Keywords: stream pyrethroids Insecticides Systems: stream Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Chlorpyrifos (SBPBAQFWLVIOKP-UHFFFAOYSA-N) Acrinathrin (YLFSVIMMRPNPFK-WEQBUNFVSA-N) Cyphenothrin (FJDPATXIBIBRIM-UHFFFAOYSA-N) Deltamethrin (OWZREIFADZCYQD-NSHGMRRFSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N)