Afarm is located on the edge of a river. the farmer has an insect problem and doubles the amount of pesticides used for several months on his crops. what negative impact, if any, do you think this could have on the river? excess pesticides would become runoff, which would pollute the river. excess pesticides would become runoff that is reabsorbed by the river sediment. pesticides are always natural and would not have a negative impact on the river. plants absorb pesticides; they would not be washed away into the river.