Brief guide to analytical methods for measuring lead in paint
WHO Library Cataloguing-in-Publication Data
Brief guide to analytical methods for measuring lead in paint.
1.Lead - analysis. 2.Paint - analysis. 3.Lead - chemistry . 4.Chemistry techniques, Analytical. 5.Spectrometry, X-ray emission. 6.Laboratory techniques and procedures. I.World Health Organization.
ISBN 978 92 4 150212 2
(NLM classification: QV 292)
This publication was developed in the IOMC context. The contents do not necessarily reflect the views or stated policies of individual IOMC Participating Organizations. The Inter-Organization Programme for the Sound Management of Chemicals (IOMC) was established in 1995 following recommendations made by the 1992 UN Conference on Environment and Development to strengthen co-operation and increase international co-ordination in the field of chemical safety. The Participating Organizations are FAO, ILO, UNEP, UNIDO, UNITAR, WHO, World Bank and OECD. UNDP is an observer. The purpose of the IOMC is to promote co-ordination of the policies and activities pursued by the Participating Organizations, jointly or separately, to achieve the sound management of chemicals in relation to human health and the environment.
© World Health Organization 2011
All rights reserved. Publications of the World Health Organization are available on the WHO web site (www.who.int). The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use.
Contents Acknowledgements.................................................................................................................iv 1. Purpose and scope ............................................................................................................. 1 2. Background......................................................................................................................... 1 3. Available analytical methods............................................................................................... 2 3.1 Chemical test kits .......................................................................................................... 3 3.2 Portable X-ray fluorescence (XRF) spectrometry ......................................................... 3 3.3 Laboratory analysis ....................................................................................................... 4 3.3.1 Flame atomic absorption spectrometry (FAAS) ..................................................... 5 3.3.2 Graphite furnace atomic absorption spectrometry (GFAAS).................................. 6 3.3.3 Inductively coupled plasma atomic emission spectrometry (ICP-AES).................. 6 4. Important aspects of laboratory practice............................................................................. 6 4.1 Preventing external contamination................................................................................ 6 4.2 Quality assurance (QA)................................................................................................. 7 5. Method selection................................................................................................................. 7 6. References.......................................................................................................................... 8
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Acknowledgements This document was written by Dr Pascal Haefliger. The following people reviewed and provided comments on the document, and their contributions are gratefully acknowledged: Dr R. Braithwaite, Department of Forensic Science and Drug Monitoring Centre, King’s College London, London, England Mr P. Gottesfeld, Executive Director, Occupational Knowledge International (OK International), San Francisco, United States of America (USA) Dr I. Naik, Analytical Services, National Health Laboratory Services, National Institute for Occupational Health, Johannesburg, South Africa Dr P. Nisse, l’Unité de Toxicovigilance, Centre Antipoison de Lille, Lille, France Dr A. Taylor, Supra-regional Assay Service, Trace Element Laboratory, Centre for Clinical Science, University of Surrey, Guildford, England The document was finalized by Ms Joanna Tempowski, Department of Public Health and Environment, WHO, Geneva, Switzerland. The document was edited by Ms Marla Sheffer. WHO gratefully acknowledges the financial support of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. For further information on this document please contact ipcsmail@who.int.
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1. Purpose and scope This document provides a brief overview of analytical methods available for measuring lead in paint. It is primarily aimed at informing environmental health personnel and policy-makers who are not laboratory specialists but who may need to develop plans for lead paint testing and abatement programmes. This document lists well-established analytical methods for measuring lead in paint, briefly describes some of their characteristics, including their advantages and disadvantages, and highlights considerations for selecting the most appropriate method for various requirements and contexts. The document does not aim to provide an exhaustive description of analytical methods and protocols or to make specific recommendations regarding methodologies or specific instruments. Links to further information and reading are provided in section 6.
2. Background Lead is a toxic metal whose widespread use has caused extensive environmental contamination and health problems in many parts of the world. Human exposure to lead is estimated to account for 143 000 deaths every year and 0.6% of the global burden of disease (1). Lead is a cumulative toxicant that affects multiple body systems, including the neurological, haematological, gastrointestinal, cardiovascular and renal systems. Children are particularly vulnerable to the neurotoxic effects of lead, and even low levels of exposure can cause serious and, in some cases, irreversible neurological damage. Childhood lead exposure is estimated to contribute to about 600 000 new cases of children with intellectual disabilities every year (2). Despite recent reductions in the use of lead in petrol (gasoline), plumbing and solder, significant sources of exposure to lead still remain, including lead-based paint. Lead-based paint has been used, and is still in use in some countries, to paint the interiors and exteriors of homes and other buildings and to paint toys, furniture, playground equipment and other articles with which children can come into contact. Lead-based paint can be found in virtually every country. It is still available and in use in many parts of the world; even in countries where it has been banned for specific uses, leaded paint can be found in older houses and articles (3). Non-occupational exposure to lead from paint occurs mainly in the home, from house paint that has flaked or chalked as it has aged or that has been disturbed during home maintenance and renovation. This results in the generation of lead-containing dust that can be inhaled or ingested. Soil around the home may also become contaminated. Lead-contaminated house dust has been recognized as a major contributor to the total body burden of lead in children (4). Young children are particularly at risk of ingestion of lead through normal hand-to-mouth activity. In addition, some children with pica persistently pick off and eat fragments of leaded paint. Young children can also be exposed through the mouthing of painted objects and toys. In some countries, lead-based paint may be the most widespread and dangerous high-dose source of lead exposure for children.
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Brief Guide to Analytical Methods for Measuring Lead in Paint Removing existing leaded paint from housing and articles and eliminating the use of leadbased paint in residential areas and on furniture, equipment and toys are therefore important contributions to the primary prevention of lead poisoning globally. The ability to accurately determine lead concentrations in both new paint and dry paint on surfaces is a crucial requirement to guide these tasks.
3. Available analytical methods There are three main approaches for determining the lead content in paint: 1) Test the paint for lead in situ using a chemical test kit. 2) Measure the amount of lead in paint in situ using a portable X-ray fluorescence (XRF) device. 3) Collect a paint sample and measure its lead content in a laboratory using various analytical techniques. These approaches are described in the next sections and summarized in Table 1. Table 1. Overview of analytical methods for lead in paint Method Chemical test kits Strengths Immediate results Cheap Relatively simple to use Limitations Limited accuracy Qualitative or semiquantitative Can test mainly top (surface) layers May need to damage the paint surface Difficult to observe colour change for dark paints Potentially larger margin of error compared with laboratory analysis Requires some training/certification Relatively high purchase cost Cannot measure lead in small objects or on highly curved or intricate surfaces, including many toys Paint surface must be disturbed Very expensive if equipment must be purchased and set up Requires trained laboratory personnel and strict quality assurance measures Results are not available immediately
Portable X-ray fluorescence spectrometry
Good accuracy Immediate results Low use costs No damage to the paint surface Rapid
Laboratory analysisa
Most accurate method Relatively affordable if laboratory is available and only few samples No technical limitations Can determine both the soluble and insoluble lead fractions Can be used to analyse new (wet) paint
a
Various analytical methods exist to measure the concentration of lead in the sample, including flame atomic absorption spectrometry, graphite furnace atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry. Although these methods differ in their accuracy and limits of detection, all of them are usually adequate to determine lead in paint at commonly required detection limits and accuracy levels.
