Monitoring bioconcentration of potentially toxic trace elements in soils trophic chains

Abstract

Potentially toxic trace elements (PTEs) may be transferred to plants and consequently enter the food chain. Environmental monitoring of PTEs is important to control their concentrations in the environment and, particularly in farmland soils. The study aims at estimating the concentration of PTEs in the soil, its grass cover and collected soil invertebrates and consequently to investigate the transfer of pollutants in the soil–plant–fauna trophic chain. None of the PTEs was recorded in soil concentrations at levels exceeding the limits defined by the Regulation of the Minister of Environment. Mean concentrations of Zn, Pb, Cd, Ni, and Cu in soil were 55, 52, 44, 23, and 10 % of the permitted values, respectively. The concentrations of potentially toxic trace elements in soil samples were higher compared to their levels in grass, except for Cd which was the other way around. Higher concentration of Cd in grass than in soil may be attributable to direct deposition of metal particulates emitted from motor vehicles on grass, rather than soil along the road. As far as other metals (Pb, Ni, Cu, Zn) are concerned, concentration in soil was higher than in grass, however, lower than in the fauna. In the investigated meadow, both grass cover and the collected soil fauna accumulated cadmium in largest amounts and incorporated the studied metals in the following order: Cd > Zn > Cu > Ni > Pb. All considered elements showed greater concentrations (nearly tenfold higher for cadmium) in fauna than grasses.