the marketing of this product. The secondary peak in the April-May period is probably due to the release of HCH residues stored in the body fat in the late winter months during the weeks following the spring calving when utilisation of fat reserves is high.The elevated levels of HCH in meat noted above can similarly be ascribed to the use of louse powder. The products involved have now been withdrawn from the market.416 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. Surface Waters It has been customary to attribute the occurrence of OC residues in surface waters in the UK as a whole primarily to the agricultural and industrial use of such compounds. However, a recent survey2 of OC residue levels in waters of the major rivers discharging into Lough Neagh indicate that in Northern Ireland they may well have a different origin.The only OC residues detected in all river water samples were the a- and y-isomers of HCH: other OC compounds occurred in only 10% of the samples and at very low concentrations. Surprisingly, total HCH concentrations, which ranged from 16 to 41 ng l-l, displayed a very high correla- tion ( I = 0.99,p < 0.001) with urban population density in the catchment area of the river. In an attempt to determine the basis for this unexpected relationship, input and effluent from four sewage disposal works in Northern Ireland were sampled at times of peak flow. As the input to such works contains industrial efluent the concentration of the HCH from solely domestic sources was determined by monitoring the loading of HCH in sewage from a housing estate.The results of this investigation are shown in Table 11, where it can be seen that HCH concentrations in the effluents from sewage works were of a similar order to those recorded elsewhere in the UK where y-HCH concentrations of 18-200ng1-1 have been ob~erved.~ Domestic sewage from the housing estate contained HCH in concentrations comparable to those in the input into the sewage works, implying that domestic sewage could account for most of the HCH entering the works and hence the HCH content of effluent, as little HCH is removed by conventional sewage treatment processes. TABLE I1 MEAN HCH RESIDUES IN TREATED AND UNTREATED SEWAGE EFFLUENT AND I N THE DOMESTIC WATER SUPPLY Residuelng 1-1 Sample Domestic water supply . . .. . . Mean Domestic sewage from housing estate .. Input to sewage disposal works .. Mean Effluent from sewage disposal works . . Mean Mean* Range Range Range * Adjusted for changes in flow-rate. a-HCH 3 17 4-35 20 10-27 22 17-30 Y-HCH 2 130 30-320 144 81 96-240 62-103 Total HCH 5 147 34-339 164 112-267 103 82-120 The HCH loading of domestic sewage per capita was calculated as 48 pgd-l. Total dietary intake of HCH calculated from data on the HCH content of foodstuffs in Northern Ireland is 15 pg d-l per person, which is higher than the calculated UK figure of 10 pg d-1.4 The difference can largely be explained in terms of the higher levels of HCH in dairy products and is confirmed by a limited study of OC residues in human fat2 in Northern Ireland shown in Table 111. Despite the higher per capita intake, even assuming all HCH ingested is excreted, human excretion cannot account for more than 30% of the observed HCH loading in sewage.This suggests that most HCH in sewage effluent is derived not from HCH in the diet but other sources in the home. TABLE I11 ORGANOCHLORINE RESIDUES IN HUMAN FAT Mean residues in fat, p.p.m. r > h Location Hexachlorobenzene Total HCH Dieldrin Total DDT N. Ireland, 1975 . . .. .. 0.15 0.45 0.10 1.94 United Kingd~m,~ 1969-71 . . 0.05 0.29 0.16 2.32 As about 60 tonnes of HCH are employed annually in the UK as a wood preservative and approximately a third of y-HCH sprayed on the surface of wood is lost by volatilisation6October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 417 within 2 months, a possible source of HCH residues in domestic sewage effluent is the use of wood preservatives.Less than 2% of HCH employed for this purpose per year would, on reaching the domestic sewage system, produce the concentrations observed. Fabrics used in the home for clothing, bedding and furnishing could adsorb HCH from the atmosphere and on washing would release the compound into the wash water. Support for this hypothesis is provided by the observation that HCH concentrations and total loading in domestic sewage rise to a maximum value between 12.00 and 14.00 h, the most likely time for release of washing water into the sewage system. It is significant that the time of peak HCH loading cannot be correlated with either BOD maxima or urea/creatinine maxima, and hence is unlikely to be related to human excretion patterns.I t is concluded that the bulk of low level OC pollution in surface waters in Northern Ireland arises from the domestic use of HCH rather than from agriculture or industry. References 1. 2. 3. 4. 5. 6. Harper, D. B., and McAnally, R. J., Pestic. Sci., 1977, 8, 35. Harper, D. B., Smith, R. V., and Gotto, D. M., Environ. Pollut., 1977, 12, 223. Lowden, G. F., Saunders, C. L., and Edwards, K. W., Water Treat. Exam., 1969, 18, 275. Department of Trade and Industry, “Report of the Government Chemist 1972,” HM Stationery Abbott, D. C., Collins, G. B., and Goulding, R., Br. Med. J . , 1972, 2, 553. Department of the Environment, “The Non-agricultural Uses of Pesticides in Great Britain,” HM Office, London, 1974. Stationery Office, London, 1974.Organometallic Compounds in Relation to Pollution Frank Glockling Chemistry Department, The Queen’s University of Belfast, Belfast, B T 9 5AG, Northern Ireland Organometallic chemistry is concerned with compounds in which one or more carbon atoms are directly bonded to a metal: by 1830 both main group metals and certain transition metals were known to bond to carbon. In the succeeding 150 years many thousands of compounds have been prepared and studied and, not surprisingly, a few of these have found extensive and important applications. Like all synthetic chemicals that are widely used in industry or agriculture, these constitute possible sources of pollution either as the parent compounds or as degradation reaction products derived from them, and one of the important questions that needs to be answered in relation to any application is: what is the fate of the compound in the environment? If it is degraded to non-toxic end products then what is its half-life and what are the half-lives of any intermediates? In this paper I shall refer to four types of organometallic compounds: organosilanes, organolead compounds, organomercurials and organotin compounds.One important point in relation to the biological activity, particularly toxicity, of organometallic compounds is the high degree of specificity shown by the metal and other ligands bonded to it. For example, methyl and phenyl groups bonded to silicon, as in silicone polymers, and areamong the most biologically inert materials, so much so that they are used extensively in medicine, for example as replacement heart valves, and for impregnating wound dressings because of their water-repellant properties.However, if the groups bonded to silicon are changed to those in structure I, derived from triethanolamine, the compound is an extremely effective rat p0ison.l Although the group IV elements silicon, germanium and tin are similar in their chemical properties, the germanium analogue of I has a very low mammalian toxicity, whereas the corresponding tin compound also has a low mammalian toxicity but is a reasonably effective fungicide and insecticide. Organolead compounds, mainly tetramethyl and tetraethyl, have long been used to improve the antiknock properties of fuel for internal combustion engines; in 1964 it was estimated that about 250000 tons were used in this way in the USA.These lead alkyls are more toxic than inorganic lead and, by virtue of their high volatility and lipid solubility, pose a health hazard to those coming into close contact with them. The problem does not end there because, with the addition of ethylene dibromide, lead alkyls are burned in the cylinders of418 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. \ / OCH2CH2 ( 1 ) internal combustion engines and a proportion of the lead is emitted from the tail of an exhaust system as fine particulate lead, lead oxide and lead bromide. The danger comes from the inhalation of low doses over a long period, as the excretion rate is low. There seems at present to be no agreement on the extent to which this represents a health hazard, but perhaps the point to make here is that minimising or even eliminating any possible risk is entirely in the hands of governmental legislators who have to balance possible health benefits against economic penalties.In the UK lower limits are now in force on the use of lead alkyls as a petroleum additive, and in the USA a complete ban is in operation. A very interesting recent observation is that inorganic lead compounds undergo methylation to tetramethyllead by organisms present in fresh-water lakes2 TABLE I DISTRIBUTION OF TOTAL MERCURI’ I N RED (OX BLOOD) CELLS Mercury present : 400 p g per 2 ml of blood cells. Location Hg(Me)OAc, % Hg(CH,SiMe,)OAc, % Supernatant isotonic saline .. 2.1, 2.3 3.2, 1.8 Cell walls . .. . . . . . 0.2, 0.3 1.0, 2.5 Cell sap . . . . .. .. 96.0, 92.6 99.7, 97.1 Organomercurials have found extensive use in industry and agriculture ; many applica- tions stem from their potency and broad spectrum effectiveness as fungicides. All soluble mercury compounds are toxic but monomethyl mercurials, which were responsible for the so-called Minamata disease in Japan, are exceptional in that they rapidly produce irreversible brain damage in animals. Demethylation and excretion from the animal body are slow. We have made a study of the chemistry of various trimethylsilylmethylmercury compounds3 such as Me3SiCH2HgC1, (Me,Si),CHHgCl and (Me3Si) ,CHgCl and find that their chemical reactivity is very similar to highly toxic methylmercurials; this led us to investigate their fungicidal and toxicological behaviour.Although, like methylmercurials, Me,SiCH,HgX compounds rapidly enter red blood cells (Table I), their mammalian toxicity is low (similar to that of inorganic mercury using rats as test animals), even though they are not extensively dealkylated in the animal body. TABLE I1 FAECAL EXCRETION OF MERCURY BY RATS These effects are illustrated in Tables I1 and 111. After a single dose of 3.36 mg of Hg per kg of body mass given either as MeHgOAc or Me,SiCH,HgOAc (intraperitoneally or by gastric lavage). One sample was collected from two animals per day. Excretion as yo of the dose (mean f S.E.M.) A NO. of r > Compound Administration rats 1st day 2nd day 1st and 2nd days Hg(Me)OAc .. . . 1.p. 3 0.60 & 0.15 2.0 f 0.58 2.67 f 0.49 Hg(Me)OAc .. . . Intragastric 4 2.43 f 0.29* 2.78 f 0.11 5.21 f 0.32* Hg(CH,SiMe,)OAc . . 1.p. 3 2.29 f 1.02 12.46 & 2.107 14.37 2.577 * Significantly different (two-tailed Student t-test) from the i.p. group, p < 0.05. 7 Significantly different (two-tailed Student t-test) from the MeHgOAc group with the same route of administration, p < 0.05. In contrast to its low mammalian toxicity, the activity of Me,SiCH,HgX compounds towards two plant pathogens Fusarium culmorum and Fusarium nivale and towards theOctober, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS TABLE I11 419 ORGAN CONCENTRATION AND EXCRETION OF MERCURY FROM RATS After nine daily doses (with 2 days’ interval between the fifth and sixth doses) of MeHgOAc or Me,SiMeHgOAc. Both compounds were given by gastric lavage in a dose of 3.36 mg of Hg per kg of body mass.The numbers in parentheses give the proportion of mercury attached to carbon as a percentage of the total mercury. Hg per gram of tissuefpg A t 7 Organ MeHg treatment Me,SiCH,Hg treatment Brain . . .. .. 12.8 (95.6) 2.9 (87.2) 10.2 (95.0) 2.8 (90.4) Blood .. .. .. 157 (96.8) 128 (93.8) 135 (95.5) 133 (95.5) Kidneys . . .. 86.7 (72.9) 26.0 (90.4) 104.0 (78.5) 40.5 (88.9) Liver . . .. .. 35.6 (99.2) 20.1 (98.5) 32.0 (99.4) 18.0 (98.9) Hg per 100 g of body masslpg h \ 24-h urine . . .. 32.3 (88.9) 19.9 (71.3) 24-h faeces . . .. 43.3 (28.1) 85.5 (81.5) saprophyte Gliocladium roseum was high and some degree of selectivity towards the plant pathogens was indicated. In these studies (by Dr.J. Malone) the organisms were incorpora- ted into an agar medium and the mercurial solution placed in a well in the centre of a Petri dish (85 mm diameter). The diameter of the zones of inhibition, measured after a period of incubation, are given in Table IV using HgC1, for comparison. These results suggest that inhibition is due mainly to effects in the vapour phase, and in further experiments the mercurial solutions were placed in watch-glasses on the surface of the seeded plates. The inhibition zone then occurred at the outer edge of the Petri dish progressing inwards and the mean diameter of the colonies are given in Table V. TABLE IV INHIBITION OF FUNGAL GROWTH Diameter of inhibition zonelmm A r \ Compound Fusarium culmorum Fusarium nivale Gliocladium roseum HgCl, (18.4 mmol 1-l) .. .. . . 69 70 15 MeHgOAc (15.0 mmol 1-l) . . . . Complete Complete Complete MeHgOAc (1.5 mmol 1-l) . . .. 83 Complete MeHgOAc (0.15 mmol l-l) , . .. 57 62 Me,SiCH,HgOAc (15 mmol 1-l) . . Complete Complete Complete Me,SiCH,HgOAc (1.5 mmol 1-l) . . Complete Complete Control . . .. .. .. .. 0 0 0 Me,SiCH,HgOAc (0.15 mmol 1-l) . . 16 43 TABLE V INHIBITION OF FUNGAL GROWTH Diameter of colony f A \ Compound Fusarium culmorum Fusarium nivale HgC1, (18.4 mmol l-l) . . .. . . 85 (max.) 85 (max.) MeHgOAc (0.15 mmoll-l) . . .. 72 78 Me,SiCH,HgOAc (0.15 mmol 1-l) . . 16 85 (max.) properties of an organomercurial and minimise the mammalian toxicity. MeHgOAc (1.5 mmol 1-l) . . . . 57 55 Me,SiCH,HgOAc (1.5 mmol l-1) . . 0 0 Thus, by introducing chemical changes it appears possible to retain the desirable biological This may be420 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal.Proc. academically interesting but the over-riding consideration in favour of minimising or banning the use of all organomercury compounds, especially in agriculture, is the prevalence of biological methylation of mercury metal and its inorganic compounds to the highly volatile dimethylmercury. This biomethylation reactions occurs in marine and fresh waters and in soils ; it therefore provides a mechanism whereby mercury, once introduced into the environ- ment, may become even more widely distributed. From sea waters methylmercury com- pounds are often concentrated in edible fish and shell fish, and many of the cases of methyl- mercury intoxication in humans have been traced to these sources.As a final illustration of organometallic pollutants I shall discuss some aspects of organotin compounds. These find extensive and wide-ranging applications, mostly because of their fungicidal and molluscicidal activity and as PVC stabilisers. The compounds most used are of the type R,SnX and R,SnX, [such as (Bu,Sn),O and Ph,SnO]. The main applications are as timber preservatives, fungicides (e.g., for potato blight), insecticides, PVC stabilisers, anti-fouling additives to marine paints andanthelmintics ( e g . for tapeworm, roundworm, flukes), and of these the agricultural and marine uses result in a wide distribution, as does their incorporation into PVC in order to improve its photochemical stability.Hence the extreme importance of establishing the toxicity and environmental degradation products of com- mercially used organotin compounds is clear. Their toxicity is a function of the number and structure of the organic groups bonded to tin, the trimethyl and triethyl compounds being the most toxic (Table VI). For those who are over-complacent about toxic effects, it TABLE VI INFLUENCE OF ORGANIC GROUPS ON TOXICITY OF ORGANOTIN COMPOUNDS Compound LD,,*/mg kg-1 Me,SnOAc . . .. .. .. 9 Et,SnOAc . . .. . . .. 4 Bu,SnOAc . . .. .. .. 380 (C,H,,),SnOH . . .. .. 540 * LD,, = lethal dose t o kill 50% of test animals (rats). might be as well to recall that in France the drug Stalinol, introduced in 1954, contained among other things a mixture of ethyltin compounds that was taken orally for the treatment of a variety of conditions including acne, and it has been estimated that about 100 deaths resulted There from its use.4 TABLE VII ANTIFUNGAL ACTIVITY OF SOME TRIORGANOTIN ACETATES Minimum concentration causing complete inhibition of growth of the fungilmg 1-1 ‘Botrytis Penicillium A spergillus Rhizopus’ R in R,SnOAc allii italicurn ?tiger nigricans Me .... .. 