Interactions Between Microplastic and Heavy Metals in the Aquatic Environment: Implications for Toxicity and Mitigation Strategies

Heavy metals (HMs) and microplastics (MPs) are toxic environmental pollutants that severely risk ecosystems and living organisms. The interactions of these pollutants in the aquatic environment can impact their bioavailability, toxicity, and bioaccumulation potential in organisms. Various factors, including temperature, pH, salinity, polymer type, particle size and microbial abundance, influence these interactions and are likely to increase their influence on aquatic biota and human beings. MPs have been recognized as heavy metal transporters in aquatic environments that exhibit various harmful effects. However, MP interactions with heavy metals are poorly understood. Hence, it is important to understand the detailed mechanism, mainly absorption vs ingestion, MPs degradation with metal fate and combined effects on living organisms. To tackle and reduce the harmful effects on biodiversity, it is essential to comprehend the underlying mechanisms (e.g. adsorption, desorption, bio-uptake, and synergistic effects). Also, more research is required to comprehend the intricate connections between MPs and HMs in an array of environmental situations, which could lead to innovative solutions for mitigating their detrimental environmental consequences. This review paper discusses microplastic's prevalence, concentration, adsorption, and dissociation characteristics concerning HMs in aquatic ecosystems that must be understood to reduce their deleterious effects on aquatic biodiversity. Understanding these complex interactions between MPs and HMs is critical to assessing the ecotoxic effects and preventing environmental pollution. This review paper also underscores the nature of environmental pollutants, including the interaction mechanisms of MPs and HMs, emphasizing the importance of multifaceted approaches that need to be adapted to mitigate their combined effects.