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Arsenic concerns in Katrina soil prompt caution

MISSISSIPPI STATE -- Garden crops in Hurricane Katrina storm surge areas should be safe for consumption if washed properly.

Larry Oldham, soils specialist with Mississippi State University’s Extension Service, said Gulf Coast Extension Service offices are getting calls about the safety of vegetables following reports of high arsenic levels in the Katrina-affected area.

“Recent reports of arsenic in soils have been misunderstood. The study on which news reports are based only addressed the sludge, not the underlying soils,” said Oldham, who has been involved in other studies of the sludge.

The report by Altamont Environmental Inc. of Asheville, N.C., assessed sludge in eight Mississippi locations. Its summary stated that  “two facts remain unknown: the physical extent of these contaminants, and the range of existing concentrations (of arsenic).”

“Arsenic is common in Mississippi soils due to nature and previous land use,” Oldham said.

To reduce concerns about arsenic in garden plants grown in storm surge areas, Oldham recommended that gardeners:

• wash vegetables with water before bringing them into the house;
• wash them again inside the house;
• pare root and tuber crops and discard the parings;
• and do not compost the parings for later use in the garden.

In 2001, retired MSU soil scientist David Pettry found arsenic concentrations from 7 parts per million to 27 ppm in the surface layer of 129 Mississippi soils sampled. Concentrations in coastal flatwood soils averaged about 4.5 ppm.

Mike Cox, MSU associate professor of soils, has been involved in many soil arsenic studies.

“Soil arsenic concentrations are influenced by past land management,” Cox said. “Many pesticides used in row crop and orchard production in previous decades contained significant quantities of arsenate. It is also present in other soil amendments.”

Find the full Altamont assessment at http://www.sierraclub.org/gulfcoast/testing.  Locate the MSU study at http://msucares.com/pubs/bulletins/b1104.pdf.

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Writer: Ned Browning

Released: August 1, 2006
Contact: Dr. Larry Oldham, (662) 325-2760