摘要:

Box 1: A chronology of children's environmental health1776 Percival Pott, a London doctor, notes incidence of scrotal cancer in young chimney sweeps, in what is generally considered to be the first linking of cancer to environmental hazards.1904 J.L.Gibson of Queensland, Australia is the first to recognise paint as the source of lead poisoning among children.1953 Researchers in Sweden link mercury to nervous system damage in the developing foetus. Further evidence follows from incidents of mercury poisoning in Japan (Minimata, 1958), Iraq and New Mexico.1970 The enacting of the Clean Air Act in the US eliminates the worst sources of air pollution and leads to health-based standards. Similar legislation is adopted across the developed world.1970s Regulations to reduce lead in motor fuel in Europe and the US.1984 First evidence of long-term effects of low-level lead exposure (Herb Needlemanet al).1990 EPA and ILSI sponsor conference onSimilarities and Differences Between Children and Adults: Implications for risk assessment, one of the first scientific symposia on children's health issues.51993 National Academy of Sciences report highlights the pesticide exposure of infants and children through food and food consumption.6Report points to large gaps in our knowledge.1996 Food Quality Protection Act passed in the US, partly in response to the NAS report. Act requires that children's special needs be taken into account in setting pesticide standards.1997 President Clinton issues Executive Order on Children's Environmental Health and Safety.16EPA sets up Office of Children's Health Protection.15The G8 issue a Declaration on Children's Environmental Health.182000 EPA publishes a strategy for future research8and a first set of indicators on children's environmental health issues.132002International Conference on Environmental Threats to the Health of Children,held in Bangkok; Major reviews of scientific literature published by European Environment Agency,1World Health Organisation,20and Danish Environmental Protection Agency.9Children's health a key issue at Johannesburg World Summit.3Partly adapted fromref. 4

ISSN:0960-7919    

DOI:10.1039/b210561f

出版商:RSC    

年代:2002

数据来源: RSC

ISSN:0960-7919    

DOI:10.1039/b210558f

出版商:RSC    

年代:2002

数据来源: RSC

摘要:

