Keywords: stream pyrethroids pesticides Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Chlorpyrifos (SBPBAQFWLVIOKP-UHFFFAOYSA-N) Cyfluthrin (OFHFONYRMVKULH-WNYJFNBPSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N)