Micro- and nanoplastics (MNPs) have emerged as insidious pollutants within aquatic environments, representing a burgeoning threat to both ecosystem integrity and global water security. These diminutive plastic particles, ranging in size from mere nanometers to several micrometers, infiltrate every corner of water systems worldwide, compounding the challenges faced by aquatic biogeochemical processes. While their presence as physical contaminants has been acknowledged, mounting evidence reveals a broader spectrum of indirect effects that disrupt fundamental environmental functions. These effects transcend mere pollution, touching upon the very cycles that sustain life beneath the water’s surface.
One of the most profound ways in which MNPs disturb aquatic environments lies in their interference with critical nutrient cycles—the carbon, nitrogen, phosphorus, and sulfur cycles—each integral to maintaining ecological balance. By adsorbing and sequestering essential elements, MNPs alter the availability and distribution of nutrients, thus transforming biochemical pathways. For example, the interaction of microplastics with organic carbon compounds can modify carbon sequestration rates, while their affinity for nitrogenous compounds may hinder or unintentionally accelerate nitrogen transformations. These disruptions ripple through aquatic food webs, influencing microbial community structure and function, and ultimately reshaping ecosystem productivity and resilience.
Furthermore, micro- and nanoplastics act as vectors for pathogenic microorganisms, a factor that escalates public health concerns. By serving as substrates for microbial colonization, these plastics create novel niches for bacteria, viruses, and protozoa, some of which may be pathogenic to aquatic fauna and humans. The capacity for MNPs to transport and disseminate pathogens over vast aquatic distances exacerbates infection risks and challenges traditional water quality management. Such dynamics underscore the need to view plastic pollution not merely as a chemical or physical hazard, but also as a biological vector capable of mediating disease transmission in water bodies.
Compounding the complexity of MNPs’ environmental impact is their interaction with emerging chemical contaminants. Pharmaceuticals, personal care products, pesticides, and industrial chemicals frequently adsorb onto plastic surfaces, altering their bioavailability and persistence. This phenomenon results in a synergistic effect whereby MNPs not only concentrate toxicants but also protect them from degradation processes, effectively turning them into pollutant reservoirs. Consequently, biological organisms exposed to micro- and nanoplastics may also face heightened toxicological stress, complicating risk assessments and undermining ecosystem health.
The multifaceted role of MNPs challenges conventional water treatment paradigms. Traditional filtration and chemical treatment methods often fall short in effectively capturing nanoplastic particles or mitigating their complex interactions with microbial and chemical contaminants. This inadequacy demands innovation in water treatment technologies that can adapt to the dynamic nature of micro- and nanoplastics pollution. Advanced filtration systems, coupled with modular and responsive control strategies, are imperative to address fluctuating environmental parameters such as temperature, pH, and salinity, which influence MNP behavior and toxicity.
An emerging frontier in tackling the indirect consequences of MNPs involves predictive monitoring and early warning systems. Harnessing advances in environmental sensing and data analytics, these systems offer the potential to detect perturbations in nutrient cycling or pathogen prevalence linked to microplastics presence before they culminate in ecological crises. By integrating real-time data streams and machine learning, water managers can respond proactively, deploying targeted interventions that preserve water quality and safeguard human health.
A comprehensive response to the threats posed by micro- and nanoplastics requires a convergence of scientific research, technological ingenuity, and robust policy frameworks. Scientific inquiry must deepen our understanding of MNP interactions at molecular and ecosystem scales, elucidating mechanisms that govern nutrient flux alterations and pathogen transfer. Concurrently, engineering solutions should prioritize flexibility, scalability, and cost-effectiveness, ensuring that water treatment infrastructure remains resilient amidst evolving contamination profiles.
Policy development must reflect the intricacy of MNP pollution, moving beyond end-of-pipe regulation toward holistic strategies encompassing source reduction, material innovation, and public engagement. The implementation of regulatory frameworks that address the lifecycle of plastics—spanning production, usage, disposal, and environmental release—will be critical in curbing the influx of micro- and nanoplastics into aquatic systems. Public awareness campaigns can also galvanize behavioral change, mitigating upstream plastic pollution and its downstream consequences.
