124 Analytical Atomic Spectroscopy 4.5 AIR AND WATER ANALYSIS 4.5.1 Introduction There have been few significant advances in the field of environmental analysis over the past year, but rather there have been refinements of existing techniques and modest improvements in their reliability or range of application. On the instrumental side the trend towards the use of ETA in AAS, particularly for air analysis, has continued.The ICP is now clearly becoming a major source for rapid multi-element analysis by AES for water analysis. In fact, the tendency towards the use of this and other devices that result in a saving of manual labour would seem to be a portent of things to come. One development already well established is the use of microprocessors in AAS to reduce operator time and there are signs of increasing interest in the use of some form of automation in the sample preparation step.The precision and accuracy of new or existing analytical techniques are of great interest, especially at the low concentrations encountered in much environmental work. The precision of a particular method in a given laboratory is relatively easy to check, although many published reports still seem to lack adequate data in this respect.The accuracy of analytical data on a world wide basis is of growing concern, particularly in the environmental field where important economic, political or hygiene decisions may be based on the analyst's report. Probably the most convenient and reliable way for an individual laboratory to check the accuracy of its techniques is by analysis of certified reference materials (CRMs).Schroder et al. (937) have described the library of 65 standard water samples assembled by the US. Geological Survey over a period of 13 years (see 3.3). Olsen and Fassel (1819) have reported an air-filter calibration facility and the preparation of four sets of air particulate standard filters. An alternative to the use of CRMs is participation in inter-laboratory comparisons.Dybczynski er al. (533) have conducted a statistical survey of the results obtained by 35 laboratories in 19 countries for 16 trace elements in water samples. They concluded that careful consideration should be given to procedures for the rejection of outliers, and that many analysts should pay more heed to establishing the accuracy of their results, rather than merely attempting to improve precision.Plesch (361) reviewed the AAS results from several laboratories for 8 trace elements in drinking waters. He concluded that of the 8 elements studied only Zn and possibly Cr could be determined with sufficient accuracy to comply with the 1975 EEC regulations for analysis of drinking waters; all could be determined by XRF however. Knechtel et o f .(414) conducted an inter-laboratory programme to select the best technique for the analysis of sludges, the methods investigated including AAS, AES, XRF and NAA. Comparison of results by different methods within a laboratory is less reliable than inter-laboratory comparison, but can give a guide to accuracy. Beckett (1072) compared results for 73 elements in sludges obtained by techniques including AAS, emission spectrography, spark source MS and y-photon activation.Similarly, Capar et d. (1171) used up t o three methods to measure each of 30 elements in sludges, including flame and hydride AM, PCP-OES and ASV, and found the general agreement to be fairly good in most cases. Baudin (37'6) compared AAS, OBS and various other techniques for the analysis of drinking water, sea-water and industrial waste water.Criteria examined included storage, in-situ analysis, pre-concentration, choice of method, selectivity, analysis time and accuracy. Of growing interest in the environmental field i s the question of speciation of trace metals. Mercury speciation in sludge and water samples i s of considerable importance.Grimm et al. (33'3) were able to distinguish between methyl and dimethyl Hg at levels down to 30 ppb in sludges by combining GC with AAS. Baltisberger (31 3) developed an ETA-AAS technique able to differentiate between inorganic and organic Hg cations in theChapter 4: Applications 125 range l&lOO ppb in aqueous samples. Speciation of Pb i s important in atmospheric studies; Robinson and Kiesel (3'07) used a GC-AAS method with ETA to investigate organic Pb in filtered air. Reamer et aZ.(60) used GC, with a microwave plasma OES detector, to measure tetra-alkyl Pb and alkyl Se in air. ETA-AAS has been used for water samples to distinguish Se(IV) and Se(VI), either after solvent extraction (426) or after hydride generation (887)' and Cr(II1) and Cr(V1) after separation by solvent extraction (517).An HPLC system using an AAS detector has been used by Coleman and Koropchak (100) to distinguish CdSO, and CdBr, in water, while Aue and Flinn (330) have described a flame photometric Sn detector for the determination of organo-tin compounds after separation by GC. 4.5.2 Water Analysis 4.5.2.1 Sample PreparationlPretreatment.In comparison with other sample types, the degree of sample preparation needed with waters is normally relatively small and the main problem is usually that of satisfactory storage. Dellenbarg and Church (238) compared results obtained from estuarine samples, immediately extracted at sea, with those following various storage procedures. Only samples that had been filtered (<1 pm), acidified, and stored frozen gave similar results. Stoemler and Matthes (1390) found it necessary to determine inorganic Hg in sea-water immediately on collection, whereas for methyl Hg chloride the samples could be stored for up to 10 days in brown glass bottles with rigid plastic screw caps.Subramanian et al. (1 96) cornpared various techniques for preserving trace metals in synthetic and natural water samples, the most effective being acidification to <pH 1.5 and storage in 'Nalgene' containers.The filtration of water samples, either before or after storage, raises the problem of exactly what should be considered as 'dis- solved'. It was shown for filtered reservoir samples (624) that the use of 0.2pm Nucleopore membranes was preferable to 0.45pm membranes, as the latter allowed passage of some clay sized particles. Additional preparation of water samples may be necessary for the determination of organometallic species.Farey et al. (529) described a rapid breakdown procedure for organo-mercury compounds using brmination with a KBrO, / KBr solution, the excess of Br, being reduced with hydroxylammonium chloride.Preparation of sludges and sediments usually involves the complete destruction of organic matter, although less time-consuming extraction procedures may also be used. Three extractants (dilute HNO,,, 1 M NH,Cl, H202) and density separation using bromoform were tested (620) on clays spiked with Cu and Pb; none of these procedures appeared to be completely satisfactory.Rees and Hilton (Lab Pract., 1978, 291) compared traditional HNO, /H,O, digestion of sewage sludges with the rapid extraction of heavy metals using HCl/H,O,. FAAS determinations showed similar precision and similar or higher recoveries by the more simple extraction procedure. Agemian and Chau (1 389) compared four extraction procedures €or heavy metals in aquatic sediments using FAAS.They found 0.5M HCl most satisfactory, although O.OSM EDTA at pH 4.8 gave similar results. Delfino and Enderson (1071) compared five techniques (HNO,, HNO,/H,O,, HNO, /HC1, dry ashing at 550 "C, and r.f. ashing) for 13 elements in sludges and found no large differznces in results. In a comparison (1095) of HF/HCl digestion with LiBO, fusion, for the determina- tion of Ca by FAAS in lake sediments, both techniques produced very variable recoveries.Scott (534) showed that loss of Cr during HNO,/HClO, digestion of aquatic sediments is not due to volatilization of CrOCl,, but can be attributed to adsorption of Cr on the silica residue, Dissolution of the residue with HF avoided the problem. Kozuchowski (1396) combusted sediments at 870 "C in an 0, atmosphere and collected the released Hg in a trap of Au-coated glass beads.The Hg was subsequently released by heating the beads at 500 "C in He and determined by an emission technique using a d.c. discharge. Preconcentrcrtion by solvent extraction continues to be of importance in water analysis1 26 A naly tical A tomic Spectroscopy and many new reports on the technique have appeared during the past year.Most of these use a dithiocarbamate as complexing agent, either APDC or Dim, with a variety of organic solvents. The need for caution in the application of such techniques is becoming increasingly apparent. In the last review the problem of incomplete extraction in the presence of natural organic compounds was discussed (ARAAS, 1977, 7, 147); the poor stability of the extracted complexes i s now more widely recognized and many recent applications have avoided direct determinations on the extract solutions.The usual alternatives are evapora- tion to dryness followed by dissolution in 0.1M HNO, (269), or back extraction into dilute HNO, (886, 915). Sperling (1461) found that the APE/MIBK system was effective for Cd in sea-water provided CCl,/C,Cl, was used as solvent for both, the reagent and its Cd complex.Two further extensive studies of the APDC/MIBK system have been made for trace metals in potable waters (1348) and sea-water (1359). Other preconcentration techniques have also been reported. Several workers have used co-precipitation methods, such as collecting As using Fel(OH), (599, 1075), Cr using Fe(OH), (1395), Cd, Co, Cr.Cu, Ni and Pb using Fe(OH), or the Fe complex with APDC (885) and Hg using PbS (494). Wasco and Fasching (185) used the adsorption of trace. metals onto controlled-pore glass beads under alkaline conditions followed by release into dilute HNO, to achieve separation from the matrix. Tests for Pb and Cd in artificial sea-water resulted in complete separation from the matrix and excellent recoveries (90-100%).Ion-exchange concentration continues to be of interest; Horvath et al. (40) used iminodiacetic acid ethyl cellulose, a chelate-forming ion exchanger, to obtain 1- to 20-fold concentrations of Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb and Zn in various waters. Alder and Das (573) used an Amberlite IRC 50fH) column to concentrate U prior to its indirect determination.Automated sample preparations have been described by several workers. A flow- through U.V. digester system has been used to degrade organo-mercury compounds for the determination of Hg in fresh and saline waters at a rate of 30 samples 11-1 (639). This was said to avoid the interference of chloride on the cold-vapour AAS determination, which occurs using automated chemical oxidations.The latter (using persulphate oxidation followed by stannous chloride reduction) has, however, been reported (641) with a similar throughput of Hg in sediment samples. Pyen and Fishman (705) reported the analysis of Se in 150 or more water samples per day using a dry-block persulphate digestion Auto- Analyzer chemical treatment, with heated tube hydride generation and ETA-AAS deter- mination.An automated hydride generator was also used (664) in a system capable of analysing 20 samples h-1 for Sn, down to 0.001 pgml-1, in water. Pierce and Brown (10) described a semi-automated system using ion exchange followed by AES to determine Ba and Sr in surface water samples at the rate of 40 samples during a IlO~min run.Fleming (1377) described an automated continuous flow system for on-line monitoring of Mg in boiler feed water by non-dispersive AFS. 4.5.2.2 Atomic Absorption Spectroscopy. Reports of improvements to conventional FAAS methods for water analysis are now relatively rare, although interest in investigating inter- ferences continues. Rawa and Henn (1260) showed for