Industrial hygiene and toxicity studies in unorganized bone-based industrial units

A large variety of ornamental and decorative items are manufactured from bone waste by various unorganized sectors in India. An initial survey indicated that workers were exposed at various phases of final product. The subjects (12 industrial units) were tested for total suspended particulate matter (TSPM), particulate matter < 10 mu m (PM10), and particulate matter < 2.5 mu m (PM2.5). Prevalent levels of TSPM ranged between 2.90 and 5.89 mg m(-3). Respirable fractions of occupational dust as PM10 and PM2.5 were found in the range of 0.30-2.08 and 0.26-0.50 mg m(-3), respectively. Cytotoxicity study was conducted using hemolysis as a sensitive marker. In an in vitro study, rat RBCs were exposed to the concentration of 25-1,000 mu g/ml for 15-120 min. A considerable variation was observed in the hemolytic activity of samples collected from different areas. At 500 mu g/ml concentration, the hemolytic activity (12 h) was found to be in the range of 18-25%. Due to limitation in sample mass of respirable fractions, only one concentration (100 mu g/ml/2 h) was used for comparative study on hemolysis of RBCs caused by PM10 and PM2.5. Interestingly, the hemolytic activity was more at PM2.5 than PM10 and TSPM. These results suggest that the respirable particles are capable of reaching deep into the respiratory system. The finding is significant notably when there are no standards available in occupationally exposed populations. This is the first such study. Data could be of importance to policy makers and regulators.