Occupational Exposure 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 done in deep mines with huge tailings and serves as a workplace for most miners. The activity brings to the surface 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 6 months.  Environmental radiation exposure levels were measured using 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 that was 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 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 dose were 0.19±0.01, 0.19 ±0.01 and 0.18 ±0.015 millisieverts (mSv) for skin, eye and body for two sites in western 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 as 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, however the measured levels were within safe limits.

Key words; Artisanal, gold, mining, Exposure, Occupational, Radiation, health