In fluence of metals from e-waste dismantling on telomere length and mitochondrial DNA copy number in people living near recycling sites

Metals are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse e ffects on people working in e-waste recycling or living near e-waste sites have not been studied well. Taizhou is one of the three largest e-waste recycling locations in China. At present, to prevent the environmental problems stem from e-waste dismantling, the local government has shut down all the industries in 2015. In this study, we collected blood samples of residents living near e-waste dismantling factories, and in matched reference areas in Taizhou, in December 2017, after the factories have been shut down for two years. Seventeen metals were quanti fied in all blood samples. Among them, the concentrations of arsenic (As), nickel (Ni), silver (Ag), lanthanum (La), and Cerium (Ce) were statistically signi ficant higher in individuals in e-waste recycling locations than those in re- ference location. Length of telomere (LOT) and mitochondrial DNA copy number (MCN) were measured in blood as a marker of human health. In the e-waste dismantling location, the level LOT and MCN were elevated in resident living near e-waste sites (RE) and former working in e-waste recycling (OE) than residents living in the reference area (RF). Furthermore, Pearson correlation and multiple linear regression analysis between the changed metals and LOT, MCN in blood were performed. In RE and OE, the concentration of Ni signi ficantly positively correlated with MCN; in OE, the Ni level signi ficantly positively correlated with MCN and LOT. Considering that the high level of Ni, TL and mtDNA were correlated with the risk of cancer, we speculated that e-waste exposure elevate the risk of cancer, and Ni that has long been present in the body was the potential hazardous element causing cancer.