Saturday 29 March 2008

More about pesticides in the Barron River

Syd Walker continues his tale about the H2O in the Barron River...

Following the howls of anonymous outrage that followed my earlier article on CairnsBlog, I was lucky to have a chance to speak with someone who actually knows what he’s talking about.

Yesterday I had a phone conversation with Dr Jon Brodie, a water quality scientist based at James Cook University in Cairns. In what follows, I have tried to combine his information with my own commentary. Any errors in interpretation are my responsibility.

A knowledgeable man, Brodie has experience testing numerous rivers and coastal marine areas in Queensland. He has a grasp of what information on this topic is - and isn’t - available in FNQ.
Brodie was not effusive, but he was not reticent either. He was willing to answer questions and to mention relevant work undertaken by others.

I asked him quite specific questions about pesticide levels, possible conseqences, tecniques for removing pesticides from drinking water, water quality guidelines and new work in the offing.
It appears there isn’t any data about pesticide concentrations in the Barron River – not in the public domain, at any rate.

Brodie believes the Barron is likely to contain traces of a wide range of pesticides, reflecting the diversity of cropping and other land uses in the catchment.

Organochlorines were banned in 1987. The newer generation of pesticides tend to be more short-lived, with half-lives in the order of one year. Some breakdown products, however, are also be toxic and have their own breakdown pathways. The combined effects of different chemicals in this complex brew are another unknown.

Unless the water supplies for Kuranda and Mareeba have an advanced filtering system (Brodie mentioned activated charcoal filter as a solution), the pesticide content of the river is unlikely to be filtered out of municipal water supplies.

Communities which draw a water supply from the Barron, such as residents of Kuranda and Mareeba, may therefore wish to consider their own home filtering arrangements.

Also, if Val Shier and the new Cairns Regional Council are keen to use the Barron for drinking water in Cairns, an advanced filtering system will be needed to ensure the supply in not contaminated with pesticides.

Under national Australian Water Guidelines, any trace of pesticide in drinking water is regarded as unacceptable. If discovered, it triggers (or should trigger) action to discover the source and remedy the problem.

In practice, at least in Queensland, that doesn’t appear to happen. Of course, by conducting few if any tests for pesticides, no breaches of the AWG are detected, so no follow up action is required. Convenient!

Brodie has experience testing numerous rivers up and coastal marine areas in Queensland. The pesticides detected tend to be consistent for similar industries, irrespective of the catchment.
For instance, sugar cane farming is typically associated with atrazine, diuron, hexazinome and ametryn; plantation forestry with simazine; grazing lands with tevuthiuron. There are many more different chemicals used with smaller agricultural industries such as potatoes, bananas and the numerous commercial varieties of tropical fruits.

Brodie is less concerned than I have been about biological concentration in fish in the middle Barron River. He thought modern pesticides would be unlikely to bioaccumulate in river animals.
But he couldn’t be sure – or rule out the possibility that heavy metals in the river that might accumulate in fish. He thought significant heavy metal contamination of the Barron is unlikely, but no evidence = no certainty. On the other hand, he expressed rather more concern than I expected about the possibility that the water supply for Kuranda and Mareeba is unsafe. But he made it clear that no-one really knows. With regard to pesticide content, there’s no data.

Apparently a series of Water Quality Improvement Plans (WQIP) are being rolled out for catchments around Australia.

The study for the now-amalgamated Douglas Shire was done first in FNQ and a WQIP published in December 2006. But that study didn’t look at pesticides and only the most cursory references to pesticides can be found in the final report. A WQIP for Tully in is progress.

Brodie told me that the local not-for-profit ‘natural resource management’ organization Terrain has obtained the contract to do a WQIP for the Barron River.

However, apparently Terrain didn’t get much money to do this study and intends to do a desktop plan, using only existing data. No new testing, in other words. It will, however, identify 'information gaps'.

Which brings us back to the beginning: There is no publicly available data on pesticide concentrations in the Barron River. (We know that already).

Without new testing, pesticides could effectively remain off the agenda, even in the Barron’s yet to be prepared Water Quality Improvement Plan.

Catch 22.

After talking with Dr Brodie, I made a couple of web investigations of my own.
I wondered about the local Catchment Management Association and its efforts to clean up the river.

On its website, the Barron River Catchment Management Association refers to targets for sediment, phosphorous and nitrogen, but makes no mention of targets for pesticide reduction.
It is as though there is a conspiracy of wilful ignorance about the extent of pesticide pollution in the Barron River.

(Almost) no one wants to know. No one with power and resources wants to think about it. Don’t spoil the party – we’re all pretending to protect the river and it’s vital we don’t offend the farmers!

Heck, farmers can even apply via Terrain for a $5,000 grant towards the purchase or modification of shielded spray units for Diuron and Atrazine!

Close eyes and hope for the best.

One final thing. I looked up the Australian Drinking Water Guidelines. Chapter 10.6 is the Guide to monitoring and sampling frequency. I read with interest that testing for pesticides in ‘raw water’ (storage, stream or bore) should be “one sample per month should those pesticides previously detected water, or where their likely use they might be detected.”

Can someone - anyone - in Government, whether local, State or Federal, please explain how that standard is met for the Barron? If not, can we please make it happen - fast!

Water quality is not a joke and it should not be insider information. Public health is at stake.

The community deserves some real answers and action, as appropriate, based on publicly-available and adequate data.

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