Cr in water that, as with many other 'real' samples, the use of the N20/C,H, flame is essential to combine adequate sensi- tivity with freedom from interferences.Losser (703) found that results for Fe in marine sediment leachates were unacceptably low unless an addition of 0.5 NH,C1 was made; it was postulated that the latter acts as a protective agent removing cationic interferences. The applications of electrothermal atomization to water analysis continue to increase.Sheaffer et al. (914) described a technique that allowed the determination of Ag in 1 ml samples of rain or melted snow, Batches of graphite furnace tubes were precoated with paraffin (to prevent spreading and seepage into the graphite), and maintained at 80 'C on a hot-plate while 20 successive 50-pl injections of sample were added to each.The detec-Chapter 4: Applications 127 tion limit for Ag was given as 1 X 10-6 pg ml-1 with a precision of better than 2 20% for triplicate analyses. Several workers have described procedures for pyrolytic graphite coating of ETA tubes. Lagas (519) found that use of the correct coating temperature, together with addition of an optimal quantity of La during coating, improved reproducibility and reduced memory effects for the determination of Be, Ba and V in surface and tap waters. Matrix interference problems in ETA-AAS remain of concern, although the number of publications in this area is small for water samples.Ohta and Suzuki (1144) investigated a selective extraction of As from Bi, Cu and Sb as the thionalide complex and found that the presence of S-containing agents in a Mo-microtube atomizer enhanced the As atomisation and pre- vented interferences by most of the 14 accompanying elements found in river and sea-waters.Regan and Warren (521) observed that ascorbic acid was useful for reducing interferences in the determination of Pb in drinking waters, although certain types of samples still showed interference.Automation of AAS determinations continues to be of interest in water analysis, either by the use of automatic sequential analyzers for multi-element determinations or simply by the addition of microprocessors to provide computer calculated calibrations with curve correction. The advantages of the latter in water pollution measurements have been pointed out by Routh et al.(13’9); pollutant concentrations varying by several orders of magnitude can be measured quickly and precisely with one set of instrumental conditions as a result of the extended AAS working range achieved using microprocessor electronics. An unattended AAS water monitoring station has been described (328), each sample being automatically analysed for 7 elements (Cd, Cr, Cu, Fe, Mn, Pb and Zn) in 21 min.Skogerboe et al. (939) have described the analysis of water samples using simultaneous multi-element AAS in which several spectral line sources were multiplexed and a photodiode array used as the detector. Nakajima et d. (208) described an automatic system for heavy metals in waste waters, while Stoeppler (595) discussed the possibilities of using computer control for sampling and AAS determinations of Cd, Cu, Ni and Pb by ETA.The indirect determination of non-metals by AAS continues to be of interest. Le Bihan et d. (12) have imprwed earlier FAAS methods (Analusis, 1973, 74, 695) for detergent determination by using smaller sample volumes and ETA. Anionic detergents in water were extracted into MIBK as the detergent-tris( 1,lO-phenanthroline) Cu(I1) complex and the Cu determined directly by AAS.Non-ionic detergents of the polyethoxylated type were extracted into benzene as the ammonium cobalt thiocyanate complex. Glaeser et al. (859) determined long-chain primary amines (e.g., octadecylamine) in cooling waters by extraction into nitrobenzene as amine-chromate ion complexes. Organosilicon compounds in sewage sludge have been determined directly (1251) in MTBK solution after clean-up by passage through active charcoal.Phosphate in sea and river waters was determined (580) by co-precipitation with Al(OH), and extraction into butanol as a phosphomolybdate complex, the Mo being measured directly by AAS. 4.5.2.3 Atomic Emission Spectroscopy. As mentioned in Section 4.5.1, watcr analysis by AES is now experiencing a major revival of interest as a result of the availability of inductively coupled plasmas with large multi-element spectrometers.Using such a system, Ronan and Kunselman (4‘80) were able to analyse a surface or waste water sample every 30s for 23 elements, giving a capability of thousands of elemental analyses per man day. Garbarino and Taylor (657) have suggested that high accuracy i s unnecessary for many trace metal in water surveys and have used an ICP-OES system with computer software which rounds off the concentrations of 30 elements to appropriate ‘reporting levels’.Taylor (201) has investigated factors affecting the reliability of ICP-OES for watcr analyses, particularly relating to Ca and Mg determinations, and after comparing the accuracy and12s Analytical Atomic Spectroscopy reproducibility with that of data obtained by spark source MS, concluded that the technique was precise, rapid and accurate. The problems of automating commercial ICP spectrometers for natural water analysis have been discussed (1426, 1427).Interest has also been shown in the use of other types of source for OES, particularly the d.c.arc argon or heZiurn plasma. Taylor and Skogerboe (938) have compared results for natural water samples, obtained by using the latter source with an cchelle grating spectrometer, with those produced by an Ar ICP with a computer-controlled direct-reading spectrometer. Ball et al. (888) used a d.c. Ar plasma and echelle spectrometer to determine B in a variety of natural waters at levels from 002-250 pg ml-1; the results were reliable provided frequent recalibrations of the spectrometer were made and matched standards used for sea-waters.Braman and Tornpkins (951) madc a detailed study of interference effects when using hydride generation with a d.c. He plasma to determine Sb and Ge in environmental samples. Several workers have used electrothermal atomizers for emission measurcments and comparisons have been made of the relative merits of AAS and AES determinations under otherwise similar atomization conditions.Epstein et al. (849, 91 1) concluded that a satisfao tory evaluation could only be made for individual elements in particular samples. Hobbs (759) has described the use of a microwave plasma emission detector with a GC system for the determination of chlorinated hydrocarbons in water. 