Biodegradable plastics may not be as environmentally friendly as they are perceived to be, according to a recent report from the Australian government.
In a report commissioned by federal body Environment Australia, Melbourne-based research firm Nolan-ITU Pty. Ltd. said biodegradables pose ``adverse environmental risks,'' including:
* Oxygen depletion in waterways due to the breakdown of starch-based plastic.
* Byproducts of degrading plastics, such as additives and modifiers, could pollute ground and surface water via run-off and leachate from landfills and compost facilities.
* Biodegradables that only partly or slowly degrade could pose a threat to marine species.
* Soil and crop degradation could result from the use of compost with high organic or metal contaminants derived from biodegradable residuals.
* Littering of biodegradable plastics could increase because people may believe the products will disappear quickly, and established recycling systems for conventional plastics could be in jeopardy.
The report was commissioned in consultation with the Plastics & Chemicals Industries Association and undertaken by Nolan-ITU in association with ExcelPlas Australia, a Melbourne plastics technology consulting firm.
Its key recommendation is to develop an Australian standard, based on international standards, for biodegradable plastics disposal routes, recovery systems and processing infrastructure.
The report fueled new debate on Australia's use of plastic bags. Legislators are looking for the best way to discourage plastic bag-related pollution, and one option is to encourage the use of biodegradable plastic shopping bags.
The government's national plastic bags working group was briefed on the report's findings.
``With Australians using more than 6 billion plastic bags a year and no conclusive evidence about the environmental impact of degradable plastic, there are many complex issues to consider,'' said environment minister David Kemp.
The working group submitted a final report to the National Packaging Covenant Council in late November. The council is to submit recommendations on plastic bags to the government Dec. 23.