On the Trail of Sexual Chemistry: Australia Is Behind in Understanding the Levels of Endocrine-Disrupting Chemicals in Waterways and Their Effects on Wildlife Reproductive Systems. Now Concerted Research Efforts Are Being Made to Better Assess Local Impacts
Pyper, Wendy, Ecos
Since the late 1930s scientists around the world have been documenting unusual changes to the reproductive behaviour and anatomy of wildlife with elevated concentrations of 'endocrine-disrupting chemicals'--EDCs--in the environment.
In British rivers and streams, steroid hormones are thought responsible for the feminisation of male fish. At Lake Apopka in Florida, reproductive abnormalities in alligators have been attributed to unusually high levels of organochlorines from industry. And in Australia and Japan, female marine shellfish exposed to tributyhin--a biocide used in anti-fouling paints on ships--grow male sex organs and can become infertile.
It wasn't until the early 1990s, and the publication of the book Our Stolen Future in 1996, that EDCs got real attention. Since then, a range of international research programs have followed to address and prioritise the impacts of EDCs.
Science has shown that endocrine disrupters have the potential to mimic or interfere with the natural hormones controlling development and behaviour, thereby altering the body's response. Tests are now being refined so that a wide range of chemicals can be screened for these effects, including natural and synthetic hormones such as androgens (male sex hormones) and oestrogens (female sex hormones), and selected pesticides, heavy metals, pharmaceuticals, phytoestrogens (plant hormones), and detergent by-products. Such chemicals are released from a variety of sources including domestic sewage, agricultural activities, industrial wastes, mining activity and landfills, and eventually filter down to waterways.
While most EDC research has focussed on aquatic ecosystems, human and animal waste (such as sewage sludge) commonly applied as fertiliser in some countries also contains a variety of natural and synthetic EDCs, potentially exposing terrestrial organisms to such compounds.
Research in Europe and North America has given good insight to the occurrence of EDCs in streams, aquifers and sediments, and their movement and fate. Both continents have also invested large amounts of resources in the biological effects of EDCs, and screening and testing programs.
The potency of many EDCs has been established by comparing their endocrine disrupting effect against 17[beta]-estradiol (the natural female sex hormone). Highly potent EDCs such as oestrogens may be present in small amounts in the environment, but generally contribute more to the endocrine disruption effects than other less potent chemicals that may be present at higher levels.
Australian research needs
In Australia, the body of research is much less comprehensive, but scientists are already involved in some 30 projects on EDC monitoring, effects, environmental fate, and on the development of models and tools to assess their risks. However, according to CSIRO Land and Water scientist, Dr Rai Kookana, the time is right for a more pro-active and coordinated approach to understanding the extent and fate of EDCs in our environment, and on the consequences to wildlife and human health, although there is as yet no clear direct evidence that human health is affected.
Kookana also says that resources targeted to the right areas of investigation will also allow Australia to pursue its new water recycling and reuse initiatives with confidence.
'Reuse of wastes and water are critical for the future of Australia,' he says.
'The environmental concentrations of EDCs, their persistence, mobility and their potency, need to be considered together with the nature of our unique Australian fauna, so that we can assure the public that our practices are safe for both human and ecosystem health.'
Mr Dana Kolpin, a research hydrologist coordinating the US Geological Survey Emerging Contaminants Project, and a keynote speaker at a recent EDC workshop in Australia, says we can use overseas research as a guide, but that additional local research is needed to account for differences in our local environmental conditions. …