Global lead contamination in soils, sediments, and aqueous environments: Exposure, toxicity, and remediation
Pratibha Mishra, Shakir Ali, Rakesh Kumar, Shashank Shekhar
Abstract
Lead (Pb) is a heavy meta(loid) and historically been used in paints, jewelleries, electronics, soldering, plumbing, and cookware due to its high malleability, low melting point, resistance to corrosion, and ability to bond with other metals. However, Pb is recognized as one of the toxic elements commonly occurring in soils, sediments, and natural water. This article provides a comprehensive review of the current status of Pb contamination, underscoring its distribution, persistence, fate, and impacts on humans and plants. We investigated recent literature focusing on: (a) sources of Pb contamination in soils, sediments, and aqueous environments, (b) lead mobilization, occurrences, toxicity mechanisms, and their potential health effects; and (c) various remediation methods for Pb contamination in soil and water. Additionally, case studies from the USA, China, and India on Pb sources and pollution in different ecosystems are discussed. Our findings indicate that: 1) Lead concentrations exceed permissible limits in numerous soils, sediments, and water globally, while remediation efforts remain largely localized and limited in scale. 2) The mobility of Pb facilitates its bioaccumulation, enabling it to substitute for Ca²⁺ as a signalling messenger in plants and animals. This results in adverse effects such as impaired germination and nutrient uptake in plants, as well as neurotoxicity and other cascading negative impacts in humans and animals. The study reveals that soils, sediments, and aqueous environments are moderately to highly polluted with Pb, necessitating further investigation into its mobilization and toxicity. Therefore, this contaminant should be comprehensively studied and mitigated through appropriate policy interventions.