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3.1 Chemical test kits There is a range of chemical test kits, from simple qualitative tests to more sophisticated semiquantitative tests. Many rely upon a colour change to indicate the presence of lead above a certain concentration. In the simplest kits, the result is either positive (i.e. lead is present above a certain concentration) or negative (i.e. lead is absent above a certain concentration), according to whether a colour change occurred. The threshold concentration for the colour change depends upon the test kit used and may be regulated in the country where the test is marketed. In the USA, for example, test kits should detect concentrations above 0.5% lead by weight (5000 mg/kg). Depending on the context in which they are meant to be used, some chemical test kits may have lower limits of detection. The simpler kits either test the paint using a swab soaked in a chemical reagent that is rubbed onto the painted surface or require the removal of a chip of paint of a specified area that is then mixed with reagents in a tube. More sophisticated spot test kits use fluorimetric or photometric methods on paint chips. The United States Environmental Protection Agency (USEPA) has evaluated a number of these kits, and additional information can be found on its web site (5). Chemical test kits are relatively cheap and do not require specific training, although training of the user will give more reliable results. The results are immediate. These kits have a number of limitations, however. The kits can test exposed layers only; therefore, to test underlying layers that may be more likely to contain lead, it is necessary to score the paint surface or to remove a chip of paint (depending on the method). For some kits, the colour change may be difficult to observe, particularly when testing dark paint colours. In general, these kits cannot measure the amount of lead present in the paint; even the semiquantitative methods provide only concentration ranges. Finally, chemical test kits may have limited accuracy; in other words, they may indicate that lead is present above a certain concentration when it is not (false positive) or that lead is not present above a certain concentration when it is (false negative). The USEPA, for example, currently recognizes only three lead test kits as being compliant with the false negative criterion of the United States 2008 Renovation, Repair and Painting rule. These three tests are recommended only when used by a certified renovator for paint present on specific substrates, and none is recognized by the USEPA for the false positive criterion of the Renovation, Repair and Painting rule (6). For these reasons, methods other than chemical test kits are generally preferred for the accurate determination of lead in paint (7).
3.2 Portable X-ray fluorescence (XRF) spectrometry XRF spectrometry is based on the fact that, when exposed to high-energy radiation, lead (like many other elements) emits X-rays at a characteristic frequency. The intensity of the rays can be measured and correlated to the amount of lead per unit area (usually in units of milligrams per square centimetre). As regulatory standards for lead in paint may be expressed in other units (e.g. parts per million or per cent concentration by weight), the XRF results may need to be converted. Portable XRF instruments can measure the total amount of lead in a painted surface in situ without damaging the paint or the substrate. Portable XRF
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Brief Guide to Analytical Methods for Measuring Lead in Paint devices are very easy to use but, because of the radiation hazard, require special training. In some countries, operators must be certified. The accuracy of portable XRF devices is good, although they have a larger margin of error compared with adequately executed laboratory analysis (this is particularly true of X-ray tube–based instruments). Borderline measurements (i.e. readings that are within the device’s margin of error and are close to the established national limit for lead in paint) should therefore be confirmed by laboratory analysis. Depending on their size and characteristics, XRF devices require a relatively large and flat surface to conduct a measurement. This method is therefore particularly adapted to measuring flat paint surfaces, but is less applicable to testing highly curved or intricate surfaces, including many toys, because of safety concerns, poor reliability of results and the inability to determine the exact surface area measured (7, 8). Some new devices may overcome these limitations. Portable XRF devices are available from several manufacturers. They are relatively expensive, ranging in price from approximately US$ 10 000 to US$ 50 000, but require little maintenance and no consumables. Measurements are very rapid (about 1 minute, although less precise results can be obtained in a shorter time), allowing operators to measure many paint surfaces in a short period of time. Guidelines for the determination of lead in paint using XRF devices are available from various sources, including manufacturers and national institutions (8).
3.3 Laboratory analysis This approach requires that a sample of paint, either new paint or dry paint removed from a surface, be collected and analysed in a laboratory using various techniques. Laboratory analysis requires careful sample collection and preparation. For dry paint on surfaces, it is generally recommended that:
all layers of paint are collected, as the lower levels are more likely to contain lead; as little as possible of the underlying material (e.g. wood, plaster, metal) is included, as this might give erroneous results; within a house or building, several representative samples are collected from different areas; the location of each sample is recorded; surfaces from which paint samples have been collected are repaired to prevent future exposure in case the paint contains lead.
A minimum sample size of about 300 mg is usually required to conduct an analysis, although this depends on the concentration of lead, sample preparation and the method of analysis. Results can be provided in weight per cent if the weight of the sample is measured or in weight per unit surface area if the exact surface area of the sample can be determined. In the laboratory, the paint sample must be processed before being analysed. For the measurement of total lead, the sample should undergo acid digestion. For the measurement of soluble lead (i.e. the lead likely to be available for absorption if a child mouths or swallows
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the paint), an acid extraction process is used. Whether total lead or soluble lead is measured depends on the reason for the analysis and on the relevant national regulations (9, 10). The actual analysis can be conducted using different techniques, including flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Guidelines, recommendations and standard operating procedures for sample collection, preparation and analysis using these and other methods are available from numerous sources, including manufacturers, national institutions and international standardization agencies (8–16). Laboratory analysis is considered the most accurate method for measuring lead in paint, provided adequate quality assurance (QA) principles are followed (see section 4.2) and, in the case of paint chip samples, all layers of paint are included, but not substrate material (17). This method requires, however, that a painted surface be disturbed and repaired. This is the only method that can be used for measuring lead in wet paint. It also requires significant time and financial resources for sample collection, transport and laboratory analysis. Analysis can be performed only by trained laboratory technicians in adequate laboratory settings. The following sections briefly describe three of the most frequently used instrumental techniques for laboratory determination of lead in paint chips: FAAS, GFAAS and ICP-AES (11, 18). Although these methods differ in their levels of accuracy and their limits of detection, all of them are adequate to determine lead in paint at commonly required detection limits and accuracy levels. Other less commonly used instrumental methods that are not described here include inductively coupled plasma mass spectrometry, direct current plasma atomic emission spectrometry, dithizone spectrophotometry, anodic stripping voltammetry and potentiometric stripping voltammetry. 3.3.1 Flame atomic absorption spectrometry (FAAS) Atomic absorption spectrometry (AAS) is based on the fact that free atoms absorb light at wavelengths characteristic of the element of interest: 283.3 nm in the case of ground-state atoms of lead. The amount of light absorbed can be correlated in a linear fashion to the concentration of the analyte in the sample. To conduct an AAS measurement, the leadcontaining sample must first be processed by the instrument so as to generate ground-state atoms as a vapour within the light path of the instrument, a process known as atomization. FAAS uses an air–acetylene or a nitrous oxide–acetylene–air laminar flame to atomize lead at temperatures up to 2600 °C. FAAS detection limits are moderate, but still sufficient for most cases. As direct sample aspiration is required, a minimum of about 5 ml of digest is needed for aspiration and measurement of a stable signal. FAAS measurements are subject to some interference from light scattering and molecular absorption by matrix components, which can be adequately corrected by various approaches. FAAS devices, which require some laboratory skills to operate, are widely available with or without autosamplers. The initial instrument cost is relatively low, and consumables, such as acetylene gas, are relatively inexpensive. Maintenance needs are relatively low, and sample throughput can be several samples per minute.
