Dioxins, dioxin-like PCBs and non-dioxin-like PCBs in foodstuffs: occurrence and dietary intake in The Netherlands.

Data on occurrence of dioxins (polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs]), dioxin-like PCBs (polychlorinated non-ortho and mono-ortho biphenyls) and non-dioxin-like PCBs (as represented by the so-called indicator-PCBs: congeners 28, 52, 101, 118, 138, 153 and 180) in food products consumed in The Netherlands that were collected in measurement programs carried out during 1998 and 1999, and combined with food consumption data to assess the dietary intake of these persistent food contaminants. The estimated median life-long-averaged intake of the sum of dioxins and dioxin-like PCBs in the population is 1.2 pg WHO-TEQ (toxic equivalents) per kg body weight (bw) per day, while the estimated median life-long-averaged intake of indicator-PCBs is 5.6 ng per kg bw per day. The contribution of different food groups to the total intake of both dioxins + dioxin-like PCBs and non-dioxin-like PCBs is fairly uniformly distributed over the foods consumed: meat products (23% and 27%, respectively), dairy products (27% and 17%, respectively), fish (16% and 26%, respectively), eggs (4% and 5%, respectively), vegetable products (13% and 7%, respectively), and industrial oils and fats (17% and 18%, respectively). Compared with earlier intake estimations the present estimation shows a continued reduction in the intake of dioxins as well as PCBs. This reduction is related to the decrease in the concentration of these substances in the majority of foodstuffs. Nevertheless, a small part of the population still has a rather high life-long averaged intake: 8% of the population is exposed to intake levels above the tolerable weekly intake for dioxins and dioxin-like PCBs of 14 pg WHO-TEQ per kg bw per week, as recently derived by the Scientific Committee on Food of the European Commission. For the non-dioxin-like PCBs an internationally accepted maximum intake level is still lacking. However, to provide risk managers with a health-based guideline to prevent health effects of exposure to non-dioxin-like PCBs, the (international) derivation of a tolerable daily intake is recommended. Monitoring the dietary intake of PCBs is just as important as monitoring the intake of dioxins and dioxin-like PCBs, and attempts to decrease the exposure to both compound classes need continuous attention.