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'''Biomonitoring''' is a technique in [[analytical chemistry]] for studying the presence and concentration of natural or synthetic [[chemical substance]]s in the [[human body]] at a specific point in time, often through the analysis of blood, urine, breast milk or tissue samples. These samples are analyzed for specific substances or their [[metabolite]]s to document whether exposure has occurred.

Biomonitoring for some substances, such as lead in children, has been occurring regularly since the 1970s. In 2001, the [[Centers for Disease Control and Prevention]] began to publish its biennial ''National Report on Human Exposure to Environmental Chemicals'', which reports biomonitoring findings from a statistically representative sample of the U.S. population.<ref name=CDC_about>{{cite web | title = About the Program | work = cdc.gov | publisher = Centers for Disease Control | date = 3 April 2008 | url = http://www.cdc.gov/biomonitoring/about.htm | accessdate = 25 May 2009}}</ref> Public health advocacy groups have also conducted biomonitoring studies on a limited number of individuals to bring attention to chemical exposures.<ref name=EWG/>

==Overview==

Biomonitoring is defined in the [[United_States_National_Research_Council|National Research Council]]'s 2007 report, ''Human Biomonitoring for Environmental Chemicals'', as "one method for assessing human exposure to chemicals by measuring the chemicals or their metabolites in human issues or speciments, such as blood and urine."<ref name=NRC>{{Citation | title = Human Biomonitoring for Environmental Chemicals | year = 2008 | publisher = National Research Council | url = http://www.nao.edu/catalog/11700.html}}</ref>

Historically, public health regulations have been based on theoretical risk calculations according to known levels of chemical substances in air, water, soil, food, other consumer products and other sources of potential exposure. Human biomonitoring offers the opportunity to analyze the actual internal levels of bodily substances from all potential routes of exposure at one time, which may contribute to improving risk assessments.<ref>{{Citation | last = Juberg | first = Daland R. | last2 = Bus | first2 = James | last3 = Katz | first3 = Diane S. | title = The Opportunities and Limitations of Biomonitoring | journal = Policy Brief | date = February 2008}}</ref> Scientific advancements have made it possible to detect a greater number of chemical substances in smaller concentrations in the body, with some chemicals detectable at levels as low as parts per trillion.<ref>{{cite web |url=http://www.americanchemistry.com/s_acc/bin.asp?CID=257&DID=1584&DOC=FILE.PDF |title=What is Biomonitoring? |format=PDF |work=American Chemistry Council |accessdate=11 January 2009}}</ref> However, a major limitation of biomonitoring studies is that they are unable to provide information on the source, magnitude, frequency or duration of a chemical exposure.<ref name=BEs/> A single biomonitoring measurement is only one snapshot in time and may not accurately reflect the level of exposure over longer periods.<ref name=Foster_Agzarian>{{Citation | last = Foster | first = Warren G. | last2 = Agzarian | first2 = John | title = Reporting results of biomonitoring studies | journal = Analytical and Bioanalytical Chemistry | volume = 387 | pages = 137-140 | year = 2007 | doi =10.1007/s00216-006-0822-6}}</ref>

In 2006 the National Research Council published a report, ''Human Biomonitoring for Environmental Chemicals''. The report recognized the value of biomonitoring for better understanding exposure to environmental chemicals, and included several findings and recommendations to improve the utility of biomonitoring data for health risk assessment. In summary, the report called for more rigorous health-based criteria for selecting chemicals to include in biomonitoring studies; the development of tools and techniques to improve risk-based interpretation and communication of biomonitoring data; integration of biomonitoring into exposure assessment and epidemiological research; and exploration of bioethical issues around biomonitoring, including informed consent, confidentiality of results, and others.<ref>{{cite web | title = Statement on Biomonitoring | work = acs.org | url = http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_SUPERARTICLE&node_id=1901&use_sec=false&sec_url_var=region1&__uuid=d3db2ed2-5853-4b7f-932b-fe46125e26b6 | accessdate = 23 July 2009}}</ref>

==Biomonitoring surveys==

The CDC's Environmental Health Laboratory conducts the National Biomonitoring Program, which measures exposure to both synthetic and naturally occurring chemicals in a statistically representative sample of the U.S. population biennially. The program's findings are published in the the ''National Report on Human Exposure to Environmental Chemicals''. Some of the chemicals and chemical families monitored by CDC include: [[heavy metals]] such as [[lead]], [[Mercury (element)|mercury]] and [[arsenic]]; [[Carbamate]] pesticides; [[cotinine]], an indicator of exposure to [[tobacco smoke]]; [[dioxins]] and related compounds; fungicides; herbicides; [[organochlorine]] pesticides; [[organophosphate]] insecticides; [[perchlorate]]; [[perfluorinated compounds]]; [[phenols]] such as [[Bisphenol A]], [[triclosan]] and others; [[phthalates]]; [[phytoestrogens]]; [[polybrominated diphenyl ethers]]; polychlorinated biphenyl ethers (PCBs); [[polycyclic aromatic hydrocarbons]] (PAHs); [[polycyclic aromatic hydrocarbons]] (PAHs); [[pyrethroid]] pesticides; and [[volatile organic compounds]] (VOCs).<ref>{{cite web |url=http://www.cdc.gov/nchs/data/nhanes/nhanes_03_04/environmentalhealth_03.pdf |title=Environmental and Related Chemicals Measured in Blood, Serum or Urine in NHANES |author= |date= |work= |publisher=Centers for Disease Control |accessdate=10 November 2009 }}</ref>

