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NATURE

Microbes tested in groundwater cleanup

ENN



The ability of natural bacteria to cleanup atrazine-contaminated groundwater is being tested in Australia.
The ability of natural bacteria to cleanup atrazine-contaminated groundwater is being tested in Australia.  

September 30, 1999
Web posted at: 11:34 a.m. EDT (1534 GMT)

The ability of natural bacteria to cleanup atrazine-contaminated groundwater is being tested in Australia. Australian scientists are testing the ability of microbes to clean up pesticide-contaminated groundwater, making it safe for drinking or domestic use reports CSIRO, the country's federal science agency.

Working with native Australian soil microbes that have been found to break down atrazine, a popular weed killer, the team of researchers has devised an underground "curtain" to strip the pesticide out of flowing groundwater.

The method is being tested on a 1,300-foot plume of atrazine that lies underneath the town of Perth, Western Australia, where groundwater forms part of the city's water supply. The contaminated groundwater plume is the result of a chemical spill that occurred some years ago.

The researchers have dug a series of 50-foot boreholes to deliver oxygen to microbes on permeable matting that has been placed over the atrazine-impacted zone of the groundwater. The extra oxygen ought to allow the microbes to thrive, the researchers said.

"Our aim is to build up the microbe population in the barrier to such a level that they strip out and degrade all the atrazine passing through," said team leader Greg Davis.

Since the microbes occur naturally in the soil, the tests, which begin in November, will determine how many, if any, additional microbes must be injected into the boreholes in order to effectively get rid of all the atrazine.

corn
Atrazine is a widely used pesticide on crops such as corn.  

Monitoring equipment that measures oxygen and atrazine levels in the underground waterflow both upstream and downstream of the barrier have been put in place. The equipment will enable the team to check the microbes' efficiency at removing atrazine.

"The main challenge is to change the population of underground microbes to those that best degrade whatever is the target pollutant, and design the curtain so that they thrive and their population increases," said Davis.

If the system works, it could be adapted and used to clean up groundwater at industrial sites contaminated by chemicals, solvents, pesticides and oils, removing the pollutants at the downstream end of the site and preventing off-site contamination of drinking water supplies.

"Cost has not been established, and will depend on depth to contaminant plume and width of plume, largely," he said. "Our system also has somewhat high upfront costs (when compared with conventional water treatment systems) but has minimal on-going maintenance costs."

While the system is based on microbes that occur naturally in Australian soil, the microbes could be used in other parts of the world if the right geochemical environment can be created, said Davis.

"Having said that, it may be possible to identify such microbes in soils/groundwater in other countries if one were to look in the right locations, and using the right techniques."

Copyright 1999, Environmental News Network, All Rights Reserved



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RELATED SITES:
Commonwealth Scientific and Industrial Research Organization
Atazine: A Suspect Environmental Endocrine Disruptor
EPA: Office of Pesticide Programs
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