Herbicide contamination of surficial groundwater in Northern Italy.

Data on herbicide pollution in groundwater are rather scarce; monitoring data are based on single investigation, focussing on limited area and on few compounds of interest. The large number of approved active ingredients (approximately 600 chemicals) makes difficult to obtain an accurate and actual information on herbicide application in different countries, even if herbicides are the second most important class of pesticides used in the European Union. The results of a two-year monitoring campaign undertaken in two areas intensively cultivated at Lombardy, Northern Italy, showed a diffuse groundwater contamination due to active ingredients and their metabolites. More than 50% of samples overcame M.A.C. and the most common herbicides were Atrazine, Terbuthylazine and Metolachlor, while DEA and DET metabolites were often characterized by greater concentrations than their relative active principles.