CDC has established six criteria for including chemicals in future editions of the National Report:
#Independent scientific data which suggest that the potential for exposure of the U.S. population to a particular chemical is changing (i.e., increasing or decreasing) or persisting;
#Seriousness of health effects known or suspected to result from exposure to the chemical (for example, cancer, birth defects, or other serious health effects);
#Proportion of the U.S. population likely to be exposed to levels of chemicals of known or potential health significance;
#Need to assess the efficacy of public health actions to reduce exposure to a chemical in the U.S. population or a large component of the U.S. population (for example, among children, women of childbearing age, the elderly);
#Existence of an analytical method that can measure the chemical or its metabolite in blood or urine with adequate accuracy, precision, sensitivity, specificity, and speed; and
#Incremental analytical cost (in dollars and personnel) to perform the analyses (preference is given to chemicals that can be added readily to existing analytical methods).<ref>{{Citation | title = Final Selection Criteria and Solicitation of Nominations for Chemicals or Categories of Environmental Chemicals for Analytic Development and Inclusion in Future Releases of the National Report on Human Exposure to Environmental Chemicals | journal = Federal Register | volume = 67 | number = 194 | pages = 62477 | date = 7 October 2002 | accessdate = 10 November 2009}}</ref>

CDC has also established three criteria for removing chemicals from future editions of the National Report:8
#A new replacement chemical (i.e., a metabolite or other chemical) is more representative of exposure than the chemical currently measured, or
#If after three survey periods, detection rates for all chemicals within a method-related group are less than 5 percent for all population subgroups (i.e., two sexes, three race/ethnicity groups, and the age groups used in the National Report), or
#If after three survey periods, levels of chemicals within a method-related group are unchanged or declining in all demographic subgroups documented in the National Report.<ref>{{Citation | title = Public Comments and Revised Criteria for Removing Chemicals Future Editions of CDC's National Report on Human Exposure Environmental Chemicals | url = http://www.cdc.gov/exposurereport/pdf/fr_032808.pdf| journal = Federal Register | volume = 73 | number = 61 | pages = 16688 | date = 28 March 2008 | accessdate = 10 November 2009}}</ref>

In collaboration with the National Institute of Child Health and Development (NICHD), National Institute of Environmental Health Sciences and U.S. Environmental Protection Agency, the CDC's Environmental Health Laboratory has announced it will play a key role in the biomonitoring components of the ongoing National Children's Study, which follows 100,000 children across the United States from birth until age 21. The study was authorized as part of the [[Children's Health Act]] of 2000 and is the largest effort undertaken to address the effects of social, economic and environmental factors on a child's health.<ref>{{cite web | title = National Children's Study | work = cdc.gov | date = 2009-07-07 | url = http://www.cdc.gov/biomonitoring/national_childrens_study.htm | accessdate = 23 July 2009}}</ref>

Some U.S. states have conducted biomonitoring programs. In 2001, the CDC awarded planning grants to 33 states to assist in capacity building for expanding human biomonitoring.<ref name=NAS>{{Citation | last = National Research Council | title = Human Biomonitoring for Environmental Chemicals | place = | publisher = National Academies Press | year = 2006 | url = http://www.nap.edu/catalog.php?record_id=11700 | isbn = 0-309-10272-3}}</ref> Subsequently, several states have enacted laws to specify state-level biomonitoring.The California Environmental Contaminant Biomonitoring Program (CECBP), administred by the [[California Department of Public Health]], established by law in 2006.<ref>{{cite web | title = California Biomonitoring Program | work = CA.gov | url = http://www.cdph.ca.gov/programs/Biomonitoring/Pages/default.aspx | accessdate = 23 July 2009}}</ref> Minnesota's Biomonitoring Pilot Program was established by law in 2007 and is run by the Minnesota Department of Health.<ref>{{cite web | coauthors = | title = Environmental Public Health Tracking & Biomonitoring | work = | publisher = Minnesota Department of Health | date = 2009-07-21 | url = http://www.health.state.mn.us/divs/eh/tracking/index.html | accessdate = 23 July 2009}}</ref> The CDC continues to provide grant support to state programs.<ref>{{cite web |title=State Grant Activities |url=http://www.cdc.gov/biomonitoring/state_grants.htm |work= |publisher=[[Centers for Disease Control and Prevention]] |date=9 September 2009 |accessdate=30 September 2009}}</ref>

