Sunlight turns microplastics into a new form of dissolved pollution in water
Maximum Academic Press
This microplastic-derived dissolved organic matter (MPs-DOM) differs fundamentally from natural organic matter in water and may alter microbial activity, pollutant behavior, and carbon cycling across aquatic ecosystems.
Microplastics are now ubiquitous in surface waters worldwide, often reaching concentrations of thousands of particles per liter. Over time, prolonged contact with water and exposure to sunlight causes plastics to leach dissolved organic compounds, collectively known as MPs-DOM. In heavily polluted surface waters, this material can contribute up to 10% of dissolved organic carbon (DOC) in the surface microlayer. Unlike natural organic matter (NOM), which originates from plants and soils, MPs-DOM is anthropogenic and enriched in low-molecular-weight, highly reactive compounds. Despite its growing presence, most studies have focused only on the initial or final states of MPs-DOM, leaving the dynamic processes governing its formation and transformation largely unexplored.
A study (DOI:10.48130/newcontam-0025-0016) published in New Contaminants on 05 December 2025 by Jiunian Guan’s team, Northeast Normal University, implies that microplastics influence ecosystems not only as particles, but also as dissolved chemical agents.
Using controlled leaching experiments, the study systematically compared dissolved organic matter released from four representative microplastics—polyethylene (PE), polyethylene terephthalate (PET), polylactic acid (PLA), and polybutylene adipate-co-terephthalate (PBAT)—with that derived from NOM under dark and UV-irradiated conditions. DOC release was quantified over time and interpreted using zero-order and pseudo-second-order kinetic models, together with intraparticle diffusion and Boyt analyses to identify rate-limiting steps. Chemical evolution during derivation was further characterized by FT-IR spectroscopy for functional groups, excitation–emission matrix fluorescence combined with PARAFAC for component dynamics and indices (FI, BIX, HIX), and ultrahigh-resolution FT-ICR-MS for molecular formulas, elemental classes, and van Krevelen-type compositional shifts. Under dark conditions, DOC increased steadily for both sources, but N-DOM released significantly more DOC than MPs-DOM, while biodegradable plastics released more DOC than conventional plastics. Kinetic and diffusion analyses indicated faster DOC derivation for N-DOM, with intraparticle diffusion limiting MPs-DOM release and film diffusion controlling N-DOM. Under UV irradiation, DOC derivation accelerated markedly, especially for biodegradable MPs, and zero-order kinetics remained valid, indicating a constant release rate governed by polymer properties and irradiation rather than concentration. Diffusion control shifted to film diffusion for both MPs-DOM and N-DOM, and DOCUV/DOCdark increased over time, with UV sensitivity ranked PBAT > PLA > PET > PE ≫ NOM, confirming UV light as the dominant driver of MPs-DOM formation. Spectroscopic analyses revealed that UV exposure promoted the release of polymer monomers, oligomers, and additives such as phthalates, alongside the formation of oxygen-containing functional groups via hydrolysis and photochemical reactions. Fluorescence analyses showed that MPs-DOM evolved from additive-dominated signatures toward more protein-like and low-molecular-weight humic-like components, whereas N-DOM remained terrestrially humic and comparatively stable. FT-ICR-MS further demonstrated polymer-specific molecular trajectories: PET-derived DOM became increasingly oxidized and aromatic, PLA-derived DOM shifted toward carbohydrate- and tannin-like compounds, and overall MPs-DOM followed distinct UV-driven pathways largely absent in natural DOM, highlighting its unique and dynamic role in sunlit aquatic carbon cycling.
The findings suggest that MPs-DOM is not merely an additional carbon source, but a chemically active agent capable of reshaping aquatic biogeochemistry. Its low molecular weight and oxidized nature make it highly bioavailable, potentially stimulating or inhibiting microbial growth and altering food-web dynamics. MPs-DOM can bind metals, influence mineral transformations, interfere with pollutant adsorption, and act as a precursor for disinfection byproducts in water treatment. Under sunlight, it can also generate reactive oxygen species, affecting contaminant degradation and nanoparticle formation.
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References
DOI
Original Source URL
https://doi.org/10.48130/newcontam-0025-0016
Funding information
This work was financially supported by the National Natural Science Foundation of China (42471089, 4231101419), the Research Foundation of the Science and Technology Agency (20250102178JC), and the Education Department of Jilin Province (JJKH20250337KJ).
About New Contaminants
New Contaminants is a multidisciplinary platform for communicating advances in fundamental and applied research on emerging contaminants. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of new contaminants research around the world to deliver findings from this rapidly expanding field of science.
