A Systematic Review on Classification, Exposure Pathways of Micropollutants in the Aquatic Environment, and Its Associated Human Health Risks

Micropollutants are a diverse group of trace-level emerging contaminants present in different parts of the environment and causing notable risks to human health and aquatic life. They mainly originate from industrial, agricultural, pharmaceutical, and domestic sources, contaminating water bodies, where they induce toxicity in aquatic biota, bioaccumulate through food webs, and ultimately reach humans via ingestion, inhalation, and dermal exposure. Accumulating scientific research shows that exposure to micropollutants is associated with endocrine disruption, reproductive disorders, hormone-sensitive cancers, and dysfunction of the cardiovascular, respiratory, and immune systems. Their persistence, tendency to bioaccumulate, and chemically diverse modes of action further complicate their toxicological profiles. This systematic review evaluates findings from epidemiological, experimental, and molecular research published between 2000 and 2025 to provide a comprehensive perspective on micropollutant toxicity. Notably, it highlights critical research gaps, including inconsistent datasets, variation in defining chronic exposure, and limited investigation of combined or antagonistic effects of micropollutant mixtures. Addressing these gaps requires coordinated policy strategies, advances in remediation technology, and continuous scientific innovation to ensure public health protection and preserve the integrity of aquatic ecosystems. To bridge this gap, the present review proposes a systematic classification framework based on key sources, chemical nature, pathways, and ecotoxicological effects, while simultaneously elucidating their environmental dissemination in aquatic systems and characterizing their toxicological implications for both aquatic ecosystems and human health.