Abstract
The results of 3 years' research into the effect of herbicides used in rape crops in France on soil and water quality are presented. Information on the frequency of use of the 19 different products approved for use is summarized, and the dangers posed by pollution are explored. Surveys conducted to measure the levels of trifluralin and metazachlor (the most widely-used herbicides) in groundwater in Central Region indicated that trifluralin was absent, but metazachlor was found at 7 of 51 sites sampled, and at one of these at a level of0.1 Ág/litre. Field experiments conducted in 1996 in Champagne on fluvial soils over a calcareous base to monitor the levels and movement of trifluralin and metazachlor into surface drainage water indicated that trifluralin levels were generally lower than metazachlor levels, and it also moved through drainage water the faster; however, both herbicides remained above levels of the previous year at the end of the 4-month sampling period. The results of sampling underground water from below rendzina monoblocks indicated that trifluralin was found on 8 of 14 sampling dates at 0.02-0.09 Ág/litre while metazachlor was found on 2 at 0.03 Ág.7 ref.The results of 3 years' research into the effect of herbicides used in rape crops in France on soil and water quality are presented. Information on the frequency of use of the 19 different products approved for use is summarized, and the dangers posed by pollution are explored. Surveys conducted to measure the levels of trifluralin and metazachlor (the most widely-used herbicides) in groundwater in Central Region indicated that trifluralin was absent, but metazachlor was found at 7 of 51 sites sampled, and at one of these at a level of0.1 Ág/litre. Field experiments conducted in 1996 in Champagne on fluvial soils over a calcareous base to monitor the levels and movement of trifluralin and metazachlor into surface drainage water indicated that trifluralin levels were generally lower than metazachlor levels, and it also moved through drainage water the faster; however, both herbicides remained above levels of the previous year at the end of the 4-month sampling period. The results of sampling underground water from below rendzina monoblocks indicated that trifluralin was found on 8 of 14 sampling dates at 0.02-0.09 Ág/litre while metazachlor was found on 2 at 0.03 Ág.