In Canada, Statistics Canada administers the Canadian Health Measures Survey, a component of which includes biomonitoring for environmental chemicals.<ref>{{cite web |title=Canadian Health Measures Survey |url=http://www.statcan.gc.ca/concepts/hs-es/measures-mesures-eng.htm#3 |work=statcan.gc.ca |publisher=Statistics Canada |date= 19 March 2004 |accessdate=2 October 2009}}</ref> Health Canada administers a program called Mother-Infant Research on Environmental Chemicals, which focuses on 2,000 pregnant women and their infants.<ref>{{cite web |title=Maternal-Infant Research on Environmental Chemicals (The MIREC Study) |url=http://www.hc-sc.gc.ca/ewh-semt/contaminants/mirec/index-eng.php |work=hc-sc.gc.ca |publisher=Health Canada |date=12 December 2007 |accessdate=2 October 2009}}</ref> Several European countries also have human biomonitoring programs.<ref>{{cite web |url=http://www.invs.sante.fr/beh/2009/hs/160609/beh_bs_versiongb_la.pdf |title=Human biomonitoring and environmental health |author= |date=16 June 2008 |work=Bulletin Épidémiologique Hebdomadaire |publisher=Insitut de Vielle Sanitaire |accessdate=10 November 2009 }}</ref> Public health advocacy groups have conducted several small biomonitoring studies to bring attention to issues around chemical exposures and potential health effects. The [[Environmental Working Group]]'s (EWG) Human Toxome Project and the Canadian group Environmental Defence's Toxic Nation project are two examples.<ref name=EWG>{{cite web |author= |title=About the Human Toxome Project |url=http://www.ewg.org/sites/humantoxome/about/ |work=Human Toxome Project |publisher=Environmental Working Group |date= |accessdate=30 September 2009}}</ref><ref>{{cite web |author= |title=Toxic Nation Studies |url=http://www.toxicnation.ca/toxicnation-studies |work=Toxic Nation |publisher=Environmental Defence |date=17 October 2007 |accessdate=30 September 2009}}</ref>

===Biomonitoring methods===

Chemicals and their metabolites can be detected in a variety of biological substances such as blood, urine, hair, semen, breast milk, or saliva.<ref name=cdcbio>{{cite journal | last=Sexton | first=S. | last2=Needham | first2=L.L. | last3=Pirkle | first3=J.L. | title=Human Biomonitoring of Environmental Chemicals | journal=American Scientist | volume=92 | issue=1 | pages=38–45 | year=2004 | month=January&ndash;February | format=PDF | pmid= | pmc= | doi=10.1511/2004.1.38 | url=http://www.cdc.gov/biomonitoring/pdf/AS_article_biomonitoring.pdf
}}</ref> [[Breast milk]] is a favored matrix (substance) to measure [[lipophilic]] (fat-loving) [[Persistent organic pollutant|persistent, bioaccumulative, and toxic (PBT) compounds]] during [[lactation]]; this exposure route is dominant for breastfeeding children.<ref>{{cite journal | author=Smolders R, Schramm KW, Nickmilder M, Schoeters G | title=Applicability of non-invasively collected matrices for human biomonitoring | journal=Environmental Health | volume=8 | issue=8 |pages= | year=2009 | pmid=19272133 | pmc=2660315 | doi=10.1186/1476-069X-8-8 | url= }}</ref> A lipophilic compound might also be detected in [[blood]], while a [[hydrophilic]] (water-loving) compound might be detected in [[urine]]. Analytical methods used by the CDC include [[Isotopic dilution|isotope dilution]] [[mass spectrometry]], [[inductively coupled plasma mass spectrometry]], or [[Graphite furnace atomic absorption|graphite furnace atomic absorption spectrometry]].<ref name=Third/>

===Interpretation===

While biomonitoring provides a tool for determining human exposure to substances in air, water, soil and food, it cannot determine the source or duration of exposure to a substance, nor its potential health effects, if any. In addition, the U.S. Centers for Disease Control and Prevention has said that the presence of an environmental chemical in the body does not necessarily indicate harm. A chemical's toxicity is determined by a range of factors, including its [[dose-response relationship|concentration]] and a person's individual [[susceptibility]]. Small amounts of a chemical may produce no health effects, whereas larger amounts may have an impact.<ref name=Third>{{Citation | contribution = Interpreting the Data | title = Third National Report on Human Exposure to Environmental Chemicals | year = 2007 | place = Atlanta, GA | publisher = Centers for Disease Control and Prevention | url = http://www.cdc.gov/exposurereport/report.htm}}</ref>