200 500 200 500 Et .. .. . . 1 10 2 2 Bu .. .. . . 0.5 0.5 1 1 C6H13 . .. >500 > 500 > 500 500 Cyclo-C6Hll .. 20 20 50 20 are various factors that favour the use of organotin compounds over organo- mercurials, for example. One is that those compounds w:th a low mimmalian toxicity are often the most effective fungicides. To return to one of the earlier points: it is not just the biological activity of a particular organotin compound and its half-life that are important in relation to environmental effects, but also those of all intermediates, through to non-toxic inorganic tin as the final degradation product, that need to be considered.These problems inevitably come down to highly refined analytical chemistry where starting with, say, a low concentration of a triorganotin compound one would like to This is illustrated in Table VII.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 42 1 be able to follow the degradation via various intermediates through to inorganic tin, remembering that the toxicity of intermediates might be even higher than that of the original compound.It is a formidable problem, and one which we5 and others6 have been studying. Alkyltin halides can be separated by gas - liquid chromatographic techniques, although there are limitations to the method because various species interconvert at elevated temperature. What we have done is apply high-performance liquid chromatography to the separation of mixtures of the lower alkyltin halides; using high concentrations and a standard detector we have established that effective separations are possible, provided that the flow-rates are suitably adjusted (Fig. l), but at the concentrations in which one is really interested normal 2 I 0 2 T ime/m in 1 0 Fig. 1. MeSnC1,. HPLC : variation of flow-rates for : A, Me,Sn ; B, Me,SnCl ; C, Me,SnCl, ; and D, Flow-rates: (a), 2.0; ( b ) , 1.0; (c) 1.8; and ( d ) 0.8 cm3 min-1.detectors are ineffective and we have made use of an atomic-absorption spectrometer as a sensitive detector. By introducing a hydride reduction stage into the operation, thereby giving the highly volatile organotin hydrides, detection limits are markedly improved. I I I I (b) B C D L A 3 2 1 0 3 2 1 0 Ti me/m in Fig. 2. (a) HPLC for: A, Me,Sn; B, Me,SnCI; C, Me,SnCl,; and D, MeSnC1,. Column: Spherisorb S5 ODs, 250 x 30 mm. Temperature: 23 "C. Mobile phase: acetone - pentane (3 + 2). Flow-rate: 1.0 cm3 min-l. Detector: R1 x 4. (b) HPLC for: A, Et,Sn; B, Et3SnC1; C, Et,SnCl,; and D, EtSnC1,. Mobile phase: acetone - pentane (7 + 3). Flow-rate: 1.2 cm3 min-l. Detector: R1 x 4.422 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Anal.Proc. Thus the principle of the system becomes as follows: Mixture of alkyltin halides I j, I 1 mixed solvents HPLC separation NaBH, L Volatile alkyltin hydrides Electrothermal atomic absorption detector 4 Illustrations of the detector response are shown in Fig. 2 and the detection limits, which are better than 1 ng, in Fig. 3. This method, in its present form, failed for mixtures of butyl- G F 4 D B A tJ Y Fig. 3. Methyl- and ethyltin compounds: separation by HPLC, hydride reduction, and determination by electrothermal atomic absorption. Methyltin compounds: A, Me,%, 10 ng; B, Me,SnCl, 10 ng; and C, Me,SnCl,, 10 ng. Ethyltin compounds: D, Et,Sn, 24 ng; E, Et,SnCl, 24 ng; F, Et,SnCl,, 16 ng; and G, EtSnCI,, 10 ng. or phenyltin halides, owing to the lower volatility of the resulting hydrides, but suitably adapted this is probably a useful general method,' and development work aimed at studying genuine environmental problems is in progress.References 1. 2. 3. 4. 5. 6. 7. Voronkow, M. G., Topics Curr. Chem., 1979, 84, 77. Huber, F., and Schmidt, U., "Proceedings of the 2nd International Conference on Organometallic Glockling, F., Hosmane, N. S., King, T. J., Mahale, V. B., Magos, L., and Swindall, W. J., J . Chem. Stoner, H. B., Barnes, J . M., and Duff, J . T., BY. J . Pharmacol., 1955, 10, 16. Harriott, M., M S c Thesis, Queen's University, Belfast, 1979. Braman, R. S., and Tompkins, M. A,, Anal. Chem., 1979, 51, 12, and references cited therein. Hodge, V. F., Seidel, S. L., and Goldberg, E. D., Anal.Chem., 1979, 51, 1256. and Coordination Chemistry of Germanium, Tin and Lead," 1977, p. 7. Res., 1977, (S)116, (M)1201.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 423 Control of Environmental Pollution by Catalytic Oxidation A. Cuthbertson and E. Robinson Lambeg Industrial Research Association, Lambeg, Lisbztm, Northern Ireland Increasingly throughout the world, social and legislative pressure is being brought to bear on many industries to reduce the discharge of polluting substances to both air and water. Many of these pollutants can be destroyed by oxidation to form carbon dioxide and water, and this reaction forms the basis of many processes for pollution control, such as combustion for treatment of odorous and toxic emissions to the atmosphere, and aerobic biological treatment of industrial wastewater.The use of heterogeneous catalysts in such oxidation reactions has been employed previ- ously in the treatment of air pollution problems, but the successful use of catalytic oxidation for water pollution control is a new concept. Precious metal catalysts have been used for the treatment of industrial gaseous emissions, including odours and toxic gases, at much lower temperatures than are required for thermal combustion. However, the use of these catalysts has been accompanied by several problems, notably their sensitivity to poisons, and while the cost benefit in comparison to thermal combustion is great, the temperatures required for oxidation are still such that, with increasing costs, the technique is becoming more and more unattractive.A new, robust, base-metal catalyst is now available that catalyses the combustion or oxidation of pollutants at lower temperatures than have been used previously, specifically in the range of 150-350 "C. In addition, it has been found possible to use this type of catalyst in aqueous-phase oxidations at ambient temperature, allowing the successful treatment of many industrial wastewater problems, which have not responded well in the past to biological oxidation. Catalytic Oxidation for Air Pollution Control The presence of malodorous and toxic compounds in the gaseous effluents from many important industries contributes significantly to air pollution throughout the world and constitutes a major social problem. Most people encounter briefly the smells from animal rendering, fish meal production, intensive farming, etc., but those who must live and work within the influence of such industries understandably press for remedial action.This need for effective air pollution control can be met by the LIRA manganese-based catalyst, which requires much less energy than thermal incineration, while its performance parallels those of precious metal catalysts, which require significantly higher catalyst bed temperatures for equivalent oxidation efficiencies. Catalyst performance is dependent primarily on temperature and, to a lesser extent, space velocity (the ratio of volume of gas treated per unit time to catalyst volume), reactant concentration, catalyst form and bed configuration.The conditions necessary for the treatment of industrial emissions are illustrated in the following examples of the use of this catalyst. Animal rendering. The level of odour reduction obtained in an animal rendering plant employing a semi-continuous process and expellers for tallow separation was greater than 99% at a catalyst bed temperature of 250 "C. The polluted air treated was drawn from the expeller area of the plant where the worst odour arises. Odour was measured using the ASTM syringe dilution method (ASTM D 1391-57). The wire enamelling industry emits mainly heavier organic compounds including phenol, cresols, cresylic acid, benzene, toluene and xylene. The reductions in concentration of phenol/cresol, xylene, benzene and carbon monoxide using this catalyst were 91, 98, 100 and 95%, respectively. The temperature of the emission from enamelling ovens is generally above 300 "C and additional heating is not required.A catalytic oxidation system without a heat exchanger has been installed in a fish-meal factory, and a gas hourly space velocity of 15000 h-l was selected. Sufficient flexibility was built into the burner unit to examine the effect of temperature Wire enamelling. Fish meal manufacture.424 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. variation of the catalyst and odour measurements were made over a 4-month period. Average odour reductions of 91% at 250 "C, 87% at 275 "C and 92% at 300 "C were obtained. The emission consists of trimethylamine, ammonia and other malodorous compounds released by the degradation and breakdown of protein. The gas hourly space velocity, selected after field trials, was 30000 h-l. The efficiency of the system, tested after installation and again after 9 months' operation, showed that the catalyst was providing 96-98y0 odour reduction. These results show that this catalyst is effective in the oxidation of common air pollutants and provides a solution to many serious problems.It can be seen that the temperatures employed are much lower than those required by other catalytic systems which generally operate in the range 350450 "C. In the light of current concern over the cost and availa- bility of all forms of energy, the savings possible are important. Maggot breeding. Catalytic Oxidation for Water Pollution Control For many purposes conventional wastewater treatment is adequate except, for example, where the waste contains toxic or refractory organics. Wastewater from industrial processes is therefore likely to be less amenable to conventional treatment than is municipal waste- water because it often contains substances that resist biological degradation.An example is the liquors resulting from the dyeing of textiles, which frequently pass through biological treatment unchanged. Catalytic oxidation, the physico-chemical equivalent of aerobic biological treatment, is, however, effective in the purification of such effluents. In addition, the process does not have the disadvantages that can attend biological treatment such as sensitivity to pH, temperature, shock load, toxic and refractory compounds, the requirement for dilution and period sludge disposal and the need for large areas of land.In the process, wastewater is contacted with catalyst, oxygen and an initiator, such as sodium hypochlorite. While a number of alternative means of undertaking the process exist, a typical plant has the wastewater mixing with sodium hypochlorite as it enters the treatment vessel and the pH is adjusted as necessary. Air, introduced as fine bubbles, holds the catalyst in suspension and provides oxygen for the oxidation. The capacity of the vessel is such as to retain the wastewater for a period of 2 h before discharge. Removal of catalyst from the discharged liquor may be accomplished by various means, but typically it is allowed to settle in a settlement cone and returned to the system.The effectiveness of the process for the treatment of industrial effluent is illustrated in the following examples. Nylon hosiery dyeing. The treatment of dyehouse effluent that contained acid and disperse dyes together with organic auxiliaries necessary for dyeing was undertaken using the following conditions: catalyst loading, 10 g 1-l; initiator dosing, 0.08 g of sodium hypochlorite per litre of effluent ; pH adjustment using 0.15 g of concentrated sulphuric acid per litre of effluent; and a retention time of 2 h. The COD and colour reductions obtained were 67% and 99%, respectively. Effluent from the scouring of woollen yarns in hank form was treated using the following conditions: catalyst loading, 10 g 1-l; initiator dosing, 0.065 g of sodium hypochlorite per litre of effluent; pH adjustment using 0.124 g of con- centrated sulphuric acid per litre of effluent; and a retention time of 1 h.A COD reduction of 92% was obtained. The treatment of exhausted dye liquors from subsequent dyeing of these yarns was accomplished using the following slightly different conditions : catalyst loading, 10 g 1-l; initiator dosing, 0.03 g of sodium hypochlorite per litre of effluent; pH adjustment using 0.1 g of concentrated sulphuric acid per litre of effluent; and a retention time of 2 h. Typical results were a colour reduction of 85% and a COD reduction of 61%. A COD reduction of 91% was obtained when the effluent discharge from a chicken processing plant was treated under the following conditions : catalyst loading, 10 g 1-l; initiator dosing, 0.04 g of sodium hypochlorite per litre of effluent; pH adjustment using 0.06 g of concentrated sulphuric acid per litre of effluent; and a retention time of 2 h.The range of application of this process in the treatment of waste dye liquors has been examined by treatment of selected dyes from those classes of dye commonly used. Table I shows the colour reduction achieved. Carpet yarn scouring and dyeing. Chicken processing.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS TABLE I DYE OXIDATIOK 425 NaOCl added/ Dye g 1-1 Acid . . . . 0.065 Basic . . . . 0.008 Direct . . .. 0.016 Disperse . . .. 0.016 Vat .. .. 0.03 Sulphur .. .. 0.002 Catalyst loading/ 5 5 5 5 5 5 g 1-1 Colour reduction, yo 88.5 100 99 77 66 89 Thus catalytic oxidation as a pollution control technique is seen to be a means of dealing with many serious problems both effectively and economically. Some Aspects of Water Pollution Control in Coastal and Estuarial Regions of Northern Ireland J.D. Cooke Water Quality Branch, Industrial Science Division, Department of Commerce, 5-1 1 Verner Street, Belfast, Northern Ireland As the capital and maintenance costs of conventional biological sewage treatment are rapidly increasing, one of the most economical methods of sewage disposal is by direct discharge to the sea. Theoretically the sea has an enormous capacity to deal safely and effectively with domestic and industrial waste, provided that appropriate controls are employed. As discharges normally take place to inshore waters, effective effluent dispersion depends on the existence of suitable currents in the proposed discharge area.In an open coastline the main tidal current is symmetrical, flowing parallel to the shoreline for about 6 h in each direction throughout the tidal cycle. Closer inshore, the main tidal flow is influenced by the general shape of the coastline and unfavourable eddy currents may be induced. Indeed individual indentations and promontories can create secondary eddies that may further complicate the siting of outfalls. However, at some locations these local eddies and distortions can create suitable conditions. Many proposed outfall locations provide adequate dilution of wastes within the immediate outfall zone to prevent, or control within acceptable limits, potential ecological damage.Alternatively, it is often the protection of the amenity value of the region that gives most cause for concern. In either instance a knowledge of the pattern of inshore water movement is of fundamental importance. Such information may be obtained by following the paths of drogue floats. The following examples of these water movements illustrate how the local tidal current patterns can differ at separate locations within the same coastal region (see Fig. 1 ) . 0 2 Miles - 1 I -..:.