A Decade-Long Comparison of Heavy Metal(loid)s in the River and Children's Health Risk Assessment of an E-Waste Recycling Area

Informal e-waste recycling can cause serious heavy metal(loid) pollution to nearby bodies of water, thereby increasing the risk of heavy metal exposure to local residents. This study investigates metal(loid) pollution levels in the Lianjiang River, which flows through Guiyu, an e-waste recycling town in Shantou, Guangdong. In 2009 and 2020, water samples from the Lianjiang River were taken, and the levels of 12 metal(loid)s (V, Cr, Mn, Sr, Ni, Cu, Zn, As, Se, Cd, Ba, and Pb) were measured by ICP-MS. In total, 380 valid questionnaires from Guiyu kindergarten children were selected to assess child health. Exposure health risks for children were calculated using two forms of exposure (dermal and inhalation) and statistical methods (multiple linear regression and Bayesian kernel machine regression-BKMR). The concentrations of Mn, Ni, Pb, and Cd in 2009 were significantly higher than those in 2020. The concentration of heavy metal(loid)s had been decreasing in 2020. The non-carcinogenic risk levels of the 12 metal(loid)s in both exposure routes were at an acceptable risk level. The average carcinogenic risk levels for As, Cr, Ni, Pb, and Cd exceeded the ILCRi <10-6 acceptable range. According to MLR, it was found that daily oral intake doses of Pb [beta(95% CI): -0.949 (-1.596, -0.863), p < 0.001 and Se [beta(95% CI): -0.911 (-1.888, -0.092), p = 0.031] were negatively associated with body mass index. A BKMR model was developed, through which the synergistic effects of co-exposure to 12 heavy metal(loid)s on growth and development indicators in children were analyzed. Concentrations of heavy metal(loid)s in rivers near e-waste recycling sites have been decreasing for 10 years. It was found that the growth and development of children are affected by the intake of heavy metal(loid)s in water. The reduction in heavy metal(loid) contamination in e-waste recycling areas needs to be continued, and concern about its impact on children's health must remain.