IntroductionThe objective of any educational institution is to prepare the students for the next stage of their development. In scientific disciplines, University is normally considered to be the final stage of formal education and the transition between University and the workplace can arguably be considered the most difficult. This is because the modern University system is one in which students have undergone a structured programme of lectures and set practicals with only very few elements of self-driven study introduced in the final years. Suddenly, they graduate and are expected to be competent scientists, self-motivated and organised. To many, this is a new and traumatic experience.This paper describes a scheme, introduced to our undergraduate teaching programme in 1996, which introduces some of the most important transferrable skills as an integrated part of the final year course. Students work in groups and conduct their own project within the elastic boundaries of Environmental Analytical Chemistry. Due to the nature of the scheme, students find that they quickly become better at managing their time and communicating efficiently, designing and executing their practical strategies, managing the work of others as well as working for others and applying previously learned scientific techniques in real situations.The PPME programmeThe programme was introduced to the practical element of the final year course in Environmental Analytical Chemistry. It could equally have been trialed on other practical classes with the only pre-condition that students taking the course should have already had formal training on the techniques which would be required to execute the experimental tasks in the PPME block. The course runs for 6 weeks with nominally 2 × 3 hour lab sessions per week. Additional study time is also available for planning, discussion,etc.Four experimental topics are identified and the class is divided into four groups.Table 1illustrates four selected projects and resources used in the Environmental Analytical Chemistry course. All techniques practical and instrumental were taught in the third year of the Chemistry course. It should be mentioned that we have also run other projects in which sampling strategies are emphasizede.g.the characterization of a river estuary which is within walking distance of the campus.Selected topics for different projects, which can run parallel in one lab classProjectTopicTechniquesInstrumentsAAS, atomic absorption spectrometry; FES, flame emission spectrometry; IC, ion chromatography; pH, pH determination; HPLC, high performance liquid chromatography; GC-MS, gas chromatography-mass spectrometry.1Rainwater analysisSamplingAAS, FES, IC, pH2Cu in treated timberLeaching, samplingAAS3Uptake of metals in plantsSequential extractionsAAS4Biodegradation of petrolHeadspace analysisHPLC, GC-MSEach group is assigned ownership of one of the topics at the start of the course and is identified as the Managing Group for their project. Group sizes vary according to class size but groups can organise themselves into sub-groups to increase their own efficiency. The experimental topic is chosen to support an open-ended study, so that the challenge is to ask the right questions which can be answered in the limited time available for experiments and interpretation. A laboratory manual and a collection of relevant literature is provided which contains a basic outline of experimental ideas and literature references to help the students get started. Subsequently, the managing group collects and reads the relevant material in the Preparation and Planning Week (Week 1) to enable an experimental and data collection strategy to be identified. At the end of Week 1, each managing group gives a short presentation on their plans for the project, which enables the whole class, and the academic advisors, to contribute suggestions and provide warning of over ambitious programs.In Week 2, all managing groups begin practical work on their projects. This proceeds according to the planning in Week 1 which will have identified who is doing what and when. As data is collected, it will be logged according to the scheme devised during planning and this may be in the form of a spreadsheet or on pre-printed forms. At the end of Week 2, all groups prepare the planning report and detailed instructions for the sub-contracting group. This should only include modifications to prescribed methodologies or special instructions relating to procedures devised which are not described elsewhere. Each group then prepares to ‘sub-contract’ their project to another group while accepting the experimental programme of another project from another group. The organizational rota for the exercise is outlined inFig. 1and the interactions between a project (Project 1 in this case) and the individual groups is illustrated inFig. 2.The organizational structure of the PPME.Group involvement on Project 1 (seeFig. 1).Information which is passed from one group to another in the detailed instruction sheet or task list has to be concise and accurate to maintain a high level of continuity in the project. Further, the managing group is encouraged to introduce elements of quality control, since they do have to rely on data produced by a different party so that they have to assess the quality of data produced. For example they could provide the sub-contractors with a ‘home-made’ reference sample. At the end of Week 2, the sub-contracting group revises the instructions and the task list in consultation with the managing group and report the data they have produced back to the managing group. The collected data have to be presented in a precise and accurate way, so that the managing group is able to validate or to assess the quality of the data.In Week 3 and in subsequent weeks when groups accept experimental responsibility for a new project, they should have briefed themselves on the background to the project, obtained from the task lists and instructions. The importance in meeting deadlines is illustrated in the fact that the sub-contractors have to have the task list available at the latest at the start of the first laboratory session of the week, otherwise precious lab-time is lost. The rotation of projects and groups continues through to the end of Week 5, with the transfer of information between groups at the end of each week.At the end of Week 5, all experimental work is to be completed although limited, small scale, essential work can be carried out in Week 6 if approved by the advisors. Week 6 is mainly for discussion within groups and amongst groups regarding final accumulation of data although this has been a feature of the ‘free study time’ from the beginning of the PPME. Also in Week 6, data are processed, following discussion with advisors, to generate tables and graphs as are necessary to present the entire data set accumulated by the class and to develop conclusions. Student groups use their own time to prepare oral presentations in which each group member has responsibility for presenting a distinct element of the work. The emphasis is on a coherent and seamless presentation in which data are discussed in relation to background provided by an interpretation of the relevant literature. The presentation is attended by the whole class, the advisors and a postgraduate class who are encouraged to question the students on the presentation.The final responsibility of each student is to prepare and submit a final report on the project which they undertook as part of the managing group. Unlike the interim report, this is a full report, written in the conventional style, but containing all data generated throughout the 6 week block. While much of this was undertaken by a group, the student obtains an individual mark based on their individual treatment and interpretation of the data generated and on their presentation style.Learning