PBDE exposure from food in Ireland: optimising data exploitation in probabilistic exposure modelling

Abstract

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants added to plastics, polyurethane foam, electronics, textiles, and other products. These products release PBDEs into the indoor and outdoor environment, thus causing human exposure through food and dust. This study models PBDE dose distributions from ingestion of food for Irish adults on congener basis by using two probabilistic and one semi-deterministic method. One of the probabilistic methods was newly developed and is based on summary statistics of food consumption combined with a model generating realistic daily energy supply from food. Median (intermediate) doses of total PBDEs are in the range of 0.4-0.6 ng/kg bw /day for Irish adults. The 97.5th percentiles of total PBDE doses lie in a range of 1.7-2.2 ng/kg bw /day, which is comparable to doses derived for Belgian and Dutch adults. BDE-47 and BDE-99 were identified as the congeners contributing most to estimated intakes, accounting for more than half of the total doses. The most influential food groups contributing to this intake are lean fish and salmon which together account for about 22-25% of the total doses.

Exposure of the Irish population to PBDEs in food: consideration of parameter uncertainty and variability for risk assessment

“…Table 3 shows the MOS derived for the individual congeners BDE-47, -99, -153, -183 and -209 and for the total dose of congeners BDE-47, -99, -100, -153 and -154, which are the major components of commercial penta mixtures (Konstantinov et al 2008). All derived MOS for the 97.5th quantile of the doses as presented in Trudel et al (2010) (for comparison we use the external doses presented therein, i.e. before uptake of the substance into the body) are larger than 1 Â 10 5 with the lowest MOS at 1.6 Â 10 5 for BDE-99 (endpoint impaired spermatogenesis).…”

“…Therefore, the doses derived in this study together with doses derived in a previous study (Trudel et al 2010) are compared to the relevant NOAEL or LOAEL (lowest-observed-adverse-effect level) identified in the EU risk assessment reports by following the margin of safety (MOS) concept (van Leeuwen and Vermeire 2007). The risk assessment is performed for effects on the liver caused by the commercial mixtures of pentaBDE (product name: DE-71) and decaBDE, and for effects on reproduction caused by octaBDE: Individual congener data are compared to the relevant NOAEL, LOAEL or BMDL (benchmark dose lower confidence level) for potential effects on the liver, neurodevelopment, reproduction and impaired spermatogenesis as identified by a number of different researchers (for details, see Supporting Information, Section 4).…”

“…ROS assumes that the data are lognormally distributed. Trudel et al (2010) could show that this assumption is reasonable for the Irish concentration data and, therefore, the concentrations were modeled with lognormal distributions. More details on how datasets with nondetects were treated are given in Section 2 of the Supporting Information.…”

“…This was to appropriately extrapolate values below LOD based on information gained from data points above LOD (Helsel 2005;Trudel et al 2010). ROS assumes that the data are lognormally distributed.…”

“…Notes: BMDL: Benchmark dose lower confidence level, LOAEL: Lowest-observed-adverse-effect level, NOAEL: No-observed-adverse-effect level, POD: Point of departure.Average of the mean of external doses of female and male adults, respectively, as presented inTrudel et al (2010).Average of the 97.5th quantile of external doses of female and male adults, respectively, as presented inTrudel et al (2010).High quantile doses for average of female and male adults taking into account variability and uncertainty at Q Indicates which dose estimate was used for calculating the margin of safety.…”