Human milk as a bioindicator for body burden of PCDDs, PCDFs, organochlorine pesticides, and PCBs

In the State Laboratory ofNorth Rhine-Westphalia for Food, hann ceuticalandEAnmnentalChemisry (Chemisches landesuntersucungsamt), more than 600 individual human milk samples have been analyzed for polychoated dibenzo- p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and more than 1400 individual milk samples have been analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) since 1984.All samples were col- lected on a voluntary basis from nursing mothers mostly living in North Rhine VAstphalia, a federal state in Germany.The samples analyzed so far show a typical pattern of PCDDs and PCDFs.Out ofthe 210 possible congeners, only those with 2,3,7,8-chlorine substitution were found.While OCDD normally shows the highestconcentration, the levels ofthe other dioxin congeners decrease with decreasing number ofchlorine atoms.A different pattern was found for PCDFs.Within this group 2,3A,7,8-P5CDF is the most abundant congener, followed by the hexachlorodibenzofurans.The mean level of tetrachlorodibenzodiain (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 investiptions ofthe past 2years have revealed somewhat lower levels compared to former years.This might be an indication that the efforts undertaken tominimize dioxin emis- sions and to shut down known sources have already had an effect on the body burden ofhumans.Although mostly banned for a considerable period oftime now, some lipophilk ent dessuchas D , diekdrin, hhiorobemene (HCB), and hexachlorocyclohatanes (HCH) can still be found in human milk.However, the levels ofthese residueshave decreased during the past few years, indicating that the ban is having an effect.A similar trend was found for PCBs.Although their concentration 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 tolerable daily intake concept, which is based on lifetime intake, should not be applied to the relative short nursing period, the results ofhuman milk analyses are far above these levels.Despite the fact that noadverse health effects in babies could definitely be related to date to background levels ofxenobiotics in human milk, it seems reasonable that all efforts should be undertaken to mniie the emission ofthese poltants and to shut down known sources to achieve a reduction of the body burden of humans.