Dioxins and Dioxin-like Compounds in the Food Supply Strategies to Decrease Exposure (2003) / Chapter Skim
Currently Skimming:
2. A Summary of Dioxin Reports, Assessments, and Regulatory Activity
2. A Summary of Dioxin Reports, Assessments, and Regulatory Activity
Pages 17-52
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 17... ...
and polychlorinated biphenyls (PCBs) with dioxin-like activity, and on the potential human health effects from exposure to these compounds.
|
From page 18... ...
exposures to DLCs through feed and food pathways, the discussion on adverse health effects focuses on general exposures, but a brief description of adverse health effects from high exposures to DLCs is also included. The final part of this section consists of a summary of body burden and intake data in the general population and certain vulnerable groups.
|
From page 19... ...
An initial report and an update from the Scientific Committee on Food of the European Commission, Health and Consumer Protection DirectorateGeneral, Opinion of the Scientific Committee on Food on the RiskAssessment of Dioxins and Dioxin-like PCBs in Food (Scientific Committee on Food, 2000, 2001~. The initial report focuses on dietary exposure and toxicity of DLCs; it does not address pathways of contamination.
|
From page 20... ...
Although the TEF system is useful for determining toxicity in mixtures of DLC congeners, it cannot be used to simplify environmental fate and transport analyses of DLCs because individual congeners differ in their physical and chemical properties, an important consideration in fate modeling. Several TEF schemes have been developed over the years; they differ regarding the inclusion of dioxin-like PCBs and TEFs TABLE 2-1 Sample Toxicity Equivalents (TEQ)
|
From page 21... ...
The reports cited earlier (AEA Technology, 1999; ATSDR, 1998; EPA, 2000; Fiedler et al., 2000; IARC, 1997; Scientific Committee on Food, 2000,
|
From page 22... ...
These reports describe certain populations as "poisoned" or "highly exposed," including those in pesticide manufacturing studies, the Ranch Hand studies, the Seveso reports, and the Yusho and Yu-cheng investigations (see below)
|
From page 23... ...
The relative risk for total cancer for the lowest-exposed stratum in the epidemiological studies cited by EPA ranged from 0.9 to 1.24 (see Appendix Table A-3~. However, as reported by EPA (2000)
|
From page 24... ...
None of the evaluations reviewed by the committee (AEA Technology, 1999; ATSDR, 1998; EPA, 2000; Fiedler et al., 2000; IARC, 1997; Scientific Committee on Food, 2000, 2001) derives a conclusion about the carcinogenic potential of DLCs to humans solely from general exposures.
|
From page 25... ...
AEA Technology (1999) concludes that the epidemiological data suggest that TCDD exposure increases the rates of all cancers.
|
From page 26... ...
Toxicity Benchmarks Several governmental bodies have derived or recommended acceptable daily intakes or similar parameters for TCDD or DLCs as a group (AEA Technology, 1999; ATSDR, 1998; EPA, 2000; Fiedler et al., 2000; Scientific Committee on Food, 2000, 2001~. These guidance levels are summarized in Table 2-2.
|
From page 27... ...
EPA, 2000 1 x 10-3 pa/kg/d (TCDD) None given or 0.001 pa/kg/d at a 1 in 1 million excess risk level Scientific Committee on Food, 2000, 2001 AEA Technology, 1999; Fiedler et al., 2000 14 pg TEQ DFp wHog8lkglwk 1-4 pg TEQ/kg/d (CDDs, CDFs, PCBs)
|
From page 28... ...
Cancer is not considered one of the more important adverse effects of background DLC exposure; the Scientific Committee on Food (2000, 2001) believes that TCDD is a nongenotoxic carcinogen best evaluated with a threshold model, and that TCDD body burdens associated with cancer in laboratory animal bioassays and high-exposure human populations are "several orders of magnitude higher" than body burdens in the general population.
|
From page 29... ...
The other reports that were examined (AEA Technology, 1999; ATSDR, 1998; Fiedler et al., 2000; IARC, 1997; Scientific Committee on Food, 2000, 2001) do not contain slope factors for TCDD or other DLCs.
|
From page 30... ...
Recent body burden data (DLCs were measured in blood or adipose tissue) for persons living in Europe and North America are presented in several reports (AEA Technology, 1999; ATSDR, 1998; EPA, 2000; IARC, 1997~.
|
From page 31... ...
current body burdens are not at steady state given current intakes. European estimates of mean adult dietary intakes of CDD/CDF range from about 0.4 to 1.5 pg I-TEQ/kg/d.
|
From page 32... ...
, 49 to 57 percent for the Swedish mean total dietary exposure (AEA Technology, 1999; Fiedler et al., 2000) , 48 to 62 percent for dietary intake in Spain (AEA Technology, 1999)
|
From page 33... ...