outcomesAfter active participation the student should be able to:• draw a realistic detailed working plan for a project• delegate work and to write short and precise lab manuals or instructions• implement elements of QC/QA and to assess the quality of analytical data• report data in a clear, precise and accurate way• present the work to their peers in an oral presentation• evaluate their own results and interpret the data appropriately• synthesize a report or a paper in a traditional way.Value of individual elements of the PPMEGroup workThe PPME introduces several new skills to the students. Although group work experience has usually been encountered before, perhaps even in such a basic form as working in pairs, students still find this quite an uncomfortable situation at first, especially if groups are selected at random. However, having accepted this, they quickly adapt and in most cases, natural leaders take charge in the early stages, leading discussions and ‘chairing’ meetings. The main criticism of group work is that some people benefit from the work of more productive group members but experience has shown that groups generally identify problems quickly and have their own ways of dealing with them. Clearly, however, this cannot be taken for granted and advisors should be alert to developing problems.Self and peer assessmentDue to the sub-contracting work, it is necessary to have a performance indicator and a measure about the quality of the data which they receive from the other groups. Since they have no control how the data are produced they have to implement stringent protocols and QC/QA procedures (e.g., introduction of samples with known concentrations in order to control the analytical performance of their own group and/or the sub-contractors). This is absolutely necessary in this set-up but can be easily forgotten particularly when everything is under their own supervision and knowledge is available how the data were produced.Sense of responsibilityDespite the possible problems in a group, most group members feel a sense of responsibility and loyalty to their own group so will work hard to ensure that they are not going to be the ones to let others down. There is also a sense of ownership of the work so there tends to be a certain amount of pride and increased conscientiousness. This automatically guarantees an enhanced work rate and an increase in the quality of lab work.Personnel and time managementAll projects are designed to have more work in them than can satisfactorily be completed in the time available and this usually influences the weekly allocation of tasks for individual groups. Therefore group members have to distribute the workload amongst themselves. Group sizes vary depending on class size but generally, there are at least 4 or 5 students in each group enabling sub-groups to undertake separate tasks. Students also need to set themselves targets and achieve them. The consequences of not completing their allocated tasks are that they do not have sufficient (or any) data to pass on to the next group. Their sense of responsibility encourages them to meet deadlines.CommunicationsThe transfer of information is vital to the success of the PPME. In the early stages, students are unfamiliar with the concept of writing task lists or short instructions and generally only begin to adapt slowly to the concept of leaving superfluous material out of the report, writing using bulleted points and in incomplete sentences, and highlighting the most important facts. They also quickly learn how poor communication can lead to mistakes and omissions. Consequently, a greater effort is made to get the relevant messages across as the PPME progresses. Experience has shown that, without exception, students adapt to being better communicators regarding transfer of technical information between groups. The preparation of oral presentations is not unique to the PPME but the confidence that students have built up in managing, planning and executing projects without significant staff involvement leads to better quality presentations; the students have actually sought out the information themselves to piece the story together. This leads to better retention and understanding of the material.Reinforcement of earlier learningVirtually all of the techniques used in the projects should be familiar to all the students. Thus, the students should be able to use the necessary techniques efficiently and accurately as tools in the PPME exercise. Having only used these techniques previously in a set laboratory exercise where they were being tested on accuracy of analysis for example, the students perceive their analysis in the PPME exercise as being more relevant because there is no ‘correct’ answer and they learn to use trends as a guide to data reliability. It is more important to the student that the results they get are reliable so they will try to reinforce their earlier learning of the technique to get the best results possible.Staff resourcesThroughout this description of the PPME, it is clear that staff involvement is deliberately minimized. This is important because the sense of achievement for students is greater. The main staff effort is in setting up the experimental projects, ensuring adequate facilities and a laboratory manual with background information, lists of references and safety information are available. Assessment is much less demanding on staff time, with only one interim report per group per week and individual reports only in the last week to assess.AssessmentAlmost all learning outcomes are assessed. All forms of assessment are incorporated. Diagnostic assessments such as the interim reports allow the advisor to identify problems of understanding, while a summative assessment is guaranteed at the end at which each individual student has to write their own interpretation of the data. In general students are assessed on their interim reports (one per group per week) in which all students in a group get the same mark; it is made clear to the students from the beginning that group work carries certain responsibilities and rewards as well as penalties. All students obtain individual marks on their final individual report and on their oral presentation.Feedback on PPMEThe course has run for six years and has experienced small refinements in each of these years. This has largely been as a result of feedback from the student ‘victims’ who have undertaken the PPME. The general feeling amongst staff and students was that this approach to teaching has been successful. All agreed that having previous awareness of the operating procedures and interpretation skills associated with analytical instrumentation and techniques was vital to the success of this applications-based laboratory course. Students also identified the relevance to ‘real world’ problems and the introduction to ‘transferrable skills’. They also recognized the advantages of the approach to better preparation for employment and this is now an essential part of Chemistry and Environmental Science degree courses, which are about to be accredited. The exercise has also been adopted on a postgraduate course (MSc Analytical Chemistry) at Aberdeen and has received favorable comments from the European Masters Degree Advisory Committee, comprising academic staff from a number of European Universities.Finally, it should be mentioned that this kind of practical class places emphasis on ‘learning on the job’, rather than on a practical in which the student is only a consumer but not a contributor. The student feels, maybe for the first time, that they can determine which aspect they want to study. The projects are so designed that each year, depending on the groups’ interest, other aspects of Environmental Science may be covered. They can satisfy themselves by following their own self-determination and gain confidence in the subject they studied.

