2006: Johnstone River Qld (offshore). Pesticides: Diuron, Atrazine, Hexazinone, Tebuthiuron

A WATER QUALITY ISSUES ANALYSIS FOR THE JOHNSTONE RIVER BASIN

Report No. 11/05

for Terrain NRM

Stephen Lewis and Jon Brodie

Australian Centre for Tropical Freshwater Research, James Cook University

Final report April 2011

Agrochemicals

Herbicides

... Diuron, atrazine, hexazinone and tebuthiuron residues were detected in ‘grab’ samples collected along a transect from the Johnstone River to Russell Island (Kapernick et al., 2006). While herbicide residues detected were at relatively low levels (~5 ng/L diuron; others at 1-2 ng/L) compared to guidelines and effect concentrations, this sampling was conducted 2 weeks after Tropical Cyclone Larry had crossed the coast and so concentrations may have been much higher in the earlier stages of the plume.

A WATER QUALITY ISSUES ANALYSIS FOR THE JOHNSTONE RIVER BASIN

Report No. 11/05

for Terrain NRM

Stephen Lewis and Jon Brodie

Australian Centre for Tropical Freshwater Research, James Cook University

Final report April 2011

Agrochemicals

Herbicides

… Diuron, atrazine, hexazinone and tebuthiuron residues were detected in ‘grab’ samples collected along a transect from the Johnstone River to Russell Island (Kapernick et al., 2006). While herbicide residues detected were at relatively low levels (~5 ng/L diuron; others at 1-2 ng/L) compared to guidelines and effect concentrations, this sampling was conducted 2 weeks after Tropical Cyclone Larry had crossed the coast and so concentrations may have been much higher in the earlier stages of the plume.