Environmental contamination with dioxins: experience of ecotoxicity survey and assessment using wild mammalian model (bank vole C. glareolus) inhabiting forests outside sanitary zones of municipal waste landfills.

Dioxins are known to be toxic for biota at every dose and their long-term effects are reported for almost 50 years of investigations. Our researches of dioxin accumulation by bank voles living in the vicinity of several landfills near Moscow (landfills "Lesnaya" and "Kouchino") demonstrated the similarity of dioxin profiles in soil and animal samples, and an increase of highly toxic congeners' concentrations in the bank voles' bodies. We investigated also the probable public cancer risk resulting from the comparable lifetime exposure of the voles' population with dioxins' low doses, and our evaluation verified the hazard of cancer development supported by alterations in the ahr gene expression in the liver cells. The results of this study determined the usefulness of calculating the probability of cancer development in hypothetical residents of the area around both landfills. For the landfill "Lesnaya," the values corresponded to the level acceptable for professional groups (3.72E-04), but unacceptable for the population, whereas for residents of the area in the vicinity of the landfill "Kouchino," the level was considered to be unacceptable (1.91E-03) neither for the population nor for the professional groups. The revealed ecotoxicological situation may be quite hazardous for the population living in the area contaminated with dioxins, and the human health risks should be assessed. Thus, the prospects of the initial public health screening should consider our set of techniques used, as the effects described permit taking into account the mechanisms of interaction between the environmental factors and those determined by the characteristics of population real exposure.