To evaluate the airborne exposure concentrations of total suspended particulate matters (TSPM), repirable suspended particulate matters (RSPM) and silica in brickfields and the prevalence of respiratory symptoms and illnesses among brickfield workers.Methods
A cross-sectional study was conducted in Kathmandu valley targeting all the brickfield workers during February – March 2015. Out of 106 operating brick kilns in Kathmandu Valley, 16 kilns were selected for the study applying multi-stage probability proportionate to size (PPS) sampling technique. A total of 800 participants, 400 brick workers as exposed and 400 grocery workers as referent group were recruited for interviews. Samples for silica, respirable and total particulate were collected following NIOSH methods. One-way ANOVA along with Tukey’s test were applied to compare significance of the extent of particulate matters among similar exposure groups (SEGs). Bivariate and multivariate logistic regression analysis were carried out to evaluate association between respiratory symptoms/illnesses and participant groups (exposed and referent) and SEGs among brickfield workers.Results
Mean results were as follows for the SEGs, respectively for silica, RSPM and TSPM: red brick loading/carrying (RBL/C), 0.388 mg/m3, 17.944 mg/m3, 22.657 mg/m3; green brick stacking (GBS), 0.204 mg/m3, 5.886 mg/m3, 16.271 mg/m3; green brick moulding (GBM), 0.119 mg/m3, 2.193 mg/m3, 4.581 mg/m3; fire master (FM), 0.111 mg/m3, 3.452 mg/m3, 3.435 mg/m3; and for coal crushing/carrying (CCC), 0.098 mg/m3, 7.478 mg/m3, 7.094 mg/m3. One-way ANOVA was conducted for silica, RSPM and TSPM showing significant relationships across the SEGs. The majority (55%) of brick workers complained of coughing during the previous year. The prevalence of chronic cough among this group was 14.3% compared to 6.8% for grocery workers. Brick workers were also significantly more likely to have chronic phlegm production while coughing, chronic bronchitis, wheezing, chest tightness and other chest illnesses. Among SEGs, green brick moulders were nearly six times more likely to experience chronic cough (OR: 5.80; 95% CI: 1.20 to 27.93; p: 0.028) with red brick loaders three times more likely to have chronic bronchitis (OR: 3.08; 95% CI: 1.26 to 7.51; p: 0.013) when compared with workers involved in CCC work. Age and duration of work were significant predictors for chronic cough (p=0.001 each). Age of workers (p=0.003) and smoking habit of workers (p=0.002) were significant predictors for causing chronic bronchitis. Smoking practice of the workers was a significant predictor of wheezing (p=0.018) and asthma (p=0.026) among work groups.Conclusions
All of the respiratory symptoms and illnesses were significantly high among brickfield workers. These finding indicate urgent action for protection of workers and prevention of diseases. Furthermore, the symptoms and illnesses are the clear signs that exposure to TSPM, RSPM and silica are affecting the brickfield workers.