Salmonella spp. and fecal coliform loads in coastal waters from a point vs. nonpoint source of pollution

Coastal areas are often contaminated by the dissemination of pathogenic bac teria from terrestrial inputs. In this study, we compared fetal coliforms ( FC) and Salmonella spp, loads from a coastal Mediterranean river and from t he submarine outfall of a coastal wastewater treatment station, A stratifie d sampling strategy was used to analyze storm events. Bacterial fluxes were estimated during a 16-mo period. Salmonella spp. loads from the river were high during storm events, and the annual loads were higher than those esti mated from the coastal outfall. Bacterial Loads from the river represented 3.0 x 10(16) FC yr(-1) and 6.9 x 10(12) Salmonella yr(-1), with at least 95 % occurring during high waterflow (21% of the year). Those from the submari ne outfall represented 4.3 x 10(16) FC yr(-1) and 4.7 x 10(10) Salmonella y r(-1), with a regular temporal discharge. Bacterial loads from the river we re associated with small clay particles (<2 mu m), which originate from dif ferent reservoirs, These particles-sediment-trapped bacteria accumulated in the river-bed during the lowest water levels in the downstream part of the river and were resuspended during storm events, The quantitative relations hip between both bacterial parameters vary depending on the source point of contamination. Salmonella spp. loads from the river are of great sanitary concern since high loads were recorded in summer (bathing activities) and a utumn (oyster production and consumption), Our results should help water qu ality managers to define priorities to improve the bacterial quality of riv er discharges.