ABSTRACT: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.

The effects of nickel and methyl‐parathion were studied in subinhibiting concentrations (40 and 62.5 μg/mL, respectively) on the levels of cellular peroxidation in Escherichia coli. These effects were evaluated using the thiobarbituric acid (TBA) test and the determination of lipofuscin‐like substances. Both toxicants caused an increase in cellular peroxidation levels, although at the concentrations used, nickel was shown to be a better inducer than methyl‐parathion. The TBA test gave more significant differences than the determination of lipofuscin‐like substances when the control cultures were compared to those containing the toxicant. This finding reveals that the TBA test could be used as a toxicity marker in E. coli for the development of ecotoxicity biotests. © 1994 by John Wiley & Sons, Inc..

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. ©1997 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 12: 249–256, 1997