Ecological risk assessment of arsenic, cadmium, copper, and lead contamination in soil in e-waste separating household area, Buriram province, Thailand

This study aimed to determine the arsenic (As), copper (Cu), cadmium (Cd), and lead (Pb) concentrations in the soil at e-waste separating houses in Buriram province. Soil samples were collected from five e-waste separating and five non-separating houses in each of two neighboring communities and from six reference houses located approximately 4 km away from the e-waste community. At each selected house, the surface (0–15-cm depth) and the subsurface (15–30-cm depths) soils were taken to be digested by a microwave digester and then analyzed for the heavy metal contents by atomic absorption spectrophotometry. The As, Pb, and Cd levels in the e-waste separating sites ranged from < 0.012 to 1.380, 0.110 to 15.283, and < 0.014 to 0.284 mg/kg, respectively, which were not in excess of the Thai standard level for residential soil (As = 3.9, Pb = 400, and Cd = 37 mg/kg), while Cu ranged from 1.180 to 380.413 mg/kg and exceeded the intervention value (190 mg/kg) of contaminated soil at three sites from a total of ten sampling sites. The physical e-waste dismantling activity enhanced the As, Cd, and Cu contamination levels in the surface soils. Ecological risk assessment revealed that the risk posed by the heavy metals in soils was higher at the e-waste separating houses than those at the non-separating sites and was mainly attributed to the levels of Cu > As > Cd > Pb for the surface soils and Cd > Cu > As > Pb for the subsurface soil. The association of the heavy metal soil levels with e-waste activity showed that if the e-waste activities were continuously operated, the As and Cu levels in the surface soil were more likely to exceed those levels in the reference houses. A good procedure for e-waste dismantling is necessary to be developed and implemented to prevent soil contamination and other related environmental problems.