-- w Portrush I I I I County Antrim Fig. 1. Coastal region in County Antrim, Northern Ireland.426 POLLUTANTS I N THE TROPOSPHERE AND NATURAL WATERS Aiaal. Proc. Portrush Portrush is a popular holiday resort on the North Antrim coast where the existing sewage outfall was the cause of considerable complaint.Water movement studies revealed a complex pattern where strong currents flowing between Ramore Head and The Skerries induced eddy currents on both sides of the penninsula, which rotated clockwise during the east-going stream and anti-clockwise during the west-going stream (see Figs. 2 and 3). The Skerries Fig. 2. Water movements near Portrush during Fig. 3. Water movements near Portrush during the east-going tidal stream. the west-going tidal stream. It was discovered that, adjacent to the western face of the penninsula towards its northern extremity, seaward flowing currents existed for a large proportion of the tidal cycle. To examine this in detail, several tidal stream indicators were anchored close to the rocks in this region.These devices showed that near the end of the penninsula the tide flowed in a sea- ward direction for more than 10 h in one tidal cycle (see Fig. 4). A new discharge site in this region was recommended. Bally castle A short distance eastwards from Portrush near the town of Ballycastle, a completely different current pattern was recorded. The investigation was undertaken to establish the most suitable location for a proposed discharge of domestic sewage. The float-track data, divided into hourly periods of movement, indicated an inequality in the duration of the inshore eddy currents induced by the main tidal streams. Fig. 5 shows the onset of reversal in the direction of the inshore current. Near the western extremity of the survey area a t Castle Point, the tide just begins to flow north-westwards even though at Pans Rock and Colliery Point the tidal flow maintains an east-north-eastwards direction away from the town, and it was recorded that this favourable current direction persisted for more than 9 h in a tidal cycle.Current velocities near Pans Rock and Colliery Point were examined using a direct-reading current meter and average velocities a t the two sites were found to be similar during spring tides. During the weaker neap tides, the velocity a t Pans Rock never exceeded 0.35 m s-l (Fig. 6) while a t Colliery Point (Fig. 7 ) the maximum surface velocity was nearly twice this value (0.60 m s-l). Consequently, Colliery Point was recommended as a suitable discharge site.Fig. 7 also illustrates the inequality of the duration of the inshore tidal streams in the area. The arrows at the top of the diagram indicate the current direction and show that the flow was generally easterly from 0800 to 1730 BST. ' When studying the feasibility of a discharge to an estuary, the situation must be assessed very carefully. I t is a very common, but usually erroneous, belief that pollution can be minimised by retention of the effluent for about 6 h to discharge only during ebb tides. In an estuary the oscillatory motion of the tide creates an accumulation of pollutants as the effluent plumes more or less fold back and forth upon themselves with each successive tide.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS c 'v) E > 0.4 + .- + 5 L 3 0.3 0.2 0 o.l 427 N Surface Pan's Rock neap tide, 8.5.76 Current direction - f / I \-7 - \ \-- -- -' - f i - , / 7 - H '- I!!?-- '\ \---\------\ \ \ / / / - / / / .I / h b 7 , 7 \ ,f-.-,,,- r - Surface J 6 m \ / _ _ _ _ _ v Ballycastle Fig. 5. Onzet of reversal in direction of the inshore tidal current a t Ballycastle. Fig. 4. Inshore current direc- tions south of Ramore Head during one tidal cycle.428 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Anal. Proc. vertical salinity profile of a salt wedge estuary contains a characteristic plateau region called a halocline. Wastes discharged to the surface layer of a salt wedge estuary are quickly flushed from the system in the net seaward flowing surface water. As the ratio of river flow to tidal flow decreases, turbulence at the interface of salt and fresh water destroys the sharp halocline boundary and salt water becomes entrained into the upper layer.As this is essentially a one-way process, the salinity of the upper layer increases while the salinity of the lower layer maintains the value associated with sea water. Flushing of wastes from highly stratified estuaries is similar to the salt wedge estuary. When the river flow is less than the tidal flow the increased turbulence promotes further mixing and entrain- ment and a correspondingly larger flow in each direction. Such conditions can seriously retard the flushing of wastes because, although pollutants discharged to the surface layer will initially be carried seawards, they will, in part, subsequently be transferred to the lower layer where the net movement is directed landwards.Seawards of the point of discharge the con- centration of pollutant will be greater in the upper layer than in the lower layer but landwards of the discharge position the converse will be true. c I * 0.6 E > .? 0.5 0 0, c \ - > 0.4 0.3 w 0 0.2 0.1 I I 8 I I I I I I I 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 B.S.T. Fig. 7. neap tide. Current speeds and directions recorded a t Colliery Point during a Finally, when the tidal flow is much greater than the river flow, the freshwater and seawater become completely mixed and pollutants are slowly flushed from the estuary in the net seaward flow. Freshwater Salt wedge + + - - - p t l y stratified c i \ \ R < T - i t - i -ically mixed I R < < T _____ Salinity Velocity -Seawards Bottom 2 A 0 s zone 0 s Entrainment 0 e Mixingand n t ra i n rn e n t __- T T zone 12 0 s n vertical ~ mixing Fig.8. Idealised steady-state flow diagrams for four estuary types. R = River flow ; T = tidal flow.October, 1980 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS 429 In the investigations carried out by the Water Quality Branch in the Foyle estuary it has been shown that the estuary can behave either as a vertically mixed or as a stratified estuary, depending on the ratio of river flow to tidal flow. Vertical salinity and velocity profiles recorded at Craigavon Bridge in Londonderry reveal that during the strong tidal velocities of spring conditions the estuary is “vertically mixed,” while during the weaker velocities of neap tides the estuary behaves as a “slightly stratified” system.Estuary classification provides a framework on which the concepts of mixing and dispersion can be mathematically simulated to help resolve management problems. As comprehensive survey data are required for the development of mathematical models, estuary monitoring programmes should ideally be framed to take account of this requirement. Effects of Pollutants Upon the Benthic Ecology of Belfast Lough J. G. Parker Department of Agriculture ( N I ) , Fisheries Research Laboratory, 38 Castleroe Road, Coleraine, BT51 3 R L , Northern Ireland Belfast Lough (Fig. 1) has received little ecological study in recent years although reports from early in this century (Royal Commission on Sewage Disposal, 1908l) recognised the deleterious effects of raw sewage upon the lough.The objective of this study was to describe the main physical, chemical arLd biological trends in the benthic ecosystem of Belfast Lough. Because of their relative immobility, benthic ecosystems are able to integrate the changes in the quality of the overlying water and are widely used in the assessment of coastal pollution. As relevant data upon this ecosystem in Belfast Lough were lacking, our preliminary studies were spatial in emphasis, as recommended by Moore.2 Fig, 1. Belfast Lough, December 1978. Distribution of organic matter and silt-clay particles. Methods During December of 1976 and 1978 samples of sub-tidal sediment were collected from 41 sampling sites by means of a 0.1-m2 benthic grab.3 Granulometric analyses were carried out on sub-samples of the sediment and grain size statistics were calculated according to Folk.4 The 1976 samples were used for an examination of the distribution of fauna in relation to sediment s t r ~ c t u r e .~ The 1978 survey examined the content of oxidisable organic matter and the total content of metals (chromium, manganese, iron, nickel, cobalt, zinc, copper and lead),430 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Anal. PYOC. using the methods described by Loring and Rantala5; the redox potential (Eh in millivolts) of the sediments was measured in situ by inserting a platinum electrode (Metrohm), connected to a portable Metrohm pH - Eh meter, into the top 10 mm of the undisturbed grab sample.On each sampling occasion, the salinity (parts per thousand) and temperature (degrees centigrade) of the water column at 0.5 m depth and at the sea bed were measured using an EIL salinity and temperature measuring bridge. Associations within and between physical, chemical and biological data were examined using a correlation matrix. The distribution of single variables was plotted using computerised contour mapping (SYMAP). Results and Discussion In this paper, Belfast Lough is defined as the body of water that lies to the landward of a line from Black Head to Orlock Point. The area between this limit and a line from Carrickfergus to Grey Point is referred to as the outer lough. The remainder of the lough is termed the inner lough, except for the harbour installations in Belfast, which are termed the docks area.The lough slopes gradually from Belfast, where there are extensive inter-tidal flats, to a maxi- mum depth of 20 m at the outer limit. Salinity and Temperature Regimes Parker3 described the general trends in the salinity of the lough whilst Parker et aZ.6 described the hydrography of the tidal River Lagan. The surface water of the docks area was influ- enced strongly by the fresh water from the River Lagan. Because of stratification, the bottom water of the docks was influenced mainly by sea water, and had a minimum salinity of 28 parts per thousand Bottom water in the inner lough had a minimum salinity of 31 parts per thousand. At the outer limit of the lough, both surface and bottom water had a salinity of 34 parts per thousand, which is typical of the northern part of the Irish Sea.During the winter, the water in the outer lough was some 3 "C warmer than that in the inner lough, where fresh water and wind appeared to exert a considerable cooling effect. The gradients of salinity and temperature may be important for long-term benthic monitoring, as both factors may cause differences in the life-cycles of the fauna at different sites within the lough. sea water). Sediment Structure and Chemistry The bottom of Belfast Lough is fairly uniformly composed of muds and muddy sands, with a high proportion of shell debris at some sites. All of the grain size statistics showed significant positive correlations between the years 1976 and 1978.Furthermore, the distribution maps of each sediment statistic showed that the individual sites, with some notable exceptions, did not differ markedly between the two years. This suggests that over the period of study the sedimentary ecosystem was stable. This is to be expected from the generally sheltered aspect of the lough and the occurrence of weak tidal currents. These low-energy conditions promote the settlement of fine particulate material, resulting in the occurrence of high silt-clay values (maximum 94% m/m) in the areas where least water movement occurred. A marked differ- ence in silt-clay content between 1976 and 1978 at Grey Point sampling sites indicated that this may be an unstable area where bedload movements may occasionally redistribute the deposited material to other sites.The accumulation of fine particles in sediments is often accompanied by raised levels of organic detritus, for the two types of material have similar depositing characteristics. Thus, organic matter and silt-clay contents showed a highly significant (P <O.OOl) positive correlation. Fig. 1 illustrates the effect by comparing areas of high organic content ( ~ 3 % ) with those areas that contained less than the mean value of silt-clay (about 40% m/m), showing the two types of sediment to be mutually exclusive. The in situ measurements of Eh showed a highly significant (P (0.001) negative correlation with organic matter in the lough sediments, showing the usefulness of this factor for rapidly assessing the effects of pollution in marine sediments.7 The main reservoir of organic matter lay in the docks area, where up to 12% of the sediment mass was readily oxidisable (Table I).The River Lagan and the associated urban streams appear to carry faecal waste into the tidal reaches of the river,6 where sedimenta- tion results in the organic load settling to the bed of the estuary; the sediments here were anaerobic and rich in sulphide.October, 1980 43 1 The levels of industrially important metals in the sediments showed significant positive correlations with the content of organic matter. Thus, metal levels were elevated in the vicinity of Belfast and decreased in concentration in a seawards direction (Table I). Cobalt was exceptional in this respect as it showed no significant correlation with organic matter, nor a seawards trend of decreasing concentration.Zinc and copper were most closely associated with the content of organic matter (correlation coefficients, 0.95 and 0.83, respectively) and are probably the most important toxic metals within the lough sediments. Sediment structure and chemistry are thus closely related in Belfast Lough. In general, there is a trend of decreasing impact of pollution in a seawards direction, but within this trend there is a marked patchiness, due probably to irregular hydrographical conditions. TABLE I MEAN VALUES OF READILY OXIDISABLE ORGANIC MATTER AND TOTAL ZINC AND COPPER IN BELFAST LOUGH SEDIMENTS, DECEMBER 1978 POLLUTANTS IN THE TROPOSPHERE AND NATURAL WATERS Sub-tidal Organic Number area/ matter/ Znl CUl Place of sites km2 g kg-1 mg kg-1 mg kg-l Docks . . .. 5 2.0 59.5 529.4 90.0 Inner Lough . . 15 43.5 14.8 308.7 28.1 Outer Lough . . 21 75.5 8.3 134.7 18.9 Benthic Fauna Excessive inputs of organic matter into marine sediments adversely affect the benthic life by creating inhospitable physical and chemical conditions. The reaction of a benthic community to increasing organic pollution may be summarised thus : the elimination of sensitive species, accompanied by an increase in total productivity, followed by removal of all but the most tolerant species and, finally, the exclusion of benthic life other than bacteria.8 The presence of trace metals in excess may hasten the development of azoic conditions by preventing the settlement of juvenile forms from the plankton. Parker3 described the major trends in the benthic fauna of Belfast Lough in relation to pollu- tion. A site in the inner lough that was contaminated by industrial waste (800 p.p.m. of zinc) contained only the polychaetes Capitella capitata and ScoZeZePis fuliginosa, which are characteristic of polluted marine sedi- menk8 Polychaetes dominated the fauna of the lough and were fairly evenly distributed. However, the oligochaetes showed a marked increase in numbers in the vicinity of Belfast, where they probably thrive on the abundant organic food. Conversely, three species groups, namely, amphipods, bivalve molluscs and echinoderms showed statistically significant in- creases in abundance with increasing distance from Belfast. Various species within these groups are typically absent from polluted marine areas8 Thus, in Belfast Lough the distribu- tion of some faunal groups appears to be influenced by pollution; the extent of this influence may only be revealed by an appraisal of individual species distributions. Several sites within the docks were devoid of benthic fauna. Conclusions The influence of pollution upon Belfast Lough may be identified more precisely by examining the chemistry and biology of the sediments than by using conventional water quality measure- ments. Weak tidal currents and the sheltered aspect of the lough tended to promote the settlement of fine particles, although several areas of scouring were evidenced by their low silt- clay content. The organic matter that accumulated along with fine particles was enriched with metals. There was a marked tendency for both organic matter and metal levels to decrease in a seawards direction and the distribution patterns of some benthic faunal groups appeared to be influenced by pollution. References 1. 2. 3. Royal Commission on Sewage Disposal, “Methods of Treating and Disposing of Sewage. Appendix 1 : Moore, P. G., Mar. Pollut. Bull., 1971, 2, 37. Parker, J. G., Mar. Pollut. Bull., 1980, 11, 80. Minutes of Evidence,” HM Stationery Office, London, 1904, p. 591.432 RESEARCH AND DEVELOPMENT TOPICS Anal. Proc. Folk, R. L., “Petrology of Sedimentary Rocks,” Hemphill, Austin, Texas, USA, 1974. Loring, D. H., and Rantala, R. T. T., “Geochemical Analyses of Marine Sediments and Suspended Particulate Matter,” Environment Canada, Fisheries and Marine Service Technical, Report No. 700, 1977, p. 58. Parker, J . G., Damoglou, A. P., and Stewart, D. A,, Rec. Agric. Res. Dept. Agric. Nth I d . , 1979,27, 43. Pearson, T. H., and Stanley, S. O., Mar. Bzol., 1979, 53, 371. Pearson, T. H., and Rosenberg, R., Ambio, 1976, 5, 77. 4. 5 . 6. 7. 8.

