Guest guest Posted January 1, 2006 Report Share Posted January 1, 2006 01/01/2006 Landfill leachate can pull arsenic from rocks, soil Evan Brandt , ebrandt@... http://www.pottstownmercury.com/site/news.cfm?newsid=15850068 & BRD=1674 & PAG=461 & d\ ept_id=18041 & rfi=6 The level of arsenic found in landfill leachate may be heightened by the leachate itself, a study by the federal government suggests. Arsenic is a natural element that is widely distributed in the earth’s crust and, at high levels, is poisonous to people. It has been connected to bladder, skin, lung and prostate cancer and the concentration of it allowed in drinking water will be reduced this year as the result of new federal standards. Arsenic is most commonly used now as a preservative to make wood resistant to rotting and decay. In the past, it was a component of pesticides and in alloys for lead-acid batteries for automobiles. In the late 1990s, the U.S. Environmental Protection Agency became concerned with the high level of arsenic found in the leachate from many landfills in New England. When abnormally high levels of arsenic -- several hundred micrograms per liter -- were found in a leachate plume from a landfill in Saco, Maine, the government decided to investigate. When the U.S. Geological Survey conducted a study of leachate from that landfill, which is also a federal Superfund clean-up site, it found some surprising results. " USGS studies on the geochemistry of the leachate plume at the Saco Landfill have shown that the source of the arsenic is not the landfill, but appears to be the sediments the plume is moving through, " according to a study report issued in October by the USGS Toxic Substances Hydrology Program. What a computer model created from samples and tests at the site showed, was that " dissolved organic carbon in the leachate plume is dissolving arsenic from arsenic-containing iron oxides in the aquifer and the bedrock, " the report showed. When the organic carbon in the leachate degrades, it removes oxygen from the water and " creates the conditions that favor the dissolution of iron oxides and the release of arsenic from the sediments, " the study concluded. The study also found that an impermeable membrane installed on top of one of the landfill cells in 1997 to reduce the amount of arsenic in the leachate would be ineffective for several years until conditions that consume the oxygen in water are finally used up. Once oxygen levels in the groundwater and leachate returned to normal, less arsenic would be leached out of the rock and soil through which the leachate is moving, the study found. * The material in this post is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.For more information go to: http://www4.law.cornell.edu/uscode/17/107.html http://oregon.uoregon.edu/~csundt/documents.htm If you wish to use copyrighted material from this email for purposes that go beyond 'fair use', you must obtain permission from the copyright owner. Quote Link to comment Share on other sites More sharing options...
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