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Brief Guide to Analytical Methods for Measuring Lead in Paint 3.3.2 Graphite furnace atomic absorption spectrometry (GFAAS) GFAAS is an AAS technique that uses an electrically heated graphite tube to vaporize and atomize the analyte at temperatures up to 3000 °C prior to its detection. GFAAS instruments give very low detection limits and require only very small digest volumes (about 20 µl). GFAAS measurements are often subject to significant interference from light scattering and molecular absorption by matrix components, but this can be adequately corrected using various approaches, including the use of matrix modifiers. GFAAS devices must be operated by trained laboratory technicians. GFAAS devices are widely available and require autosamplers to increase precision and throughput. Initial instrument cost is intermediate, and maintenance and consumable costs are significant. Sample throughput is approximately one sample every 2 to 3 minutes. 3.3.3 Inductively coupled plasma atomic emission spectrometry (ICP-AES) ICP-AES uses an inductively coupled plasma (a very high temperature ionized gas composed of electrons and positively charged ions) source to dissociate the sample into its constituent atoms or ions. Under these high-energy conditions, lead (like many other elements) emits light at characteristic wavelengths. The amount of light emitted can be measured and correlated to the concentration of lead in the sample. ICP-AES instruments offer the advantage of being able to determine several elements simultaneously. The detection limit for lead is intermediate, but still sufficient to measure lead accurately in paint at commonly observed concentrations. Sample volume requirements are moderate. Some spectral interferences are common, but can be corrected. ICP-AES instruments must be operated by trained laboratory personnel. The initial instrument cost is high, but the major consumable is only argon gas. Maintenance costs are relatively high because of the complicated design of ICP-AES instruments. Sample throughput is intermediate, typically about one sample per minute.
4. Important aspects of laboratory practice In analytical chemistry, even the most sophisticated and accurate equipment will provide incorrect results if samples have not been appropriately collected and handled, if the equipment has not been used correctly or if analytical protocols have not been followed. Two concerns associated with measurements of lead in paint are unrecognized contamination and inadequate QA. These issues are briefly discussed in the following sections.
4.1 Preventing external contamination Lead is pervasive and can contaminate samples in numerous ways, particularly in the case of paint chip laboratory analysis. Contamination can occur during sample collection, sample storage and transport, and sample manipulation. The quality of sample collection and handling is therefore a crucial aspect for the accurate determination of lead in paint. Sample handling within the laboratory entails as much risk of contamination as sample collection in the field. Laboratories should be as close to lead free as possible, and laboratory staff
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should be properly trained to prevent sample contamination. Specific protocols are available for the different analytical methods, including from manufacturers and standardization agencies (8–15). These must be strictly adhered to. Contamination risks can be significantly reduced by the application of adequate QA measures.
4.2 Quality assurance (QA) QA refers to all steps that must be taken to assure that laboratory results are reliable and reproducible. It covers the utilization of scientifically and technically sound practices for laboratory investigations, including the selection, collection, storage and transport of specimens and the recording, reporting and interpretation of results. It also refers to training and management designed to improve the reliability of investigations. From the point of view of an analysis, QA can be divided into two stages: 1) initial assessment of an analytical method as to its practicability and trueness, which includes linearity, specificity, recovery, calibration standards, blanks and interference; and 2) subsequent quality assessment. Quality assessment refers to the quality of the analytical results. It has two components: 1) internal quality control, which is a set of procedures used by the staff of a laboratory for continuously assessing results as they are produced in order to determine whether they are reliable enough to be released; 2) external quality assessment (EQA), which is a system for objectively checking laboratory performance using an external agency. Further information on laboratory QA and quality management and examples of EQA programmes specific for lead in environmental samples are available from various sources (19– 21). It is crucial that adequate QA measures be followed by the laboratory conducting the paint sample analysis, including, if possible, EQA. International and/or national accreditation should also be considered.
5. Method selection The choice of method depends on numerous factors, including the level of accuracy required, the substrate to be tested (including whether it is new paint or a painted surface), the availability of trained personnel and analytical equipment, and financial considerations. As a result of their limited accuracy and practical limitations and despite their ease of use, chemical test kits are usually not recommended for the accurate determination of lead in paint, with the exception of a few kits for specific applications and circumstances (6, 7). The portable XRF lead-based paint analyser is the most commonly used primary analytical method for inspections in housing. This is because of its demonstrated ability to determine whether lead-based paint is present on many surfaces and to measure the lead content of the paint without destructive sampling or paint removal, as well as its high speed and low
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Brief Guide to Analytical Methods for Measuring Lead in Paint cost per sample. This method, however, cannot be used to test small items and highly curved or intricate surfaces, including many toys. It is generally considered that laboratory analysis is the most accurate method to measure lead in paint, provided all the requirements for adequate QA are met (17). However, this process requires significant skill and time for sample collection, transport and laboratory analysis. If analysis is conducted by a commercial laboratory, the cost of analysis per sample is relatively high. Damage from sampling is also an unavoidable consequence if dried paint is being tested. For these reasons, determination of lead in paint by the sole use of laboratory analysis is generally not recommended, and portable XRF analysis is often preferred (8). Laboratory analysis is, however, recommended in the following situations:
for new paint; when a high accuracy and/or low limits of detection are needed; for small items, such as toys, and inaccessible areas or building components with irregular surfaces that cannot be tested using XRF instrumentation; to confirm borderline XRF results.
