Abstract
Majority of contaminated sites in the world contain complex mixtures of heavy metals and organic contaminants from diverse natural processes and anthropogenic activities. Mixed interactions of heavy metals and organic contaminants may affect their bioavailability and accumulation in soil and biota through synergistic or antagonistic processes. Evaluation of contaminant bioavailability is a necessary component of the overall site assessment process for establishing either bioavailability-based or risk-based, site-specific remedial options. However, contemporary approaches aimed at the effective characterisation of contaminated soils for risk assessment, remedial and regulatory purposes are frequently challenged by knowledge gaps in contaminant bioavailability, mixed contaminant effects and emerging contaminants. Understanding mixed contaminant interactions at the elemental and molecular levels is, therefore, imperative not only to explain the underlying mechanisms controlling the fate and transport of these contaminants in soils, but also predict their bioavailability, ecotoxicological effects on natural communities under realistic exposure conditions and remediation endpoints. In this paper, scattered literature is harnessed to review specific soil-contaminant interactions, inter-contaminant (metal-metal, organic-organic, metal-organic) interactions and their implications for bioavailability, risk assessment and soil remediation.
Key words: Heavy metals, organic contaminants, mixed contaminant interactions, co-contaminated soil, bioavailability, risk assessment, soil remediation.
