“Thomas et al(1998) tested the acute toxicity of ten pesticides used in the Murrumbidgee Irrigation Area (MIA), NSW to the Australian cladoceran Ceriodaphnia dubia. The pesticides atrazine, bensulfuron-methyl, bromacil. Chlorpyrifos, diuron, malathion, metolachlor, molinate, simazine and thiobencarb had been detected at elevated levels in drainage channels in previous irrigation seasons (Korth et al. 1995). With the exceptions of molinate and diuron, the acute toxicity decreased when tests were performed in irrigation supply water, in comparison to laboratory water…”
Source: p141 Pesticide Use in Australia. A Review Undertaken by the Australian Academy of Technological Sciences and Engineering.
Diuron recorded at 9.5ug/L in main drain 1991-3, and 20ug/L in main drain 1997-2001