2018: Tully River (Queensland). Pesticide Shirtan (contains Mercury)

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2018 Tully River Queensland. Mercury from use of Shirtan Fungicide

Evaluation of mercury in a freshwater environment impacted by an organomercury fungicide using diffusive gradient in thin films



“…Mercury was surveyed in soils close to the Tully River at 3 different depths (100, 200 and 300 mm). Additionally, total Hg (THg) and the labile fraction of Hg in water (measured by the diffusive gradient in thin film technique) were determined in the Tully River. A pristine site, the Tully Gorge National Park upstream of sugarcane fields, was selected for background Hg concentration estimation. In soils, Hg levels ranged from 18 to 264 μg kg− 1, with one of the soil samples being almost 10 times higher than at other sites at the surface level (199 μg kg− 1). Total and labile concentrations of Hg in water increased from the Hg-elevated soil sampling sites (0.085 μg L− 1 and 0.061 μg L− 1) to downstream sites (0.082 μg L− 1 and 0.066 μg L− 1), which is likely due to agricultural runoff. Indeed, except for the upstream control site, the THg concentration in water is over the limit permitted by the Australian freshwater quality guideline for protection of 99% species (0.06 μg L− 1). These findings point to the need to perform further research to reveal the mechanisms for release of Hg from soil and whether this might be causing important adverse effects to the Great Barrier Reef located in front of this river catchment…”