Does heavy metal hurt in the secondary battery production sites? The case study of occupational risk from Yangtze River Delta, China

The purpose of this study was to determine the occupational health risk to employees of lithium-ion battery factories in Yangtze River Delta, China. Soil samples were collected from materials synthesis workshop and battery assembly line workshop, which are named site A, site N1, site N2, and site Z according to different battery products. We analyzed the heavy metals for Co, Cd, Mn, Cu, and Ni. The soil heavy metal exposure model and the health risk characterization model were built to assess occupational health risk. Besides, uncertainty analysis with the aid of Monte Carlo simulation was used to perform error propagation for model parameters. The health risk assessment with uncertainty results indicated that all the four sites have relative low risk of carcinogens for employees, and N1, A, and Z sites also have relative low risk of non-carcinogen for employees, but N2 site has value of 6.94, which is heavily higher than the threshold value (defined as 1.0). It means that the employees in N2 site are facing threat of the heavy metals. These results provide basic information of heavy metal pollution control and environment management in lithium-ion battery factory. It also answered the question of the occupational risk in the sites.