If laboratory analysis is preferred, numerous analytical methods are available, including FAAS, GFAAS and ICP-AES. All of these methods are adequate to determine lead in paint with commonly required limits of detection and accuracy as long as guidelines, standard operating procedures and strict QA measures are followed. Method choice will depend on numerous factors, such as:
availability of operational equipment and laboratory; availability of adequately trained laboratory personnel; level of laboratory QA measures; number of samples and analysis turnaround time; analytical costs, including running and maintenance costs; equipment purchase and installation costs if new instrumentation must be purchased; availability of an external laboratory if analytical capacities are not available locally.
6. References 1. Global health risks: Mortality and burden of disease attributable to selected major risks. Geneva, World Health Organization, 2009 (http://www.who.int/healthinfo/global_burden_disease/Global HealthRisks_report_full.pdf, accessed 20 December 2010). 2. Exposure to lead: A major public health concern. Geneva, World Health Organization, 2010 (http://www.who.int/ipcs/features/lead..pdf, accessed 20 December 2010). 3. Global study to determine lead in new decorative paints in 10 countries: Executive summary. New Delhi, Toxics Link, 2009 (http://www.ipen.org/ipenweb/documents/work%20documents/paint_ executivesummary.pdf, accessed 20 December 2010). 4. Bornschein RL et al. Exterior surface dust lead, interior house dust lead and childhood lead exposure in an urban environment. In: Hemphill DD, ed. Trace substances in environmental
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health. Vol. 20. Proceedings of the University of Missouri’s 20th Annual Conference, June 1986. Columbia, MO, University of Missouri, 1987:322–332. 5. Performance characteristics of qualitative spot test kits for lead in paint (completed 2010). Washington, DC, United States Environmental Protection Agency, Environmental Technology Verification Program (http://www.epa.gov/nrmrl/std/etv/este.html#pcqstklp, accessed 30 December 2010). 6. EPA recognition of lead test kits. Washington, DC, United States Environmental Protection Agency (http://www.epa.gov/lead/pubs/testkit.htm, accessed 30 December 2010). 7. Lead-based paint: Testing methods. Missoula, MT, United States Department of Agriculture Forest Service, Technology & Development Program, 1996 (http://www.fs.fed.us/eng/pubs/ htmlpubs/htm96712353/, accessed 20 December 2010). 8. Guidelines for the evaluation and control of lead-based paint hazards in housing. Washington, DC, United States Department of Housing and Urban Development, 1995 (http://www.hud.gov/ offices/lead/lbp/hudguidelines/index.cfm, accessed 20 December 2010). 9. ASTM F963 - 08 Standard consumer safety specification for toy safety. West Conshohocken, PA, ASTM International, 2008 (http://www.astm.org/Standards/F963.htm, accessed 20 December 2010). 10. ISO 8124-3:2010 Safety of toys—Part 3: Migration of certain elements. Geneva, Switzerland, International Organization for Standardization, 2010 (http://www.iso.org/iso/iso_catalogue/ catalogue_tc/catalogue_detail.htm?csnumber=43471, accessed 31 May 2010). 11. Pb-based paint laboratory operations guidelines: Analysis of Pb in paint, dust, and soil. Revision 1.0. Washington, DC, United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, 1993 (EPA 747-R-92-006; http://www.epa.gov/lead/pubs/92-006.pdf, accessed 20 December 2010). 12. ASTM E1729 - 05 Standard practice for field collection of dried paint samples for subsequent lead determination. West Conshohocken, PA, ASTM International, 2005 (http://www.astm.org/ Standards/E1729.htm, accessed 20 December 2010). 13. ASTM E1645 - 01(2007) Standard practice for preparation of dried paint samples by hotplate or microwave digestion for subsequent lead analysis. West Conshohocken, PA, ASTM International, 2007 (http://www.astm.org/Standards/E1645.htm, accessed 20 December 2010). 14. Binstock D et al. Standard operating procedures for lead in paint by hotplate- or microwave-based acid digestions and atomic absorption or inductively coupled plasma emission spectrometry. Research Triangle Park, NC, United States Environmental Protection Agency, 1991 (http:// cfpub.epa.gov/ols/catalog/catalog_display.cfm?&FIELD1=AUTHOR&INPUT1=Grohse%20AND% 20P%20AND%20M&TYPE1=ALL&item_count=9, accessed 20 December 2010). 15. ASTM E1613 - 04 Standard test method for determination of lead by inductively coupled plasma atomic emission spectrometry (ICP-AES), flame atomic absorption spectrometry (FAAS), or graphite furnace atomic absorption spectrometry (GFAAS) techniques. West Conshohocken, PA, ASTM International, 2004 (http://www.astm.org/Standards/E1613.htm, accessed 20 December 2010). 16. Test method: CPSC-CH-E1003-09: Standard operating procedure for determining lead (Pb) in paint and other similar surface coatings. Gaithersburg, MD, United States Consumer Product
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Brief Guide to Analytical Methods for Measuring Lead in Paint Safety Commission, 2009 (http://www.cpsc.gov/about/cpsia/CPSC-CH-E1003-09.pdf, accessed 20 December 2010). 17. Schmehl RL et al. Lead-based paint testing technologies: summary of an EPA/HUD field study. American Industrial Hygiene Association Journal, 1999, 60:444–451. 18. Flanagan RJ et al. Fundamentals of analytical toxicology. John Wiley & Sons Ltd, 2007. 19. Environmental Lead Proficiency Analytical Testing (ELPAT) Program. Fairfax, VA, AIHA Proficiency Analytical Testing Programs, LLC (http://www.aihapat.org/ProficiencyTesting Programs/elpat/Pages/default.aspx, accessed 20 December 2010). 20. Quality assurance. San Francisco, CA, United States Environmental Protection Agency, Region 9 Quality Assurance Office (http://www.epa.gov/region9/qa/, accessed 20 December 2010). 21. Laboratory quality management system training toolkit. Lyon, World Health Organization, International Health Regulations (http://www.who.int/ihr/training/laboratory_quality/en/index.html, accessed 20 December 2010).
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ISBN 978 92 4 150212 2
11
涂料中 铅测定 分析方 法简要 指南
WHO Library Cataloguing-in-Publication Data Brief guide to analytical methods for measuring lead in paint. 1.Lead - analysis. 2.Paint - analysis. 3.Lead - chemistry . 4.Chemistry techniques, Analytical. 5.Spectrometry, X-ray emission. 6.Laboratory techniques and procedures. I.World Health Organization.
