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Superbugs offer solvent solution



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CRC for Contamination Assessment and Remediation of the Environment

M e d i a R e l e a s e

Superbugs offer solvent solution

September 16, 2013 - for immediate release CLEARED

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 carcinogen - 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 cleaning agents - 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

refineries, 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 beneficial microbes.

“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 groundwater used for household purposes.

CleanUp 2013 is hosted by the CRC for Contamination Assessment and

Remediation of the Environment (CRC CARE). It is taking place at the Crown

Conference Centre, Melbourne, Victoria, from 15 to 18 September 2013 and

incorporates the 5th International Contaminated Site Remediation Conference.

Program and details: www.cleanupconference.com

Media wishing to attend the conference may contact Adam Barclay on +61 429

779 228 to ensure access to the CleanUp venue.

More information:

Associate Professor Mike Manefield, UNSW, +61 (0)405 477 066

Prof. Ravi Naidu, Managing Director, CRC CARE, +61 (0)407 720 257

Adam Barclay, Communications Manager, CRC CARE, +61 (0)429 779 228

www.crccare.com

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