4.5.3 Air and Atmospheric Particulate Analysis 4.5.3. I Sample Preparation /Pretreatment. Dreesen et al. (482) compared various extractants (HNO,, HC1, citric acid, H,O and aqueous NH,) for their effect on coal fly ash samples. They found a positive correlation between decreasing extraction efficiency and increasing pH for As, B, Be, Cd, Cr, Cu, F, Se, V and Zn, but not for Mo.McDonnell and Hilborn (1210) compared alkali fusion and HNO, extraction for Pb particulates on glass-fibre filters; the wet procedure gave better precision but recoveries of some Pb compounds (PbO, and PbS) were significantly higher using the fusion technique. Chelation concentration systems have been studied (54) for Cd and Ni in HNO,/HC10, digests of air-filter samples. Good results were obtained with Ni using a 100 : 1 preconcentration with 1-nitroso-2-napthol in MIBK, but reliable results could not be obtained for Cd.TOPO-MIBK has been used (1231) to extract Sb from H,SO, solutions of air-filter digests. Degan and Haerdi ($19) were able to determine Hg down to 1 ng by ETA-AAS after preconcentration on a micro-column of silver wool.Yamashige et 01. (1375) used ion-exchange to separate Se from extracted air particulates prior to AAS determination as the hydride. 4.5.3.2 Atomic Absorption Spectroscopy. A novel method of determining Hg vapours in laboratory atmospheres has been described by Tyson and Kaseke (731). The Hg was trapped as an amalgam on carbon rods coated with Ag or Au before direct atomization in an ETA, the detection limit being about 90 pg.Newstead and Whiteside (123) reported that the direct determination of Be on atmospheric filters is possible provided that adequate background correction is available. Kovatsis (967) determined CS, in air indirectly by FAAS. The CS, was trapped in a solution of Zn acetate and N,N-dibenzylamine in methanol; the Zn dibenzyl dithiocarbamate formed was then extracted into toluene for determination of the Zn in an air/C,H, flame.Most other reports in this area were concerned with investigation of interferences occurring in ETA measurements, Denyszyn et al. (952) found that As determinations (after collection on charcoal and dissolution in acid) were improved by the addition of Ni to stabilize the As.Carelli et al. (496) measured Sb in air by ETA after extracting the filters with HNO,, evaporating, redissolving in HCl, adjusting to pH 7 and adding tartaric acid and Triton X-100. Sutter and Leroy (230) showed that HNO, interferes with determinationsChapter 4: Applications 129 of Ni and V in airborne particulates.Cohen and Kurchatova (497) found that interferences of PO,3-, C032-, I-, F- and CH,COO- on determinations of atmospheric Pt could be avoided by adding 0.1M EDTA to the HNO, solutions. 4.5.3.3 Atomic Emission Spectroscopy. Several workers have investigated the microwave (2450 MHz) plasma as a source for AES measurements on air samples. Hanamura (176) used the air being sampled as the plasma gas (at atmospheric pressure): the system was similar to that normally used with low pressure Ar plasmas except that a Pt electrode was placed in the torch to reduce the power needed to maintain a discharge.The sensitivity was adequate to monitor Pb concentrations of 5pgm-3 in air with an absolute detection limit of about 1 pg. Hobbs (157) and Zoller and O’Haver (1007) have used microwave plasmas as GC detectors, the former to monitor organic volatiles collected in an industrial environment and the latter for monitoring tetra-alkyl Pb spccies collected from the atmosphere.Braman ei al. (912) used a flame photometric detector to determine H,S and organo-S compounds collected on Au-coated glass beads from coastal air. Detection limits in a H2 diffusion flame were about 0.01 ng or 0.1 parts per 1012 V / V for 100-1 samples.Table 4.5A AIR AND PARTICULATES Element X/nm Matrix Sampte treatment Atomization Ref.Concentration Tech. Analyie form As Be Be Cd Cd Cd Ge Hg Hg Mn Mn NI Ni Ni 193.7 Air 1-10 pg/m3 - Airborne particulates 234.9 Airborne particulates 228.8 Airborne par:iculaies 228.8 Aiborne par.icula!es - Air 265.1 Air 253.7 Labora:ory airnospheres - Air.water - Air - Airborne particulates - Airborne particulates 232.0 Air borne particulates - Welding fumes 7.5-775 ng/ni3 (in air) Trace levels - 3-48 ng (absolute) 0.1-2 ,ug/rn3 From 1 ng (absolute) 0.002-0.22 fig/m3 0.5-1 1.8 ng/mJ ( i n air) - 0.1-1 mg/m3 A .4 A A A A E A A A A A A A L S s, L L L L L, G L, G G L L L L L Collect as ASH, on charcoal, extract wilh acid and add Ni before introduction to ETA Study of background correction system Graphite furnace - Graphite furnace Wet-digest filter samples with 1:l Graphite furnace 14NO3/HCIO,.Neutralize and apply directly to furnace. See aiso Ni, ref. 54 (Extractlon- concentration method not successful for Cd) Collect on PVC filter, extract with F Air/C,H, HNO,.evaporate to dryness and Graphite furnace re-dissolve in HNO, - Graphite furnace Collect Ge and/or me!hyl-Ge compounds P D.C plasma in acid solution (pH 1.5) and reduce with NaBH, Collect Hg by amalgamation with Ag Graphite furnace or Au electro-deposited on graphite rod Pre-concentrate on. Ag microco:umn Cold vapour Graphite fUrnaCe (HGA-2100) - Graphite furnace (methylcyclopentadienyl