The pervasive nature of MNP contamination reflects the intersection of technological progress and environmental vulnerability. As global plastic production continues to climb, the environmental sinks for microplastics expand correspondingly, amplifying their ecological footprint. This dynamic underscores the urgency of integrating interdisciplinary approaches that bridge environmental science, engineering, toxicology, and socioeconomics to craft sustainable solutions.
In aquatic ecosystems, microbial communities form the backbone of nutrient cycling, driving processes such as nitrogen fixation, nitrification, and sulfur reduction. The influence of MNPs on microbial function, therefore, has profound implications for ecosystem stability. Research reveals that microplastics can selectively enrich or suppress particular microbial taxa, leading to altered community composition and diminished functional capacity. These microbial shifts may disrupt redox reactions and enzymatic activities, cascading into broader impacts on water chemistry and biotic interactions.
Intriguingly, micro- and nanoplastics also affect the sorption and desorption dynamics of essential trace elements. These plastics exhibit heterogeneous surface chemistries that attract metal ions and organic compounds, mediating their transport and bioavailability. This selective adsorption can sequester essential nutrients, depriving microorganisms and aquatic plants, or conversely, facilitate the mobilization of toxic metals. Such dualistic behavior complicates predictions of ecological outcomes and necessitates refined analytical methodologies for environmental monitoring.
The distribution patterns of MNPs in water bodies are subject to complex hydrodynamic and physicochemical forces. Their buoyancy, size distribution, and surface properties influence sedimentation rates, aggregation tendencies, and interactions with dissolved organic matter. These factors determine the spatial heterogeneity of microplastics and their associated contaminants, posing logistical challenges for sampling, quantification, and impact assessment. Enhanced modeling efforts are required to predict MNP fate and transport under diverse environmental scenarios, informing targeted mitigation.
From a human health perspective, the ingestion of microplastics via contaminated water may carry implications beyond mechanical blockage or inflammatory responses. The capacity of MNPs to adsorb pathogens and chemical pollutants raises concerns about their role as vectors in transmitting infectious agents and toxic substances. Epidemiological data remain sparse, yet the potential for exposure underscores the necessity of precautionary measures and rigorous water quality standards that account for nanoplastic contaminants.
The entanglement of MNPs with emerging contaminants also implies altered degradation pathways. Photodegradation, biodegradation, and chemical breakdown of pollutants may be hindered or accelerated in the presence of plastics, depending on environmental conditions. Understanding these kinetic modulations is vital for evaluating contaminant persistence and designing remediation strategies that account for complex pollutant-plastic matrices.
Addressing the challenges posed by micro- and nanoplastics to water health demands global coordination and knowledge exchange. Developing countries, often bearing disproportionate plastic pollution burdens, require support in implementing tailored water treatment and monitoring infrastructures. Capacity-building initiatives, coupled with open-access data repositories, can democratize access to cutting-edge science and technology, fostering equitable stewardship of aquatic resources.
The path forward in safeguarding aquatic ecosystems and water quality confronts a novel pollutant paradigm, where micro- and nanoplastics act not only as pollutants but as active participants in environmental transformations. Embracing this complexity through integrative research, innovative technological solutions, and decisive policy actions is imperative. Only through such concerted efforts can the hidden threats of micro- and nanoplastics be unveiled and mitigated, preserving the vitality of water ecosystems upon which all life depends.
Subject of Research: The indirect impacts of micro- and nanoplastics on aquatic biogeochemical cycles, microbial functions, pathogen transmission, and interactions with emerging contaminants affecting water quality and ecosystem health.
Article Title: The threats of micro- and nanoplastics to aquatic ecosystems and water health.
Article References:
Liu, X., Wei, W., Chen, Z. et al. The threats of micro- and nanoplastics to aquatic ecosystems and water health. Nat Water (2025). https://doi.org/10.1038/s44221-025-00464-1
Image Credits: AI Generated
