ABSTRACT
Surface waters are particularly vulnerable to contamination by pesticides, because most agricultural and urban areas drain into surface water systems. Once pesticides are in the moving surface water system, they can be transported downstream and widely dispersed into other rivers, lakes, reservoirs, and ultimately, the oceans. The presence of pesticides in surface waters has been recognized since the 1940’s. P. H. Howard has compiled data on the physical and chemical properties and the environmental behavior of 70 pesticide compounds. Included are tabulations of detections of each compound in the different environmental matrices, including surface water. Ciba-Geigy Corporation has reviewed studies in which atrazine concentrations were measured in surface waters, primarily in rivers, streams, and reservoirs in the central United States, in a series of technical reports. A national overview of the occurrence and geographic distribution of pesticides in surface waters is developed from the observations reported in the reviewed studies, with particular emphasis on the large-scale studies.
