Brenda Rosser

If their recommendations are to be accepted — and Minister David Llewellyn has said he has done just that — exclusions zones around schools will be cut from 1 kilometre to 100 metres and the requirement to notifiy immediate neighbours will be dropped altogether. Any data on aerial spray operations will remain outside of public scrutiny.

THE Agricultural, Silvicultural and Veterinary Chemicals Council (ASCHEM) released a report this last month (June 2006) outlining their recommendations for changes in the regulation of aerial spraying in Tasmania.

Tasmanians should be alarmed. Despite some shallow rhetoric relating to the need to protect bystanders there is a clear and indisputable intention for business as usual.

Water bodies, neighbours and workers in the area will receive about the same level of protection from toxic agricultural chemicals as the very crop being sprayed. This is,effectively, far less than none!

If their recommendations are to be accepted — and Minister David Llewellyn has said he has done just that — exclusions zones around schools will be cut from 1 kilometre to 100 metres and the requirement to notifiy immediate neighbours will be dropped altogether. Any data on aerial spray operations will remain outside of public scrutiny.

But, although they seek to keep the public in ignorance, the Ministers and the ASCHEM Council have no excuse. All regulatory bodies associated with this activity have access to spray drift modelling. Outlines of appropriate scientific protocols are readily accessible and do explain what planning, procedures and techniques are required to assist in the management of spray drift.

There are two key documents that are used as a guide to pesticide spray drift regulation in Australia. The first, is the Australian Pesticide and Veterinary Medicines Authority (APVMA) publication entitled ‘Operating Principles and Proposed Registration Requirements in Relation to Spray Drift Risk’, August 2005. The second is a booklet distributed by the CSIRO. This is the ‘Primary Industries Standing Committee Spray Drift Management Principles, Strategies and Supporting Information PISC (SCARM) Report 82’. The latter was published in 2002.

In ATTACHMENT 1 of the first document you will find some data in relation to ‘long range risk assessment of large-scale broadacre applications’ of pesticide for aerial spraying. The graphs clearly show drift occurring for kilometres under optimal atmospheric conditions and with a very low spray release height of 3 metres for aerial spraying and 1 metre, for ground spraying?

This data is confusing to even the most literate reader and the other assumptions built into this model are NOT even mentioned. No attempt is made to explain. For example, the graphs assume flat terrain and an aircraft kept even and level above the ground. The type of nozzle and the percentage of fine droplets is not mentioned but ‘spray quality’ is described as ‘medium’?? What does this mean?

What are the implications of the assumptions behind this modelling data. What are the flaws in the logic? For there are many.

This is a perversion

Here is where the second document may provide some clarity to the confused citizen. But only a little. A very careful study of this publication reveals that ALL spraying operations entail some amount of offtarget drift. On Page 53 of the PISC Report 82 it explains that the peak incidence of fine droplet drift will occur at 5 to 10 times the release height of the aircraft. Well, ponder this. In Tasmania there is no current legal limit on how high a helicopter or plane can be when
releasing toxins above our towns and residences.

But in the last few years the federal pesticide regulator has been considering — after some considerable community pressure for change — limiting forestry applications to no more that 15 metres above the ground. 15 metres?!

Doing the simple calculations that arise from this statement can raise adrenalin levels. A helicopter a ‘mere’ 15 metres above the ground means that the most voluminous fine droplet drift of these dangerous pesticides will fall 5 to 10 times that distance away. 75 to 150 metres by my calculation. This is both well within and outside the ‘exclusion zone’ being recommended by the ASCHEM in Tasmania!

That is, houses and water bodies within 150 metres of the aircraft will often receive more chemical exposure than the target crop. And this in almost ideal aerial spray conditions!

But far from a worse case scenario.

Again, we need to get back to the assumptions built into such modelling. In the imaginary land of spray drift models there are NO hills. The aircraft are kept level to the ground, so no wing tip vortices to spread the chemical much higher and further. Optimal atmospheric conditions exist. No turbulence, no katabatic winds to push mists of chemicals downhill. No errors in nozzle adjustment.

No excessive speed of the aircraft that would exacerbate the number of fine droplets. There are no accidents, no misjudgements and no miscalibrations. For what purpose, then, are aircraft exclusion zones set?

This is a perversion. An extreme debasement of the plain meaning of the word ‘protection’.

Well, I say ‘No’. NO! to cronyism and the establishment of ‘regulators’ hostile to the purpose of environmental and safety precautions. We’re not being asked to take senseless and frightening risks (as Rachel Carson asserted in ‘Silent Spring’ some decades ago).

No. This is much worse. This is in fact a known and premeditated endangerment of the Tasmanian population in favour of cost cutting for a failed industry. We now have to start from scratch. Rediscover the truth.

That tyranny is often perpetrated under the guise of law and in the name of ‘protecting’ human health.

Links:
http://downloads.publish.csiro.au/books/download.cfm?ID=3452
www.apvma.gov.au/users/spray_drift_risk.pdf
www.geocities.com/rosserbj
www.dpiw.tas.gov.au – ‘What’s New’