manganese tricarbonyl) from vehicle exhausts Wet-digest filter sample with 1:l HNOJHCIO, neutralize and extract Ni with 1-nitroso-Bnaphthol in MIBK.See also Cd, ref. 54 Meihod for detection of MNT F - Graphite furnace Interference study Graphite furnace (IL-455) - Graphite furnace 952 123 1250 54 497 81 3 951 731 81 9 a13 1209 54 230 752Pb - Air From 60 pg (absolute) E G Combined GC/microwave plasma P hilicrowave 60 2 Pb 405.7 Air (automobile exhaus:s) From 5 m/m3 E G Collect sample (20 I) in plastic bag P Microwave 176 $ 5 b (Pt electrode) ctr as :e:ramethyl Pb detector system plasma plasma in air and introduce to plasma by pumping Fb 217.0 Dus?s 283.3 12-200 pg/ml A.L Dry at 120 "C, sieve and grind. Boil 1 g F Air/C,H, 245 (in extract) sample with 10 ml 2M HNO,, filter n* 2 x, and dilute, with addition of EDTA.Dithizone/CHCI, extraction (pH 9.5) also employed orgar7ic Pb levels From 1 ng/ms A L, G Study of relative inorganic and Graphite furnace 307 Pb Pb 283.3 Air 283.3 Atmospheric particulates A L Graphite furnace Coiles! on Millipore filter, treat successively with HNO,, HN0JHCI0, (HGA-74) and HF, evaporate to low bulk and prepare final solution in HNO, - F Delves cup 421 Pb Pb A L A L 430 497 - Airnospheric particulaies 21 7.0 Airborne particulates 3.4 :1g/m3 - See Cd, ref. 497 F Air/C,H, Graphite furnace Pb A L Study of sampling and dissolu!ion F - methods Collect Pb fall-out samples directly Graphite furnace with graphite cup 506 - Air 25-250 ,ug/mJ 0.23-3.7 pg/m' (urban) (control) A L 594 898 Pb - A:r 81 3 1007 Fb F:, - Air 405.7 Air A t E G - Graphite furnace GC/MIP method for tetra-alkyl-Pb P MIP species Review (263 refs.) F, A - Collect on micropore filter, char in F Air/C,H, Ta cup at 200-250 " C and ash i n air at 350 "C Collect on 2 graded Nvclepore filters, F - ;o sr-para'e respirable and non-respirable Pb, and extract with HNO, +Ta cup A, E L A L 1104 1136 Pb Pb - Environmental samples - Airborne particulates - 0.3-1 .O pgjrns 1208 Fb - Airborne particulates 0.1-1 pg/m3 A LTable 4.5-4 AIR AND PARTTCuLATEs-conrii~ued _ _ _ _ _ _ ~ ~~ ~ Element X/nm Matrix Conceniration Tech.Ana'yte Sample treatment Atomization Ref. form Pb 283.3 Sb - Sb Sb Se Se 252.8 - - 196.0 Airborne particulafes Air Air Industrial airborne particulates Air Airborne particula:es Air Airborne particula!es From 0.01 ng (absoluie, i n 101) I sample) 1-10 yg (absolute) From 0.2 mg/m3 2-41 ng (absolute) From 1 kg/ml ( i n extract) From 20 pg (absolute) as dimethyl Se (absolute) 0.1-5.0 ,/ig L G L L L, G L G 0 Collect sample (approx. 0.2 g) on F Air/C,H, 1210 glass-fibre filter. (A) Extract with HNO, ( 1 : l ) under reflux (B) Fuse with alkali at 900 "C and extract with HNO, Colect H,S and organo-S compounds F Air/H, 91 2 by drawing sample over Au-coated giass beads.Heat and collect vapours i n liquid-N, trap. Heat and sweep final sample in stream of H, to diffusion flame Trap CS, in Zn acetate solution in F Air/C,H, 967 methanol + "1-dibeiizylamine. Add H,O, extract with toluene and measure Zn Collect sample on Millipore filter Graphite furnace 496 (0.45 prn) extract wiih HNO,, evaporate io dryness, dissolve in HCI, dilute and adjust to pH 7 with NH,OH. Add tnrtaric acid, boil, add 1 drop Triton X-100 and dilute to volume See Ge, ref. 951 P - 951 Collect on filter, extract with F - 1231 b HNO,/H,O,, filter, evaporate and dissolve "C See Pb, ref. 60 P Microwave 60 ' M s. in H,SO,. Extract from Kl/ascorbic medium with TOPO/MIBK 2.$ plasma Dissolve filter sample i n HNO,/H,O, Heated SiO, cell 1375 and evaporate extract to dryness. (950 "C) Dissoive in 0.05N HNO, and pass through Dowex 50 W-X8 column. Evaporate effluent, dissolve in 3.5N HCI and reduce with Zn. Pass H,Se to heated cell r/l 2 s 2 0 '0 '4V 318.4 Airborne par!iculates - Various - V s.r i o u s - Various d Variom - Various d Various - Various - (7) Air - Airborne particulates - Airborne particulates - Airbor2e particulates ng levels (absolute) Airborne particulates - Indus?rial airborne - particu:ates Air - Air - Airborne material - A L E G E L A L A L A L, s A L.S A L A L, s A L See Ni, ref. 230 Graphite furnace (IL-455) Combined GC/microwave plasma P Micro:*rave aetectcr system. Possible elements: C, H, D, 0, N, F, CI, Br, I , P, S, Se, As, Hg and Pb Comparison of ICP and XRF results P ICP on air particulate standard reference ma!erials Paper filters are preferred to glass fibre F - filters Treat 10 cm2 filter paper with hot HNO, F Air/C,H, fo:lowed by HCIO,.Evaporate and redissolve in HNO,. Determine Zn by FAAS and Cd, Cu, Fe, Pb by ETA-AAS - Graphite furnace plasma Graphite furnace (HGA-74) Review (23 refs.) d d Comparison of FAAS and X-ray F - speciroscopy (for Mn, Fe, t n , Pb) Review of methods Graphite furnace Results given for Mg, V, Fe, Ni, Cu, Cd F and Pb in New York City aerosols - 230 $ I57 ct % 2 $ ?? b 189 3. 209 2 229 321 432 838 1201 1211 c w wl-l Table 4.5B WATERS, SEWAGE AND EFFLUENTS form x Element X/nm Matrix Concentration Tech.Sample treatment Atomization Ref. Ag - Sea-water 0.04-0.1 pg/l A Ag - Waters, fish Ag 328.1 Snow, rain - A 0.1 ng/ml level A As - Waters, effluents pg/l levels A As 193.7 Natural waters 1-12 p g / i A As - Well water 1-13 pg/I A As As As As 193.7 Municipal was% materials Up to 100 p g / g A - Water 193.7 Waters 189.0 Waters 193.7 From 1 ng/ml A 0.5-20 pg/i A A - L L L L G L L G L L Extract 1000 m l sample with 4 ml 2% Graphite furnace DDC solution and 20 m l CHCI,.Repeat and evaporate combined organic phases to dryness. Redissolve in 1 ml 0.1M HNO, Extract with AP DC/M I BK F - Acidify samples with HNO, and freeze until tequired. Concentrate sample by sequential evaporation, at 80 "C, of 20 50 pi aiiquots i n furnace tube Comparison of AAS, polarographic and F - colorimetric methods Hydride-evolution method, with liquid- Graphite furnace Acidify with HCI at time of sampling.F Ar/H, Add FeCI, solution, adjust to pH 7-70 with NH,OH, filter and dissolve precipitate in 4N HCI. Reduce to ASH, with KI/Zn/SnCI, Add Mg(NOj)2 + Ni(NO,), + at 450-500 "C. Add H,O/HNO,, evaporate t o dryness, treat with HF/HNO,, again evaporate and redissolve in HN0,/H,02 Reduce with NaBH,, to form ASH, Co-precipitate with Fe(OH), at F Ar/Air/H, pH 8-9.Separate by flotation and dissolve i n HCI. Reduce with NaBH, Add K l + H,SO,, followed by 0.1M Na,S,O, solution and extract As as thionalide complex into isopropyl ether Graphite furnace N, trap (HGA-2100) Graphite furnace C,H,OH. Dry gently and finally ignite (HGA-2100) Heated SiO, tube (950-975 "C) + SiO, tube Heated Mo tube 269 622 914 31 2 51 8 551 569 L x 5 i x -. 