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Endocrine Disruptors

5. What are potential sources of EDC exposure?

    The source document for this Digest states:

    Often the weakest link in determining whether observed adverse effects in humans and/or wildlife are linked to EDCs is the absence of adequate exposure data. Often data are limited to accidentally highly exposed groups. Most exposure information has focused on the presence of persistent organic pollutants in Europe and North America. Data on the magnitude and trends of global human or wildlife exposure are limited. Potential sources of exposure are through contaminated food, contaminated groundwater, combustion sources, and contaminants in consumer products. Information on exposure during critical development periods is generally lacking. The exposure data sets that exist are primarily for various environmental media (air, food, water) rather than the most relevant internal exposure (blood, tissue). Limited exceptions are human breast milk and adipose tissue samples. Worldwide, despite large expenditures of money, time, and effort, comparable data sets for assessing exposures to EDCs for humans or wildlife are not available. Such information is essential to adequately evaluate exposure–response relationships in field and epidemiological studies and to use these relationships to produce credible risk assessments.

    Source & ©: IPCS"Global Assessment of the state-of-the-science of Endocrine disruptors "
     Executive Summary (Chapter 1) page 3 section 1.6

    General exposure:

    For details on: See IPCS assessment:
    Exposure issues for EDCs  Chapter 2, section
    2.5, page 8
    The kind of exposure studies that are needed on EDCs  Chapter 6, section
    6.1, page 89

    Sources and pathways:

    For details on: See IPCS assessment:
    Sources of exposure to EDCs  Chapter 6, section
    6.2.1, page 90
    Pathways of exposure to EDCs via air, water, soil, sediment, food and consumer products  Chapter 6, section
    6.2.2, page 91
    Exposure via air to volatile compounds such as lindane, nonhalogenated aromatic hydrocarbons, phenols and phthalate esters  Chapter 6, section, page 91
    Exposure via water to water-soluble compounds such as pesticides, industrial chemicals and natural hormones  Chapter 6, section, page 91
    Exposure via soil and sewage sludge to compounds such as PCBs, dioxins and PBDEs  Chapter 6, section, page 91
    Exposure of wildlife via sediments  Chapter 6, section, page 91
    Exposure via food, the major exposure route for humans and wildlife  Chapter 6, section, page 91
    Exposure via consumer products such as exposure to phthalate esters in young children chewing on toys and teething rings  Chapter 6, section, page 92

    Intake and uptake:

    For details on: See IPCS assessment:
    The difference between intake and uptake of environmental chemicals with EDC potential  Chapter 6, section
    6.2.3, page 92
    The internal dose and pharmacokinetics of EDCs  Chapter 6, section
    6.2.4, page 92

    Wildlife exposures:

    For details on: See IPCS assessment:
    Exposure to persistent organic pollutants in the Baltic sea, Great Lakes region and Arctic region  Chapter 6, section, page 93
    Global distribution of DDT and PCBs in marine mammals  Chapter 6, section, page 95
    The impact of TBT, used in antifouling paints applied to hulls of ships, on coastal areas  Chapter 6, section, page 96
    The source and fate of alkyl phenols (APs), alkylphenol ethoxylates (APEs) and their degradation products  Chapter 6, section, page 96
    Summary and conclusions on wildlife EDC exposures  Chapter 6, section, page 98

    Human exposures:

    For details on: See IPCS assessment:
    Dioxins ingested through food and decreasing levels in breast milk  Chapter 6, section, page 98
    PCB exposure due persistence in the environment and continued use in some parts of the world  Chapter 6, section, page 100
    PBDEs that are present in food and may be released from television sets and computers, and are found in increasing amounts in human breast milk  Chapter 6, section, page 100
    DDT that is still used in some developing countries  Chapter 6, section, page 100
    Phthalates that are present in various types of plastics  Chapter 6, section, page 100
    Atrazine that may be present in groundwater and drinking water  Chapter 6, section, page 100
    Phytoestrogens that are naturally present in foods such as soy  Chapter 6, section, page 100
    Conclusions on human EDC exposures  Chapter 6, section, page 101


    For details on: See IPCS assessment:
    Ways of measuring EDC exposure  Chapter 6, section
    6.4, page 101
    Key issues involved in sampling to measure EDC exposure  Chapter 6, section
    6.4.1, page 102
    Multi-residue methods that can test for a broad range of chemicals in a single sample used for screening purposes  Chapter 6, section, page 102
    Using combined chemical and biological methods to identify EDCs in environmental samples  Chapter 6, section, page 102
    Biological methods currently available for detecting hormonally active substances  Chapter 6, section, page 102
    The toxic identification evaluation (TIE) approach that uses in vitro bioassays in conjunction with chemical methods for identifying EDCs  Chapter 6, section, page 103

    Mixtures, QA/QC, exposure models & SARs:

    For details on: See IPCS assessment:
    Potential endocrine disruptors that exist as mixtures of related chemicals (isomers and congeners)  Chapter 6, section
    6.4.3, page 103
    PCB congeners and other EDCs that exist as mirror images (chiral pairs)  Chapter 6, section, page 103.
    The various systems for weighting the amounts of individual congeners in a mixture in proportion to their toxicity  Chapter 6, section, page 103
    The importance of quality assurance and quality control (QA/QC) procedures to ensure EDC measurements from around the world are comparable  Chapter 6, section
    6.4.4, page 104
    Exposure models that can be used when measurements are limited  Chapter 6, section
    6.4.4, page 104
    Structure-activity methods that can be used to estimate the potential EDC activity of untested chemicals  Chapter 6, section
    6.4.5, page 104
    Summary and conclusions on EDC exposure issues in wildlife and humans  Chapter 6, section
    6.5, page 105

    Themes covered
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