Influence des rejets de deux stations d'épuration sur la teneur en phosphore des sédiments côtiers du Léman

The effect of discharges from two sewage treatment plants located on the northern shore of lake Geneva on surrounding sediments was investigated. Four forms of phosphorus were analyzed, together with extractable iron and organic carbon. Areal distribution of the parameters and correlation analysis show that the sewage treatment plant at Vidy discharges into the lake significant amounts of phospho-ferric precipitate. The influence of the other plant at Morges is more discrete, but its extent can be traced by the areal distribution of the ratios [Feextr.]/[non-apatite inorganic P] and [organic carbon]/[organic phosphorus].