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
A recent study from the neighbouring Tully catchment showed that a number of photosystem-II inhibiting herbicides were regularly detected in the freshwater streams and also offshore in river water plumes in the Great Barrier Reef lagoon at concentrations either exceeding ANZECC and ARMCANZ (2000) guidelines or above known negative effect levels for marine plants (Bainbridge et al., 2009a). A clear relationship exists between the area of sugarcane and the mean diuron concentration (Bainbridge et al., 2009a). Monitoring in the Johnstone River catchment in the 1990s detected six herbicides including diuron (<2.3 μg/L), atrazine (≤0.7 μg/L), 2,4-D (0.18 – 15.6 μg/L), ametryn, trifluralin, MCPA and 2,4,5-T (Hunter et al., 2001).