ISBN 978 92 4 550212 8
(NLM classification: QV 292)
本出版物是在跨组织化学品无害管理计划（IOMC）的框架下编制的。其内容并不必然反映IOMC各参与组 织的观点或所宣称的政策。 跨组织化学品无害管理计划（IOMC）是相关组织于 1995 年按照 1992 年联合国环境与发展大会所提 出的在化学品安全领域加强合作和提高国际协调的建议所建立的。目前参与该方案的组织包括联合国粮 农 组 织 （ FAO ） 、 国 际 劳 工 组 织 （ ILO ） 、 联 合 国 环 境 规 划 署 （ UNEP ） 、 联 合 国 工 业 发 展 组 织 （UNIDO）、联合国训练研究所（UNITAR）、世卫组织（WHO）、世界银行（World Bank）和经济合作和 发展组织（OECD）。联合国开发计划署（UNDP）系该计划的观察员组织。IOMC 的目的是促进各参与机 构在政策和行动上的协调，联合地或独立地，实现与人类健康和环境有关的化学品的无害化管理。
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目录 致谢 ......................................................................................................................................iv 1.目的和范围 ......................................................................................................................... 1 2.背景 ................................................................................................................................... 1 3.可采用的分析方法 .............................................................................................................. 1 3.1 化学检测试剂盒 ........................................................................................................... 2 3.2 便携式 X-射线荧光光谱法 ............................................................................................ 3 3.3 实验室分析 .................................................................................................................. 3 3.3.1 火焰原子吸收光谱法（FAAS） ............................................................................. 4 3.3.2 石墨炉原子吸收光谱法（GFAAS） ....................................................................... 5 3.3.3 电感耦合等离子体原子发射光谱法(ICP-AES) ........................................................ 5 4. 实验室操作重要事项 .......................................................................................................... 5 4.1 防止样品外部污染 ........................................................................................................ 5 4.2 质量保证（QA） .......................................................................................................... 6 5. 方法选择 ........................................................................................................................... 6 6. 参考文献 ........................................................................................................................... 7
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致谢 本文件由 Dr Pascal Haefliger 执笔起草。以下人员审读了文件草案，并提供了宝贵意 见。对他们做出的贡献在此深表感谢： Dr R. Braithwaite, 伦敦大学国王学院法医学和药物监测中心（英国伦敦） Mr P. Gottesfeld, 职业知识国际(OK International)执行主任（美国旧金山） Dr I. Naik, 国立职业卫生研究所，国立卫生实验室服务中心，分析服务处（南非约翰内斯 堡） Dr P. Nisse, 里尔中毒控制中心，毒理监测处（法国里尔） Dr A. Taylor, 萨里大学，临床科学中心，微量元素实验室，跨区域检测服务处（英国吉尔 福德） 本文件终稿由世卫组织公共卫生和环境司 Joanna Tempowski 女士（瑞士日内瓦）定稿， 由 Marla Sheffer 女士编辑。 世界卫生组织衷心感谢德国联邦环境、自然保护与核能安全部提供的财政支持。 如需更多与本文件相关的信息，请联系： ipcsmail@who.int。
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1. 目的和范围 本文件对涂料中铅测定的分析方法进行了简要概述，主要是为环境卫生工作人员及政 策制定者提供信息，他们虽然不是实验室专业工作人员，但可能需要制订与涂料中铅的检 测有关的计划和铅危害消除规划。本文件列出了业已成熟的用于测定涂料中铅含量的分析 方法，并对这些方法的特点，包括优点和缺点进行了简要描述。此外，本文件针对不同的 要求和背景，强调了在选择最合适的方法时应考虑的问题。本文件的目的不是为了对分析 方法和操作规程进行详尽的说明，也不是或就方法学或特定仪器提供具体的建议。更多信 息和阅读内容的链接见第 6 节。
2. 背景 铅是一种有毒金属，其广泛使用已经在世界很多地方造成了严重的环境污染和健康问 题。人类因暴露于铅而导致死亡的人数每年约为 143 000 例，占全球疾病负担的 0.6% （1）。铅是一种蓄积性有毒物质，对人体多个系统（包括神经系统、血液系统、胃肠系 统、心血管和肾脏系统）均有影响。儿童尤易受到铅的神经毒性影响，即使低水平暴露 量，也可能会导致严重后果。在某些情况下，可出现不可逆的神经损害。据估计，全球每 年新增的智障儿童中，约有 600 000 名系暴露于铅所致（2）。 近年来，尽管铅在汽油、管道设备和焊料中的使用量有所减少，但一些重要的铅暴露 源仍然存在，其中包括含铅涂料。在某些国家，含铅涂料一直在使用，且目前仍用于住宅 和其他建筑物内部及外部物体表面涂层，还用于玩具、家具、运动场设施及其它一些儿童 可接触到物品。几乎每个国家都有含铅涂料。含铅涂料在世界各地都可见到，并还在使 用，即使是对铅的一些特殊用途已经加以禁止的国家也是如此。老式房屋和物品中仍可发 现含铅涂料（3)。 铅的非职业性暴露主要见于家装涂料。由于房屋老化剥落、粉化或在维护和翻新过程 中剥落，致使形成含铅粉尘，进而可能导致铅被吸入或摄入。此外，房屋周边的土壤也可 能会受到污染。受到铅污染的屋内粉尘已被认为是儿童体内总铅负荷的主要来源（4)。儿 童通过日常手-口动作摄入铅的风险尤其高。此外，某些异食癖儿童也可能持续性摄入含 铅涂料的碎片。此外，儿童还可经口摄入含铅涂料的物品和玩具中的铅。在某些国家，含 铅涂料成为最为广泛、最具危险的儿童铅高暴露源。 从家装和物品中除去现存的含铅涂料，并从住宅区域和家具、设备和玩具中限制含铅 涂料的使用对于全球铅中毒的初级预防具有重要意义。为指导完成这些任务，迫切需要准 确测定物体表面的新涂料和干涂料中的铅浓度。
3. 可采用的分析方法 测定涂料中的铅含量主要有3种方法：
