Mechanistic insights into Thallium mobility through microplastics: Environmental fate and risks – a review

Microplastics (MPs) are increasingly recognized as serious environmental pollutants, posing significant threats to aquatic ecosystems and human health. Thallium (Tl), although less frequently studied, is of particular concern due to its high toxicity, environmental persistence, and strong bioaccumulative potential. Recent studies suggest that MPs may play a role in the transport and mobility of Tl in the environment, raising concerns about their contribution as emerging vectors of trace elements. The adsorption behavior of Tl onto MPs is a multifaceted process influenced by parameters such as pH, salinity, ionic strength, and the physicochemical properties of both MPs and Tl species. However, our understanding of Tl interactions with MPs remains limited. This review explores current knowledge on the occurrence, distribution, and environmental behavior of Tl, with a particular focus on its interactions with MPs. It emphasizes mechanistic insights into adsorption processes, compares Tl behavior with other environmentally relevant elements, and explores the role of MPs in influencing Tl mobility and toxicity. The review also identifies critical knowledge gaps and highlights the need for further research on MPs-trace element interactions to inform strategies that mitigate environmental and health risks. Understanding the interactive effects of Tl toxicity and MPs behavior can ultimately support the development of more effective environmental protection policies.