When surface water is used to supply urban settlements, exhaustive studies of the composition of the source are necessary to ensure its potability, and to assess the possible environmental effects associated with contamination by pesticides. The present study centers on the pesticide content of the waters from a section of the Guadalquivir River and its affluents in southern Spain. At many of the sampling points analyzed, high concentrations of both organochlorine and organophosphorus pesticides were detected.
The presence of these toxic substances in dangerously high concentrations, as well as the linear tendency of the mean values for total pesticide concentration at sampling points, allows us to conclude that the agricultural character of this area has ultimately contributed to the contamination of the Guadalquivir River and its affluents, creating a sanitary and ecological hazard. In some cases the levels of contamination were found to consistently exceed the limits established by the European Union concerning water quality for human consumption.
Because the substances analyzed are not eliminated through conventional water treatment methods, we conclude that the sampled section of the Guadalquivir River basin should not be currently used as a source of water for human consumption. Both pretreatment and advanced water treatment techniques would be required to reduce micropollutant concentrations to potable levels.