Geochemical speciation and bioaccumulation of trace elements in different tissues of pumpkin in the abandoned soils: Health hazard perspective in a developing country

Abstract

Trace elements contamination in vegetables especially pumpkin is a major concern for public health where human beings are continuously exposed to trace elements through consumption of pumpkin grown in the trace elements contaminated abandoned soil. The present study was conducted to assess the geochemical speciation of essential and toxic elements in abandoned agricultural soil, contamination and bioaccumulation of essential and toxic elements in different tissues of pumpkin plant and probable risk to human health using an integrated research methodology. Soils and different tissues of pumpkin (Cucurbita pepo) plants were collected from agricultural fields around the tannery industries in Dhaka City, Bangladesh. The values of pH, electrical conductivity and organic carbon were ranged from 5.7 to 7.6, 16 to 44 μS/cm and 0.36–3.3%, respectively. The geochemical speciation analysis indicated that Cr, Ni, Cu, Fe and Zn were predominantly associated with the residual fraction followed by organically bound phase where As, Cd and Pb were associated with the weakly bound fractions (exchangeable and carbonate). The average concentrations of essential and toxic elements in plants parts were in the decreasing order of Fe > Zn > Ni > Cu > Mn > Cr > Pb > As > Cd. The concentration of Cr, As, Cd and Pb in vegetables were higher than the standard limits of elements in food, indicates that toxic elements may pose potential risk to the consumers. The translocation factor (TF) revealed that studied elements were more accumulated in leaves than roots. Considering health risks of essential and toxic elements due to pumpkin consumption, Cr, As, Cd and Pb caused non-cancer and cancer risk for the adult’s inhabitants in the study area.