818 5 1075 k 5 3' b 1144 2 5 c? c,B 249.8 Sea-water Trace levels A B 249.8 Natural waters 0.02-250 pg/ml E Ba 455.5 Surface waters 0.012-1.14 mg/l E Ba Ba Ba Be C Ca Ca Ca Cd ( co, 1 - 553.6 553.6 234.9 - (Ca) 422.7 - - 228.8 Po:ab!e waters, sediments 0.01-0.20 mg/i Waters 35-100 p g / l Sea-wa;er Up to 30 pg/l Waters 0.1-0.3 pg/l Waters - Lake sediments - Waters; sewage effiuents Rain, snow - Water 200 mg/I level Up to 40 yg/ml Cd - Sea-water 1 pg/l level A Cd - Sea-water Cd - Lake waters 0.01-0.03 hg/I A A - Cd - Wate:, sediments - A L L L L L L L L L L L L L L L L Prepare as 3M H,SO, solution and F N,0/C2H2 228 $ extract with 2-ethyl-1,3-hexanediol Add L i buffer solution.Match P D.c. argon 888 5 s:andards for sample matrix plasma Adjust to pH 3 with HCI, using F N,0/C,H2 10 methyl yellow indicator. Automated cation exchange system then removes Ca and other ions and separates Ba, Sr for analysis Acidify with 0.6 ml conc. HN0,/100 ml Graphite furnace 224 2 - Graphite furnace 519 ? 2 =: 2 6. sample, on collection (HGA-72) (HGA-74) Graphite furnace 570 Graphite furnace 519 (HGA-BOO) (HGA-74) - F - 1142 Ash at 600 "C and either digest with F Air/C,H, 1095 HF/HCI or fuse wth LiBO, Acidify and add La salt F - 1232 F Air/C,H, 1311 Combined LC/FAAS system, t o F Air/C,H, 100 investigate characterization of metal compounds in sample, e.g., CdSO, + CdBr, Adsorb Cd, Pb on prepared glass beads Graphite furnace 185 solution.Filter, wash and dissolve metals with dilute HNO, See Ag, ref. 269 Graphite furnace 269 N,O/C,H, - (Bio-Glas-200) i n ammoniacal (HGA-2000) Graphite furnace 621 (HGA-72) (A) Waters-acidify with HCI F - 624 (B) Sediments-Dry at 105 "C, sieve (80-mesh) and digest with HNO, - wTable 4.5B WATERS, SEWAGE AND EFFLUENTS-contirzued ~~ - ~ - Element X/nm Matrix Concentration Tech.Ana'yte Sample treatment Atomization Ref. form Cd 228.8 Waters Trace levels A Cd - Waste waters - A Cd 228.8 Water Cd 228.8 Sea-water ng/ml levels A - A c o 240.7 Waters Trace levels A Cr 357.9 Natural waters - A Cr 357.8 Waste waters 0-5 m g j l A Cr Cr 357.9 Sea-water 357.9 Aquatic sediments Cr - Water Cr 357.9 Wster Cr - Water 0.02-3.3 &g/i - A A 5 ,ug/ml level E Trace leve!s A From 0.05 pg/ml A L L L L L L L L L L L L Concentrate impurities by coprecipitation with APDC or Fe(OH), and redissolve in HNO,. Evaporate to dryness and dissolve in H,SO, Acidify, boil and either aspirate directly, or, for low levels, extract with APDC/MIBK Acidify with HNO, Modification of APDC/MIBK method, using CCI, or C,CI, solvent for reagent See Cd, ref. 885 Method for determination of total Cr, C r ( l l l ) and particulate Cr To 30 mi sample, adjusted to pH 1.7 with mineral acid, and containing 0.5-50 Mg Cr, add H,02 + 10 ml MIBK.Shake for 1 min. and separate organic phase (A) Cr(Vi)-extract with Aliquat-336 in toluene, from solution at pH 2 ( 8 ) Cr(1II)-extract from solution at pH 6-8, in presence of thiocyanate Digest with HNOJHCIO,. Filter off any insoluble residue and treat with HF/HNO,.Determine Cr in both extracts Add 2.5 pg/ml TI and Li, as buffers and also 5% C,H,OH t o enhance sensitivity. Use graphite electrodes See Cd, ref. 885 Study of flame conditions Graphite furnace (HGA-70) F - Graphite furnace Graphite furnace ( FLA-100) Graphite furn,ace Graphite furnace F Air/C,H, (HGA-2100) Graphite furnace (HGA-72) A - Graphite furnace F N,O/C,H, 885 1195 1372 1461 885 1395 232 517 5 a x -. 534 $ 3 ;i' 668 h 2 1260 $ 'r; 885 2Cr 352.0 Sewage sludge - c u - Natural waters - A L A L c u - Saline waters Trace levels A L L L c u c u - Sea-water - Sediments 0.4-1.2 &g/l - c u cu c u cu c u - Lake waters 324.7 Water - Water - Waste waters - Lake sediments c u 324.7 Water Fe - Saline waters Fe - Water films and surface foams Trace levels Trace levels A A A L A L A L A L A L ng/ml levels A L Trace levels A L - A L Digest with HCI/HNO, F Air/C,H, N,O/S2H2 Study of speciation of trace metals, F Air/C,H, based on a pH titration/size Graphite furnace Filter, acidify and store frozen.(S:udy F Air/C,H, of sample s!orage. Results compared Graphite furnace with those given by on-site extraction with APDC/MIBK) See Ag, ref. 269 Study of extraction procedures, using F Air/C,H, model sediment (Bentonite, MnO,, humic separation procedure (HGA-2000) (CRA-63) Graphite furnace acid) : (A) Dilute HNO, (8) 1M I\IH,CI (D) Density separation (with CHBr,) (C) H,O, See Cd, ref. 885 Application to geological surveys See Cd, ref. 1195 Determine Cu, Fe, Mn, Zn in fractions obtained by successive extraction with (A) 1.OM acetic acid, (B) 0.lM HNO,, (C) acidified H,O, (pH 2) -t 1.OM NH, acetate in 6% HNO,, (D) 0.25M NH,OH.HCI in 25% acetic acid (E) HNO,/HCIO,/HF (3:2:5) See Cd, ref. 1372 See Cu, ret. 238 Graphite furnace Graphite furnace Graphite furnace (HGA-72) F - F - Graphite furnace F Air/C,H, Graphite furnace (FLA-100) (CRA-63) F - 1313 199 238 269 620 62 1 885 940 1195 1309 1372 238 61 9Table 4.5B WATERS, SEWAGE AND EFFLUENTS-continued - W ~ ~ ~ _ _ ~ __ Element X/nm Matrix Concentration Tech.Sample treatment Atomisatlon Ref. form - Water 5 ,ug/ml level E 305.9 Marine sediment leachates 50&4600 pg/ml A - Water 0.25 ng/ml - Lake sediments - 265.1 Waters - - Waters 10-100 pg/l - Sludges, sediments From 