Keywords: trace analytics stream pyrethroids pesticides Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Cyfluthrin (OFHFONYRMVKULH-WNYJFNBPSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N)