Transport to groundwater of six commonly used herbicides: a prediction for two Italian scenarios

In Italy suitable standard scenarios for pesticide risk assessment based on computer models are lacking. In this paper we examine the use of the VARLEACH model to assess the potential danger of ground-water pollution by six herbicides (alachlor, atrazine, cyanazine, linuron, simazine and terbuthylazine) which are used to protect irrigated (maize) and non-irrigated (sorghum) crops in the Po Plain, one of the most important agricultural lands in Italy. Two extreme scenarios are taken: real worst case (sandy soil) and real best case (clay loam soil). The simulation suggests that cyanazine, linuron and terbuthylazine can be safely used in clay loam soil in both non-irrigated and irrigated crops, while alachlor, atrazine and simazine can be safely used only in non-irrigated crops. On the other hand, the application of all the herbicides tested should be avoided in sandy soil, with the exception of linuron in non-irrigated crops.