For some chemicals, the levels in the body that cause health effects in humans are well-known (e.g. mercury and lead). For many others, scientists lack an understanding of the relationship between levels in blood or urine and potential health risks. As noted in the National Research Council's report, the ability to measure the presence of chemicals in the body has advanced more rapidly than the ability to interpret biomonitoring information in the context of health risk assessment.<ref name=NRC/> Scientific evaluations of health risks from chemicals typically involve toxicity studies in laboratory animals and subsequent extrapolation to humans. Such studies have been used extensively to establish regulatory exposure standards, but their relation to levels measured in biomonitoring studies is imprecise, and developing tools to facilitate risk-based interpretation and communication of biomonitoring results is an active area of research for the National Research Council. One example of such tools, the Biomonitoring Equivalent, determins the level of a substance in the human body (i.e., blood, urine or tissue) consistent with exposure at the acceptable level established by a regulatory agency.<ref name=BEs>{{cite journal | last = Hays | first = S.M. | last2 = Becker | first2 = R.A. | last3 = Leung | first3 = H.W. | last4 = Aylward | first4 = L.L. | last5 = Pyatt | first5 = D.W. | title = Biomonitoring equivalents: A screening approach for interpreting biomonitoring results from a public health risk perspective | journal = Regulatory Toxicology and Pharmacology | volume = 47 | issue = 1 | pages = 96-109 | date = February 2007 | url = http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WPT-4M27X7M-1&_user=10&_coverDate=02/28/2007&_rdoc=1&_fmt=high&_orig=browse&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=773cb1a3096a6a939b54dda8297ae0aa | doi = 10.1016/j.yrtph.2006.08.004 | accessdate = 23 July 2009}}</ref>

===Communication===

A key challenge in designing and executing biomonitoring studies involves what and how to communicate about the potential health effects of chemicals found in the study. Communication is complicated by the fact that studies necessary to understand how the levels in people relate to the regulatory standards that have been set for exposures to chemicals in air, or water, or food have yet to be completed. While many chemicals have extensive toxicity datasets, scientific methods to translate this informationinto knowledge of whether the levels of chemicals detected in humans may or may not pose health risks are just emerging.

Participants in biomonitoring studies typically want to know whehether the chemical compositions measured in their bodies indicate that they are healthy (or not); however, biomonitoring studies are not designed to answer this particular question. While biomonitoring is useful for assessing exposure, without other information, it is not alone useful in determining a person's health or likelihood of developing ill effects.<ref name=Foster_Agzarian/><ref>{{cite web |title="Interpreting the Data" |url=http://www.cdc.gov/exposurereport/report.htm |work=Third National Report on Human Exposure to Environmental Chemicals |publisher=Centers for Disease Control and Prevention |date=2007 |accessdate=30 September 2009}}</ref> According to the National Research Council, accurate communication of results is essential for the proper use of biomonitoring surveys, but states "there is no accepted standard for good biomonitoring communications".<ref name=NRC/>

Warren G. Foster and John Agzarian wrote in the journal ''Analytical and Bioanalytical Chemistry'' that dramatic advancements in analytical chemistry have led to an increase in the ability to detect more chemical compounds in smaller concentrations, "creating the perception that contamination of our environment has continued to increase." While there are more synthetic chemicals in the environment since the advent of the [[Industrial Revolution]], the [[EPA]]'s Toxic Release Inventory data indicates the presence of most environmental chemicals has decreased from 1988 to 2001.<ref name=Foster_Agzarian/>

Standards and guidelines that health professionals can use to communicate biomonitoring information are still evolving. Foster and Agzarian write, "Because of the lack of clear reference ranges and standards, however, it is unlikely that providing study subjects with their individual exposure results in the absence of information about the health significance of the results would create anxiety and anger among study subjects."<ref name=Foster_Agzarian/> An expert panel on Biomonitoring Equivalents has published guidelines for communicating information to the general public and health care providers.<ref>{{Citation | last = LaKind | first = J. | last2 = Aylward | first2 = L.L. | last3 = Brunk | first3 = C. | last4 = DeZio | first4 = S. | last5 = Dourson | first5 = M. | last6 = Goldstein | first6 = D.A. | last7 = Kilpatrick | first7 = M.E. | last8 = Krewski | first8 = D. | last9 = Bartels | first9 = M.J. | last10 = Barton | first10 = H.A. | last11 = Boogaard | first11 = P.J. | last12 = Lipscomb | first12 = J. | last13 = Krishnan | first13 = K. | last14 = Nordberg | first14 = M. | last15 = Okino | first15 = M. | last16 = Tan | first16 = Y.| last17 = Viau | first17 = C. | last18 = Yager | first18 = J.W. | last19 = Hays | first19 = S.M. | title = Guidelines for the communication of Biomonitoring Equivalents: Report from the Biomonitoring Equivalents Expert Workshop | journal = Regulatory Toxicology and Pharmacology | volume = 51 (3, supp 1) | pages = S16-26 | year = 2008 | doi =10.1016/j.yrtph.2008.05.007}}</ref>

