Seasonal fluctuations of nutrients and pesticides in the basin of Evrotas river, Greece

Water and sediment samples from several stations along the Evrotas river, were collected for one year period, from August 1991 to August 1992, and were analysed for nutrients (Total N, NO3-N and Total P) and pesticides. Higher nutrient concentrations were detected in the part of the river which is flowing through the plain of Sparta and is receiving industrial and domestic effluents, as well as the runoff from the agricultural land of the area. The industrial effluents (orange juice plants) and the agricultural land runoff, seem to play the major role during winter and spring, while the discharge of domestic septage (cesspools contents) in the reduced water flow, appears to be an important source of nutrient pollution during summer. In the water and sediments of the liver were detected the herbicides alachlor, atrazine, amitrol and simazine, the insecticides azinphos ethyl, carbofuran, diazinon, dicofol, endosulfan, fenthion, methyl parathion, as well as the fungicide captan. In the river water, the highest concentrations of herbicides atrazine, simazine and alachlor were found in summer (August 1991). The same herbicides as well as the insecticides azinphos ethyl, diazinon, dicofol, fenthion and methyl parathion, were found in significant amounts in the riverine sediments.