30 pg/l I Natural waters - - Sea-water - - Mineral waters pg/l levels - Waters, sewage, effluents - A 253.7 Fresh and saline waters 0.02-0.7 ,ug/l A - Aquatic sediments From 0.1 mg/l A - Waters ng/l levels A - Sea-water - A L L L L L L, G G - G L, s G G G G G See Cr, ref. 668 Digest with 5N HNO,, wash, centrifuge and dilute with 5N HNO,. Dilute for analysis with addition of NH,CI Pre-concentrate by evaporation See Cu.ref. 1309 Hydride-generation method, using liquid-N, trap Method for differentiation of organic and inorganic Hg Combined GC/AAS system - - Co-precipitate Hg with PbS, by addition of Pb acetate + Na,S to sample made acid (pH 1.0) with HNO,. Decant, wash residue with H,O, dry at 50-60 "C and excite in Fe electrode Add HCI + KBrOJKBr solution and shake. Add 1-2 drops NH,OH.HCI + NaCl and dilute.Reduce with SnCI, Preserve samples by addition of H,SO, + K,Cr,O,, using glass vessels. Method includes u.v.-digestion stage Add dichromate preservative solution to samples. Oxidize with K,S,O, and reduce with SnCI, Oxidize with K,S20, + H,SO,, add SnCI, and pass vapour in stream of air or argon to Ag-wool trap. Release Hg by rapid furnace heating Study of sample storage behaviour A - F Alr/C2H, Graphite furnace F - P D.c.plasma Cold vapour (He) Cold vapour - - Cold vapour A 10 A a.c. Cold vapour Cold vapour Cold vapour Cold vapour Cold vapour 668 703 1279 1309 951 31 3 333 410 412 494 529 b 639 & 3 x k 3 748 0 B ? -. 64 1 k -. cr, 1390 5Hg Hg K K L1 L i Mg Mg Mn Mn Mn Mn Mn Mo Na Ni NI P (PO,) Pb Pb Pb Pb Pb Pb Aquatic sedimenis Liquid effluents Water Rain, snow Natural waters Waters Rain, snow Boiler and feed waters Water films and surface foams Water Water Lake sediments Saline waters Water Rain, snow Waters Waste waters Sea-water Sea-water Drinking water Sediments Lake waters Waters.sediment8 Water Up to 100 ng (absolute) 1-10 pg/ml I 500 pg/l level - I 0.01-3 ,ug/ml - 0.5 pg/ml level - - - Trace levels - Trace levels - Trace levels - 5 pg/ml level E A E A A A A F A E A A A A A A A A A A A A A E G G L L L L L L L L L L L L L L L L L L L L L L Heat in O, at 870 "C and collect P - 1396 2 Fig on Au-coated glass beads.Heat at 500 "C in H e flow - Cold vapour 1403 $ % > L Study of Na interference F - 1134 Add Na (1000 pg/ml) F Air/C,H, 1311 Dual-beam AAS system, monitoring F - 92 $- bLi/7Li abundance ratio Y - Graphite furnace 448 - F Air/C,H, 1311 Add La salt F - 1377 - F - 61 9 b See Cr, ref. 668 None See Cu, ref. 1309 - See Cu, ref. 940 - See Cd, ref. 885 See Cd. ref. 1195 Co-precipitate PO,- ion with AI(OH),, extract into butanol as phospho- molybdate complex and measure Mo See Cd. ref. 185 Adjust to 0.15M HNO, strength and add ascorbic acid See Cu, ref. 620 See Cd, ref. 624 See Cd, ref. 668 A - Graphite furnace F - Graphite furnace Graphite furnace F Air/C,H, Graphite furnace F - F - Graphite furnace Graphite furnace (HGA-2000) (HGA-72) F - Graphite furnace (HGA-72) F - A - 668 885 1309 1361 940 1311 885 1195 580 185 52 1 620 621 624i5 Table 4.53 WATERS, SEWAGE AND EFFLUENTS-continued Element X/nm Matrix Concentration Tech.Sample treaiment Atomization Ref. form Pb 283.3 Water Pb - Waste waters Pb - Water Trace levels A - A - A S - Waters Trace levels E Sb 206.8 Municipal waste materia!s Up to 100 Ng/g A Sb - Geo?hermal waters Sb 252.9 Waters Se 196.1 Water Se - Se I Sn - Sn - Water Water Sewage sludge Environmental samples Water, s?reambed rna!er iais Sr 460.7 Surface waters Sr 460.7 Water From 6 Fg/I A - E 240 ng/ml A - A A Trace levels E From 1 gg/l (waters) A From 0.1 gg/g (others) 0.0'35-1.02 mg/l E 0.02-0.28 mg/i A L L L L L L L L L G L G G L L See Cd, ref. 885 Method for detection of organo-Pb antifouling paints MECA method See As, ref. 569 See Ge, ref. 951 Stcciy of extraction procedures, using DDC, APDC and dithizone. Final method differentistes Se( I V ) and Se(VI) Add KLSL08 + HCI, boil and dilu:o.Generate Se hydride by addition of SnCI, + K I + NaBH, Generate H,Se evolution with NeBH, and collect gas in liquid-N, trap. Release in s'ream of Ha. Modifications given for speciation of Po compounds Adjust to pH 6-7 with NaOH or HCI, extract with toluene and evapora:e. Redissolve in MIEK, pass through activated C column and measure Si (Me:hod for dimethylpolysiloxane) GC + flame detector system Add EDTA to remove inLerferences and generate SnH, by addition of NaBH,.Pass vapour to atomizer in &ream of N, See Ba, ref. 10 Add 1 m l conc. HNO, to 200 ml sample, evaporate to dryness, dissolve i n HNO, and add LaCI, Graphite furnace F - F - F - Graphite furnace (HGA-2100) F - P - Graphite furnace (FLA-10; HU-10) Heated tubs (800 "C) F Air/H, F - Heated tube 835 1192 1202 745 569 709 951 426 705 887 1251 3: 2. 3 2 a 5- 330 654 $ 10 1335 3 2 c s vn U V Zn Zn Zn Zn Zn Zn Zn Zn Zn Amines (indirect) Detergents (indirect) Various (9) 324.7 Water (CU) 318.4 Waters - River water, sediments, 213.9 Waters plants, fish - Lake waters - Waters, sediments - Water - Water - Waste waters - Wasie waters - Lake sediments - Cooling waters 324.7 Natural waters 240.7 (CU) (CO) - Waters 0.01-6 pg/rnl A Trace levels ng/rnl levels - Trace levels - - - From 20 pg/l (octadecylamine) 10 pg/I level 0.02-1 mg/l A A A A A A A A A A A A A L L L L L L L L L L L L L L Add EDTA, adjust to pH 7 and pass through Amberlite IRC-50(H) column.Wash with H,O and elute U with 3M H,SO,. React with Cu/ neocuproine, extract with CHCI, and back-extract with HCI See Cd, ref. 624 None See Cu, ref. 940 See Cd, ref. 1195 See Cu, ref. 1309 Extract long-chain primary amines as amino-Cr complex into nitrobenzene (A) Anionic detergents-add tris( o-phenanthroline) copper ( I I ) sulphate + NaCl and extract with MlBK (pH 2) NH, cobaltothiocyanate + NaCI and extract with C,H, (pH 7.3) (€3) Nonionic detergents-add Adsorb trace metal impurities on iminodiacetic acid ethyl cellulose and extract with acid, to obtain 10- to 20-fold concentration for Cd, Co, Cu, Fe