Microplastics in Aquatic Environments

This primer is for chemists who seek to move beyond descriptive inventories of microplastics toward a mechanistic understanding of their environmental fate and effects. Our primary audience includes undergraduate and graduate students, early career scientists, and professionals in environmental chemistry, aquatic sciences, materials science, and related disciplines who wish to understand why microplastics behave as they do in water, rather than simply where they are found. Throughout the primer, microplastics are treated not as passive particles but as dynamic chemical interfaces whose properties evolve in response to salinity, pH, dissolved organic matter, biofouling, and climatic forcing.

The primer is structured to reflect the life cycle of microplastics in aquatic systems. The opening chapters trace the discovery and definition of microplastics through seminal case studies, framing their emergence as a shift in how chemists and aquatic scientists conceptualize particulate pollution. Subsequent sections examine the environmental chemistry that governs transport, aggregation, vertical migration, and surface transformation, drawing on frameworks such as electrical double layer theory, DLVO interactions, and linear solvation energy relationships. These mechanistic tools provide the foundation for understanding why polymers distribute unevenly across water columns, sediments, and biota and why certain plastics act as particularly effective vectors for organic contaminants.

Later chapters focus on biological and molecular consequences, integrating particle toxicity, additive leaching, and vector-mediated pollutant transfer into a unified mechanistic narrative. Particular attention is given to the plastisphere, where microbial colonization transforms polymer surfaces into biologically active habitats with implications for pathogen transport and ecosystem health. The final sections explore remediation strategies, emphasizing how advances in surface chemistry, catalysis, and separation science can be leveraged to address microplastic contamination in real-world aquatic systems.

Rather than offering an exhaustive catalog of studies, this volume prioritizes conceptual clarity and chemical insight. Complex topics are intentionally retained and scaffolded—through focused explanations of key theories and mechanisms—to support readers without diluting scientific rigor. Our goal is to provide a framework that enables readers to interpret current research critically, design mechanistically informed experiments, and anticipate how microplastics will behave under future environmental and climatic conditions.

Microplastics now intersect with questions of water quality, food security, climate change, and environmental justice. By grounding their study in aquatic chemistry and molecular-scale processes, this primer aims to equip the reader with the tools needed to understand microplastics not merely as pollutants but as active participants in the chemistry of the Anthropocene.