Dr. Charles McKay of the Connecticut Poison Control Center provides a perspective to assist medical toxicologists with understanding human biomonitoring data<ref>{{Citation | last = McKay, Jr. | first = C.A. | last2 = Holland | first2 = M.G. | last3 = Nelson | first3 = L.S. | title = A Call to Arms for Medical Toxicologists: The dose, not the detection, makes the poison | journal = International Journal of Medical Toxicology | volume = 6(1) | pages = 1 | year = 2003 | doi = }}</ref> is interviewed in a video titled "A Medical Doctor's Perspective on Biomonitoring", which is focused on helping the general public better understand biomonitoring.<ref>{{cite web |author=John Heinze, Ph.D. |title=Science Advisory Council member Dr. Charles McKay provides a medical doctor's perspective on biomonitoring |url=http://biomonitoringinfo.org/mckay.html |work=Biomonitoringinfo.org |publisher=Biomonitoring Info |date=2009 |accessdate=30 September 2009}}</ref>

===Boston Consensus Project===

In 2007, the [[Boston University School of Public Health]] organized a panel, the Boston Consensus Conference on Biomonitoring, for the purpose of educating residents about the scientific, legal and ethical issues of biomonitoring, and coming to an understanding of the lay panel's priorities and concerns related to measuring human exposure to environmental chemicals. The conference produced a report for public health policy makers and scientists who deal with or study the issues.<ref>{{cite web | title = Consensus Statement on Human Biomonitoring | work = Measuring Chemicals in Poeople -- What Would You Say? | publisher = Boston University School of Public Health | url = http://www.biomonitoring06.org/uploads/Main/Consensus_statement_final.pdf | accessdate = 23 July 2009}}</ref>

==See also==
*[[Biomarker]]
*[[Pharmacokinetics]]
*[[Exposure assessment]]
*[[Dose-response relationship]]

==References==
{{reflist}}

==External links==

*[http://www.biomonitoringinfo.org Biomonitoringinfo.org]
*[http://www.cdc.gov/biomonitoring/ National Biomonitoring Program]
*[http://www.nap.edu/catalog.php?record_id=11700 Human Biomonitoring for Environmental Chemicals], National Research Council
*[http://www.gao.gov/new.items/d09353.pdf Biomonitoring &ndash; EPA Needs to Coordinate Its Research Strategy and Clarify Its Authority to Obtain Biomonitoring Data], [[United States Government Accountability Office]]
*[http://www.liebertonline.com/doi/pdfplus/10.1089/bfm.2008.0121?cookieSet=1 The heart of the matter on breastmilk and environmental chemicals: essential points for healthcare providers and new parents], Review
*[http://www.icmr.nic.in/ijmr/2008/october/1012.pdf The interpretation of trace element analysis in body fluids], Review

[[Category:Analytical chemistry]]
[[Category:Chemistry]]
[[Category:Environmental chemistry]]

Revision as of 17:58, 12 November 2009

This article is about human chemistry. For aquatic ecology, see Aquatic biomonitoring.

Biomonitoring is a technique in analytical chemistry for studying the presence and concentration of natural or synthetic chemical substances in the human body at a specific point in time, often through the analysis of blood, urine, breast milk or tissue samples. These samples are analyzed for specific substances or their metabolites to document whether exposure has occurred.

Biomonitoring for some substances, such as lead in children, has been occurring regularly since the 1970s. In 2001, the Centers for Disease Control and Prevention began to publish its biennial National Report on Human Exposure to Environmental Chemicals, which reports biomonitoring findings from a statistically representative sample of the U.S. population.[1] Public health advocacy groups have also conducted biomonitoring studies on a limited number of individuals to bring attention to chemical exposures.[2]

Overview

Biomonitoring is defined in the National Research Council's 2007 report, Human Biomonitoring for Environmental Chemicals, as "one method for assessing human exposure to chemicals by measuring the chemicals or their metabolites in human issues or speciments, such as blood and urine."[3]

Historically, public health regulations have been based on theoretical risk calculations according to known levels of chemical substances in air, water, soil, food, other consumer products and other sources of potential exposure. Human biomonitoring offers the opportunity to analyze the actual internal levels of bodily substances from all potential routes of exposure at one time, which may contribute to improving risk assessments.[4] Scientific advancements have made it possible to detect a greater number of chemical substances in smaller concentrations in the body, with some chemicals detectable at levels as low as parts per trillion.[5] However, a major limitation of biomonitoring studies is that they are unable to provide information on the source, magnitude, frequency or duration of a chemical exposure.[6] A single biomonitoring measurement is only one snapshot in time and may not accurately reflect the level of exposure over longer periods.[7]

