Seasonal changes in the contents of widely used pesticides in waters and sediments from small lakes in the Province of Leon (Spain)

Abstract
The effect of pesticide treatments on small lakes in the vicinity of cultivated lands has been studied. Pesticides of widespread use in the selected area were determined in water and sediment samples from 27 different lakes, in different seasons, using multiresidue analysis methods. Many of the pesticides analyzed were found in the samples suggesting that these pesticides are mobile enough to reach the water in the small lakes. This must be considered because this water is used in some cases to irrigate the neighboring crops.