Health risk assessment of heavy metals in exposed workers of municipal waste recycling facility in Iran

Abstract

Exposure to heavy metals (HMs) present in the particulate matter from municipal solid waste during pretreatment and recycling processes may pose a serious health risk to workers. This was the first study on the exposure of municipal solid waste (MSW) recycling workers to toxic metals. The concentrations of HMs (Cd, Pb, As, Co, Cr, Ni, Cu, Fe, Mn, and Zn) during personal exposure to PM2.5 among municipal waste recycling facility workers in Kashan City, Iran, were investigated from January 15 to March 15, 2023. The research was performed in the three main stages of the waste recycling process: dismantling, sorting, and collecting. PM2.5 samples were collected using a personal environmental monitor (PEM) attached to a sampling pump. The non-carcinogenic and carcinogenic health risk values and related uncertainty for waste recyclers from HMs inhalational exposure were calculated using USEPA methodology and Monte Carlo simulations. The results showed that the dismantlers exhibited the highest exposure concentrations of PM2.5 (mean 2148 ± 1257 μg m−3), followed by sorters (mean 1864 ± 965 μg m−3), and collectors (mean 1782 ± 876 μg m−3). Health risk assessment indicated that 95th percentile contents of Ni, As, Co, and Zn were responsible for the non-carcinogenic risk (HQ) values exceeding the acceptable level of 1. The contents of As, Ni, and Cr in PM2.5 caused a non-acceptable carcinogenic risk for waste recyclers due to inhalational exposure, as the carcinogenic risk (CR) values exceeded the acceptable threshold of 1 × 10−6. Monte Carlo simulation results revealed that the mean and median CR values from inhalational exposure to carcinogenic HMs exceeded the acceptable level of 1 × 10−6 for municipal waste recyclers. As results of this study indicated the high-risk to hazardous metals for waste recyclers due to occupational exposure in the MSW recycling sites, it is suggested to consider workers’ exposure as the public health concern.