At least 20 to 30 years of exposure are needed to reach steady state if the half-life of TCDD is 7.5 years (the value the Scientific Committee on Food [2000, 20011 uses in its calculations of body burden or intake) ; half-lives also increase with age, perhaps due to changes in metabolism and fat burden.
|
From page 34... ...
subgroups. Subgroups of the general population that are exposed to higher levels of DLCs through the food supply include indigenous populations in northern North America, subsistence and sports fishermen, small populations whose food supplies are affected by local contamination, and breastfed infants.
|
From page 35... ...
These data are also shown in Appendix Table A-4. Body Burdens of People Residing Near Local Sources of Contamination.
|
From page 36... ...
Regulations have also been implemented that focus on DLC uptake rather than source reduction, limiting total human body burden levels. In recent years, as food has been identified as the primary route to human exposure, several new regulations and programs have been implemented to reduce DLC contamination in food.
|
From page 37... ...
Australia and Japan have also adopted tolerable DLC intake levels (see Appendix Table Am.
|
From page 38... ...
There are a number of environmental acts that give EPA jurisdiction to create regulations regarding DLCs in the environment, including the Clean Air Act, the Clean Water Act, the Safe Drinking Water Act, and the Resource Conservation and Recovery Act. Appendix Table A-7 details the current federal regulations for DLCs.
|
From page 39... ...
addressing processes or media not regulated by existing directives. Appendix Table A-10 presents a detailed summary of each member state's DLC legislation and guidelines that go beyond the EC directives.
|
From page 40... ...
This regulation took effect in July 2002. According to the EC's Community Strategy for Dioxins, Furans, and Polychlorinated Biphenyls, these maximum limits are set at a strict but feasible level in order to discard unacceptably contaminated products (Scientific Committee on Food, 2001~.
|
From page 41... ...
EC recommended that authorities monitor food and take measures to reduce or eliminate contamination sources when DLC levels are found above the action threshold. These legally nonbinding action levels and legally binding levels are presented in Appendix Tables A-14, A-15, and A-16.
|
From page 42... ...
FDA also follows up on any unusually high values in any of their studies to determine sources of DLCs in the food supply. FDA does not target any specific imported foods, but it tries to create a representative sample of the diet of the general U.S.
|
From page 43... ...
Monitoring Programs of Other Countries and Organizations EC. Appendix Table A-l9 summarizes the nationally funded monitoring programs' research activities that were underway as of 1999 in each EC member state.
|
From page 44... ...
These results are to be submitted to prefectural governors. Beyond the regulatory requirements, it appears that there are not any ongoing surveillance programs in Japan (see Appendix Table A-20.
|
From page 45... ...
In order to efficiently develop a reliable picture of DLCs in the food supply, both screening methods (which can be used to analyze a large number and variety of feed and food samples) , and trace analysis (which can quantify low levels of DLCs in follow-up to a positive screening result)
|
From page 46... ...
Although to quantify contamination levels, trace analysis must follow a positive screening result, screening methods can be very useful in detecting a contamination event or identifying critical control points in a potential contamination pathway. Two cost-effective approaches have been developed for screening purposes: instrumental methods and biotechnology approaches.
|
From page 47... ...
The analytical cost estimates associated with the standard analytical method for DLCs obtained from a number of sources are summarized in Appendix Table A-24. EPA-Approved Method for Analysis of Dioxins and Furans in Wastewater In 1997, to augment less sensitive methods approved earlier, EPA Method 1613: Tetra- Through Octa-Chlorinated Dioxins and Furans by Isotope Dilution High Resolution Gas Chromatography/High Resolution Mass Spectrometry (HRGC/HRMS)
|
From page 48... ...
Recent Contamination Levels in Foods Appendix Table A-25 provides DLC values for foods other than breast milk. The data are very heterogeneous with regard to collection date, the number of samples of a particular food, sampling method (individual versus composite samples)
|
From page 49... ...
In Germany, milk, meat, and fish contributed 31 percent, 23 percent, and 17 percent, respectively, of dietary I-TEQ from PCDD/PCDF (Scientific Committee on Food, 2000~. Temporal Trends Several of the reviewed reports describe data that suggest a decrease in DLC intakes over recent decades.
|
From page 50... ...
Research on DLC levels in human foods indicates that the greatest contribution to exposure from the food supply is from animal fats in meat, dairy products, and fish. REFERENCES AEA Technology.
|
From page 51... ...
2003. Second National Report on Human Exposure to Environmental Chemicals.
|
From page 52... ...
Brussels: European Commission. Scientific Committee on Food.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.