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The aim of our study is to investigate the spatial distribution of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane ( p,p′ -DDT) and its metabolites, α- and γ-isomers of hexachlorocyclohexane (HCH) in 155 samples of human milk (HM) from Eastern Siberia (six towns and seven villages in Irkutsk Region, one village of the Republic of Buryatia and one town in Zabaikal'sk Region, Russia), and to examine the dietary and social factors influencing the human exposure to the organochlorines. The median and range of the concentration of six indicator PCBs in HM in 14 localities in Eastern Siberia (114 (19–655) ng g −1 lipids respectively) are similar to levels in the majority of European countries. However, in one village, Onguren, the median and range of levels of six indicator PCBs (1390 (300–3725) ng g −1 lipids) were comparable to levels measured in highly contaminated populations. The Lake Baikal seals are highly exposed to persistent organic pollutants (POPs) and could be a potential source of PCB and DDT exposure in the Onguren cohort via the consumption of the Lake Baikal seal tissue. The location of food production in areas exposed to the emissions of local POP sources can also significantly influence POP levels in HM samples from industrialized areas. Estimated daily intakes (EDI) of HCH and HCB for infants are considerably lower or close to acceptable daily intake (ADI). The EDI of total DDTs and total PCBs are higher than ADI. [ABSTRACT FROM AUTHOR]

Abstract: Polychlorinated biphenyls (PCBs) were measured in soil in some industrial towns (Ulaanbaatar, Suhbaatar, Erdenet, Darhan, Tsetserleg, Hovd, Ulaangom, Altay, Bayanhongor, Arvayheer, Saynshand, Choybalsan) and in background and rural areas of Mongolia. The average sum of all investigated PCB congeners in soil of Mongolia comes to 7.4 ng/g dry weight (DW) and varies from 0.53 ng/g DW till 114 ng/g DW. PCB levels in soil from towns are significantly higher than those in soil from background and rural areas. The PCB homological composition in soil sampled in highly-PCB-polluted sites is similar to the PCB homological pattern in Sovol and Aroclor 1254. Significant correlation between soil organic carbon and low chlorinated PCB both for towns and background sites was found. Significant differences in PCB means in soil in different natural zones were found. [Copyright &y& Elsevier]

The aim of the study is to investigate POP levels in environmental media (air, snow, soil and sediment), certain food items in the Olkhon district (Irkutsk Region, Russia) and Lake Baikal seal (nerpa) fat and meat in order to define the main pathways of elevated human exposure to POPs in the area. POP levels in soil and air samples and in almost all of the food items from the Olkhon district were comparable to levels in background areas of the Lake Baikal region. Only certain chicken eggs, large fish and blubber of nerpa pups exceeded maximum permissible levels of ΣDDTs and ΣHCHs. The combination of elevated levels of POPs in the Baikal nerpa with the use of Baikal nerpa fat (traditional nutritional habits, feed additives, as well as medicine for humans and domestic animals) results in two pathways for POPs to enter the human body: from seals it enters the human body directly, and indirectly from seals to poultry and livestock and then to the human body. Several scenarios of human exposure to POPs including the incidental ingestion of soil, inhalation of air, and ingestion of food were considered. The largest part of POPs enters the human organism through chicken eggs followed by fish and cow's milk in the scenario without the consumption of nerpa meat and blubber. The high consumption rate of fish as well as the consumption of the fat of nerpa pups or melted fat of nerpa increases the daily intake of POPs 1.3–11 times. The indexes of non-cancer risk and total cancer risk were assessed for residents of the Olkhon district and compared with indexes of risk for the average population of Irkutsk Region. Limiting the use of nerpa fat and meat as food and feed supplement reduces the potential human health risk. Unlabelled Image • POPs were quantified in food and the environment of Olkhon district, Lake Baikal. • PCB and DDT levels in environment in the Olkhon area correspond to background area. • Consumption of the fat of nerpa pups results in high human exposure to POPs. • The addition of melted nerpa fat in animal feed increases POP levels in human food. • Risk indexes for the residents are higher than those for other residents of region. [ABSTRACT FROM AUTHOR]