ISSN:0144-557X    

DOI:10.1039/AP9801700406

出版商:RSC    

年代:1980

数据来源: RSC

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432 RESEARCH AND DEVELOPMENT TOPICS Anal. Proc. Research and Development Topics in Analytical Chemistry The following is a summary of one of the papers presented at the Research and Development Topics in Analytical Chemistry meeting of the Analytical Division held on July 4th and 5th, 1979, at the University of Edinburgh. A further paper, by Aziz-Alrahman and Headridge, appeared in full in the October 1979 issue of The Analyst (p. 944), and summaries of twelve other papers appeared in the January and February issues of Analytical Proceedings (pp. 2 and 40). Acoustic Emissions from Polymers. Part I." Chemical and Analytical Aspects T. Lilley Department of Chemistyy, University College of Swansea, Singleton Park, Swansea, SA2 8PP Acoustic emissions are the small, irreversible bursts of noise given out by solids under stress.They are monitored by attaching a microphone to a test material, which is then stressed in a controlled manner. The intensity and occurrence rate of the emissions are used to predict the working lifetime in a given app1ication.l The signals are irreversible at a given stress level. This property is used to determine whether structures have exceeded their loading limits. The present study was carried out on polymers, the objectives being (i) to be able to predict the long-term properties of polymers from the acoustic emissions, and hence its suitability in a given application, and (ii) to establish the relationship between the molecular and mechanical properties of the polymer that give rise to acoustic emission behaviour. In so doing, it was hoped to determine the role of chemical factors in causing the sound.The major source of the acoustic signal is the coalescence and formation of microcracks during the loading cycle of the p ~ l y m e r . ~ , ~ Such a process involves changes in the molecular structure, particularly the severing of tie moleculars and chain unwinding. In parallel Clamp Counter r Low-noise amplifier . I Amplifier + filter Sample \ Clamp u output DL 450 signal processing system ( m icroprocessor, transient recorder and visual display) Fig. 1. Schemati; diagram of apparatus. * For Part 11, see p. 434.October, 1980 RESEARCH AND DEVELOPMENT TOPICS 433 experiments, free radicals have been observed during the stressing of the polymer. The concentration of the radicals is seen to increase with increasing load.The signals are detected by a piezoelectric transducer which is coupled directly to the polymer with polybutene. The signal is then amplified and filtered leaving only the ultra- sonic component, typically 100-300 kHz; this is because of the high level of background sound at lower frequencies. (i) It can be subjected to a counter, which registers counts in proportion to the signal, the so-called ring- down technique. A count rate per minute is plotted against load, (ii) to measure the rate of acoustic emission energy, acoustic power by an r.m.s. device, and plot this in conjunction with a loading parameter. A schematic diagram of the apparatus is shown in Fig. 1; typical results are presented in Fig.2. The signal can then be processed in two ways. I f # 40 80 T ime/m i n Fracture / 0 0 50 100 150 Tim e/m in Fig. 2. Typical results obtained with polymer samples: (a) acoustic emission count rate and load versw Whilst it is hoped to be able to find correlations between the acoustic data, and the mole- cular and mechanical information, it is envisaged that these will not be simple in nature. It is therefore proposed to use pattern recognition techniques to resolve any grouping of the acoustic, spectroscopic and mechanical proper tie^.^ References time; and (b) cumulative acoustic count rate vevsus time. 1. 2. 3. 4. Guild, F. J., Walton, D., Adams, R. D., and Short, D., Composites, 1976, No. 7, 173. Grubec, I., and Peterlin, A., J . Polym. Sci., Polym. Phys. Ed., 1976, 114, 651. Zhurkov, S. N., Zakrevskyi, V. A., Korsukov, V. E., and Kuksenko, V. S., J . Polym. Sci., Part A 2 , Batchelor, B. G., “Practical Approach to Pattern Classification,” Plenum, London and New York, 1972, 10, 150. 1974. Notice to Subscribers Subscription rates for 1980 (with indexes) Analytical Proceedings with The Analyst and Analytical Abstracts: f 136.00 (U K/Eire); $31 0.00 (USA) ; f 143.00 (Rest of world) (Subscriptions are not accepted for Analytical Proceedings alone) Subscriptions should be sent to: The Chemical Society, Distribution Centre, Blackhorse Road, Letchworth, Herts., SG6 1 HN, England

