Evaluation of residual soil contamination from commercial oil well drilling activities and its impact on the naturally occurring background radiation environment

Abstract

Radiation exposure received by individuals living and working on a farmland contaminated with radium was evaluated by measuring the technologically enhanced radiation background using portable survey instruments and a high‐pressure ionization chamber. Analysis of selected organic compounds, metals, and radioactive material in samples of soil and water obtained from the farm demonstrate a potential risk to inhabitants that needs to be evaluated, especially for future generations living and working on this land who may not be aware of the potential hazard. The distribution of radium and several other hazardous waste materials was found to be significantly elevated in areas where sludge ponds and waste pits were formerly located. Transport of these contaminants in soil was detected by in situ measurement of radium, which may be a useful analog for determining the translocation of metals and other contaminants associated with oil well‐drilling activities. Conventional risk assessment models, using default input parameters, assume that exposure to radium in the soil is via the food chain and radon, and that inhalation of resuspended particles is less important. These models also assume that the chemical and physical characteristics of the radium contamination remain constant in time. However, under certain environmental conditions, the radium compounds will become more soluble with time, increasing their significance as a source of radiation exposure, especially as the radium will persist in soil for many thousands of years. Assessment of present and future risk to populations living and working on these contaminated lands must account for the potential change in radium solubility with time and the increased risk from both inhalation and ingestion of radium This research describes environmental conditions found at one former well site in the Martha oil field in eastern Kentucky and identifies several important concerns related to the current and future risk associated with use of land contaminated with naturally occurring radioactive material.