Levels of polychlorobiphenyls (PCBs), polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in human milk.

The design and results of a WHO-coordinated study on the assessment of PCDDs and PCDFs in human milk are presented. Factors affecting levels of these contaminants are discussed and the protocol of the study is illustrated together with a summary of milk collection requirements and of the analytical method. Results of both quality control and field studies are summarized and discussed. Conversion of analytical findings into 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) "toxicity equivalence" (TE) units is also illustrated together with risk assessment issues based on the results of field studies.