Scientists have explored how to improve the PERSAM model used by the European Food Safety Authority (EFSA) in pesticide regulation. They have analysed the risks posed by four pesticides on two types of soil organisms in northern, central and southern Europe.Scientists have explored how to improve the PERSAM model used by the European Food Safety Authority (EFSA) in pesticide regulation. They have analysed the risks posed by four pesticides on two types of soil organisms in northern, central and southern Europe.