PCDDS, PCDFS, AND PCBS IN HUMAN-MILK FROM DIFFERENT PARTS OF NORWAY AND LITHUANIA

Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin s (PCDDs) and dibenzofurans (PCDFs) as well as 16 polychlorinated biph enyls (PCBs) have been determined in pooled samples of breast milk fro m 10-12 mothers living in three different geographical areas in both N orway and Lithuania. The results indicate no apparent dependency of th e PCDD/PCDF levels, expressed as toxic equivalents (TEQs), and total P CB levels on the geographical residence of the donors within a country . This confirms the findings from a corresponding Norwegian study in 1 985/1986 where individual samples from the same areas were analyzed. T he total TEQs, including dioxin-like PCBs, ranged from 31 to 42 pg TEQ s/g fat in Norway and from 45 to 49 pg TEQs/g fat in Lithuania. The me an concentration of PCDDs/PCDFs in the Norwegian samples (10.4 pg TEQs /g fat) was slightly lower than in the Lithuanian samples (14.8 pg TEQ s/g fat). Dioxin-like PCBs were found to contribute two to three times more to the total TEQs than the PCDDs and PCDFs. Major contributors a mong the dioxin-like PCBs were PCBs 126, 156, 114, 118, and 170. Compa rison of the present data with those obtained in the Norwegian study i n 1985/1986 shows that for PCDDs/PCDFs the mean TEQ levels have decrea sed by about 37% in the 7-yr time span, while the levels of total PCBs , as determined by packed-column gas chromatography, have remained unc hanged or only slightly decreased. Future studies are necessary to con firm this potential temporal trend.