Pesticides in Surface Waters and Groundwaters

Diffuse pollution by pesticides, particularly herbicides, has been recognized in the UK for several years. Atrazine, Simazine, Mecoprop, Dimethoate and, more recently, Isoproturon and Chlortoluron have been found frequently in surface waters at concentrations up to 0.5 μg/l, with a maximum of 11.5 μg/l. Pesticides are detected less frequently in groundwaters, at concentrations generally lower than 0.1 μg/l. Atrazine is found most frequently. Concentrations in untreated surface and ground‐waters have generally been below the maxima recommended for drinking water by the Department of the Environment (DoE). Concentrations in treated drinking water have not exceeded the DoE recommended maximum concentrations, but measures are being taken to reduce concentrations to below 0.1 μg/l.