1998: Gwydir River Basin. PFAS pesticide: Fluometuron

1998: Gwydir River Basin: Pesticides Detected – Endosulfan, Atrazine, Amitraz, Chlorpyrifos, Profenofos, Diuron, Fluometuron, Metolachlor, Pendimethalin, Prometryn, Simazine & Trifluralin. Source of Contamination: Crops : Irrigated cotton, sorghum, maize
Where found: Rivers & streams. Reference: Muschal 1998.

https://www.environment.gov.au/node/21899#pesticidesininlandwaters

Detections are less frequent in riverine environments than in irrigation drainage, particularly in areas such as northern NSW where tailwater returns to the river are tightly controlled. The Central and North West Regions Water Quality Program finds chlorpyrifos in a very small number of samples (well below 1%) at concentrations generally between 0.1 and 1μg/L. However, chlorpyrifos accumulated to quite high levels in passive samplers deployed during 1998. This could reflect accumulation from background levels, or from occasional high pulses entering the river, with the latter appearing more likely given that such pulses are detected from time to time. Such detections, generally below 10μg/L but reaching as high as 26μg/L in one sample from the Gwydir, may reflect non-agricultural uses such as termite protection of bridges. However, predicted concentrations of this magnitude may also occur in shallow water contaminated through excessive spray drift from higher rate uses, such as for cotton. It seems likely that higher concentrations would occur in minor tributaries where pesticide residues first enter the riverine system.

https://apvma.gov.au/sites/default/files/publication/14756-chlorpyrifos-irr-environment.pdf

January 29 1998 Diuron 24ug/L

January 30 1998 Fluometuron 9ug/L

January 1998 Prometryn 9ug/L

*Cooperative Research Centre for Sustainable Cotton Production. Proceeding of the Cropping Systems Forum 2 & 3 December 1998 Narrabri NSW