Occupational Health Risk Assessment in Artisanal and Small-Scale Gold Mining in Kakamega and Migori, Regions, Kenya

Abstract

Due to the nature of activities associated with artisanal gold mining, there is an increase in among gold miners. This study sought to assess the occupational health risk in artisanal gold miners in Rosterman village-Isulu and Ikolamani-Liranda corridor in Kakamega County and Francis-Suna-East and Masara-Suna west in Migori County. Stratified random sampling was used to gather empirical data from miners, foremen, supervisors and mine owners using questionnaires and interviews. A total population of 770 participants from which 260 were selected as follows: Ikolomani – 40, Rosterman – 85, Masara West – 35, Francis – Suna East – 100. From each stratum, the selected participants were issued with the research instruments. From the empirical study, 77.5% of the respondents were male while 22.5 % were female aged between 19 - 60 years with 72.5% being of the age 19-35 years, 2.5% of these respondents had no formal education, 88.7% had basic education and 8.8% had higher education qualifications. 93.3% of these respondents used personal protective equipment (PPEs), 6.7% did not use PPEs, whereas 8.3% rarely used PPEs. The concentration of PM2.5, which was measured using a low-cost purple air PA-II-SD sensor, ranged between 2.06 – 150.63 µg/m3way above WHO guidelines. Ionizing radiation at selected mines were established using Geiger- Muller tube, PHYWE model detection while a Thermolumiscence dosimeter (TLD) badges was provided to respondents. It was observed that average radiation exposures for skin, eye and body were 0.197±0.40-.399±0.09, 0.197±0.31 - 0.547±0.14 and 0.186±0.30 - 0.405±0.10 millisieverts per month (mSv/m) respectively (p>0.05) way below threshold levels. Furthermore, female respondents exhibited higher levels of skin radiation (mean rank=38.93) and eye radiation (mean rank=37.24) as compared to male (p<0.0001) respondents. However, no statistically significant difference was observed in body radiation exposure by gender (U=379.00, p=0.392). Noise was measured using integrating sound level meter (LA220) 2 Meters (M) from noise emitting machine that were identified through survey. The noise levels ranged between 83.98 ± 15.5 to 96.97± 9.21 dB (A) way above OSHA 2007 standards which could easily cause hearing loss (p<0.05). To evaluate the concentration of heavy metal to which miners were exposed too, sediments samples (dry ore, wet tailings, personal hair and nails) were subjected to Atomic Absorption Spectrophotometric (AAS-6200 Shimadzu) analysis after digestion. The heavy metals in dry were lead (3.15 ± 0.1 - 5.48 ± 0.5), Cadmium (0.37 ± 0.05 – 1.46 ± 0.3), Mercury (0.01 ± 0.002 – 0.63 ± 0.05) and Arsenic (0.8 ± 0.18 to 2.02 ± 0.37) mg/kg. While wet samples had Lead (0.75± 0.11 – 3.64 ± 0.53), Cadmium (0.48 ± 0,03 – 1.57 ± 0.65), mercury (0.03 ± 0.003 - 1.44 ± 0.07) and Arsenic (0.56 ± 0.38 - 1.81± 0.06). Mini-tab analysis was used to assess carcinogenic health risk using the hazard quotient (HQ). There were high hazard quotient (HQ) values in wet samples ingested from Rosterman, Ikolomani, Masara and Francis and dermal dry samples from Rosterman that ranged between 1x10-2 - 1x10-4, indicating high risk of developing cancer. The gold miners in the study areas were exposed to radiations, noise, particulate matter, and heavy metals. Hence, there is need for adoption of health policies, continuous risk assessment and provision of PPEs to reduce the exposure to these hazards.