Variables: concentration Keywords: stream pyrethroids Insecticides Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Chlorpyrifos (SBPBAQFWLVIOKP-UHFFFAOYSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N)