Respiratory Impairment and Personal Respirable Dust Exposure among Underground and Open Cast Gold Miners in North-Mara Tanzania

Abstract

Background: Mining is one of the most hazardous sectors to work in because it is a sector that predisposes workers to various hazards including dust. Exposure to dust in the mines is inevitable because the whole process of extracting gold has to involve rock breaking. This dust can penetrate up to the alveoli of the pulmonary system and cause respiratory impairment. Objectives: To determine respiratory impairment, personal respirable dust exposure levels and associated factors among miners in a gold mine in Tanzania. Material and methods: Cross-sectional study design was used employing use of questionnaires for data collection on respiratory symptoms. Lung functions were measured using spirometry. Personal respirable dust exposure was collected from similar exposure groups using air sampling pumps. A simple random sampling technique was used to select participants. 112 workers were included in the study. Data analysis was done using SPSS computer software version 20.0. Results: The overall Geometric Mean of respirable dust was 0.26mg/m3 (GSD=0.32) over a mean sampling time of 8hours (with a range between 7-11hours). The GM for underground (0.41±0.28mg/m3) was significantly higher compared to open pit (0.17 ±0.23 mg/m3) with p<0.01. For underground, the GM was highest among bogger operators 0.53mg/m3(GSD=0.27) while for open pit, the highest GM was found among quality controllers 0.39mg/m3 (GSD=0.18). Respiratory symptoms were phlegm (49.1%), Breathlessness (42.9%), cough (37.5%), wheezing (18.8%) and chest tightness (10.7%).Cigarette smokers were more likely to suffer from breathlessness compared to non-smokers. Prevalence of airflow obstruction (FEV1/FVC<0.7) was 1.9% while prevalence of lung restriction was 8.8%. Age, smoking and previous exposure to dust could not predict lung function impairment. Conclusion and recommendations: Despite levels of respirable dust exposure being below recommended occupational exposure limits, prevalence of respiratory symptoms was still high among gold miners. There is a need to conduct further studies on quarts.