Radon effective dose from TENORM waste associated with petroleum industries

Abstract

Technically enhanced naturally occurring radioactive material (TENORM) associated with petroleum industries can be accumulated with elevated quantities and therefore can threat the workers through external and internal exposure. Measurements of radon-related parameters give information about the radioactivity levels in the TENORM waste using the well-established correlation. Also, it is useful to calculate the internal exposure due to radon inhalation in terms of effective radon dose. Among radon-related parameters, areal exhalation rate is the most suitable for characterising land and objects with only upper surface contamination in the case of petroleum waste. The TENORM in this study is collected from waste storage areas located near oilfields at south Sinai governorate, Egypt. The average values of exhalation rates as measured by Lucas cell based on delay count method are 273 +/- 144 and 38 +/- 8 Bq m(-2) h(-1) for scale and sludge, respectively. Whereas, two count method gives results with 18 and 20 % lower values for scale and sludge, respectively with good correlation coefficient of 0.999 and 0.852, respectively. Sealed cup fitted with CR-39 gives results compatible with Lucas cell with minor deviation in case of scale due to its thoron content. The results of CR-39 are qualified by taking into consideration the correction for back diffusion effect. The effective radon dose was calculated for different simulated radioactive waste storage areas with different contaminated areas and air ventilation rate. Minimising the contaminated areas and building up efficient ventilation systems can reduce the internal exposure even in the case of RWSA-containing TENORM with elevated radioactivity.