In 2006 the National Research Council published a report, Human Biomonitoring for Environmental Chemicals. The report recognized the value of biomonitoring for better understanding exposure to environmental chemicals, and included several findings and recommendations to improve the utility of biomonitoring data for health risk assessment. In summary, the report called for more rigorous health-based criteria for selecting chemicals to include in biomonitoring studies; the development of tools and techniques to improve risk-based interpretation and communication of biomonitoring data; integration of biomonitoring into exposure assessment and epidemiological research; and exploration of bioethical issues around biomonitoring, including informed consent, confidentiality of results, and others.[8]

Biomonitoring surveys

The CDC's Environmental Health Laboratory conducts the National Biomonitoring Program, which measures exposure to both synthetic and naturally occurring chemicals in a statistically representative sample of the U.S. population biennially. The program's findings are published in the the National Report on Human Exposure to Environmental Chemicals. Some of the chemicals and chemical families monitored by CDC include: heavy metals such as lead, mercury and arsenic; Carbamate pesticides; cotinine, an indicator of exposure to tobacco smoke; dioxins and related compounds; fungicides; herbicides; organochlorine pesticides; organophosphate insecticides; perchlorate; perfluorinated compounds; phenols such as Bisphenol A, triclosan and others; phthalates; phytoestrogens; polybrominated diphenyl ethers; polychlorinated biphenyl ethers (PCBs); polycyclic aromatic hydrocarbons (PAHs); polycyclic aromatic hydrocarbons (PAHs); pyrethroid pesticides; and volatile organic compounds (VOCs).[9]

CDC has established six criteria for including chemicals in future editions of the National Report:

  1. Independent scientific data which suggest that the potential for exposure of the U.S. population to a particular chemical is changing (i.e., increasing or decreasing) or persisting;
  2. Seriousness of health effects known or suspected to result from exposure to the chemical (for example, cancer, birth defects, or other serious health effects);
  3. Proportion of the U.S. population likely to be exposed to levels of chemicals of known or potential health significance;
  4. Need to assess the efficacy of public health actions to reduce exposure to a chemical in the U.S. population or a large component of the U.S. population (for example, among children, women of childbearing age, the elderly);
  5. Existence of an analytical method that can measure the chemical or its metabolite in blood or urine with adequate accuracy, precision, sensitivity, specificity, and speed; and
  6. Incremental analytical cost (in dollars and personnel) to perform the analyses (preference is given to chemicals that can be added readily to existing analytical methods).[10]

CDC has also established three criteria for removing chemicals from future editions of the National Report:8

  1. A new replacement chemical (i.e., a metabolite or other chemical) is more representative of exposure than the chemical currently measured, or
  2. If after three survey periods, detection rates for all chemicals within a method-related group are less than 5 percent for all population subgroups (i.e., two sexes, three race/ethnicity groups, and the age groups used in the National Report), or
  3. If after three survey periods, levels of chemicals within a method-related group are unchanged or declining in all demographic subgroups documented in the National Report.[11]

In collaboration with the National Institute of Child Health and Development (NICHD), National Institute of Environmental Health Sciences and U.S. Environmental Protection Agency, the CDC's Environmental Health Laboratory has announced it will play a key role in the biomonitoring components of the ongoing National Children's Study, which follows 100,000 children across the United States from birth until age 21. The study was authorized as part of the Children's Health Act of 2000 and is the largest effort undertaken to address the effects of social, economic and environmental factors on a child's health.[12]

Some U.S. states have conducted biomonitoring programs. In 2001, the CDC awarded planning grants to 33 states to assist in capacity building for expanding human biomonitoring.[13] Subsequently, several states have enacted laws to specify state-level biomonitoring.The California Environmental Contaminant Biomonitoring Program (CECBP), administred by the California Department of Public Health, established by law in 2006.[14] Minnesota's Biomonitoring Pilot Program was established by law in 2007 and is run by the Minnesota Department of Health.[15] The CDC continues to provide grant support to state programs.[16]

In Canada, Statistics Canada administers the Canadian Health Measures Survey, a component of which includes biomonitoring for environmental chemicals.[17] Health Canada administers a program called Mother-Infant Research on Environmental Chemicals, which focuses on 2,000 pregnant women and their infants.[18] Several European countries also have human biomonitoring programs.[19] Public health advocacy groups have conducted several small biomonitoring studies to bring attention to issues around chemical exposures and potential health effects. The Environmental Working Group's (EWG) Human Toxome Project and the Canadian group Environmental Defence's Toxic Nation project are two examples.[2][20]

Biomonitoring methods

Chemicals and their metabolites can be detected in a variety of biological substances such as blood, urine, hair, semen, breast milk, or saliva.[21] Breast milk is a favored matrix (substance) to measure lipophilic (fat-loving) persistent, bioaccumulative, and toxic (PBT) compounds during lactation; this exposure route is dominant for breastfeeding children.[22] A lipophilic compound might also be detected in blood, while a hydrophilic (water-loving) compound might be detected in urine. Analytical methods used by the CDC include isotope dilution mass spectrometry, inductively coupled plasma mass spectrometry, or graphite furnace atomic absorption spectrometry.[23]

