Impact of arsenic and antimony contamination on benthic invertebrates in aminor Corsican river

The chemical and biological characteristics of a Corsican river that drains contaminated waters and sediment from an abandoned realgar mine were studi ed. The concentrations of pollutants such as As and Sb were found to be not ably high. For example, in the Presa River, downstream the realgar mine, th e mean As concentrations in the water and in the sediment were 3010 mu g 1( -1) and 9450 mu g g(-1) respectively. Species richness and abundance of ben thic invertebrates decreased downstream the As mine. The disappearance of o ligochaetes, leeches and a rarity of mayfly populations have been evidenced . On the contrary, a large increase in species belonging to stoneflies and gastropods was found. Some species like Baetis cyrneus, Ephemerella ignita, Sericostoma clypeatum and Ibisia marginata were more sensitive to As and S b concentrations while others species like Ancylus fluviatilis, Isoperla in sularis, Hydropsyche cyrnotica, Caenis luctuosa and Silonella aurata were l ess sensitive. The benthic invertebrates show different reactions in this c ontaminated environment, which could be explained by their feeding behaviou rs and certain morphological characteristics.