Occupational exposure risk to radiation in open cast artisanal and small-scale gold mining in Western Kenya

Abstract

Artisanal and small-scale gold mining (ASSGM) is practiced at open-cast gold mines in Western Kenya. Mining is still going on in deep mines, with huge tailings littering the workplace for most miners. This mining exercise brings to the surface myriad radioactive materials from the earth’s crust, which pose physical and radiation hazards to miners. The aim of this study was to determine occupational exposure to radiation at artisanal gold mining sites. Four sites were studied for a period of six months. Environmental radiation exposure levels were measured using the Geiger Mueller tube (GMT) model; PHYWE, whereas thermoluminescent dosimeter badges (TLB) 802A were used to record personal radiation exposure levels. d-Orbital Limited Company provided UD-716AGL, used to read the radiation levels from the TLB. Exposure levels were reported in terms of monthly skin, eye, and body exposures. Results revealed an increase in counts per minute with an increase in depth in a range of 19.83 ± 3.87 to 27.83 ± 2.10 and a mean of 23.62 ± 5.17 cpm. Personal effective radiation exposure doses for the skin, eye and body were 0.19 ± 0.01, 0.19 ± 0.01 and 0.18 ± 0.015 for two sites in Western Kenya, whereas those in Nyanza had 0.27 ± 0.01, 0.27 ± 0.01 and 0.25 ± 0.05 mSv on skin, eye and body. The maximum dose threshold limit was estimated at 1.67 mSv per month. There was no significant difference in the radiation exposure of the eye, skin, and body between the sites as indicated by χ2 = 2.0 and p = 0.157 (at p<0.05) with df = 1. The study revealed that workers are exposed to ionising radiation, but the measured levels were within safe limits.