Worker health risk of heavy metals in pellets of recycled plastic: a skin exposure model

Objective According to epidemiological studies, heavy metals such as arsenic, cadmium, chromium, and lead are “known” carcinogenic substances. After recycling, these metals remain in processed plastics. The purpose of this study was to assess the health risks of heavy metal skin exposure to workers in facilities that recycle plastics. Methods We used inductively coupled plasma-mass spectrometry to measure the dissolution concentrations of heavy metals in artificial sweat. Twenty-five samples of pellets of recycled plastic were examined, which were composed variously of polypropylene, high-density polyethylene, acrylonitrile–butadiene–styrene copolymer, high impact polystyrene, and polyamide. In addition, we used a “two-step assessment model,” divided into exposure and risk characterization, to evaluate the health risks of heavy metal exposure in a simulated exposure environment of pellets of a recycled plastic processing workshop. Results Except for chromium (92%), the detection of lead, cadmium and arsenic was 100% in 25 samples of pellets of recycled plastic. The possible carcinogenic risk levels of As and Cr were, respectively, 2 and 38 times greater than the unacceptable risk level of 10 –4 proposed by the US EPA. In addition, arsenic had the highest noncarcinogenic risk of 1.381 × 10 –6 , which was in the potential risk range of 10 –6 –10 –4 proposed by the US EPA. Conclusion We found clear exposure-risk associations between heavy metals (lead, cadmium, chromium, arsenic) and worker health. Particularly, we found workers exposed to As and Cr were more likely to incur cancer.