Radioactivity concentration and heavy metal content in fuel oil and oil-ashes in Venezuela

Abstract

Ecological Risk Assessment is used to evaluate the potential hazards to the environment that are attributable to emissions of pollutants from industries. There is guidance available regarding the general ecological risk assessment process including problem formulation, exposure and effect analyses, and risk characterization. In a first step, the Screening-Level Ecological Risk Assessment (SLERA) is used to evaluate whether the emissions can put the receptor ecosystems at risk or not. Concerning releases from nuclear facilities under authorization, any SLERA is a challenging task because of (1) the large number of substances, (2) the various quantities that may be emitted to the aquatic ecosystems and (3) the various environmental situations to be considered. This task must be performed for two categories of pollutants, radionuclides and chemicals, each exhibiting specificities in terms of concentration in media or dose-effect relationships. Since these relationships for radioactive substances are based on the tissue-absorbed dose in Gray, the first step is to express critical exposure values to radionuclides in a consistent way with the critical concentration used for chemicals. We describe here the screening and ranking method that was developed and an application to the electronuclear sites along the Rhône River.