Saving the Great Barrier Reef

WE may live in the information age, but how true are many of the scientific claims we read and hear?  For ten years the World Wide Fund for Nature, WWF, has been campaigning to ‘Save the Great Barrier Reef’. [1,2,3]  When the WWF campaign was first launched in June 2001 it was claimed Diuron was killing seagrass and dioxins were killing dugongs and so both these pesticides should be banned.  Ten years on and the ban on Diuron appears imminent, but the chemical is probably no more harmful than the dioxin that was found to be natural.[4]

The WWF campaign is an example of prejudice against industry and pesticides and also how alarmism is increasingly favoured over evidence resulting in junk science. [5]

My introduction to the exploitation of the Great Barrier Reef as a reason for banning chemicals came in August 1998 soon after I started working for Queensland Canegrowers Ltd .  Jon Brodie, a scientist with the Great Barrier Reef Marine Park Authority, GBRMPA, phoned me as the industry’s new environment manager, with information that a soon-to-be published research study had found elevated levels of pesticide residue, most likely from sugarcane farming, accumulating in the fat tissue of dugongs. [4]

I was concerned, alarmed, I wanted to see the data.  But I was told it was not yet available.  When I was finally faxed the few pages, I found it was primarily an analysis of the type and quantity of dioxins found in the fat tissue of dugongs that had been killed in fishing nets.    Reference was made to another study which analysed dioxins found in cane land soils and commented that perhaps there was a link.

Meanwhile a dioxin expert at the University of Queensland, Brian Stanmore, advised me that the particular dioxin generating the concern and interest was very common.   Four years later, in 2002, investigations undertaken by the National Research Centre for Environmental Toxicology, concluded that the pesticide Brodie had phoned me about in 1998, was in fact a natural, non-toxic dioxin common along the entire Queensland coast. [6]

Just a year earlier, in 2001, when it was already apparent that there were problems with the claim that runoff from sugar farms was killing dugong, WWF made exactly this claim at the launch of their ‘Save the Great Barrier Reef Campaign’. [1]

Their campaign was well resourced and immediately stirred governments into action with various committees and enquiries established.

I found myself on the Reef Protection Taskforce as the Canegrowers’ representative.  The Taskforce was to advise the Queensland Government on the development of a Reef Protection Plan to “reduce the impacts on the Great Barrier Reef of land based sources of nutrients, sediment and pollution” and was lauded in a WWF campaign progress report as a key WWF ‘anti-pollution achievement’. [5]

But the WWF representative on the Taskforce, Imogen Zethoven, was not happy when the first 3-page science statement presented to the Taskforce for endorsement didn’t include anything about damage to the reef.

Zethoven demanded it be redrafted, and government obliged.   The revised statement came out with a covering email with comment that: “whilst there is no evidence of widespread deterioration (of the Great Barrier Reef), there is documented evidence of localized deterioration on individual near-shore reefs.”   It was another three days before the scientific papers purporting to support this claim were provided and heading the list was an unpublished report commissioned by the Queensland Department of Fisheries hypothesizing that Diuron from cane lands was the cause of mangrove dieback at the mouth of the Pioneer River in 1999. [5]

The report was the work of Norm Duke, then a botanist at the University of Queensland, subsequently funded to publish a series of research papers on the issue, each generating a media headline claiming Diuron from cane land killed mangroves. [7]

John Abbot, a research chemist at Central Queensland University, and I, have reviewed the work of Duke and his team.  Our findings just published in the international Journal Human and Ecological Risk Assessment detail the many substantial flaws in this research.   We explain how concentration of chemical bound to sediment was used as a measure of biological availability when the relevant literature indicates they should have been measuring concentration in solution.  In order to get a result in experimental investigations the researchers dosed seedlings with concentrations of chemical orders of magnitude higher than anything found in waterways.  Worst still, their experimental design mixed waters from the control and treatments. [7]

The research nevertheless made it through the peer-review process perhaps because it plays on a popular Litany – the widespread belief that pesticides are harming the environment and that without political pressure for change we are all doomed.

In the very first report Duke corroborates his concern about an impact from Diuron by calculating a hypothetical value for the amount of Diuron applied to mangroves expressed as the amount of Diuron applied in a particular catchment divided by the area of mangrove in that catchment. Of course Diuron is applied to sugarcane, not mangroves, and only a fraction of the herbicide applied to sugarcane will be transported to the vicinity of mangroves and the area of mangrove will not affect concentration levels.   So Duke’s example is not logical.  For example, consider a situation where mangroves are growing on opposite sides of a river, if all the mangroves on one side are removed, this would not change the concentration of the herbicide affecting the remaining mangroves.

Most Australians would expect that policies, including whether to ban a particular pesticide, are based on sound science including the testing of hypotheses, the consideration of alternative causal factors, and an awareness of the relevant scientific literature – not to mention logical argument.    Yet such considerations have been lacking in much of the purported scientific discussion concerning potential impacts of land-based activities on the Great Barrier Reef.

There is a need for activists and researchers to begin with more open minds and take a more systematic approach, in short there is a need for cultural change as opposed to the current obsession with amassing evidence to support ever more regulation, legislation and the banning of product important to industry.

In the past books were frequently banned.  Nowadays we tend to approach this issue with some caution recognising that dangerous ideas are best openly discussed.  And history could conclude that many pesticides, including Diuron, are best kept registered and used appropriately, rather than simply banned because of prejudice.

First published at On Line Opinion.


1.  Clear? – or present danger?  Great Barrier Reef Pollution Report Card.  WWF Great Barrier Reef Campaign.  June 2001

2. Barclay P. 2011. Our waterways: are we poisoning them and ourselves? Australia Talks, ABC Radio National. June 28, 2011.

3. Williams B. 2011. Farm chemical diuron found in Great Barrier Reef catchment at levels 50 times higher than those considered safe.  Courier Mail.

4. Marohasy, J. 2003. Deceit in the name of conservation.  IPA Review.  Volume 55,  Page 7-9. 

5. Marohasy J., and Johns G. 2003.  WWF Says ‘Jump’, Governments Ask ‘How High?’.  IPA Occasional Paper.’jump!’-governments-ask-’how-high-’

6. Prange J.A., Gaus C., Papke O. and Muller J.F. 2002. Investigations into the PCDD contamination of topsoil, river sediments and kaolinite clay in Queensland, Australia.  Chemosphere Volume 46, Pages 1335-1342.

7. Abbot J., Marohasy J. 2011.  Has the herbicide Diuron caused mangrove dieback? A re-examination of the evidence.  Human and Ecological Risk Assessment. Volume 17,  Pages 1077-1094.

posted October 10, 2011

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