Keywords: trace analytics toxicity stream pyrethroids Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N) Cypermethrin (KAATUXNTWXVJKI-UHFFFAOYSA-N)