Global water sustainability is increasingly threatened by microplastic (MP) contamination, yet a unified understanding of the specific polymer and morphological profiles across different water systems remains fragmented. This review provides the first comprehensive synthesis focusing specifically on polymer and morphological characteristics, rather than abundance alone, across four critical water matrices: treated, bottled, groundwater, and surface water. A total of 143 global studies were systematically analyzed (2011–2025) to: (a) identify dominant MP polymers and morphologies; (b) map their distribution across water types; (c) elucidate potential sources; (d) assess regional variations; (e) evaluate polymer-specific toxicity; (f) analyze exposure pathways; and (g) project future trends. Findings reveal that polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) as fibers and fragments are ubiquitous, with surface water being the most studied matrix. Polyvinyl chloride (PVC) and polystyrene (PS) raise the highest toxicological concerns due to additive leaching. Tropical regions show a higher propensity for fibrous contamination. Projections indicate escalating pollution, driven by increasing plastic production and climate change, with disproportionate impacts on developing nations. This synthesis emphasizes an urgent need for polymer-targeted mitigation strategies, advanced water treatment, and harmonized global monitoring to safeguard water resources and achieve Sustainable Development Goal (SDG) 6.
Egbueri et al. (Thu,) studied this question.