Aporte de los afluentes a la contaminación fecal del estuario de Bahía Blanca, Argentina

Bahia Blanca estuary, Argentina, receives the contribution of the Naposta Grande stream and the Sauce Chico river. Channel Maldonado and the Saladillo de Garcia stream are minor tributaries whose contribution is meaningful only during periods of high rainfall. The objective of the study was to determine the health status of the main tributaries that the estuary of Bahia Blanca receives, quantifying populations of heterotrophic mesophilic aerobic bacteria (BH), Escherichia coli (EC) and Salmonella spp., as well as to set the impact they have on the estuary. Significant differences between the stations for both EC (p < 0.02) and BH (p < 0.01) were found. The comparison of means (LDS Fisher) showed that the significant differences detected by ANOVA for both indicators corresponded to the Maldonado Channel. In the other three stations, we could not say pollution differed significantly (p < 0.05). Salmonella spp. was detected in 50 % (11/22) of the samples of the Maldonado Channel and in 45 % (10/22) of the Naposta stream. Maldonado Channel and Naposta stream are the courses with greatest impact on the estuary. Garcia de Saladillo stream and the Sauce Chico river, showed a similar behavior and are not a problem of contamination of the estuary. The Bahia Blanca estuary is heavily impacted by human activity, which maintains high concentrations of faecal bacteria in certain areas. This problem will remain if the clandestine dumps sewage arriving through fresh water courses are not controlled.