Interpretation

While biomonitoring provides a tool for determining human exposure to substances in air, water, soil and food, it cannot determine the source or duration of exposure to a substance, nor its potential health effects, if any. In addition, the U.S. Centers for Disease Control and Prevention has said that the presence of an environmental chemical in the body does not necessarily indicate harm. A chemical's toxicity is determined by a range of factors, including its concentration and a person's individual susceptibility. Small amounts of a chemical may produce no health effects, whereas larger amounts may have an impact.[23]

For some chemicals, the levels in the body that cause health effects in humans are well-known (e.g. mercury and lead). For many others, scientists lack an understanding of the relationship between levels in blood or urine and potential health risks. As noted in the National Research Council's report, the ability to measure the presence of chemicals in the body has advanced more rapidly than the ability to interpret biomonitoring information in the context of health risk assessment.[3] Scientific evaluations of health risks from chemicals typically involve toxicity studies in laboratory animals and subsequent extrapolation to humans. Such studies have been used extensively to establish regulatory exposure standards, but their relation to levels measured in biomonitoring studies is imprecise, and developing tools to facilitate risk-based interpretation and communication of biomonitoring results is an active area of research for the National Research Council. One example of such tools, the Biomonitoring Equivalent, determins the level of a substance in the human body (i.e., blood, urine or tissue) consistent with exposure at the acceptable level established by a regulatory agency.[6]

Communication

A key challenge in designing and executing biomonitoring studies involves what and how to communicate about the potential health effects of chemicals found in the study. Communication is complicated by the fact that studies necessary to understand how the levels in people relate to the regulatory standards that have been set for exposures to chemicals in air, or water, or food have yet to be completed. While many chemicals have extensive toxicity datasets, scientific methods to translate this informationinto knowledge of whether the levels of chemicals detected in humans may or may not pose health risks are just emerging.

Participants in biomonitoring studies typically want to know whehether the chemical compositions measured in their bodies indicate that they are healthy (or not); however, biomonitoring studies are not designed to answer this particular question. While biomonitoring is useful for assessing exposure, without other information, it is not alone useful in determining a person's health or likelihood of developing ill effects.[7][24] According to the National Research Council, accurate communication of results is essential for the proper use of biomonitoring surveys, but states "there is no accepted standard for good biomonitoring communications".[3]

Warren G. Foster and John Agzarian wrote in the journal Analytical and Bioanalytical Chemistry that dramatic advancements in analytical chemistry have led to an increase in the ability to detect more chemical compounds in smaller concentrations, "creating the perception that contamination of our environment has continued to increase." While there are more synthetic chemicals in the environment since the advent of the Industrial Revolution, the EPA's Toxic Release Inventory data indicates the presence of most environmental chemicals has decreased from 1988 to 2001.[7]

Standards and guidelines that health professionals can use to communicate biomonitoring information are still evolving. Foster and Agzarian write, "Because of the lack of clear reference ranges and standards, however, it is unlikely that providing study subjects with their individual exposure results in the absence of information about the health significance of the results would create anxiety and anger among study subjects."[7] An expert panel on Biomonitoring Equivalents has published guidelines for communicating information to the general public and health care providers.[25]

Dr. Charles McKay of the Connecticut Poison Control Center provides a perspective to assist medical toxicologists with understanding human biomonitoring data[26] is interviewed in a video titled "A Medical Doctor's Perspective on Biomonitoring", which is focused on helping the general public better understand biomonitoring.[27]

Boston Consensus Project

In 2007, the Boston University School of Public Health organized a panel, the Boston Consensus Conference on Biomonitoring, for the purpose of educating residents about the scientific, legal and ethical issues of biomonitoring, and coming to an understanding of the lay panel's priorities and concerns related to measuring human exposure to environmental chemicals. The conference produced a report for public health policy makers and scientists who deal with or study the issues.[28]

