Pesticides and the Great Barrier Reef: Extensive new data and analysis and increased concerns (a note from Jon Brodie)

As a result of an extensive research and monitoring program funded by the Queensland and Australian Governments over the last 5 years  a greatly better understanding of the risks to Great Barrier Reef ecosystems from pesticide residues is now available and in the process of being published in the scientific literature. Most of the papers are or will be published in special issues of Marine Pollution Bulletin and Agriculture Ecosystems and the Environment. Some of the MPB papers are already published online and the rest from both issues will follow over the next few months. While the complete set is still uncertain (due to reviewing still in progress) the following are already out:

  1. Davis, A.M., Lewis, S.E., Bainbridge, Z.T., Brodie, J.E., Glendenning, L., Turner, R. 2011 this volume. Dynamics of herbicide transport and partitioning under event flow conditions in the lower Burdekin region, Australia. Marine Pollution Bulletin. Online. doi:10.1016/j.marpolbul.2011.08.025
  2. Smith, R., Middlebrook, R., Turner, R., Huggins, R., Vardy, S. and Warne, M. 2011. Large-scale pesticide monitoring across Great Barrier catchments – Paddock to Reef Integrated Monitoring, Modelling and Reporting Program. Marine Pollution Bulletin. Online. doi:10.1016/j.marpolbul.2011.08.010
  3. W. van Dam, Andrew P. Negri, Jochen F. Mueller, Sven Uthicke.  2011. Symbiont-specific responses in foraminifera to the herbicide diuron. Marine Pollution Bulletin. Online.


About another 8 papers are still to be published so readers can look out for these. Also out in 2011 were:


  1. Negri, A.P. Flores, F. Röthig, T. Uthicke, S. 2011. Herbicides increase the vulnerability of corals to rising sea surface temperature. Limnology and Oceanography 56, 471-485.


  1. van Dam, J.W., Negri, A.P., Uthicke, S., Mueller, J.F., 2011. Chemical pollution on coral reefs: exposure and ecological effects. In: Sanchez-Bayo, F., van den Brink, P.J., Mann, R.M. (Eds.), Ecological Impact of Toxic Chemicals. Bentham Science Publishers Ltd.


We also have the pesticide results of this year’s extreme river discharge events coming out, both in rivers and in marine waters – initially in reports but in process of being written up for papers.

My conclusions from this body of work and previous results is that pesticides present a severe risk to coastal freshwater and estuarine systems along the GBR coast and a moderate risk to marine systems further offshore. There has already been press interest (Courier Mail 22 September 2011) regarding the Smith et al. paper which shows the large exceedance of Australian water quality guidelines for a range of pesticides along coastal waterways. The abstract from MPB is below.


The transport and potential toxicity of pesticides in Queensland (QLD) catchments from agricultural areas is a key concern for the Great Barrier Reef (GBR). In 2009, a pesticide monitoring program was established as part of the Australian and QLD Governments’ Reef Plan (2009). Samples were collected at eight End of System sites (above the tidal zone) and three sub-catchment sites. At least two pesticides were detected at every site including insecticides, fungicides, herbicides, and the Reef Plan’s (2009) five priority photosystem II (PSII) herbicides (diuron, atrazine, hexazinone, tebuthiuron and ametryn). Diuron, atrazine and metolachlor exceeded Australian and New Zealand water quality guideline trigger values (TVs) at eight sites. Accounting for PSII herbicide mixtures increased the estimated toxicity and led to larger exceedances of the TVs at more sites. This study demonstrates the widespread contamination of pesticides, particularly PSII herbicides, across the GBR catchment area which discharges to the GBR.


All this is happening at the same time as the Australian Pesticide and Veterinary Medicine Authority (APVMA) is considering the banning of diuron in Australia:



Jon Brodie

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