Lead and cadmium contamination and exposure risk assessment via consumption of vegetables grown in agricultural soils of five-selected regions of Pakistan

Abstract

Rapid urbanization and industrialization result in serious contamination of soil with toxic metals such as lead (Pb) and cadmium (Cd), which can lead to deleterious health impacts in the exposed population. This study aimed to investigate Pb and Cd contamination in agricultural soils and vegetables in five different agricultural sites in Pakistan. The metal transfer from soil-to-plant, average daily intake of metals, and health risk index (HRI) were also characterized. The Pb concentrations for all soils were below the maximum allowable limits (MAL 350 mg kg ⁻¹) set by the State Environmental Protection Administration of China (SEPA), for soils in China. Conversely, Cd concentrations in the soils exceeded the MAL set by SEPA (0.6 mg kg ⁻) and the European Union (1.5 mg kg ⁻¹) by 62-74% and 4-34%, respectively. The mean Pb concentration in edible parts of vegetables ranged from 1.8-11 mgkg ⁻¹. The Pb concentrations for leafy vegetables were higher than the fruiting and pulpy vegetables. The Pb concentrations exceeded the MAL (0.3 mg kg ⁻¹) for leafy vegetables and the MAL for fruity and rooty/tuber vegetables (0.1 mg kg ⁻¹) set by FAO/WHO-CODEX.. Likewise, all vegetables except Pisum sativum (0.12 mg kg ⁻¹) contained Cd concentrations that exceeded the MAL set by SEPA. The HRI values for Pb and Cd were <1 for both adults and children for most of the vegetable species except Luffa acutangula, Solanum lycopersicum, Benincasa hispada, Momordi charantia, Aesculantus malvaceae, Cucumis sativus, Praecitrullus fistulosus, Brassica oleracea, and Colocasia esculanta for children. Based on these results, consumption of these Pb and Cd contaminated vegetables poses a potential health risk to the local consumers.