ISSN:0144-557X    

DOI:10.1039/AP9801700432

出版商:RSC    

年代:1980

数据来源: RSC

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434 NEW NUMERICAL METHODS Anal. Proc. New Numerical Methods, Optimisation and Pattern Recognition The following is a summary of one of the papers presented at the Analytical Division Sym- posium held at the Chemical Society Autumn Meeting on September 19th and 20th, 1979, at the University of Lancaster. This Symposium was organised in conjunction with the Education and Training Group. Summaries of six other papers appeared in the April issue of Analytical Proceedings (p. 120). Acoustic Emissions from Polymers. Part ll.* Use of Pattern Recognition Met hods D. Betteridge and T. Lilley and M. E. A. Cudby Department of Chemistry, University College of Swansea, Swansea, SA 2 8PP I C I PIastics Division, Welwyn Garden City, Hertfordshire We are engaged on a long-term project to evaluate the analytical information which may be gained from acoustic emissions given out by polymers under stress (see Part I1).The basic experiment is to place a microphone on a stressed polymer and to record the sound given out by the sample as a function of stress. There are two objectives to the work: (i) to see whether the acoustic emission pattern can be used to predict mechanical behaviour (material testing) ; and (ii) to investigate the possibilities that acoustic emissions have these origins in molecular events such as bond breaking. Thus we seek, on the one hand, direct analytical information about the quality of a product, and for this purpose need to establish an empirical correlation between the acoustic signal and mechanical behaviour, and on the other, some relationship between acoustic signals and molecular events.It is most unlikely that any simple relationships e ~ i s t , ~ - ~ so we are exploring the possi- bilities of pattern recognition methods or cluster analy~is.~*~ Attractive features of these methods are (i) diverse parameters may be used, (ii) data may be presented on a cardinal or ordinal scale, (iii) it is easy to use different selections of parameters and (iv) the results can be conveniently expressed. Hence the approach is very flexible, allowing the same set of results to be used in a number of ways. The principle disadvantages of the methods are (i) their flexibility, which means that there can be no unique pattern recognition procedure that is applicable to all systems, and (ii) the clustering is on a mathematical basis, which means that whilst it is permissible to say of a particular sample that, as a consequence of the analysis of the acoustic emission data, it falls into a particular group, it is not possible to attach a precise physical meaning to that group.To make a simple analogy, it is possible to list as a group of compounds those with an offensive smell. Such a grouping has real interest to those concerned with environmental pollution, but no molecular information about the compounds can be assumed or deduced from that listing. From the practical point of view it may be useful to establish a concrete, unique and reproducible correlation between a signal and the properties of a material. It may also be the case that such groupings lead to molecular insights.For example, an elementary example of a pattern recognition pro- gramme familar to analytical chemists is the Qualitative Group Analysis Table. In the procedures we have adopted, each data parameter is treated as an axis for a multi- dimensional graph. Highly correlated samples plot close to each other; they are said to cluster. Cluster analysis is a form of classification known as pattern recognition. There are two levels upon which the data can be classified: (i) within an individual test on a sample to establish any obvious pattern of signal evolution; and (ii) to be able to compare, simply, results for different samples. The pattern recognition problem is to deter- mine the right combination of parameters that gives a reproducible and meaningful result.The individual samples now become points. * For Part I, see p. 432.October, 1980 NEW NUMERICAL METHODS 435 We have carried out some pilot experiments along these lines. Parameters are extracted from a digitally sampled acoustic energy trace. The parameters used included peak height, width and area, i.e., energy, time between signals and some derived measurements such as peak height divided by width. Several different combinations were tried to determine if any clustering occurs. However, combinations including peak height and peak height divided by area gave three distinct clusters (Fig. 2). Most combinations yielded random plots (e.g., Fig. 1). Ln (peak heights) v v v V F V v V v v B v v 6 Ln (peak heights) I V I A/- Ln (peak area/height x width? Fig.2 . Logarithmic plot of peak height neysus peak area/height x width.436 EQUIPMENT NEWS Anal. Proc. Preliminary results have shown that pattern recognition can usefully be used to resolve complex data into simple components that can be used for comparison. Results have been obtained for acoustic data; the next stage is to combine these with separate mechanical and spectroscopic data to determine the correlations between chemical properties, mechanical behaviour and acoustic propagation. References 1. 2 . 3. 4. 5. 6. 7. 8. Lilley, T., Anal. Proc., 1980, 17, 432. “Acoustic Emission,” ASTM STP 505, 1972. Grubec, I.. and Peterlin, A., J . Polym. Sci., Polym. Phys. Ed., 1976, 114, 651. Zlurkov, S. N., Zakrevsky, V. A., Korsukov, V. E., and Kuksenko, V. S., J . Polym. Sci. Part 4 2 , Batchelor, B. G., “Practical Approach t o Pattern Classification,” Plenum, London and New Yorlc, Taylor, P . J., “Quantitative Methods in Geography,” Houghton Mifflin, Boston, 1977. Cox, D. S., and Lewis, P. A,, “The Statistical Analysis of a Series of Events,” Monographs on Applied Childers, D. G., Skinner, D. P., and Kemerait, R. C., “The Cepstrum: X Guide t o Processing,” 1972, 10, 150. 1974. Probability and Statistics, Methuen, London, 1966. Proc. IEEE, 1977, 65, 1428.

