Current risk assessment approaches in different countries
作者:
John Ch. Larsen,
William Farland,
Dwain Winters,
期刊:
Food Additives & Contaminants
(Taylor Available online 2000)
卷期:
Volume 17,
issue 4
页码: 359-369
ISSN:0265-203X
年代: 2000
DOI:10.1080/026520300283423
出版商: Taylor & Francis Group
关键词: Reference Dose Risk Assessment Risk Management Risk Specific Dose Threshold Tolerable Daily Intake Toxic Equivalent
数据来源: Taylor
摘要:
Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) exist as complex mixtures in environmental and biological samples. There is sufficient evidence that the toxic congeners share a common mode of action, involving binding to the Ah-receptor. Toxic equivalency factors (TEFs) and chemical residue data are used to calculate toxic equivalent (TEQ) concentrations in environmental samples, foods, animal and human tissues. Two different approaches have been used in the risk assessments of PCDDs, PCDFs and dioxin-like PCBs. WHO and most countries outside the USA have derived Tolerable Daily (or weekly) Intakes (TDI) in the order of 1–10 pg per kg of body weight for TCDD or TEQs based on data from rodent carcinogenicity studies. These countries have assumed the existence of a threshold dose for the carcinogenicity of dioxins, while US EPA and USFDA have used probabilistic estimates of cancer potency, treating cancer as a non-threshold effect and using a descriptor that addresses upper bound risk, the Risk Specific Dose (RsD). In the USA and other countries there is a growing concern over the noncancer effects of dioxin-like compounds. In general, the various risk assessments have identified groups of the population that are at particular high risks and all have stressed the urgent need to reduce the sources of the environmental contamination with these compounds to the lowest possible.
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