Bioaccumulation of metals by soil-dwelling insects in a uranium production area

Mining of uranium and molybdenum ore in South-Eastern Siberia (Russia) by the Priargunsky Mining-Chemical Production Company resulted in 100-600 times enrichment of these elements in neighbouring steppe soils. Some attendant pollutants (thorium, arsenic and heavy metals) also occur in soil in high concentrations. The aim of the study is to assess the impact of the uranium production complex on bioaccumulation of uranium and some other elements in soil-dwelling invertebrates, and their accumulation in hypothetic detritial food webs. The element composition was analysed in four coleopteran and one orthopteran species in the vicinity of a rock dump. Concentrations of uranium (0.6-3.5 mg kg−1) and molybdenum (1.4-8.5) in insects sampled at contaminated sites were 2-12 times as high as in the control site. Most susceptible to accumulation of metals were saprophagous tenebrionid beetles. Nevertheless, lower concentrations of toxicants in necrophages than in phytophages suggests that they dissipate in detritial food chain. Industrial activity of PPGHO results in severe burden of surrounding ecosystems by uranium, molybdenum and attendant metals.