An approach for deriving HLVs (defined as “the life-long daily human intake of a chemical contaminant which does not result in adverse health effects”), for persistent organic pollutants (POPs) has been illustrated by RIVM. Over time, POPs accumulate in the body, which means that the whole body concentration, not just the daily (external) intake, should ideally be considered in safety evaluations. In addition, interspecies differences in POP kinetics may be much greater than the default uncertainty factor of four generally used in risk assessments, as is the case for 2,3,7,8‑tetrachlorodibenzo-para-dioxin. RIVM therefore suggests that interspecies differences in POP kinetics should be quantified for the risk assessment of POPs, and presents models of how this may be achieved. To avoid overly conservative extrapolation (of animal toxicity data), RIVM also recommends using a benchmark dose approach in the risk assessment process. Putting all this theory into practice, RIVM provides a review of the relevant data available on BDE-47 (neurodevelopmental and thyroid toxicity were identified as critical end-points), and derives a provisional HLV of 7 ng/kg bw/day for this POP.

[Bokkers B.G.H. et al. (2011). Method for the derivation of a Human Limit Value for brominated diphenyl ether-47. RIVM Letter report 320100006/2011. This report can be accessed by visiting on the website of the Dutch National Institute for Public Health and the Environment (RIVM).] {187659}

The above item was taken from the June 2011 issue of Toxicology and Regulatory News which is sent automatically to members of bibra (click here for more details).

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