FOREST SCIENTISTS’ RESPONSE TO CLAIMS THAT FORESTRY TREES ARE LINKED TO TOXIC WATER IN NORTH-EASTERN TASMANIA
"Concerns have been raised in recent media reports and on the ABC’s Australian Story, suggesting that contamination of Georges Bay is due to chemicals derived from genetically altered Eucalyptus nitens plantation trees located in the catchment. There have been many incorrect assumptions and tenuous connections raised which may have lead to unnecessary public concern.
No eucalypt plantations in the catchment, or anywhere else in Australia, use trees altered through genetic engineering. The E. nitens trees in the plantations would have been grown from naturally pollinated seed produced in seed orchards, which incorporate first or second-generation descendents from wild populations of E. nitens occurring in Victoria or southern NSW. The trees in the seed orchards have been selected in field trials for their superior growth and wood quality. They have not been selected for increased toxicity. The E. nitens trees growing in plantations in the Georges River catchment would be genetically very similar to those that occur in the native forests that shed water into Melbourne’s reservoirs and other river catchments in Victoria and NSW.
Hamilton et al (2008) Genetic improvement of Eucalyptus nitens in Australia. Australian Forestry, 71 (2). pp. 82-93
Statements have been made concerning the relative toxicity and greater foam production from E. nitens leaves sampled from genetically improved plantations compared with leaves from natural old-growth forests. While we do not know the full details of the sampling involved, it is important to note that eucalypt leaf chemistry changes markedly from the juvenile stage (as was apparently sampled in the plantations) to the adult leaves sampled in the native forests. Leaf chemistry also changes seasonally and is influenced by the growing environment, so at this point it is incorrect to conclude that the plantation trees are genetically more toxic.
The ABC program implied chemicals leaching from the leaves of trees in the E. nitens plantations flow on the surface of the river and their accumulation in Georges Bay has been responsible for human health problems and deaths of oysters. However chemicals from native vegetation occur in waterways throughout Tasmania naturally, as evidenced by the dark brown river waters of Tasmania’s World Heritage Area. There are many catchments where E. nitens occurs, either naturally or in plantations across Australia.
No evidence has come to light suggesting that this particular tree has any atypical effect on aquatic life compared with other eucalypt species. Due to public concerns, closer examination is warranted, and this issue can be resolved with well designed studies.
Eucalypts are the dominant trees of our native woodlands and forests. Many of the chemicals that naturally occur in eucalypts are toxic to some organisms in sufficiently high concentrations. The original Analytical Services Tasmania laboratory study in February 2005 identified several surface or foam samples which were toxic. Of the chemicals assayed in the toxic samples, the major ones, including cineole, are well recognised components of eucalypt oils. While toxic if swallowed in its concentrated form, eucalypt oil is widely used in medications around the world as an inhalant and a skin-rub.
Chemicals that the Analytical Services Tasmania laboratory identified in the toxic samples occur not only in E. nitens foliage but in that of many of the native eucalypts including E. globulus, E. ovata and E. viminalis which occur in the vicinity of Georges Bay. Cineole is the dominant component of the leaf oils of the majority of Tasmanian eucalypt species. There are many other chemicals which can be monitored, even at very low levels, to determine whether they further contribute to the toxicity reported and may be more specific to the Georges Bay situation and E. nitens. There are also natural plant chemicals which are known to cause foaming when shaken in aqueous solutions.
We expect these eucalypt chemicals to degrade in situ as well as move into soils and waterways to some extent through litter fall and leaching. Trees may naturally affect local aquatic ecosystems in many ways. Leaf and other organic litter from eucalypts is a major basis for the food chain in nearly all Australian stream ecosystems, often providing the main source of carbon for the invertebrates and ultimately fish in forested catchments. Eucalypt leaves in streams are eaten, usually after a period of breakdown by bacteria and fungi, by a wide variety of aquatic insects and crustaceans which have evolved to be dependent on this food source. The chemicals in eucalypt leaves are broken down and released continually through this process in thriving, healthy stream ecosystems.
We have a lot to discover about the diverse natural chemicals in our native flora, including eucalypts. We applaud any vigilance in the interests of public health or environmental integrity, and acknowledge the valuable role played by concerned members of the public, and the media, in keeping these matters in the public eye. However, it is important that future studies are designed and conducted in a scientifically rigorous way. Scientists at the University of Tasmania, CSIRO and the CRC for Forestry have all indicated their willingness to participate in future investigations."
Professor Gordon Duff, CEO, CRC for Forestry
Dr Chris Harwood, CSIRO Sustainable Ecosystems
Dr Julianne O’Reilly-Wapstra, University of Tasmania
Professor Brad Potts, University of Tasmania
Professor Jim Reid, University of Tasmania
Dr Chris Harwood, CSIRO Sustainable Ecosystems
Dr Julianne O’Reilly-Wapstra, University of Tasmania
Professor Brad Potts, University of Tasmania
Professor Jim Reid, University of Tasmania
Further Reading
Forest scientists' response to toxic water claims. Media release, CRC for Forestry, 23 February 2010, regarding effects of Eucalyptus nitens trees on water in Georges River catchment, Tasmania, as reported on the ABC's Australian Story on Monday 22 February. [Download PDF 27.6 kb]
Hamilton MG, Joyce K, Williams DR, Dutkowski GW & Potts BM (2008) Achievements in Forest Tree Improvement in Australia and New Zealand 9. Genetic improvement of Eucalyptus nitens in Australia. Australian Forestry, 71 (2). pp. 82-93. ISSN 0004-9158
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Findings of the George River Water Quality Panel
ReplyDelete29 June 2010
The George River Water Quality Panel has found there are no water quality issues in the George River, giving a clean bill of health for treated drinking water to the local community and ruling out fears of a cancer cluster in the St. Helens area, ruling out fears of pesticides in the water as well as ruling out Eucalyptus nitens toxicant issues for local oyster growers.
