FACTORS THAT INFLUENCE THE LEVEL OF CONTAMINATION OF HUMAN-MILK WITH POLY-CHLORINATED ORGANIC-COMPOUNDS

Polychlorinated organic compounds (POCs) accumulate in tissues with a high fat content. Nursed babies are exposed to POCs through the fat in human milk. Exposure levels are estimated to exceed those considered acceptable as a lifelong daily dose. Nevertheless, mothers are still p ositively advised as to breast-feeding. In 1988, a survey on contamina tion of human milk with POCs was carried out in The Netherlands. Level s of ten different organochlorine pesticides (OCPs), eight polychlorin ated biphenyl (PCB) congeners, and seventeen polychlorinated dibenzodi oxin (PCDD) and -dibenzofuran (PCDF) congeners were determined by use of gaschromatographic techniques with either electron-capture or mass- spectrometric detection. Information on some factors potentially influ encing the level of contamination of human milk was obtained by questi onnaires. The estimated response amounted to 71 percent. Regression an alysis was used to investigate associations between determining factor s and specific contaminants. It appeared that maternal age was positiv ely associated with POC concentrations. Traditional omnivorous diet wa s associated with lower concentrations of POCs when compared to all ot her types of diet. The post-pregnancy Quetelet Index [by definition ca lculated as weight/(length)(2)] and the cumulated period of previous b reast-feeding were negatively associated with POC concentrations. In c onclusion, chemical behavior and environmental distribution patterns o f the POCs measured in this study, if translated to factors of human e xposure, are in accordance with the study results. Exposure levels wil l decrease if emissions can be further reduced. Still, in the near fut ure, maternal age will probably rise (Vermunt 1992; Netherlands Centra l Bureau of Statistics 1992), whereas the duration of lactation is exp ected to decline. Consequently, there might be an increase in average POC-concentrations in human milk in the forthcoming years.