ISSN:0144-557X    

DOI:10.1039/AP9801700434

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年代:1980

数据来源: RSC

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436 EQUIPMENT NEWS Anal. Proc. Equipment News Micro balance and a temperature range of - 196 to 482 "C. The Cahn 26 incorporates all the features of the Pleated mesh elements are available in 2, 7 Series 20 range. It is fully automated and has and 15pm nominal sizes. five ranges: f6, 550, &200, If500 and Techmation Ltd. Insert E524 on the Reader & 1000 mg, with resolutions of 0.1 pg in the Enquiry Service form for further information. smallest range or 1.0 pg in the 50-nig range. Plasma Emission Spectrometer The Jarrell-Ash spectrometer, computer con- trolled with integral analytical data processing, is capable of measuring trace elements a t parts per 10l2 level. Multi-channel direct reading and continuously scanning read-out can operate simultaneously. Insert E525 on the Reader Enquiry Service form for further information.Anaspec Ltd. Programmable Chemical Analysers The Digi Chem 3000 analysers, a series of process chemical analysers for inorganic and reactive organic chemicals and metals in solu- tion, are available in titrimetric and selective- The tautband suspensions are friction free, and a BCD output permits interfacing with most programmable computers etc. Oertling Ltd. Insert E523 on the Reader Enquiry Service form for further information. In-line Filter Supro all-metal in-line filters are now equipped with Cajon VCR couplings, which require no axial clearance for installation or removal. IJsing nickel gaskets, the system can operate Modular construction offers wide from high vacuum to 34400 kPa (5000 Ib in-2) flexibility, using proven sampling hardware ion methods.October, 1980 EQUIPMENT NEWS 437 combined with specific analysis software.Enquiry Service form for further information. Techmation Ltd. Insert E526 on the Reader Assay Kits Two new enzyme-linked immunosorbent assay kits complement the existing kit for rubella screening, to determine immunity to cyto- megalovirus and Toxoplasma gondii. The tests are conducted a t room temperature with no incubation a t higher temperatures required, and the results are evaluated using a colorimeter or spectrophotometer a t 405 nm. Laboratory Impex. Insert E527 on the Reader Enquiry Service form for further information. Automatic Titration System The ETS 880 Kappa Number titration system for pulp operates automatically, with the required reagents added a t the appropriate times.Repeatability of the Kappa Number determination is 1 yo. Radiometer A/S. Insert E528 on the Reader Enquiry Service form for further information. Lamps for Atomic Absorption A new range of multi-element hollow-cathode lamps is available in combinations of 2, 3, 4, 5 and 6 elements. Lamps for phosphorus and osmium have been added to the range of single element high performance lamps. Baird-Atomic Ltd. Insert E529 on the Reader Enquiry Service form for further information. Sample Preparation A programmable sample preparation system, the PRIAS CS, can automatically prepare samples, carry out dilution, add up to four cooled reagents and aspirate the tubes for radionuclide counting. Models with capacities of 240, 408 and 504 samples are available.Packard Instrument Ltd. Insert E530 on the Reader Enquiry Service form for further information. Evaporator The Buchler Vortex Evaporator facilitates solvent removal from multiple samples. Up to 96 samples may be treated under controlled conditions; an anti-bumping device and a bleed-valve system for inert-gas flushing are fitted. Sample blocks to accommodate 12- and 16-mm test-tubes, 15-mm conical bottom centrifuge tubes and 27-mm scintillation vials are available. Baird and Tatlock (London) Ltd. Insert E531 on the Reader Enquiry Service form for further information. Gas Detection Snoop liquid leak detector for pressurised gas systems produces bubbles that indicate the size of the leak, and dries leaving no residue. In ambient temperatures below -3 "C Real Cool Snoop is available and can be used down to -54 "C.Insert E532 on the Reader Enquiry Service form for further information. Syndic0 (Warrington) Ltd. Carbon Dioxide Incubators Two bench-top carbon dioxide incubators with capacities of 6 ft3, display in large LED digits temperature (5 "C above ambient to 60 "C), humidity (70-90y0 RH) and carbon dioxide concentration (O-20~o). Both accommodate up to 16 shelves with a total area of 52 f t 2 . Laboratory Impex Ltd. Insert E533 on the Reader Enquiry Service form for further information. Freeze-drying Flasks Wide-mouthed VirTis Filter-Seal flasks permit the use of the entire straight-sided flask body to expose maximum product surface area. The flask is sealed with a silicone rubber cap with a 20-pm filter held in place by a rubber O-ring.Standard 19-mm manifold adapters are accepted. Techmation Ltd. Insert E534 on the Reader Enquiry Service form for further information. Syringes A range of syringes designed for use with the Waters U6K HPLC syringe loading valve are available with a range of capacities from 10 to 500 pl. Also available are syringes for use with Rheodyne and Valco Valves. Scientific Glass Engineering (U K) Ltd. Insert E535 on the Reader Enquiry Service form for further information. Rack-loading Vials Vials, 5-6 ml (Beta Vials), have been designed for use in beta-counters, such as Beckman Prias, LKB Rack Beta and Phillips PW4542. Although designed for rack loading, Beta Vials can be used as inserts. They are also suitable for gamma counting on, e .g . , the Beckman 4000.438 EQUIPMENT NEWS Anal. Proc. Hughes & Hughes Ltd. Insert E536 on the Reader Enquiry Service form for further information. Micropipette Tip The Microtip is useful for handling small volumes, e.g., 5p1, and for sampling from narrow bore tubes (6.5 mm minimum). Small internal diameters and different tapers enable the Microtip to accept volumes of up to 250~1. Insert E537 on the Reader Enquiry Service form for further information. Hughes & Hughes Ltd. Micropipettors A range of micropipettors are made from high- impact polystyrene with steel springs and a neoprene O-ring. Currently 50- and 100-pl sizes are available, with other sizes planned. Insert E538 on the Reader Enquiry Service form for further information.Hughes & Hughes Ltd. Dry Ice Maker The Frigimat enables small amounts of dry ice (solid carbon dioxide) to be made as required from a carbon dioxide cylinder. A block 8.6 cm diameter by 11 cm long can be pro- duced in about 2 min. R. B. Radley & Co. Ltd. Insert E539 on the Reader Enquiry Service form for further information. Magnetic Stirring Bars An illustrated chart details available magnetic stirring bars in a wide range of sizes and shapes. Insert E540 on the Reader Enquiry Service form for further information. R. B. Radley & Co. Ltd. Gas Sampling Bulbs Gas Sampling bulbs to BS 2069 are available in borosilicate glass with capacities of 100 and 250 ml. The latter size is also available in polypropylene. Insert E541 on the Reader Enquiry Service form for further information.R. B. Radley & Co. Ltd. Ion Sources A neutral output saddle field ion source auto- matically cleans all substrate materials a t high vacuum. It can be used with magnetron sputter or electron beam sources, and for ion bonding or high vacuum plating techniques. Ion Tech Ltd. Insert E542 on the Reader Enquiry Service form for further information. Sputter Source Plasmax is a high deposition rate triode sputter source, usable with targets of a few millimetres up to 6 in diameter. Testbourne Ltd. Insert E543 on the Reader Enquiry Service form for further information. Ultraviolet - Infrared Spectrophotometry The S105 spectrometer uses a plane blaze reflection diffraction grating to provide a band width of less than 5 nm over the range 380 to 920 nni.A slow motion wavelength selector indicates the actual spectral column as well as wave- length, and an automatic gain setting is incorporated. Operation can be manual, semi-automatic and scanning. The CQ75 chart recorder is an optional accessory. Semat (UK). Insert E544 on the Reader Enquiry Service form for further information. Ultraviolet - Visible Scanning Spectro- photometers Additions to the SP8 series of scanning ultra- violet - visible spectrophotometers are available ; the SP8-30 provides a choice of five scan speeds and operates with an external chart recorder, whilst the SP8-400 has a built-in recorder with automatic synchronisation with the mono- chromator. Both models have a photometric accuracy within 0.0002 nm at 0.1 nm and stray-light below 0.005~0 at 220 nm.Pye Unicam Ltd. Insert E545 on the Reader Enquiry Service form for further information. Gamma Counter The NE 1612 microprocessor-based gamma counter for radioimmunoassay provides the means of measuring radioactive iodine- 125 and cobalt-57 samples in blood. The instrument can be programmed for running routine assays, for user entry of protocol information and for running calibration procedures.October, 1980 EQUIPMENT NEWS 439 Simultaneous counting can be used to achieve a higher rate of through-put. Nuclear Enterprises Ltd. Insert E546 on the Reader Enquiry Service form for further information. Spectrofluorimeter Accessory A microprocessor based controller and signal processor is available for use with the Baird ratio recording spectrofluorimeter.Corrected excitation, emission and synchro- nous spectra as well as first derivative spectra can be obtained. Baird-Atomic Ltd. Insert E547 on the Reader Enquiry Service form for further informa tion. Fluorescence Spectrometer Accessories Accessories now available for the Model 300 fluorescence spectrometer comprise high sensi- tivity Model 3000 LC flow cells, a total emission accessory and a Go To h function for use with the Model 3000 and Sigma 10 Data Station to optimise sensitivity. Perkin-Elmer Ltd. Insert E548 on the Reader Enquiry Service form for further information. Column Monitor The ultraviolet-1/214 single path monitor is designed to monitor a t 214-nm columns used in peptide, amino acid and fatty acid investiga- tions. It can be added to the ultraviolet-1 single path or ultraviolet-2 dual path monitors.Pharmacia (Great Britain) Ltd. Insert E549 on the Reader Enquiry Service form for further information. Automatic Gamma Counter The LB MAG 310 gamma counter is available in two versions; the LB MAG 310C offers eight multi-user programmes, pre-selection of pulse count and energy channel and background subtraction. The LB MAG 310R has in addition facilities for RIA evaluations of up to 7 sample groups. A sample changer has a capacity of 310 in racks of 10 samples. Insert E550 on the Reader Enquiry Service form for further information. Laboratory Impex Ltd. Chromatograph The Series 304 is a microprocessor controlled gas chromatograph, which can be used to control all useful functions. A brochure is available.Pye Unicam Ltd. Insert E551 on the Reader Enquiry Service form for further information. Carbon Monitors The Process 5000 Series of on-line total carbon/ total organic carbon monitoring systems- com- prises four models. These monitor total carbon and total organic carbon in continuous flow by either high temperature combustion or ultra- violet oxidation reaction methods. A descrip- tive booklet is available. Techmation Ltd. Insert E556 on the Reader Enquiry Service form for further information. Sample Preparation Equipment Model TOM 30 can rapidly produce samples for plasma-emission spectroscopy or atomic- absorption spectrophotometry in a form ready for analysis. The weighed sample and flux is charged to a crucible, which is transported through a tubular induction furnace that has capacity for 30 samples.After 30 min heating, the molten sinter is taken into solution and a portion fed to the analyser. Insert E552 on the Reader Enquiry Service form for further information. EDT Research. Gas Detectors The Riken Keiki Fine Instrument Company’s range of gas detection instruments includes a lightweight electrochemical personal carbon monoxide monitor. Other monitors available include those for hydrogen sulphide, nitrogen dioxide, sulphur dioxide, hydrogen cyanide, etc.440 EQUIPMENT NEWS Anal. Proc. Blake11 (TIGD) Ltd. Insert E553 on the Reader Enquiry Service form for further information. Furnace Programmer A video furnace programmer for atomic- absorption spectrophotometry is announced. Pye Unicam Ltd.Insert E554 on the Reader Enquiry Service form for further information. Centrifugal Blood Analyser The Centri Chem System 500 makes use of centrifugal force to mix a blood sample with the required biochemical reagent prior to analysis. Union Carbide (UK) Ltd. Insert E555 on the Reader Enquiry Service form for further information. Multi- channel Analyser The TN- 1750, a processor-based multi-channel analyser, incorporates a 200-MHz Wilkinson type analogue to digital converter. Capabilities include data smoothing, stripping and normali- sation. Tracor Northern Inc. Insert E557 on the Reader Enquiry Service form for further information. Non- destructive Testing Alloys varying by as little as 0.1 yo in elemental composition can be detected by the X-ray system, radioexcitation source and pre-pro- grammed microprocessor of a new materials identification systems analyser. Link Systems Ltd.Insert E558 on the Reader Enquiry Service form for further information. Photometer