Confounding factors influencing serum dioxin concentrations in the French dioxin and incinerators study

The aim of the French Dioxin and Incinerators Study was to evaluate the serum PCDDs, PCDFs and PCBs concentration distribution in 1030 randomly selected residents living in the vicinity of 8 municipal solid waste incinerators and its association with dioxin exposure, particularly with intake of local food produced under the incinerator's plume. The geometric mean of serum concentrations for the study population was 13.7 pg TEQ/g for PCDD/Fs lipids and 27.7 for the total TEQ. Globally, we did not observe any difference in geometric mean of serum dioxin levels between the residents living around incinerators and the residents living far from any known source of dioxins. Nevertheless, the analysis of the local consumers showed an increase of their serum dioxins levels with the consumption of local products from animal origin such as dairy products, eggs and more generally lipids. It is important to stress that this influence was observed for old incinerators, but not for the recent ones. Contamination by inhalation seemed negligible in regard to dietary intake.