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Molecular-level insights into derivation dynamics of microplastic-derived dissolved organic matter
Article Publication Date
15-Dec-2025
Fathers’ microplastic exposure tied to their children’s metabolic problems
UC Riverside-led mouse study finds microplastics affect male and female offspring differently
University of California - Riverside
image:
Changcheng Zhou is a professor of biomedical sciences at UC Riverside.
view moreCredit: UC Riverside School of Medicine.
RIVERSIDE, Calif. -- A study led by biomedical scientists at the University of California, Riverside, has shown for the first time that a father’s exposure to microplastics (MPs) can trigger metabolic dysfunctions in his offspring. The research, conducted using mouse models, highlights a previously unknown pathway through which environmental pollutants impact the health of future generations.
While MPs have already been detected in human reproductive systems, the study, published in the Journal of the Endocrine Society, is the first to bridge the gap between paternal exposure to MPs and the long-term health of the next generation (the “F1 offspring”).
MPs are tiny plastic particles (less than 5 millimeters) resulting from the breakdown of consumer products and industrial waste. Metabolic disorders refer to a cluster of conditions — including increased blood pressure, high blood sugar, and excess body fat — that increase the risk of heart disease and diabetes.
To induce metabolic disorders in F1 offspring, the researchers fed them a high-fat diet. This approach helps reveal the effects of paternal exposure that might otherwise remain mild or hidden under normal diet conditions. The high-fat diet mimics common unhealthy eating patterns, such as the Western diet, and amplifies metabolic risks. Because the fathers themselves were fed a regular diet, the obesity seen in F1 offspring is diet-induced.
The research team found that female offspring of male mice exposed to MPs were significantly more susceptible to metabolic disorders than offspring of unexposed fathers, despite all offspring being fed the same high-fat diet.
“The exact reasons for this sex-specific effect are still unclear,” said Changcheng Zhou, a professor of biomedical sciences in the UCR School of Medicine and the lead author of the study. “In our study, female offspring developed diabetic phenotypes. We observed upregulation of pro-inflammatory and pro-diabetic genes in their livers — genes previously linked to diabetes. These changes were not seen in male offspring.”
The research team found that while male offspring did not develop diabetes, they showed a slight yet significant decrease in fat mass. Female offspring showed decreased muscle mass alongside increased diabetes.
To understand how the trait was passed down, the researchers used a specialized sequencing technology called PANDORA-seq, developed at UCR. They found that MP exposure alters the “cargo” of the sperm, affecting small molecules that regulate how genes are turned on and off.
Specifically, the MP exposure significantly altered the sperm’s small RNA profile, including tRNA-derived small RNAs (tsRNAs) and rRNA-derived small RNAs (rsRNAs) — types of small non-coding RNAs. Unlike DNA, which provides the “blueprint” for life, these RNA molecules may act like “dimmer switches” for genes, controlling how much or how little a gene is expressed during development.
“To our knowledge, ours is the first study to show that paternal exposure to microplastics can affect sperm small non-coding RNA profiles and induce metabolic disorders in offspring,” Zhou said.
Zhou emphasized that the study suggests the impact of plastic pollution is not limited to the individual exposed; it may leave a biological imprint that predisposes children to chronic diseases.
“Our discovery opens a new frontier in environmental health, shifting the focus toward how both parents’ environments contribute to the health of their children,” he said. “These findings from a mouse study likely have implications for humans. Men planning to have children should consider reducing their exposure to harmful substances like microplastics to protect both their health and that of their future children.”
The research team hopes the findings will guide future investigation into how MPs and even smaller nanoplastics affect human development.
“Our future studies will likely look at whether maternal exposure produces similar risks and how these metabolic changes might be mitigated,” Zhou said.
Zhou was joined in the study by Seung Hyun Park, Jianfei Pan, Ting-An Lin, Sijie Tang, and Sihem Cheloufi at UCR; Xudong Zhang and Qi Chen at the University of Utah School of Medicine; and Tong Zhou at the University of Nevada, Reno School of Medicine.
The study was partially supported by grants from the National Institutes of Health.
The title of the paper is “Paternal microplastic exposure alters sperm small non-coding RNAs and affects offspring metabolic health in mice.”
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.
Journal
Journal of the Endocrine Society
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Paternal microplastic exposure alters sperm small non-coding RNAs and affects offspring metabolic health in mice
Article Publication Date
18-Dec-202
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