BRENDON CANT brendon at iinet.net.au
Thu Dec 21 02:10:50 CET 2006

21/12/06<?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" />




A newly developed pesticide risk assessment method could determine whether
climate change will increase or decrease the risk of pesticides leaching
through the soil profile and contaminating ground water and the environment.


Rainstorms could be washing pesticides out the farm gate and across the
countryside, contaminating water bodies in their wake.


This is a concern, considering that about 31,000 tonnes of insecticides,
herbicides and fungicides are applied annually across Australia.


The University of Western Australia (UWA) Faculty of Natural and
Agricultural Sciences has therefore developed a risk assessment method,
combining three key factors: rainfall characteristics; soil properties
controlling water flow; and pesticide fate in soil.


UWA School of Earth and Geographical Sciences senior lecturer, Dr Christoph
Hinz said the common myth that once pesticides had served their purpose they
degraded into harmless substances, before reaching groundwater, was a


“Unfortunately, pesticide residues can be found in almost all water bodies,
from groundwater to streams and lakes, indicating they might move more
rapidly and further than expected,” he said.


Previous pesticide risk assessments ignored the importance of rainfall and
climate, which can cause fast flow events.


The new assessment method developed by Dr Hinz and his PhD student, Gavan
McGrath, was funded by the Water Corporation and the Australian Research


Dr Hinz explained that the first step was to assess if a rainfall event
would cause a fast flow event that carried pesticides off-site.


“However, to unravel this we need to understand how rainfall occurs and look
at rainfall at time intervals as regular as minutes, which represent a much
higher temporal resolution than reported by the Bureau of Meteorology.


“We also need to know the intensity that fast flow processes are triggered,
which requires us to have in-depth understanding of soil properties,” he


“Thirdly, we need to assess how much pesticide will be released from the
soil to be transported with the fast flowing water, which related to how
pesticides are retained by the soil and how quickly they degrade,” Dr Hinz


“Combining the three factors allowed improved assessment of the risk of
which storm, of all storms occurring annually, would generate fast flow
events carrying pesticides offsite. 


“The more frequent these critical events are, the greater the risk.


“Using new models that capture rainfall’s characteristics, from minute to
daily resolution, we can now develop risk maps for specific environments and
soil types,” he said. 


According to UWA Institute of Agriculture Director, Professor Kadambot
Siddique, this demonstrated UWA’s capacity for solutions oriented research
which incorporated fundamental and applied science.


“With Australian growers spending an average of $40,000 a year on crop and
pasture chemicals, any savings from better climate forecasting, decision
support systems and risk assessment would improve productivity and benefit
the environment,” he said.


HYPERLINK "http://www.fnas.uwa.edu.au/"www.fnas.uwa.edu.au


Authorised by FNAS and issued on its behalf by Brendon Cant & Associates,
Tel 08 9384 1122



Dr Christoph Hinz, Tel 08 6488 3466

Professor Kadambot Siddique, Tel 08 6488 7012, Mobile 0411 155 396



BACKGROUND: UWA has a proud 70 year history of teaching and research in
agriculture and natural resource management. The Faculty of Agriculture was
established at UWA in 1936 and the Institute of Agriculture in 1938 to
provide critical research facilities and staff for effective training of
professional agricultural graduates and scientists at post-graduate level.
UWA recently re-established the Institute of Agriculture, with Professor
Kadambot Siddique as Director, to strengthen the cohesion of agriculture
teaching and research within and between UWA Faculties. The Institute will
co-ordinate existing strengths of the Faculty in teaching and research in
agricultural science, while advancing UWA’s reputation in agriculture by
enhancing links with industry, farmer groups, the community and national and
international organizations.



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