See also

References

  1. ^ "About the Program". cdc.gov. Centers for Disease Control. 3 April 2008. Retrieved 25 May 2009.
  2. ^ a b "About the Human Toxome Project". Human Toxome Project. Environmental Working Group. Retrieved 30 September 2009.
  3. ^ a b c Human Biomonitoring for Environmental Chemicals, National Research Council, 2008
  4. ^ Juberg, Daland R.; Bus, James; Katz, Diane S. (February 2008), "The Opportunities and Limitations of Biomonitoring", Policy Brief
  5. ^ "What is Biomonitoring?" (PDF). American Chemistry Council. Retrieved 11 January 2009.
  6. ^ a b Hays, S.M.; Becker, R.A.; Leung, H.W.; Aylward, L.L.; Pyatt, D.W. (February 2007). "Biomonitoring equivalents: A screening approach for interpreting biomonitoring results from a public health risk perspective". Regulatory Toxicology and Pharmacology. 47 (1): 96–109. doi:10.1016/j.yrtph.2006.08.004. Retrieved 23 July 2009.
  7. ^ a b c d Foster, Warren G.; Agzarian, John (2007), "Reporting results of biomonitoring studies", Analytical and Bioanalytical Chemistry, 387: 137–140, doi:10.1007/s00216-006-0822-6
  8. ^ "Statement on Biomonitoring". acs.org. Retrieved 23 July 2009.
  9. ^ "Environmental and Related Chemicals Measured in Blood, Serum or Urine in NHANES" (PDF). Centers for Disease Control. Retrieved 10 November 2009.
  10. ^ "Final Selection Criteria and Solicitation of Nominations for Chemicals or Categories of Environmental Chemicals for Analytic Development and Inclusion in Future Releases of the National Report on Human Exposure to Environmental Chemicals", Federal Register, 67 (194): 62477, 7 October 2002 {{citation}}: |access-date= requires |url= (help)
  11. ^ "Public Comments and Revised Criteria for Removing Chemicals Future Editions of CDC's National Report on Human Exposure Environmental Chemicals" (PDF), Federal Register, 73 (61): 16688, 28 March 2008, retrieved 10 November 2009
  12. ^ "National Children's Study". cdc.gov. 2009-07-07. Retrieved 23 July 2009.
  13. ^ National Research Council (2006), Human Biomonitoring for Environmental Chemicals, National Academies Press, ISBN 0-309-10272-3
  14. ^ "California Biomonitoring Program". CA.gov. Retrieved 23 July 2009.
  15. ^ "Environmental Public Health Tracking & Biomonitoring". Minnesota Department of Health. 2009-07-21. Retrieved 23 July 2009. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  16. ^ "State Grant Activities". Centers for Disease Control and Prevention. 9 September 2009. Retrieved 30 September 2009.
  17. ^ "Canadian Health Measures Survey". statcan.gc.ca. Statistics Canada. 19 March 2004. Retrieved 2 October 2009.
  18. ^ "Maternal-Infant Research on Environmental Chemicals (The MIREC Study)". hc-sc.gc.ca. Health Canada. 12 December 2007. Retrieved 2 October 2009.
  19. ^ "Human biomonitoring and environmental health" (PDF). Bulletin Épidémiologique Hebdomadaire. Insitut de Vielle Sanitaire. 16 June 2008. Retrieved 10 November 2009.
  20. ^ "Toxic Nation Studies". Toxic Nation. Environmental Defence. 17 October 2007. Retrieved 30 September 2009.
  21. ^ Sexton, S.; Needham, L.L.; Pirkle, J.L. (2004). "Human Biomonitoring of Environmental Chemicals" (PDF). American Scientist. 92 (1): 38–45. doi:10.1511/2004.1.38. {{cite journal}}: Unknown parameter |month= ignored (help)
  22. ^ Smolders R, Schramm KW, Nickmilder M, Schoeters G (2009). "Applicability of non-invasively collected matrices for human biomonitoring". Environmental Health. 8 (8). doi:10.1186/1476-069X-8-8. PMC 2660315. PMID 19272133.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  23. ^ a b "Interpreting the Data", Third National Report on Human Exposure to Environmental Chemicals, Atlanta, GA: Centers for Disease Control and Prevention, 2007
  24. ^ ""Interpreting the Data"". Third National Report on Human Exposure to Environmental Chemicals. Centers for Disease Control and Prevention. 2007. Retrieved 30 September 2009.
  25. ^ LaKind, J.; Aylward, L.L.; Brunk, C.; DeZio, S.; Dourson, M.; Goldstein, D.A.; Kilpatrick, M.E.; Krewski, D.; Bartels, M.J.; Barton, H.A.; Boogaard, P.J.; Lipscomb, J.; Krishnan, K.; Nordberg, M.; Okino, M.; Tan, Y.; Viau, C.; Yager, J.W.; Hays, S.M. (2008), "Guidelines for the communication of Biomonitoring Equivalents: Report from the Biomonitoring Equivalents Expert Workshop", Regulatory Toxicology and Pharmacology, 51 (3, supp 1): S16-26, doi:10.1016/j.yrtph.2008.05.007
  26. ^ McKay, Jr., C.A.; Holland, M.G.; Nelson, L.S. (2003), "A Call to Arms for Medical Toxicologists: The dose, not the detection, makes the poison", International Journal of Medical Toxicology, 6(1): 1
  27. ^ John Heinze, Ph.D. (2009). "Science Advisory Council member Dr. Charles McKay provides a medical doctor's perspective on biomonitoring". Biomonitoringinfo.org. Biomonitoring Info. Retrieved 30 September 2009.
  28. ^ "Consensus Statement on Human Biomonitoring" (PDF). Measuring Chemicals in Poeople -- What Would You Say?. Boston University School of Public Health. Retrieved 23 July 2009.

External links

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