Professors Nanthi Bolan and Ravi Naidu of the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment at the University of South Australia say Australia needs to avoid a legacy of toxic waste being left as a “time bomb” close to major population centres.
“When coal is burned to generate electricity it produces a number of combustion products which contain heavy metals and organic contaminants,” Bolan said.
“Traditionally these have been dumped in large piles or ash-ponds, mostly around the power stations themselves.
“These products can pose serious threats to air, water and soil and consequently to living organisms, including people.”
The researchers say this risk from old coal-fired power stations is similar to that from old oil refineries, gas works and service stations.
As cities grow, contaminated sites are surrounded by homes, workplaces and schools, exposing more citizens to the risk of legacy toxins from decades earlier.
Naidu said governments had to take steps to ensure this contamination was managed, contained, neutralised or removed.
“Over the coming 30 to 40 years many of Australia’s old coal-fired stations will close down, partly due to the carbon tax and partly as they are replaced with cleaner, more efficient forms of power generation,” he said.
“Today these are mostly on the urban fringe but that may not be the case as cities grow.
“Ensuring the contamination is properly dealt with and budgeted for should be a part of the decommissioning plan for all our brow coal and black coal power stations.”
Bolan said technologies existed that reduced the risk from old power stations.
These include things such as phytocapping or using vegetation to cover the dumps and prevent rainfall from leaching into water ways. Or there is the use of active barriers to intercept and cleanse polluted groundwater.
“We may also be able to convert coal ash into a safe soil improver,” Bolan said.
“However, there is much work still to be done to develop a suite of solutions for any situation.”
This is where some of the revenue from the carbon tax could come in.
The researchers say an example of a clean-up levy is one imposed by the State of California on owners of underground petroleum tanks.
There also is a fund to assist small businesses with unexpected and catastrophic expenses associated with the clean-up of leaking petroleum tanks as well as other petroleum pollution emergencies posing a threat to human health, safety and the environment.
