2012-13: Boundary Creek/Herbert River Qld. Pesticides: Hexazinone, Diuron

Pesticide concentrations then seem to dissipate as they move further down the
catchment towards the Herbert River end-of-system; most likely as a result of dilution from the
upper catchment. For example, in 2012–13, 34μgL-1of diuron was detected at Boundary Creek (a
small sub-catchment of the Herbert River) (O’Brien et al., 2014b). This was approximately 23 times
the highest concentration detected at the Herbert River end-of-system site (Herbert River @Ingham; 1.48μgL-1)in the same year (GBRCLMP data, unpublished). The maximum concentration of
hexazinone in 2012–13 was 16μg.L-1also detected at Boundary Creek, which was 40 times higher
than the peak concentration detected at the downstream end-of-system site (0.4
Advancing our understanding of the source, management, transport and impacts of pesticides on the Great Barrier Reef
Compiled by Michelle Devlin and Stephen Lewis Lead Authors: Aaron Davis, Rachael Smith, Andrew Negri, Matthew Thompson, Mark Poggio
Centre for Tropical Water and Aquatic Ecosystem Research Report No 15/14 2015
James Cook University