However, the Panel has recommended to the State Government that improved and coordinated management and administration of the waters in the St. Helens catchment area should be implemented as a priority.
Further information on the use of chemicals should be recorded and made available to assist with monitoring and the security of the water.
In releasing the findings of the report, Panel spokesperson and water quality expert, Dr Graeme Batley said the bottom line is that there is no indication that the treated water is not safe to drink at St. Helens.
“In essence the panel found that the river foam samples that were referred to in the Australian Story report broadcast by the ABC in February this year were not representative of the naturally occurring water in the Georges River” Dr Batley said.
“The method that was used to sample the foam concentrated the sample so much that it became toxic when tested on sensitive water organisms".
“There are very minor levels of naturally occurring toxicants in the George River like any other catchment area, but at naturally occurring levels they pose no health risk to the community".
“All water bodies have a very thin film of less than 0.3 mm on the surface which contains ‘insoluble’ organic matter including surfactants and when mixed with air held in the water and rising to the surface they can naturally form foam bubbles. The foams were what the Scammell / Bleaney report said were a major source of toxicants".
“So, yes there are toxicants in the water, but at naturally occurring levels they pose no
health risk to the community”.
(Continues)
Findings of the George River Water Quality Panel
ReplyDelete29 June 2010 (Continued)
Other findings include:
- Community health records from 1993 to 2007 show no abnormal cancer rates within the St Helens drinking water area and there are no characteristics of a ‘cancer cluster’.
- Oysters growing in Georges Bay are subject to a number of stressors, such as water temperature, toxic algae, oyster stocking densities as well as antifouling ship paint. Contaminants associated with river or bay foam may also be a minor stressor to oyster health.
- There is no evidence of pesticides in the water supply that could pose a health risk to the community. Insecticides have never been detected, while only traces of herbicides have been detected only during high water flow periods; the concentrations has been well below safe human health guidelines.
Dr Batley said the findings of the report have been handed to the Premier, David Bartlett, earlier today and a number panel members would now travel to St Helens to meet with members of the St Helens community.
“Once the consultation process is complete, unless further investigations are requested by the Premier, then the panel will disband".
“I would like to thank all those who assisted in this investigation, particularly Drs. Bleaney and Scammell for their efforts in cooperating with the panel”.
Included in the release of the report are the other reports which helped make up the study, which will be placed by close of business today on the George River Water Quality website. The community is encouraged to examine the findings at:
www.georgeriverwater.org.au
The George River Water Quality Panel is an independent scientific panel convened to investigate claims that toxicants from eucalypt plantations are having an adverse affect on both human health and the health of oysters in oyster farms in St Helens.
It was convened at the direction of the Premier of Tasmania in March to investigate information reported on Australian Story in February 2010.
Water scare sorry demand
ReplyDeleteby Nick Clark - The Mercury
July 01, 2010 08:37am
Premier David Bartlett has called on the ABC to apologise for a "poorly researched and alarmist" news report.
In February, the ABC's Australian Story quoted a doctor who feared contaminants in the George River were causing increased rates of cancer in St Helens.
Mr Bartlett has written to the ABC asking for a correction a day after an expert panel found there were no problems with the water.
The George River Water Panel found the perceived "toxicity" of water was caused by a faulty method of collecting samples that distorted results by a factor of 1400.
"The scientific study commissioned by the Government has found that the report by Australian Story was wrong", Mr Bartlett said.
"These two episodes of ABC's Australian Story caused fear and distress in the St Helens community and damaged the town's tourist reputation throughout Australia".
Mr Bartlett said Australian Story had alleged toxins from eucalypt plantations in the George River catchment might have been linked to abnormally high cancer rates.
"All of these things have been shown to be wrong by the study of national scientific experts" he said.
"Yet this poorly researched and alarmist program is still available on the ABC website".
Mr Bartlett said he had asked the ABC to remove the program from the website.
"If that is not possible I have asked for a disclaimer to the effect that the information on which it was based has been shown to be wrong and to direct viewers to the website of the scientific report", he said.
"In addition, I have asked the ABC at the end of one of its current series of Australian Story episodes to explain to viewers that the St Helens water story was based on wrong information, and to apologise to the people of St Helens for the distress that it caused", Mr Bartlett said.
St Helens GP Alison Bleaney said she would not apologise for raising the issue.
Dr Bleaney said the panel's report did not disagree with her comments about a rise in cancer in the area.
ABC's Australian Story executive producer Debra Fleming did not return a call from The Mercury last night.