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涂料中铅测量分析方法简要指南
1) 使用化学检测试剂盒现场测定涂料中的铅含量。 2) 使用便携式X-射线荧光(XRF)仪器现场测定涂料中的铅含量。 3) 采集涂料样品，在实验室内采用不同的分析方法测定涂料样品中的铅含量。 上述分析方法在以下部分描述，并汇总于表1中。 表 1. 测定涂料中铅含量的分析方法汇总 方法 化学检测试剂盒 优势 • 结果即时可得 • 经济 • 使用相对方便 局限性 • 准确度有限 • 定性或半定量 • 主要测定最上(表面)层 • 需要损坏涂料表面 • 对于深色涂料难以分辨颜色变化 便携式 X-射线 荧光光谱法 • 准确度较好 • 结果即时可得 • 使用成本较低 • 对涂料表面无损害 • 检测快速 实验室分析 a • 最准确的方法 • 如果有实验室则成本较低，仅需要 较少样品 • 无技术局限性 • 适用于可溶解及不可溶解的铅组份 测定 • 可用于新(湿)涂料分析 a
• 与实验室分析相比，有较大误差 • 需要相应的培训/资质证明 • 采购成本相对较高 • 无法在样品量少、高曲面或复杂表 面的样品中（包括多种玩具）测定 • 必须破坏涂料表面 • 如果必须购买和安装设备则成本将 非常高 • 要求由经过培训的实验室工作人员 操作和严格的质量保证措施 • 无法立即获得测定结果
对于样品铅浓度测定，具有多种分析方法，包括火焰原子吸收光谱法、石墨炉原子吸收光谱法和电感耦合等 离子体原子发射光谱法。虽然这些方法的准确度和检测限有所不同，但在一般要求的检测限和准确度水平下 均足以测定涂料中的铅含量。
3.1 化学检测试剂盒 化学检测试剂盒可选范围很多，包括简单的定性检测试剂盒以及更为先进的半定量检 测试剂盒。此类检测更多依赖于颜色的变化以指示是否存在超过特定浓度水平的铅。对于 最简单的试剂盒，根据颜色是否发生变化来确定结果为阳性(即铅含量超过特定浓度水平) 或阴性 (即铅含量未超过特定浓度水平)。颜色发生变化的铅浓度阈值取决于所使用的试剂 盒及销售试剂盒国家可能已制订的限值。例如在美国，试剂盒应能检测出重量超过 0.5% (5000 mg/kg)的铅。根据应用情况，某些化学检测试剂盒可能具有较低的检测限。 较简单的检测试剂盒测定涂料时所采用的方法，或是通过浸有化学试剂的棉签擦拭物 体涂料表面，或是通过将特定面积的涂料碎片与试管中的试剂混合。而较为先进的检测试 剂盒则采用荧光或光谱法对涂料碎片予以测定。美国环境保护局(USEPA)对多种此类试剂 盒进行了评价，更多信息参见其网页（5）。
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化学检测试剂盒的价格相对低廉，使用时也不需要特殊培训（但经过培训的操作者可 获得更为可靠的结果），且测定结果即时可得。但此类试剂盒也存在多种局限，如仅可测 定表面层；因此当测定内层（更可能含有铅）时，需要破坏涂料表面层或获取涂料碎片 （根据方法的不同而决定)。对于某些试剂盒，可能难以观察到颜色的变化，尤其是在检 测颜色较深的涂料时。一般来说，这些试剂盒无法定量测定涂料中的铅；即便是半定量测 定方法也只能给出铅的浓度范围。换言之，化学检测试剂盒的准确度有限，即，当检测结 果表明铅含量超过特定浓度水平时，实际上并未超过（假阳性）；而当检测结果表明铅含 量未超过特定浓度水平时，实际上却已经超过（假阴性）。例如，USEPA目前仅认定3种 铅检测试剂盒符合美国2008年《翻新、改造和刷漆规则》（RRP）的假阴性标准要求。仅 当具资质的装修人员检测特定基底材料时，才建议采用这几种试剂盒，但USEPA认为其不 符合《翻新、改造和刷漆规则》（RRP）的假阳性标准要求（6)。基于这些原因，要准确 测定涂料中铅含量时，通常会采用除化学检测试剂盒以外的其他分析方法（7)。
3.2 便携式 X-射线荧光（XRF）光谱法 X-射线荧光（XRF）光谱法的原理是在暴露于高能量射线时，铅（与许多其它元素一 样 ) 可在特定频率释放 X- 射线，而射线的强度可被测定，且与每单位面积的铅含量相关 （通常为每单位平方厘米的毫克数)。由于涂料中铅含量的监管标准可能以其它单位（如 百万分率或重量的百分数浓度）表示，因此可能需要将XRF的结果进行转换。便携式XRF 仪器可现场测定涂料表面的总铅含量，而无需损伤涂料或基底材料。便携式XRF仪器极易 使用，但由于具有放射性危害，因此使用前需要接受特殊培训。在某些国家，便携式XRF 仪器操作员的资质必须经过认证。 便携式XRF仪器的准确度好，但与实验室分析相比有较大的误差范围（基于X-射线管 的仪器都是如此）。因此在测定结果为临界值时（即读数在仪器误差范围内，又接近涂料 中含铅量的国家限值标准)，应通过实验室分析进行确证。由于XRF仪器的体积和特点， 测定需要在相对较大及平坦的表面进行。因此该方法尤其适用于测定平坦的涂料表面，但 由于安全原因、结果的不可靠性以及无法准确测定表面积，该方法不太适用于测定高曲面 或复杂表面（如多数玩具）（7, 8)。然而，一些新的仪器可能会克服这些限制。 便携式XRF仪器可从数家生产商选择购买，其价格相对昂贵，从约10000美金至50000 美金不等，但该仪器基本无需维护、无需耗材，检测极为快速（约1分钟，但短时间所测 结果的准确性也相对较低），从而使操作人员可在短时间内对多个涂料表面进行测定。 关于使用XRF仪器测定涂料中铅含量的指南可从不同来源获得，其中包括XRF仪器的 生产商和国家机构（8)。
3.3 实验室分析 该分析方法需要采集涂料样品——无论是新涂料或从样品表面获取的干涂料，并采用 不同的方法在实验室对其进行分析。实验室分析要求细致采样并对样品进行预处理。 对于样品表面的干涂料，一般建议：
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涂料中铅测量分析方法简要指南
• • 采集所有层面的涂料，由于较底层涂料更可能含有铅； • • 尽可能少采集涂料层下面的物料（如木头、灰泥、金属)，因其可能会给出错误结
果； • • 在房屋或建筑物内，应从不同的区域采集几份具有代表性的样品； • • 记录每份样品的位置； • • 修复涂料样品采集处的表面，以防止含铅涂料进一步暴露。 进行分析的最低样品量约为300 mg，但其可能依赖于铅浓度、样品制备和分析方法。 如果可测得样品的重量，则结果以百分重量表示；如能够测得样品的精确表面积，则结果 以每单位面积重量表示。 在实验室中，必须在分析前对涂料样品进行预处理。如测定总铅含量，则应对样品进 行酸消化。如测定可溶性铅含量（即涂料中的铅可经儿童口部接触或吞咽而吸收），则应 采用酸提取工艺。测定总铅含量还是测定可溶性铅含量取决于测定的目的以及相关国家的 法规要求（9, 10)。 实际进行分析时可采用不同的方法，包括火焰原子吸收光谱法（FAAS）、石墨炉原 子吸收光谱法（GFAAS）和电感耦合等离子体原子发射光谱法（ICP-AES）。上述及其它 方法的样品采集、制备和分析指导原则、建议和标准操作规程均可从多种来源获得，包括 生产商、国家机构和国际标准化机构（8–16）。 一般认为实验室分析是最为准确的测定涂料中铅含量的方法，前提是遵守严格的质量 保证（QA)原则（见第4.2节），对于涂料碎片样品，应包括所有涂料层，但不应包括基底 材料（17)。该方法要求对涂料层表面破坏后进行修复。这是唯一的测定湿涂料中铅含量 的方法。样品采集、运输和实验室分析也需要较长时间和财力资源。分析测定也仅能由经 培训的实验室操作人员在完善的实验室内完成。 以下部分简要描述了涂料碎片中铅含量测定最为常用的仪器分析方法： FAAS 、 GFAAS和ICP-AES (11, 18)。虽然这些方法的准确度和检测限有所不同，但其在一般要求 的检测限和准确度水平下均足以测定涂料中的铅含量。本文件未对其它较少使用的仪器分 析方法进行描述，其中包括电感耦合等离子体质谱分析法、直流等离子体原子发射光谱 法、双硫腙分光光度法、阳极溶出伏安法和电位溶出伏安法。 3.3.1 火焰原子吸收光谱法 （FAAS) 火焰原子吸收光谱法（FAAS）的原理是被测元素的基态原子可吸收该元素特定波长 的光：铅的基态原子特定波长为283.3 nm。光吸收量与样品中分析物的浓度呈线性相关。 进行AAS测定时，必须先用仪器将含铅样品进行预处理，从而在仪器光路中产生基态原子 的蒸气，该过程称为原子化。 FAAS采用空气 -乙炔或一氧化二氮 -乙炔- 空气层流火焰在 2600oC条件下将铅原子化。 FAAS 具有中等检测限，但这在多数情况下已经足够。由于检测时需要直接吸入样 品，因此至少需要吸入约5 ml消化液，才能获得稳定的测定信号。FAAS的测定可受到某 4
