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

D. O'Brien, S. Lewis, A. Davis, C. Gallen, R. Smith, R. Turner, Michael St. J. Warne, S. Turner, S. Caswell, J. F. Mueller, J. Brodie

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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.
Original languageEnglish
Pages (from-to)3975–3989
JournalJournal of Agricultural and Food Chemistry
Issue number20
Early online date11 Jan 2016
Publication statusPublished - 25 May 2016
Externally publishedYes


Bibliographical note

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Agricultural and Food Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see


  • Great Barrier Reef
  • pesticides
  • herbicides
  • passive sampling
  • sugar cane
  • irrigation

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