Long-term nonferrous metal smelting affects metal accumulation/transfer in a soil-plant-woodlouse system.

Nonferrous metal smelting is one of the main sources of heavy metal pollution in the environment, yet its effect on heavy metal transfer in soil-plant-animal systems is not well investigated. In this work, soil, plant (Humulus scandens [HS], Digitaria sanguinalis [DS], and Setaria viridis [SV]), and woodlouse (Armadillidium vulgare) samples were collected in a long-term nonferrous metal smelting area from 26 sites over approximately 7 km and analyzed for Cd, Cu, Mn, Ni, Pb, and Zn concentrations. Cadmium and Pb were the most accumulated soil metals, with mean concentrations of 4.68 and 249 mg kg, respectively. The plant bioconcentration factor (BCF) of soil heavy metals was all <1. Mean woodlouse Cd, Cu, Mn, Ni, Pb, and Zn concentrations were 20.5, 69.7, 169, 5.41, 47.2, and 424 mg kg, respectively. Significant correlations between woodlouse heavy metal concentrations and distances from the smelter were only found for Cd. Woodlice had a greater BCF of plant Cd (mean = 11.2), Cu (52.6), and Zn (10.6) than for Mn, Ni, and Pb. No significant correlation was found between soil/plant and woodlouse for heavy metal concentrations. Heavy metal toxicities to plants and woodlice were quantitatively estimated with a newly developed model, with results indicating that woodlice had much greater (9800) values than the plants (<1300). Results indicate enhanced accumulation and toxicity of heavy metals to woodlouse in the soil-plant-woodlouse system than in a simpler soil-plant system approach. The health risks of heavy metals in woodlice to predators need further evaluation.