Bacteria found to release arsenic into groundwater.Millions of people around the world, particularly in southern and southeastern Asia, are exposed to drinking and irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. water contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. with arsenic. Now, it appears that the poison gets into groundwater largely through the action of bacteria residing in aquifer sediments. Jonathan Lloyd at the University of Manchester The University of Manchester is a university located in Manchester, England. With over 40,000 students studying 500 academic programmes, more than 10,000 staff and an annual income of nearly £600 million it is the largest single-site University in the United Kingdom and receives in England and his colleagues discovered that mechanism while analyzing sediments collected from a contaminated aquifer in West Bengal West Bengal: see Bengal. West Bengal State (pop., 2001: 80,176,197), northeastern India. It is bordered by Nepal and Bangladesh and the states of Orissa, Jharkhand, Bihar, Sikkim, Assam, and Meghalaya and has an area of 34,267 sq mi (88,752 sq km); , India. The researchers mixed the sediments with arsenic free water and incubated the samples for several weeks. Over that period, the team detected a rising concentration of arsenic in the water. Further analyses revealed that bacteria in the sediments caused the change. As the bacteria respire re·spire v. 1. To breathe in and out; inhale and exhale. 2. To undergo the metabolic process of respiration. 3. To breathe easily again, as after a period of exertion. , they obtain energy by transferring electrons to arsenic attached to sedimentary grains. In its changed chemical state, arsenic detaches from the sediments and enters the groundwater. The researchers report in the July 1 Nature that they have also simulated the influence of organic compounds on the process. They found that acetate added to the sediments enhanced the release of arsenic. Lloyd's group is now investigating how to reverse or even halt the arsenic-releasing mechanisms.--A.G. |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion