20 A Geological Miscellany

Friday, 18 March 2005
1:00 PM - 4:40 PM

URANIUM CONTAMINATION DETECTION BY WELL WATER, TREE BARK, AND STREAM SEDIMENT SAMPLING

Paper number: 20-11
Program: Technical Sessions
Time: 4:20 PM – 4:40 PM

Authors

Abstract

Elevated levels of natural uranium found in wells in the Simpsonville, S.C. area have been cause for concern as uranium is known to cause adverse health effects. 1970's data from DOE's NURE program indicate that many wells in the region may be above allowable levels. The purpose of the current study is to identify at risk areas or individuals and prevent their further exposure to uranium and associated elements. The most direct way to identify homes using contaminated well water is to directly test well water. This is a very time intensive and expensive process, though, which means that area coverage is rather slow. Alternative methods of determining at risk areas are currently being investigated. One means of finding areas of high soluble uranium is to remove bark from pines or oaks, ash the bark, and test the ash for uranium. This could be a more efficient way to identify general areas of concern. Using that information, the time consuming well sampling could be done only where necessary. Stream sediment geochemistry also offers a way to outline areas of concern.

Results from sampling during the summer of 2004 are becoming available. Uranium in pine bark ash has been found at levels as high as 200 ppm in areas known to have high levels of uranium in the groundwater. Some tree bark ash samples had as much as 1% silver, 0.1 ppm gold, and over 100 ppm arsenic. Followup well water sampling in areas where NURE data reported above background uranium confirms additional wells above the drinking water MCL of 30 ppb.

Sediment samples were split into five size fractions and analyzed after a selective leach digestion and a strong acid digestion. Stream sediment results will be discussed.