Levels and ecological risk assessment of metals in soils from a typical e-waste recycling region in southeast China

Abstract

Due to the high threat to human health and the ecosystem from metals, the levels and distribution of As, Hg, Cr, Co, Ni, Cu, Zn, Cd, Pb, Mn, V, Sn, Sb, Li and Be in various layers of soil from an e-waste recycling area in Guiyu, China were investigated. The extent of pollution from the metals in soil was assessed using enrichment factors (EFs) and the Nemerow pollution index (P N ). To determine the metals' integrated potential ecological risks, the potential ecological risk index (RI) was chosen. The concentrations of Hg, Ni, Cu, Cd, Pb, Sn and Sb were mainly enriched in the topsoil. EF values (2-5) of the elements Hg, Co, Ni, Zn, Sn, Li and Be revealed their moderate enrichment status in the topsoil, derived from e-waste recycling activities. P N presented a decreasing trend in different layers in the order topsoil (0-20 cm) > deep soil (100-150 cm) > middle soil (50-100 cm) > shallow soil (20-50 cm). With higher potential ecological risk factor (E(i)), Hg and Cd are the main contributors to the potential ecological risk. With respect to the RI, all the values in soil from the study area exceeded 300, especially for the soil at sites S2, S4, S5, S7 and S8, where RI was greater than 600. Therefore, immediate remediation of the contaminated soil is necessary to prevent the release of metals and potential ecological harm.

Sustainable Options for Mitigation of Major Toxicants Originating from Electronic Waste

“…E-waste is a complex mixture characterized by the presence of both organic and metal entities 4 . Organic compounds include persistent organic pollutants (POPs) in the form of PAHs, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol-A (TBBPA) and perfluorooctanoic acid (PFOA) 4 .…”

“…Organic compounds include persistent organic pollutants (POPs) in the form of PAHs, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol-A (TBBPA) and perfluorooctanoic acid (PFOA) 4 . Organic compounds PBDEs and TBBPA are generally used in electronic goods as fire retardants, whereas PCBs are used as insulators, lubricants and coolants 2 .…”

“…4). It is estimated that by 2018 the production will rise to around 50 mt if the current pace continues, which will further aggravate the problem associated with e-waste disposal 4,5 .…”

“…4). It is estimated that by 2018 the production will rise to around 50 mt if the current pace continues, which will further aggravate the problem associated with e-waste disposal 4,5 . According to US-EPA estimates, only 15%-20% of total e-waste produced is recycled, while the remaining is usually disposed in landfills 6 .…”

“…This further strengthens the possibility of contamination of nearby areas with e-waste pollutants. Environmental risk assessment studies of areas nearby informal and uncontrolled e-waste processing site by various researchers have shown alarming levels of heavy metals and organic compounds in surface soil, vegetation and groundwater 2,4,7 . Even elevated levels of these toxicants were also detected in blood samples of workers associated with e-waste recycling and also in nearby local residents 8 .…”