Monday, March 03, 2008

Arsenic Bioremediation Cure Might be Near

A recent serendipitious breakthrough by the Australian CRC for Contamination Assessment and Remediation of the Environment might just be the start of a seriously useful method for curing arsenic contamination.

They have isolated a microbe that can use arsenite - a common and the most poisonous form of arsenic and transform it to arsenate, a chemical form that can be fixed in soil into immobile forms.

More details are available here:

Arsenic presents in the enviroment in sites used for animal dipping, leather tanning, old mine workings, timber treatment and similar areas as well as in many shallow drinking water wells in Asia, particularly in Bangladesh. Old mine workings are often especially arsenic contaminated, and this often poisons down stream water sources, in conjunction with acid mine drainage. Arsenic, as an element of the periodic table can not be made to "go away" in the conventional sense but there are many forms of the element that are highly insoluble, resistant to leaching and could be contained within the existing sites in a relatively non toxic low solubility form, including forms that are relatively resistant even to acid leaching. Getting it into that chemical format has always been tricky.

In warmer regions, use of plants such as vetiver grass have been used to grow on contaminated soils, slowly accumulating arsenic and other heavy metals into the plant roots, and tolerating the poor soil environment, and actually growing moderately well on the site, a place where many other plants could not grow. But a multi faceted approach combining microbial remediation with use of these plants offers long term solutions in many places, as even getting a soil cover was difficult and this cover will ease issues of erosion of further arsenic from the soil into the environment too, with the organic cover from the plants assisting.

This new microbial solution seems to offer a real option, assuming that formulations of the microbes can be produced on a scale required for industrial use. Bioremediation on actual sites is a bit more difficult than a simple lab trial, and adequate microbes will be required to "saturate" the site environment, grow and proliferate and do the business of conversion. is VERY promising.

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