Organochlorine pesticides, polychlorinated biphenyls and dioxins in human milk from Swedish mothers.

Ten human milk samples, collected from two towns, Uppsala and Sundsvall, in Sweden in 1994 were analysed for selected chlorinated pesticides (HCB, alpha- and gamma-HCH, DDT, DDD and DDE) and PCB congeners (PCBs 28, 77, 101, 105, 118, 126, 138, 153, 156, 158, 167, 169 and 180), PCDDs and PCDFs. The levels found in this study, including the toxic equivalent (TEQ) values, showed a slight downward trend between 1986 and 1994 and are somewhat lower than levels reported from other countries. The contribution of both the mono- and non-ortho PCBs, together with that of PCDD/Fs to the total TEQ values was assessed. Over 70% of the TCDD equivalents was derived from PCBs, PCB 126 being the major contributor. Other high PCB contributors were PCBs 156 and 118. The levels of HCB, alpha- and gamma-HCH, and sigma DDT were generally higher in Uppsala than in Sundsvall. They were, however, over 50% lower in 1990 than in 1986 and have since changed little. For the PCDD/Fs the results show a marked decrease (ca 50%) in levels between 1986 and 1994. There is an indication that PCB 153 and PCB 126 may be good indicators for total PCB and TEQ levels respectively.