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The indigenous people of coastal areas show a low percentage of low chlorinated and dioxin-like PCB congeners (as opposed to mainland aborigines) with a significant proportion of the "triad" in the amount of PCBs. 5 years after the first survey the ratio of the analyzed groups of PCB congeners in the blood of parturients - mothers, as well as in the fetus - child in the coastal Chukotka remained unchanged, indicating that the equal share rate of clearance-accumulation of congeners and is almost equal share content of PCB congeners in the mother and child. The average duration of half-lives of PCB congeners (#105-187) from the mother's body was 4-6 years (for the sum of PCBs - 5.7 years), which is broadly consistent with the results of foreign studies. The composition of PCB congeners in the blood of the continental population significantly differs from those in the food, while coastal residents--similar to the composition of PCBs in marine mammals. The content of PCB congeners in the domestic sources of pollution has no resemblance to the composition of PCBs in the blood of the natives.

In the indigenous dwellers of coastal Chukotka, blood DDT levels are 1.5-2 times higher than those of continental areas, which is due to the higher global DDT pollution of a sea food chain. The blood levels of 4,4-DDE in the reproductive-age women of coastal Chukotka are comparable to those in other Russian Arctic regions, slightly lower than in Greenland, but essentially higher than in Canada, Alaska and Scandinavian countries. Blood DDE/DDT ratio in the coastal indigenous dwellers is almost twice higher than that in the inland inhabitants, which is indicative of the "older" exposure of coastal people to DDT. There was an about equal (70-75%) decrease in 4,4-DDE and 4,4-DDT levels with a practically invariable ratio (12-15) and a nearly equal elimination half-life period (about 3.5 years) in the mothers of coastal Chukotka 5 years after the first examination. The elevated 4,4-DDE/4,4-DDT ratios in the tissues of sea mammals generally correspond to higher isomer ratios in the blood of coastal natives and relatively low 4,4-DDE/4,4-DDT ratios in the venison, fowl, and fish predetermine lower ratios in the blood of inland inhabitants. The extremely low of DDE/DDT ratio (0.4) in the washouts and scrapes from the kitchen walls of dwellings are conclusively associated with the recent application of DDT as a household insecticide.

A considerable reduction in the blood levels of stable organic pollutants (SOP) has been noted in the mothers of native ethnicities of costal Chukotka during a 5-year period, which may be accounted for by certain purification of food chains, altered diet with emphasis on delivered products, and long-term breastfeeding. The elevated level of SOP in children from birth to age 5 years is explained by long-term breastfeeding and the early consumption of local foods. The content of heavy metals (mercury and lead) in both maternal and children's blood has unchanged for 5 years. The children's infection morbidity has been quite high; at the same time no associations of the children's blood levels of toxic substances with the incidence of infectious diseases have been found. However, two children maximally exposed to SOP and metals have been observed to be rarely susceptible to diseases.

The paper presents the results of an investigation of the blood levels of mercury, lead, and cadmium in women of indigenous ethnic groups in the Far North. A certain correlation was found between the higher incidence of some poor pregnancy outcomes and fetal maldevelopment upon increased maternal exposure to heavy metals. The found correlations were statistically insignificant. There was no significant association of female exposure to heavy metals with menstrual irregularities and the sex ratio of neonates.

The paper presents the general principles and procedure of the development and implementation of measures to decrease and prevent environmental pollution with persistent toxic substances (PTS) in the Russian Arctic and, accordingly, to reduce a risk of the deleterious effects of PTS on human health. Based on the results of a study of PTS in the Russian Arctic (from the Kola Peninsula to Chukotka), the authors first systematized the basic lines and actions and formulated specific measures to reduce the North population's exposure to PTSs, such as polychlorinated biphenyls, organic chlorine pesticides (dichlorodiphenyltrichloroethane, hexachlorocyclohexane, hexachlorobenzene, etc.), and heavy metals (mercury, lead, cadmium). A package of measures is aimed at maximally reducing the presence of PTS-containing objects and materials in the north (via detection, collection, and extermination), at neutralizing the soils in settlement lands, at setting up safe water consumption systems, at organizing effective control over the safe use of chemicals and the levels of PTS in raw food materials and foodstuffs, and at working out recommendations on safe procedures for food purchase, storage, and cooking.

The paper provides the examination findings of helminthiases in the population of the town of Anadyr, the settlements of Kanchalan, Krasneno, and in the reindeer-breeding teams of the Anadyr District, CAD. The children infected with enterobiasis were shown to amount to 15.1 to 22.9%, diphyllobothriasis was detected in 12.9 - 33.7% of the examinees. Single cases of ascariasis were revealed. Analysis of 232 cases with echinococcosis demonstrates that the infection is prevalent over the whole Chukotka territory. Infection with Echinococcus multilocularis is more common in the indigenous population in the north-east of the District and that with Echinococcus granulosus in the central and northern regions. High extensive and intensive parasitic contamination rates of environmental objects, such as soil, sewage, household appliances, fish, etc., were noted, indicating a constant risk for Chukotka population's infection with parasites.