Spatial and Temporal Variability in Pesticide Exposure Downstream of a Heavily Irrigated Cropping Area: Application of Different Monitoring Techniques

• DOI: 10.1021/acs.jafc.5b04710
• Publication Date: 2016-01-12T04:48:53Z
• Authors: Dominique O’Brien; Stephen Lewis; Aaron Davis; Christie Gallen; Rachael Smith; Ryan Turner; Michael Warne; Scott Turner; Stewart Caswell; Jochen F. Mueller; Jon Brodie
• Keywords: Agricultural Irrigation; Herbicides; Pesticide Residues; Sugar cane; Fresh Water; 15. Life on land; 1600 Chemistry; 01 natural sciences; 333; 6. Clean water; 1100 Agricultural and Biological Sciences; Passive sampling; 13. Climate action; Water Quality; Water Pollution, Chemical; Great Barrier Reef (GBR); Pesticides; Irrigation; Water Pollutants, Chemical; Environmental Monitoring; 0105 earth and related environmental sciences

Pesticide exposure threatens many freshwater and estuarine ecosystems around the world. This study examined the temporal and spatial trends of pesticide concentrations in a waterway within an agriculturally developed dry-tropics catchment using a combination of grab and passive sampling methods over a continuous two-year monitoring program. A total of 43 pesticide residues were detected with 7 pesticides exceeding ecologically relevant water quality guidelines/trigger values during the study period and 4 (ametryn, atrazine, diuron, and metolachlor) of these exceeding guidelines for several months. The presence and concentration of the pesticides in the stream coincided with seasonal variability in rainfall, harvest timing/cropping cycle, and management changes. The sampling approach used demonstrates that the application of these complementary sampling techniques (both grab and passive sampling methods) was effective in establishing pesticide usage patterns in upstream locations where application data are unavailable.