Article

Screening for risk assessment around closed uranium mining sites

¹ National Centre of Radiobiology and Radiation Protection, 3 Sv. Georgi Sofiyski st., 1606 Sofia, Bulgaria
² Faculty of Medical Sciences, Goce Delcev University of Stip, 10-A Krste Misirkov st., 2000 Stip, Republic of Macedonia

^* k.ivanova@ncrrp.org

Received: 17 August 2015
Accepted: 25 April 2016

Abstract

The aim of this study is to present the environmental impact and health risk 20 years after the closing of the uranium mining industry. The areas under observation are 31 former classical underground uranium mining and exploratory sites in Bulgaria. The geometric mean value of the gamma dose rate (0.33 μSv h^-1), measured 1 m above ground in the mining sites, was three times higher than the mean of the gamma dose in the nearby settlements (0.11 μSv h^-1). The geometric mean of specific activities for ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K and ²¹⁰Pb in mining site soil was found to be: 437 Bq kg^-1, 291 Bq kg^-1, 65 Bq kg^-1, 835 Bq kg^-1 and 318 Bq kg^-1, respectively. Analysis of variance and correlation were applied. The external dose and offsite external hazard index, as health risk indicators, were estimated based on the results. After twenty years there is still environmental contamination in some locations that may cause a health risk, so remediation and monitoring should continue and be maintained.