些来源于光散射以及基体组分分子吸收的干扰，这可通过不同的方法对其进行校正。 FAAS仪器需要相应的实验室技能才能进行操作，配备或未配备自动进样器的FAAS仪器已 被广泛应用。仪器本身成本较低，且诸如乙炔气体的耗材价格也相对较低。仪器维护的需 求相对较低，样品检测速度为每分钟几份样品。 3.3.2 石墨炉原子吸收光谱法（GFAAS) GFAAS 是原子吸收光谱技术的一种，采用电加热石墨管在测定前于3000oC条件下将 分析物灰化和原子化。GFAAS仪器的检测限极低，仅需要极少量消化液（约20 µl)。 GFAAS 测定通常会受到光散射和基体组分分子吸收的干扰，但使用不同的方法可对 其进行校正，其中包括使用基体改进剂。GFAAS必须由经过培训的实验室操作人员进行 操作。 GFAAS 仪器已得到广泛推广，要求配备自动进样器以提高精密度和分析速度（通 量）。仪器本身的成本中等，其维护和耗材成本较高。样品的通量约为每 2-3 分钟 1 个样 品。 3.3.3 电感耦合等离子体原子发射光谱（(ICP-AES) ICP-AES采用电感耦合等离子体源(一种极高温度的由电子和带正电荷离子构成的电离 气体)将样品离解为其组成的原子或离子。在此高能条件下，铅（与许多其它元素一样))可 发出特定波长的光。此种光的发射量可被测定，并与样品中的铅浓度相关。ICP-AES仪器 的优势在于可同时测定几种元素。 该方法对铅的检测限为中等，但足以准确的测定涂料中的常规铅浓度。对样品体积 的要求适中。某些光谱干扰较为常见，但可被校正。ICP-AES仪器必须由经过培训的实验 室操作人员进行操作。仪器本身成本较高，但主要耗材仅为氩气。由于ICP-AES的设计较 为复杂，因此该仪器的维护成本相对较高。样品通量中等，通常为每分钟约1个样品。
4. 实验室操作重要事项 在分析化学领域，如果样品采集和处理不适当，仪器使用不正确，或者未按照分析方 法操作，那么即使是最尖端和准确的仪器，也可能会出现不正确的结果。与测定涂料中铅 含量有关的两个问题是：对样品的外部污染认识不足，以及质量保证（QA）措施不够。 以下章节将对这些问题进行简要的论述。
4.1 防止样品外部污染 铅是一种无处不在的金属，可以通过多种途径污染样品，尤其是在对涂料碎片进行实 验室分析时。在样品采集、储存、运输以及样品处理过程中均可发生污染。因此，样品采 集和处理的质量对准确测定涂料中铅含量至关重要。实验室内的样品处理过程与现场样品 采集过程存在着同样高的污染风险。实验室应尽可能无铅，且实验室工作人员应受过适当 的培训，防止样品受到污染。不同的分析方法有各自专门的操作规程（包括由生产商和标
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涂料中铅测量分析方法简要指南 准化机构编制的） （8–15），这些操作规程必须得到严格遵守。通过采取适当的质量保 证（QA）措施可显著降低污染风险。
4.2 质量保证 （QA) 质量保证（QA）是指为保证实验室分析测定结果可靠和具有重现性而必须采取的所 有步骤。其涉及采用科学与技术上合理的、完善的实验室检验操作规程，包括样品的选 择、采集、储存和运输以及实验结果的记录、报告和对结果的解释。另外，还包括为提高 检测可靠性而进行的培训和管理。从分析测定的角度来说，质量保证（QA）可分为两个 阶段：1) 对分析方法的实用性和真实性的初步评估，包括线性关系、特异性、回收率、校 验标准、空白和干扰；以及 2) 随后的质量评价。 质量评估是指分析结果的质量。其由两部分组成： 1) 内部质量控制。指的是由实验室工作人员所采用的一整套用于持续对所产生结果 进行评估的程序，以确定结果是否足够可靠并可以出报告； 2) 外部质量评估（EQA），是指通过外部机构客观检验实验室运行的体系。
更多有关实验室质量保证（QA）和质量管理以及针对血铅检测的 EQA 程序的实例， 可从不同来源获取（19–21)）。 在实验室进行涂料样品分析时严格遵守质量保证（QA）措施是至关重要的。包括在 可能的情况下，应考虑参加国际和/或国家认可计划的 EQA 注册登记。
5. 方法选择 方法选择取决于多种因素，包括所需的准确度水平、待测基底材料(包括是新涂料或 是物体的涂料表面)、是否有经过培训的操作人员和分析仪器、以及财力方面的考虑。 由于准确度有限和实际操作的限制，尽管化学检测试剂盒使用较为简便，除几种适用 于特殊用途和情况的试剂盒外 （6, 7），通常不推荐其用于涂料中铅含量的准确测定。 便携式 XRF 含铅涂料分析仪是进行室内调查最为常用的主要分析手段。这是由于该 方法能够确定含铅涂料是否存在于多种表面，且无需破坏性采样手段或剥离涂料即可测定 涂料中的铅含量，该方法的速度较快，且每个样品的检测成本较低。但该方法不适合用于 检测小物件、高曲面或复杂表面（包括许多玩具）。 一般认为实验室分析是测定涂料中铅含量的最为准确的方法，其前提是切实符合所有 质量保证（QA）的要求（17)。但其需要相应的实验室技能，样品采集、运输和实验室分 析所需时间也较长。如果分析由商用实验室进行，则每个样品的分析成本相对较高。如需 测定干涂料，采样时不可避免地会造成破坏。基于上述原因，一般不推荐单独使用实验室
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分析方法来测定涂料中的铅含量，而常优先考虑选择便携式 XRF 分析仪（8）。但在以下 情况下推荐使用实验室分析： • • 检测新涂料; • • 需要的准确度较高和/或检测限较低; • • 对于 XRF 仪器无法进行测定的小物件（如玩具）和难以接近的地区或表面不规则
的建筑构件； • • 需要确认 XRF 结果的临界值。 如优先考虑采用实验室分析方法进行测定，则有多种分析方法可供使用，包括 FAAS、GFAAS 和 ICP-AES。这些分析方法均能够测定涂料中的铅含量，且只要符合指导 原则、标准操作规程和严格的质量保证（QA）措施即能获得所要求的检测限和准确度。 方法的选择依赖于多种因素，例如： • • 是否有分析仪器和实验室; • • 是否有训练有素的实验室工作人员; • • 实验室质量保证（QA）措施的水平; • • 需要分析的样品数量和完成分析的时间周期; • • 分析成本，包括运行和维护成本; • • 如必须采购新的仪器，则应考虑仪器的采购和安装成本; • • 如果当地不具备分析能力，是否有外部实验室。
6. 参考文献 1. Global health risks: Mortality and burden of disease attributable to selected major risks. Geneva, World Health Organization, 2009 (http://www.who.int/healthinfo/global_burden_disease/Global HealthRisks_report_full.pdf, accessed 20 December 2010). 2. Exposure to lead: A major public health concern. Geneva, World Health Organization, 2010 (http://www.who.int/ipcs/features/lead..pdf, accessed 20 December 2010). 3. Global study to determine lead in new decorative paints in 10 countries: Executive summary. New Delhi, Toxics Link, 2009 (http://www.ipen.org/ipenweb/documents/work%20documents/paint_ executivesummary.pdf, accessed 20 December 2010). 4. Bornschein RL et al. Exterior surface dust lead, interior house dust lead and childhood lead exposure in an urban environment. In: Hemphill DD, ed. Trace substances in environmental health. Vol. 20. Proceedings of the University of Missouri’s 20th Annual Conference, June 1986. Columbia, MO, University of Missouri, 1987:322–332. 5. Performance characteristics of qualitative spot test kits for lead in paint (completed 2010). Washington, DC, United States Environmental Protection Agency, Environmental Technology Verification Program (http://www.epa.gov/nrmrl/std/etv/este.html#pcqstklp, accessed 30 December 2010).