Monochromator The PMP is a programmable, stepping motor driven monochromator with an integrating analogue to digital converter. The system can be controlled by the Commodore PET micro- computer or via the IEE 488 bus from, e.g., HP45, HP85, DEC Minc, etc. The monochromator is driven through the desired spectral region, with intensity data recorded a t every point. Insert E559 on the Reader Enquiry Service form for further information. Bentham Instruments Ltd. Analyser for Vacuum-based Equipment CHALIS (concentric hemispherical analyser lens integrated system) is used with vacuum-based equipment for quantitative analysis down to sub-micron spatial resolution and monolayer sensitivity, when combined with microfocus field-emission electron gun and an X-ray source.Cambridge Consultants Ltd. Insert E560 on the Reader Enquiry Service form for further information. Autosampler A high-performance liquid chromatography autosampler, the LC-XP allows injection of up to 25 vials by gravity feed, and a pressure purge system allows high volumetric precision. Pye Unicam Ltd. Insert E561 on the Reader Enquiry Service form for further information. Electrostatic Recorder The ES 1000 electrostatic recorder can accept both analogue and digital imputs and offers a frequency response of 10 kHz on up to 16 channels. It produces permanent records of 11 in roll or fanfold paper a t chart speeds up to 250 mm s-1.By adding the optional MlOO character board, full alphanumeric annotation is possible. Gould Instruments Division. Insert E562 on the Reader Enquiry Service form for further information. Synthesised Signal Generator The SSG 220 synthesised signal generator covers the frequency range 10 kHz-800 MHz in five ranges, with resolutions of 0.1-100 Hz. Maximum output is 1 V r.m.s. into 50 Q, with 119 dB attenuation in switched 1 dB steps to provide levels down to 1.1 pV. It can be programmed via IEEE 488 or parallel input option. Gould Instruments Division. Insert E563 on the Reader Enquiry Service form for further information. Digital Multimeters The 44 digit liquid crystal display instrument, the DMM12, has an accuracy of 0.05% and a built-in electronic ability to make true r.m.s.measurements on ax. signals. Gould Instruments Ltd. Insert E564 on the Reader Enquiry Service form for further information. Oscilloscope The Gould Advance 0 s 3600 oscilloscope breaks the 100 MHz band width barrier. Gould Instruments Ltd. Insert E565 on the Reader Enquiry Service form for further information.October, 1980 EQUIPMENT NEWS 441 Pre- amplifier The Ithaco 1201 can be gate-operated via a TTL-compatible input or any wave-form type. With a selectable gain of 10-25000 at an accuracy of 1% and stability better than 0.037h OC-1, it can be operated in either d.c. or a.c. coupled modes. Noise performance on broad band (to greater than 400 kHz) is less than 4pV and spectral noise a t 1 kHz less than 7 nV Hz-l.Techmation Ltd. Insert E566 on the Reader Enquiry Service form for further information. Automatic Burette The ABU 80 auto-burette gives high precision, computerised delivery of titrant. Two-in-one assemblies are available in 25/2.5 ml, 10/ 1.0 ml and 2.5/0.25 ml versions. Radiometer A/S. Insert E567 on the Reader Enquiry Service form for further information. Flexible Glass- end Tubing One step glass to stainless-steel tubing is designed to isolate vibration and to compensate for thermal expansion and misalignment in glass systems. Glass tubing is 7740 Pyrex, available in 6, 9 and 12 mm o.d., and fused, respectively, to 4, 8 and 3 in 0.d. 321 stainless- steel flexible tubing. Pressure rating is ultra-high vacuum to 25 lb in-2.Techmation Ltd. Insert E568 on the Reader Enquiry Service form for further information. Pipette Safety Device The Pipet-Aid will accept glass or plastic pipettes from 0.1 to 100 ml, and also Pasteur pipettes, and enables a convenient alteration to mouth pipetting. A filtration unit can be fitted when using bio-hazardous materials. Shandon Southern Products Ltd. Insert E569 on the Reader Enquiry Service form for further information. Diluter A variable diluter can prepare samples up to 20 ml for, e.g., atomic-absorption spectrometry, in dilutions up to 1000 : 1. All parts in contact with liquids are either glass or PTFE. Hook & Tucker Instruments Ltd. Insert E570 on the Reader Enquiry Service form for further information. Sampler The T40 sampler is designed for automatic dilution and to feed samples to atomic- absorption spectrometers. Hook & Tucker Instruments Ltd.Insert E571 on the Reader Enquiry Service form for further information. Ferrules A range of steel- and brass-back ferrules is designed specifically for use with graphite- front ferrules for chromatography. Insert E572 on the Reader Enquiry Service form for further information. Chromasol Ltd. Gel Casting Stand Gels can be cast by pipetting monomer- ampholyte mixture under one glass plate resting on precision spacer rolls in a new acrylic casting tray. The polymerised gel sticks to the plate and not to the tray. Gels can be cast up to a maximum of 460 x 125 mm, in thicknesses of 0.8 or 1.6 mm. Bio-Rad Laboratories Ltd. Insert E573 on the Reader Enquiry Service form for further information.Gel Slab Dryer Model 1125 slab drier comprises a hot-plate with drying area of 44 x 35cm, and can be used under vacuum conditions. A thermostat and a 6-h timer are incorporated. Bio-Rad Laboratories Ltd. Insert E574 on the Reader Enquiry Service form for further information. New Products Picozyme-F is a high performance firefly luci- ferase giving minimum adenosine triphosphate detectability of 1 x 10-15 mol. Packard Instruments Ltd. Insert E575 on the Reader Enquiry Service form for further information. The new Inland 41 fluid has no flash or fire point. It is a chemically inert saturated hydrogen-free chlorofluorocarbon with a vapour pressure of 10 ,xm a t 62 O C , thus making i t useful as a high-vacuum rotary pump fluid.Oxygen (liquid and gas), fluorides and chlorides can be safely pumped. Testbourne Ltd. Insert E576 on the Reader Enquiry Service form for further information. Further particulars of the following reference materials are available. The first and second numbers in the brackets are the number of major plus minor and trace constituents, respectively, that have been assigned a certified value: haematite ore (3, 15); chromite (8, 2); magnetite ore (7, 12) ; ferrochromium alloy (8, 3); and chromite (9, 2).442 EQUIPMENT NEWS Anal. Proc. South African Bureau of Standards. Insert E577 on the Reader Enquiry Service form for further information. Hyperspheres column packing materials for HPLC, CPS (cyanopropylsilyl) Hypersil and MOS (dimethyloctylsilyl) Hypersil are announced.Shandon Southern Products. Insert E578 on the Reader Enquiry Service form for further information. Heparin-Sepharose CL-GB is available for bio- logical separations in affinity chromatography. A technical booklet can be obtained. Pharmacia (Great Britain) Ltd. Insert E579 on the Reader Enquiry Service form for further information. Literature A catalogue of liquid chromatography systems comprises important specifications and tech- nical features, information on the problem solv- ing capacity of recommended systems and a section on major accessories. Perkin-Elmer Ltd. Insert E580 on the Reader Enquiry Service form for further information. A booklet entitled “Membrane Filters- Performance and Working Life” explains the Schleicher and Schuell membrane filter systems, with the parameters required to be defined for the system to be used.Anderman & Co. Ltd. Insert E581 on the Reader Enquiry Service form for further information. Details on the use of the WASP (wide angle scanning photosedimentometer) are available. Microseal Ltd. Insert E582 on the Reader Enquiry Service form for further information. “Plasma Line,” a quarterly newsletter from Spectrometrics, a guide to the use of plasma emission spectrometers, includes a report on analysis of impurities in lead, the analysis of arsenic and selenium by hydride generation, and of zinc in tungsten carbide. Techmation Ltd. Insert E583 on the Reader Enquiry Service form for further information. Technical Bulletin No. 781 details the range of Supelco HPLC guard columns.Bioscan. Insert E584 on the Reader Enquiry Service form for further information. An elemental analysis applications study describes the use of Model 240B elemental analyser in liquid sampling applications. Perkin-Elmer Ltd. Enquiry Service form for further information. Insert E585 on the Reader A brochure summarises the current range of diagnostic and haematology products, including a range of kinetic enzyme determinations using the Dutch (NVKC) recommended methods and a CK-MB (NAC) test using the Iso-Tube separator. J. T. Baker Chemicals BV. Insert E586 on the Reader Enquiry Service form for further information. Infra Red Application Notes No. 2 deals with an infrared detector for use with gel permeation and liquid chromatographs. Wilks Scientific Ltd. Insert E587 on the Reader Enquiry Service form for further information.A bibliography lists 70 titles and brief descrip- tions dealing with infrared spectroscopy of published articles or data from their own laboratories. Perkin-Elmer Ltd. Insert E588 on the Reader Enquiry Service form for further information. A bulletin (No. 1100) describes a variety of combustion and digestion bombs for preparation of samples for subsequent chemical analysis. Scientific & Medical Products Ltd. Insert E589 on the Reader Enquiry Service form for further information. A catalogue contains reports on gas-chromato- graphic separations of aliphatic amines and nitrogen heterocycles. Two other catalogues on “Analabs” products are also available. Field Instruments Co. Ltd. Insert E590 on the Reader Enquiry Service form for further information.A catalogue on Environmental Standards and Accessories includes descriptions of poly- chlorobiphenyl isomers, polychlorodibenzo-p- dioxin and dibenzofuran isomers, haloethers, nitrosamines, water pollution chemicals such as haloalkanes and pesticides, and accessories and analytical tools. Field Instruments Ltd. Insert E591 on the Reader Enquiry Service form for further information. A brochure on open tubular column chromato- graphy, and a literature list on thermal analysis comprising 98 titles of technical reports and application studies, are available free of charge. Perkin-Elmer Ltd. Insert E592 on the Reader Enquiry Service form for further information.October, 1980 AWARD FOR CHEMICAL ANALYSIS AND INSTRUMENTATION 443 The Autumn 1979 issue of “Peak” includes information on the HP3388A reporting inte- grator, the HP79877A refractive index detector for HPLC and on fused silica capillary columns available with three different coatings.Hewlett-Packard Ltd. Insert E593 on the Reader Enquiry Service form for further information. Information on the LKB Ultrotome IV ultra- microtome, and on chromatography columns and reservoirs can be obtained from LKB Instruments Ltd. Insert E594 on the Reader Enquiry Service form for further information. Analytical Bulletin Vol. 2 No. 4 includes information on the PV8350 vacuum emission spectrometer, and on new SEM accessories. A supplement to this, ABS/6 deals with optical emission spectrometry. Pye Unicam Ltd. Insert E595 on the Reader Enquiry Service form for further information.The November 1979 No. 6 issue of “Camlab Info” includes information on tissue homo- genising equipment, a laboratory turbidometer that can cope with highly coloured liquids, and the C-63 mineralight transilluminator specially designed for recombinant DNA research. The March 1980 No. 7 issue features the Camlab-Shodex refractive index detector for liquid chromatography, and Shodex PAK packed columns for high-performance liquid chromatography. Camlab Ltd. Insert E596 on the Reader Enquiry Service form for further information. “Measurement Computation News” for Novem- ber/December 1979 provides information on the HP64000 logic development system, HP7310A hardcopy printer and the series 30 member of the HP3000 computer family. Information on a microwave frequency counter HP5343A having a range of 10-26.5 GHz, a test source to produce high performance AM/FM signals, Model 11715A, and a utility crystal detector for 10 MHz to 12.4 GHz, Model 420C, is also included. The January/February 1980 issue includes information on the HP-85 fully integrated computer, small enough for desk or bench use. Also included are the HP10023A temperature probe, the HEDS-3000 digital bar code wand and the HCPL-3700 a.c./d.c. thres- hold sensing optocoupler. Hewlett Packard Ltd. Insert E597 on the Reader Enquiry Service form for further information. A small booklet on the 800 series of titration systems described equipment for automatic end-point, recording and digital titrations. They are referenced as ETS822, RTS822 and DTS822 systems, respectively. Radiometer A/S. Insert E598 on the Reader Enquiry Service form for further information. A small leaflet presents the range of photo- metric analytical instruments manufactured by Dr. Lange GmbH of Berlin. Arnold R. Horwell Ltd. Insert E599 on the Reader Enquiry Service for further information. Information on Interscan Toxic Gas analysers as well as Sabre Oxyguard alarm monitors can be obtained from Sabre Gas Detection Ltd. Insert E600 on the Reader Enquiry Service form for further information.

