2010 Goulburn Weir: Pesticide: Glyphosate

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Residue testing of water following treatment of Nympheae mexicana (within Goulburn Weir Pool) with Weedmaster Duo (glyphosate, with an aquatic registration). October 2011 Goulburn Murray Water

The results from River Channel Site 1, show that glyphosate was detected with in the spray zone at 1,2, 4 and 6 h after spray treatment. At 1 h, glyphosate was only detect in surface sample, while at 2, 4 and 6 h glyphosate was detected at the surface of 0.5m depth. Concentration ranged from 0.05 – 0.15 mg/L which was less than half that of the ANZECC water quality for protection of 99% of aquatic life (0.37mg/L). Recreational (boating) and the subsequent wave action probably washed glyphosate off the treated Yellow Waterlily leaves and into the surrounding water…

In Backwater Site 1, glyphosate was detected in the spray zone at the surface of 0.5, 1 and 2 h after spray treatment. At the 2 h interval glyphosate was also detected at 0.5 m depth. The surface residue sample collected at 0.5 h exceeded the ANZECC 99% level of protection water quality guideline by 0.03mg/L…