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涂料中铅测量分析方法简要指南 6. EPA recognition of lead test kits. Washington, DC, United States Environmental Protection Agency (http://www.epa.gov/lead/pubs/testkit.htm, accessed 30 December 2010). 7. Lead-based paint: Testing methods. Missoula, MT, United States Department of Agriculture Forest Service, Technology & Development Program, 1996 (http://www.fs.fed.us/eng/pubs/ htmlpubs/htm96712353/, accessed 20 December 2010). 8. Guidelines for the evaluation and control of lead-based paint hazards in housing. Washington, DC, United States Department of Housing and Urban Development, 1995 (http://www.hud.gov/ offices/lead/lbp/hudguidelines/index.cfm, accessed 20 December 2010). 9. ASTM F963 - 08 Standard consumer safety specification for toy safety. West Conshohocken, PA, ASTM International, 2008 (http://www.astm.org/Standards/F963.htm, accessed 20 December 2010). 10. ISO 8124-3:2010 Safety of toys—Part 3: Migration of certain elements. Geneva, Switzerland, International Organization for Standardization, 2010 (http://www.iso.org/iso/iso_catalogue/ catalogue_tc/catalogue_detail.htm?csnumber=43471, accessed 31 May 2010). 11. Pb-based paint laboratory operations guidelines: Analysis of Pb in paint, dust, and soil. Revision 1.0. Washington, DC, United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, 1993 (EPA 747-R-92-006; http://www.epa.gov/lead/pubs/92006.pdf, accessed 20 December 2010). 12. ASTM E1729 - 05 Standard practice for field collection of dried paint samples for subsequent lead determination. West Conshohocken, PA, ASTM International, 2005 (http://www.astm.org/ Standards/E1729.htm, accessed 20 December 2010). 13. ASTM E1645 - 01(2007) Standard practice for preparation of dried paint samples by hotplate or microwave digestion for subsequent lead analysis. West Conshohocken, PA, ASTM International, 2007 (http://www.astm.org/Standards/E1645.htm, accessed 20 December 2010). 14. Binstock D et al. Standard operating procedures for lead in paint by hotplate- or microwavebased acid digestions and atomic absorption or inductively coupled plasma emission spectrometry. Research Triangle Park, NC, United States Environmental Protection Agency, 1991 (http:// cfpub.epa.gov/ols/catalog/catalog_display.cfm?&FIELD1=AUTHOR&INPUT1=Grohse%20AN D%20P%20AND%20M&TYPE1=ALL&item_count=9, accessed 20 December 2010). 15. ASTM E1613 - 04 Standard test method for determination of lead by inductively coupled plasma atomic emission spectrometry (ICP-AES), flame atomic absorption spectrometry (FAAS), or graphite furnace atomic absorption spectrometry (GFAAS) techniques. West Conshohocken, PA, ASTM International, 2004 (http://www.astm.org/Standards/E1613.htm, accessed 20 December 2010). 16. Test method: CPSC-CH-E1003-09: Standard operating procedure for determining lead (Pb) in paint and other similar surface coatings. Gaithersburg, MD, United States Consumer Product Safety Commission, 2009 (http://www.cpsc.gov/about/cpsia/CPSC-CH-E100309.pdf, accessed 20 December 2010). 17. Schmehl RL et al. Lead-based paint testing technologies: summary of an EPA/HUD field study. American Industrial Hygiene Association Journal, 1999, 60:444–451.
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18. Flanagan RJ et al. Fundamentals of analytical toxicology. John Wiley & Sons Ltd, 2007. 19. Environmental Lead Proficiency Analytical Testing (ELPAT) Program. Fairfax, VA, AIHA Proficiency Analytical Testing Programs, LLC (http://www.aihapat.org/ProficiencyTesting Programs/elpat/Pages/default.aspx, accessed 20 December 2010). 20. Quality assurance. San Francisco, CA, United States Environmental Protection Agency, Region 9 Quality Assurance Office (http://www.epa.gov/region9/qa/, accessed 20 December 2010). 21. Laboratory quality management system training toolkit. Lyon, World Health Organization, International Health Regulations (http://www.who.int/ihr/training/laboratory_quality/en/index.html, accessed 20 December 2010).
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涂料中铅测量分析方法简要指南
ISBN 978 92 4 550212 8
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