Keywords: stream pyrethroids Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Acrinathrin (YLFSVIMMRPNPFK-WEQBUNFVSA-N) Allethrin (ZCVAOQKBXKSDMS-UHFFFAOYSA-N) Cyphenothrin (FJDPATXIBIBRIM-UHFFFAOYSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N) Cypermethrin (KAATUXNTWXVJKI-UHFFFAOYSA-N)