ERDC/EL TR-11-15 "Evaluation of Volatilization Potential for Legacy Chlordane in Military Housing Area Soils"

The U.S. Air Force used the chlorinated pesticide, chlordane, to control termites around base housing until it was banned in 1988. As bases are closed, contracted, or realigned, soil issues associated with this pesticide must be addressed. One issue that is not well understood is chlordane volatility. There are documented cases where chlordane applied to soil resulted in vapor intrusion into buildings; however, these cases all involved freshly applied pesticides. The effect of aging and weathering for at least 20 years would likely change the potential for volatilization of soil-applied chlordane. This report documents three studies to assess volatility of aged chlordane in soil. The first study was a laboratory study in a forced air system. Soils studied included chlordane-contaminated soils from McGuire Air Force Base (AFB), Davis-Monthan AFB, and a reference soil from the Vicksburg, MS, area called WES soil. Tests of the various soils conducted at 20 °C and 50% RH indicated that of these, only the Davis-Monthan soil, which had the highest chlordane concentration and the lowest total organic carbon concentration, had a measurable chlordane flux. The second study, conducted in the field at Fort Dix Army Base, evaluated the effect of soil disturbance. This included simple vegetative removal, disturbance of the soil by tilling, and coring into the soil. Chlordane was found in all the sample locations and depths, with higher concentrations being found in deeper core samples. However, volatile chlordane was only detected in the borehole sample immediately after the hole was created. The last study was conducted at Mountain Home AFB and investigated volatility under slab foundations of housing at the base. Four different housing types were tested. Indoor air sampling was conducted in each housing unit tested. This was followed by sampling of the sub-slab atmosphere by drilling holes through the foundation. Cores were then drilled through the foundation, and soil samples from below the slab were collected and analyzed for chlordane. No chlordane was found in the indoor air, sub-slab soil vapor, or the sub-slab soil samples at any of the housing units tested. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/EL TR-11-15 iii