Assessment of Ecological and Human Health Risk Associated with Toxic Metals from the Consumption of Vegetables Exposed to Low Quality Irrigation Water of Industrial Zones in Semi-arid Regions.

Abstract

The aim of the study was to evaluate the toxic metals (TMs) pollution, bioaccumulation and its potential health risk via consumption of different vegetables irrigated by different water sources released from industrial estates of Khyber Pakhtunkhwa. Water (fresh and waste), soil and vegetables samples were collected in triplicates and acid digested. Digestion of samples were followed by evaporation and filtration and then assessed for TMs via atomic absorption spectrophotometer. The results showed that mean concentration of TMs were below the permissible limits (0.003-2 mg/L) set by World Health Organization, except cadmium (Cd) and lead (Pb) in freshwater, while mean concentrations of TMs exceeded the permissible limits except manganese (Mn) in wastewater of all industrial estates. The contamination factor (CF) and pollution load index (PLI) results showed that TMs had high pollution levels (especially for Pb, Ni and Mn). The average bioaccumulation factor (BAF) values of TMs were below threshold (< 1) in all vegetables. The hazard risk index (HRI) values of all TMs were below (< 1) in all vegetables of industrial estates, except Pb. The total hazard index (THRI) of TMs for all vegetables exceeded the acceptable limit (> 1). Carcinogenic risk (CR) of selected TMs was substantially higher and exceeded the permissible limit. Hence, the present findings revealed that long-term irrigation with the wastewater result to TMs contamination in soil and vegetables, and may pose a detrimental impact on human health.