Land and Water Link
September 2002
Keeping Watch on Chemicals in our Waterways
Human and animal healthcare today depends on a huge range of pharmaceuticals
including antibiotics, painkillers, contraceptives and other drugs. But
what happens to environmental health when trace amounts of these substances
end up in our waterways? And over time, could these same chemicals have
adverse impacts on human health?
These questions are increasingly capturing worldwide scientific attention.
Now, a group of Australian scientists has teamed up to look at the issue
and its implications for environmental management in Australia.
According to Dr Rai Kookana, research scientist from CSIRO Land and Water,
the starting point is to consider overseas findings on the potential impact
of endocrine disrupting chemicals (EDCs) on the Australian riverine environment.
Dr Kookana explains the significance of endocrine disruptors. 'In recent
years compelling evidence has been accumulated showing that certain chemicals
– for example estradiols, nonylphenol, bisphenol A, PCBs and some
pesticides – can, at elevated concentrations, cause disruption to
endocrine systems and hormonal control of development in wildlife and
human beings. Because EDCs do this by interfering with the natural hormonal
signals directing growth, these chemicals are sometimes referred to as
hormonally active agents.'
But as Dr Kookana points out, 'The critical question here is at what concentrations
do trace amounts of these substances begin to pose a problem – and
in what conditions?'
Public concern about the adverse effects of chemicals on reproductive
systems of wildlife and humans escalated with publication of the book
Our Stolen Future in 1996. Since then, much of the media coverage has
tended to be alarmist, hinting at possible links between EDCs and early
puberty in girls, decreasing male sperm counts and cancers in humans.
Recently, connections have even been made to dwindling frog populations.
Whilst a US study, which monitored 139 streams in industrial areas in
the United States, reported 80% of streams contaminated with trace levels
of pharmaceuticals, hormones and organic wastewater contaminants, the
implications for Australian conditions are not clear.
'This is especially true for the riverine environment,' says Dr Kookana.
'Until research has been conducted to assess the implications for Australian
environmental conditions, we should be cautious of alarmist media coverage.'
The CSIRO study on a risk assessment of EDCs in relation to Australian
rivers and waterways – funded by Land
and Water Australia – began by considering the overseas literature
and then outlined a preliminary risk assessment of fate of these contaminants
in our riverine environment as a starting point for further investigation
and risk assessment.
In June of this year a workshop was held in Adelaide to consider these
preliminary findings, their importance and further actions. The workshop
– sponsored by Land and Water Australia, Environment
Australia and CSIRO – was attended by participants from state
and federal regulatory and health agencies, natural resource managers,
industry representatives and researchers.
Potential sources of EDCs include domestic wastewater, industrial wastes,
biosolids, animal waste and agricultural activities. Delegates attending
the workshop discussed these sources, their possible extent and distribution,
as well as potential transport and exposure pathways.
Dr Kookana reports it was agreed that data on ecosystem impact of EDCs
is substantial. However, the relation to human health is not clear. Currently,
the lack of data on distribution and fate of EDCs and associated chemicals
in the Australian environment is the major hurdle in assessing the real
risks to Australian riverine ecosystems.
'Important sources of EDCs and associated chemicals deserve closer attention
under Australian conditions', says Dr Kookana. 'Our unique Australian
fauna must be considered in this process. Better screening tools need
to be developed and scoping studies need to be carried out. If we want
to minimise the risks, we need to restrict exposure to these chemicals
in the environment. And that means that we must first identify the sources,
transport pathways and attenuation of EDCs in the Australian environment.'
There are positive indications for further research in this area. The
issue has already attracted attention from the Australasian
Society for Ecotoxicology, a scientific society for biologists, chemists,
engineers and other environmental scientists concerned with environmental
protection and management. The Society has put forward a nomination
for broad thematic priority under the National Research Priorities program,
with one of its three goals being to understand and minimise the impact
of endocrine disrupting chemicals in the aquatic environment.
As Dr Kookana concludes, 'There is an urgent need for a nationwide approach
to address this issue, and for scientific research as the basis for sound
decision making about how we use and regulate a whole range of chemicals
and wastes.'
For further information
Contact
Dr Rai Kookana
Ph: 08 8303 8450
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