Superbugs offer solvent solution

Sep 16, 2013

A world-first superbug is to undergo field trials to clean up two of Australia's most polluted industrial sites at Port Botany in NSW and Altona in Melbourne in the coming year.

The microbe, the first in the world found to completely break down chloroform – a common industrial pollutant and – in groundwater, was discovered by a team at the University of NSW in 2011, Associate Professor Mike Manefield will tell the CleanUp 2013 Conference in Melbourne today.

"Organochlorine-contaminated groundwater is a major environmental concern all round the world," Prof. Manefield says. "These substances are used in the manufacture of plastics, as solvents, degreasing and – and the very qualities that make them useful to industry also make them incredibly hard to break down in the environment.

"Consequently they can hang round in groundwater for decades, maybe even centuries, and pose a risk to the health of anyone who drinks or swims in the water, eats food grown with it, or inhales vapour in areas where the chemicals are concentrated."

Australia, he says, has hundreds and possibly thousands of sites contaminated with chlorinated ethenes, ethanes and methanes – former petrochemical , mechanical workshops and dry cleaners mainly – and around 40 tonnes of these substances are still being released here yearly, despite efforts by regulators to limit their use.

Cleaning up these chlorinated compounds poses particular challenges, as they are not susceptible to oxidation with the usual bioremediation techniques and suites of .

"They are extremely tough molecules, they resist dissolving, and they sink to the bottom of the aquifer where natural breakdown occurs far more slowly," he explains "Once they start moving offsite in groundwater, you have a real problem in limiting who is exposed to them – so you need to clean them up on the spot if possible."

In 2011 Prof. Manefield and his colleague Dr Matthew Lee were examining sediment from the chemical works at the Botany Industrial Park and came across a species of bacteria which took in chloroform – the main pollutant of concern – and turned it into harmless hydrogen, acetate and carbon dioxide. Since chloroform inhibits bioremediation of other chlorinated solvents at many heavily polluted industrial sites globally, their world-first discovery was hailed internationally.

"It happened quite suddenly. We had been culturing the naturally occurring bugs for a couple of months when suddenly, on day 70, we saw a sudden surge of activity and the chloroform levels in the groundwater began to drop sharply. In a few days it was gone. Subsequent re-feeding of chloroform revealed high tolerance by the bugs and rapid degradation."

What had turned on the chloroform-munching bugs remains a mystery that Prof. Manfield and his team are still striving to decipher – but for the first time, humanity has a feasible way to eliminate a serious and widespread cancer-causing pollutant at a relatively low cost.

The team has since developed three main cultures for addressing different mixtures of chlorinated solvents and plans to trial them at two of Australia's most heavily contaminated industrial sites – the Port Botany chemical plant and Altona refinery – over the next 12 months.

Australia has lagged behind in the application of bioremediation to organochlorine-contaminated groundwater partly because the relevant diagnostic tools and cultures have not been available – but that is now about to change, Prof. Manefield believes.

"Essentially we believe these bacteria will work in any aquifer round the world where the pollutants and conditions are similar to those in the Botany Aquifer, which is quite acidic," he explains. "So this isn't just a solution for a specific contaminated site: potentially it can deliver global benefits."

Chloroform especially is a byproduct of the plastics industry and is still being produced globally in huge amounts, despite its known links to cancer. Perchloroethene is still used universally in the dry cleaning industry. All these substances pose a risk to human health via the global food chain – as more and more food is now imported from distant countries where pollution controls are poor – and in urban used for household purposes.

Explore further: Current residential development research is a poor foundation for sustainable development

More information:

Provided by CRC for Contamination Assessment and Remediation of the Environment


Related Stories

Beer-barrel bacteria breathe toxic brew

Aug 01, 2011

University of New South Wales researchers have shown that they can safely destroy hazardous industrial toxins in groundwater arising from PVC plastic production by injecting naturally occurring bacteria into a contaminated ...

New way to protect precious water

Apr 10, 2013

Australian scientists have devised a way to model polluted groundwater with computer simulation – and better protect the Earth's main fresh water supply.

Saving Earth's water from toxic waste

Aug 20, 2013

Scientists have devised a better way to protect groundwater from acids, heavy metals and toxic chemicals, helping to secure the Earth's main freshwater supply.

Pollutant-eating bacteria not so rare

Aug 26, 2013

( —Dioxane, a chemical in wide industrial use, has an enemy in naturally occurring bacteria that remove it from the environment. Researchers at Rice University have found that these bacteria are ...

Recommended for you

Study provides detailed projections of coral bleaching

5 hours ago

While research shows that nearly all coral reef locations in the Caribbean and Gulf of Mexico will experience bleaching by mid-century, a new study showing in detail when and where bleaching will occur shows ...

Germany restricts fracking but doesn't ban it

11 hours ago

The German cabinet drew up rules Wednesday on the hitherto unregulated technology of "fracking" in Germany, narrowly restricting its use, but stopping short of an outright ban.

Life in the poisonous breath of sleeping volcanos

11 hours ago

Researchers of the University Jena analyze the microbial community in volcanically active soils. In a mofette close to the Czech river Plesná in north-western Bohemia, the team around Prof. Dr. Kirsten Küsel ...

Eggs and chicken instead of beef reap major climate gains

12 hours ago

Beef on our plates is one of the biggest climate villains, but that does not mean we have to adopt a vegan diet to reach climate goals. Research results from Chalmers University of Technology show that adopting ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.