PESTICIDE CONCENTRATIONS IN THE WATERS FROM A SECTION OF THE GUADALQUIVIR RIVER BASIN, SPAIN

When surface water is used to supply urban settlements, exhaustive stu dies of the composition of the source are necessary to ensure its pota bility, and to assess the possible environmental effects associated wi th contamination by pesticides. The present study centers on the pesti cide content of the waters from a section of the Guadalquivir River an d its affluents in southern Spain. At many of the sampling points anal yzed, high concentrations of both organochlorine and organophosphorus pesticides were detected. The presence of these toxic substances in da ngerously high concentrations, as well as the linear tendency of the m ean values for total pesticide concentration at sampling points, allow s us to conclude that the agricultural character of this area has ulti mately contributed to the contamination of the Guadalquivir River and its affluents, creating a sanitary and ecological hazard. In some case s the levels of contamination were found to consistently exceed the li mits established by the European Union concerning water quality for hu man consumption. Because the substances analyzed are not eliminated th rough conventional water treatment methods, we conclude that the sampl ed section of the Guadalquivir River basin should not be currently use d as a source of water for human consumption. Both pretreatment and ad vanced water treatment techniques would be required to reduce micropol lutant concentrations to potable levels. (C) 1997 by John Wiley & Sons , Inc.