Microplastic leachates: an invisible flux and latent source of environmental toxicity

Microplastics (MPs) have emerged as ubiquitous pollutants in marine, freshwater, and terrestrial environments. Their amorphous structure, high surface area, and hydrophobicity enable the strong adsorption of environmental contaminants. At the same time, embedded additives such as phthalates, bisphenols, ultraviolet (UV) stabilizers, and polycyclic aromatic hydrocarbons (PAHs) leach into ecosystems during degradation. This review synthesizes current findings on the chemical diversity of MPs’ leachates, highlighting major sources, including tire wear, textile fibers, landfills, and wastewater treatment plants (WWTPs). Environmental drivers, such as UV radiation, temperature fluctuations, mechanical stress, salinity, and microbial colonization, accelerate additive release, while polymer-additive interactions dictate diffusion dynamics. Toxicological evidence demonstrates endocrine disruption, oxidative stress, reproductive toxicity, and ecosystem-level impacts in aquatic organisms. The persistence of these compounds in landfill leachates, wastewater sludge, and marine debris underscores their resilience and long-term ecological risk. Collectively, MPs act not only as physical pollutants but as dynamic chemical carriers, necessitating integrated risk assessment frameworks and stricter regulatory policies to mitigate their latent toxicity in the environment.