HUMAN-MILK AS A BIOINDICATOR FOR BODY BURDEN OF PCDDS, PCDFS, ORGANOCHLORINE PESTICIDES, AND PCBS

In the State Laboratory of North Rhine-Westphalia for Food, Pharmaceut ical and Environmental Chemistry (Chemisches Landesuntersuchungsamt), more than 600 individual human milk samples have been analyzed for pol ychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofura ns (PCDFs), and more than 1400 individual milk samples have been analy zed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) since 1984. All samples were collected on a voluntary basis fr om nursing mothers mostly living in North Rhine Westphalia, a federal state in Germany. The samples analyzed so far show a typical pattern o f PCDDs and PCDFs Out of the 210 possible congeners, only those with 2 ,3,7,8-chlorine substitution were found. While OCDD normally shows the highest concentration, the levels of the other dioxin congeners decre ase with decreasing number of chlorine atoms. A different pattern was found for PCDFs. Within this group 2,3,4,7,8-P5CDF is the most abundan t congener, followed by the hexachlorodibenzofurans. The mean level of tetrachlorodibenzodioxin (TCDD) was found to be of 3.2 pg/g on a fat basis and for total PCDDs and PCDFs, calculated as I-TEq (NATO/CMMS), 29.3 pg/g on a fat basis. The investigations of the past 2 years have revealed somewhat lower levels compared to former years. This might be an indication that the efforts undertaken to minimize dioxin emission s and to shirt down known sources have already had an effect on the bo dy burden of humans. Although mostly banned for a considerable period of time now, some lipophilic persistent pesticides such as DDT dieldri n, hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCH) can still be found in human milk. However, the levels of these residues have de creased during the past few years, indicating that the ban is having a n effect. A similar trend was found for PCBs. Although their concentra tion in human milk was at the same level for a long period of time, a slight decrease was observed in the past 2 years. Although the tolerab le daily intake concept, which is based on Lifetime intake, should not be applied to the relative short nursing period, the results of human milk analyses are far above these levels. Despite the fact that no ad verse health effects in babies could definitely be related to date to background levels of xenobiotics in human milk, it seems reasonable th at all efforts should be undertaken to minimize the emission of these pollutants and to shut down known sources to achieve a reduction of th e body burden of humans.