ISSN:0144-557X    

DOI:10.1039/AP9801700436

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

October, 1980 AWARD FOR CHEMICAL ANALYSIS AND INSTRUMENTATION 443 The CS Award for Chemical Analysis and Instrumentation The 1979 Award, sponsored by Perkin-Elmer Ltd., has been made to Dr. Michael Barber of the University of Manchester Institute of Science and Technology for his outstanding contributions to chemical analysis and instru- mentation in the field of mass spectroscopy, photoelectron spectroscopy and secondary ion mass spectrometry. D r . M . Barber (L) receiving the CS Award f o r Chemical Analysis and Instrumentation f r o m Dr. A . S p i n k s , CS President. The award was presented a t a ceremony in Rurlington House held on Tuesday, June loth, 1980.October, 1980 AWARD FOR CHEMICAL ANALYSIS AND INSTRUMENTATION 443 The CS Award for Chemical Analysis and Instrumentation The 1979 Award, sponsored by Perkin-Elmer Ltd., has been made to Dr. Michael Barber of the University of Manchester Institute of Science and Technology for his outstanding contributions to chemical analysis and instru- mentation in the field of mass spectroscopy, photoelectron spectroscopy and secondary ion mass spectrometry. D r . M . Barber (L) receiving the CS Award f o r Chemical Analysis and Instrumentation f r o m Dr. A . S p i n k s , CS President. The award was presented a t a ceremony in Rurlington House held on Tuesday, June loth, 1980.

ISSN:0144-557X    

DOI:10.1039/AP9801700443

出版商:RSC    

年代:1980

数据来源: RSC