Ha.Mn. Ni. Pb. Zn F Air/C,H, 573 2 Graphite furnace 2 (HGA-70) z ?? k b Graphite furnace 519 '8, (HGA-74) ;j* F - 408 $ Graphite furnace 487 Graphite furnace 621 F - 624 Graphite furnace 885 Graphite furnace 940 F - 1192 F - 1195 F - 1309 F - 059 - t: (FLA-100) (HGA-72) Graphite furnace 12 (Varian model 63) F Air/C,H, 40Table 4.5B WATERS, SEWAGE AND EFFLUENTS-continued Eieinent X/nm Matrix Concentration Tech.Ana’yle form Sampie treatment Aiomization Ref. L L L - L L L L - L L - L Various - (9) Underground waters hg/l levels A Complex impurity elements with DOC F - and oxine, extract with MlBK and n-amylacetate and evaporate mixed organic extracts to 10 ml (from initial H,O sample of 400 mi) Elements: Co, Ni, Fe, Cu, Zn, Cd, Pb, Bi, Cr elec:ronics to improve precision, Fccuracy and speed of analysis Description of high salt content sQlution P ICP in sewage sludge (0.99 g/100 ml) nebulizer.Results given lor 10 elements solubilized with HNOJHCIO, Review of methods I - Acidify with HNO, to pH < 1.5 and store i n Nalgene linear polyethylene or Pyrex glass containers. For Zn, only Teflon should be used.(Study of loss of trace metals on Sorage) - P ICP Automated FAAS system F - Application of microprocessor F - Graphite furnace (HGA-2000) - (Sb, As, Ba, Cd, Pb, Se. Ag, Te) Graphite furnace 75 A Various - Effluents 139 166 Various - Sewage sludge (10) Minor and trace levefs E Various - Waters Various - Natural waters (11) 186 196 - A Various - Various - Various - ( 8 ) Various - Various - (7) Various - ( 8 ) Various - Water Waste wafers Waters Water Water effluents Drinking water Waters Snow E mg/l levels A Trace levels A - 201 208 249 Review - - Automated monitoring system for F - Cd, Cr, Pb, Cu, Fe, Mn and Zn Assessment of AAS and XRF methods F - for Cu, Mn, Zn, Co, Cr, Ni, Pb and Cd Review of techniques, including AAS - - and OES Method for Pb, Zn, Cd, Mn, Cu Graphite furnace 288 328 Trace levels A b 361 Trace levels A 376 Various - (5) Various - Trace levels A 41 1 Inter-laboratory comparison, using F, A - FAAS, OES, XRF and NAA 414 Sewage sludges - A, E Lh Various - Waters (7) Trace levels Various - Surface waters; wastes - (23) Various - Effluent waters Trace levels (9) Various - Water (16) Trace levels Various - Environmental samples - Various - Drinking waters Trace levels (8) Various Various Various Various (25) (30) (15) (6) Various Various Various Various (13) - Coal waste leechates Trace levels - Water Trace levels - Environmental samples - - Waters Trace levels - Waters Trace levels - Paper mill effluents Trace levels - Waters - Waters A E A A A A E, A E E A A, E A E E L Digest with HCI/HNO, and ex:ract F - with APDC/MIBK (Fe, Cu, Zn, Co, Ni, Cd, Pb) L Multi-element direct-reading system P ICP L Study of trace element levels extracted Graphite furnace from fly-zsh under v a r i o s condi:ior,s (As, Be.Cd, Cr, Cu, Mo, Se, V, Zn) 19 countries) system L International study (35 laboratories; F - L Automatic sampling/computer-controlled Graphite furnace L (A) Acidify and spray (Cu, Fe, Mn, F - Zn 1 Cold vapour (B) Concentrate ( x 10) by evaporation and use sampling boat (As, Pb, Cd 1 (C) Cold vapour (Hg) L Study of 6 different leaching solutions P ICP L - P ICP F - L, G - P MIP L Extract as 1,lO-phenan:hroline/ F - perchlorate complex into nitrobenzefie (method for Fe. Cu, Zn, Mn, Cd, Co) emission modes L Comparison of absorption and Graphite furnace L - Graphite furnace L - P ICP L Series of papers OR multi-element P ICP ICP-OES analysis of waters 465 3 k '5 cc 480 5 482 ta b 5 3 533 5. 2 595 623 656 657 759 82 1 849 850 a77 aao 882 883 881 - P w...d Table 4.5B WATERS, SEWAGE AND EFFLUENTS-corzfinued 2. Element X/nm Matrix Ref. A!omizaiion Concentration Tech. Ana'yte Sample lrealmeat form Various - (7) ~~ Sea-water Trace levels A L Various - (7) Various - (8) Various - Various - Various - Water ng/ml levels E, A L Sea-water Trace levels A L A L Water Trace levels Water All levels E L A L Water - Sewage sludge Minor end A L trace levels Various - Sewage sludge (73) Minor and trace levels A, E L, S Various - Drinking waters Trace levels E L A, E L Sewage sludge - Sewage SlUdQe - Waters Trace levels A L A, E L (Zn. Cu. Cd. Co, Ni, Pb. Fe. Bi, Cr) A L Fresh and sea-waters Trace levels Extract with APDC + DDC into Freon T.F. Back-extract into 0.3M HNO, Comparison for ETA emission and absorption modes. (Al. Ba. Be, Cu. Mn, Mo, Ni) Extract wi!h APDC/MiBK and back-extract into HNO, U.S. Geological Survey standard water samples-general description Review of applications of plasma emission methods Review Of AAS + ASV methods Comparison of 5 treatments: (A) HNO, (B) HNO,/H,O, (C) HWHNO, (D) Dry-ash, 550 "C (E) R.f. ashing Dry-ash at 420 "C. dissolve in HCI/ HNO, and add La solution. (Various elements). Overall procedure includes several other techniques, p.g., OES, MS. NAA Review F Air/C,H, 836 Graphite furnace Graphi!e furnace 911 (HGA-2100) (HGA-2100) Graphite furnace 915 F - 937 (CRA-63) P ICP or 938 d.c. plasma F - 939 F Air/C,H, 1071 Graphite furnace (HGA-2000) F, A - 1072 b E. Y 2 * .. 1078 <' P ICP Comparison of ashing procedures Comparison of methods. including AAS, OES, NAA and ASV Extract with DDC and/or B-hydroxy- quinoline into MlBK or n-amyl ace?ate. Concentrate extract by evaporation Comparison of FAAS, NAA and XRF F - 1328 2Various - Drinking waters ng/ml levels A L Concentra'e Ag, Cd, Co, Cr, Cu, Fe, Graphite furnace 1348 2 (9) Mn, Ni, Pb by extraction wiih APDC/MIBK Various - Sea-waters (9) Various - Aquatic sediments - (10) Various - Natural waters Various - Natural waters A L Concentrate Cd, Co, Cr, Cu, Fe, Mn, Graphi!e furnace 1359 $ ;a "J A L Comparison of extraction methods: F Air/C,H, 1389 % Ni, Pb and Zn by extraction with APDC/M I BK 1360 ( A ) 4M HNO, + 0.7M HCI, at 70-90 " C (C) 1.OM NH,OH.HCI in 25% CH,COOH r? -.. (B) 0.5M HCI 9 z at 70-90 "C (D) 0.05M EDTA at pH 4.8 E L - P ICP E L - P ICP 1326 1427