Ecological Risk Assessment for the Terrestrial Ecosystem under Chronic Radioactive Pollution

A methodology of ecological risk assessment for the terrestrial ecosystem under chronic radioactive pollution of a biotope near a regional radioactive waste storage has been developed in terms of the critical environmental loads analyzed. It consists of five stages: determination of effect indicators and assessment of their values; establishment of reference species and indices; assessment and analysis of critical loads by plotting “dose-effect” dependencies; ecological risk assessment from critical loads versus permissible values; plotting of risk functions to calculate the expected adverse alterations in the ecosystem. Based on the results obtained the storage risk for a terrestrial ecosystem is considered to be inadmissible and this implies unstable conditions in the territory in the nearest future. The calculations and mapping have shown that in the territory studied the area with excess critical loads is 48% for CFU and 61% for 90Sr accumulation coefficient. The analyzed risk functions give evidence of highly probable negative alterations in the tested ecosystem: 85% for CFU and 99% for 90Sr accumulation coefficient.