ISSN:0960-7919    

DOI:10.1039/b209061a

出版商:RSC    

年代:2002

数据来源: RSC

摘要:

1IntroductionVolatile organic compounds (VOCs) occur in the atmosphere at low levels from natural sources and at relatively high levels (ng m−3to mg m−3) from anthropogenic sources. Generally, they occur in increasing amounts in outdoor (ambient) air, indoor air and workplace air respectively. Such compounds may pose a risk to human health or the environment, and there may be a requirement to monitor these compounds, for example, in relation to compliance with limit values, assessing the effectiveness of control measures, or assessing trends in time or space.A requirement to monitor implies the availability of an appropriate measuring procedure,i.e.one with an associated measurement uncertainty and “robustness” appropriate to the application. This, together with appropriate reference materials, quality control procedures and laboratory accreditation, should ensure that the measurement result is reliable, as any decisions made on the basis of the measurement result may ultimately be life-threatening, or, at least, costly.Many such measuring procedures for VOCs are available nationally, for example seerefs. 1 to 10. However, it is obviously desirable, to ensure consistency of method evaluation, the harmonisation of methods used and to avoid duplication of effort, if methods could be developed and published internationally. Thus the International Organisation for Standardisation (ISO) and, to a lesser extent, Comité Européen de Normalisation (CEN) have been engaged in preparing standards for VOCs and other compounds.In general, ISO standards are not obligatory, but are intended as guidance documents representing a consensus view on good practice. Usually, they are translated into national standards. In the case of the United Kingdom, the relevant national member body is the British Standards Institution (BSI), which regularly re-publishes ISO standards as BS ISO ones. In the case of the United States, the relevant national member body is the American National Standards Institute (ANSI). In addition the American Society for Testing of Materials (ASTM: a voluntary consensus standards agency) is in the habit of incorporating ISO standards as ASTM standards and the US Technology Transfer Act signed by President Clinton requires US government agencies to use voluntary consensus standards where possible. Thus ISO standards will inevitably be used by US government agencies. NIOSH and the EPA both have representation in ISO and support the process.On the other hand, Member States (within Europe) have agreed that all CEN standards will be reproduced as national standards and conflicting national standards will be withdrawn. Furthermore, CEN standards become legally binding if they are called up in European Directives.

ISSN:0960-7919    

DOI:10.1039/b207336f

出版商:RSC    

年代:2002

数据来源: RSC