Microplastics may act as pollutant shuttles, carrying chemicals, pathogens and antibiotic resistance genes
New review reveals how microplastics transport multiple pollutants across ecosystems and proposes a framework for identifying when these vector effects become serious ecological threats
Shenyang Agricultural University Collaborative Journals
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Microplastics as pollutant shuttles: unraveling the drivers of chemical and biological vector effects
view moreCredit: Zhengyingzi He, Xinping Zhu, Rui Pei, Jingliang Shi, & Qinghua Zhang
Microplastics are often viewed as pollutants in their own right, but their environmental impact may extend far beyond the plastic particles themselves. A new review shows that microplastics can act as mobile "pollutant shuttles," carrying toxic chemicals, microorganisms and antibiotic resistance genes through water, soil, food webs and even across environmental boundaries.
Published in Energy & Environment Nexus, the review by researchers from Jiangxi Agricultural University provides a comprehensive analysis of the dual role of microplastics as vectors for both chemical and biological contaminants. The authors also introduce a three-tiered framework for understanding the physical, chemical and biological factors that determine when these transport effects may become major ecological risks.
"Microplastics should not be considered isolated particles in the environment," said corresponding author Jingliang Shi. "They can interact with chemicals and microorganisms, transport them between environmental compartments and, under certain conditions, amplify their ecological effects. Understanding when these processes become dominant is essential for realistic risk assessment."
One major concern is the "Trojan horse effect." Microplastics can adsorb persistent organic pollutants, heavy metals and other contaminants on their surfaces. After being ingested by organisms, these pollutants may be released in the digestive system, increasing their bioavailability. The review highlights an important size dependence: conventional microplastics generally deliver contaminants through the gastrointestinal tract, while nanoplastics smaller than about 1 micrometer may cross biological membranes and distribute associated pollutants to internal organs.
The biological dimension may be equally important. Microplastic surfaces can develop microbial communities known as the plastisphere, which can provide protected habitats for pathogens and antibiotic resistance genes. Within these biofilms, close contact between microorganisms may promote horizontal gene transfer, potentially accelerating the spread of antimicrobial resistance.
The review further shows that chemical and biological effects may reinforce each other. Pollutants attached to microplastics can create selective pressure on microbial communities, while biofilms can alter plastic surface properties and increase subsequent pollutant adsorption. This bidirectional positive feedback may intensify both contaminant accumulation and the transfer of antibiotic resistance genes.
To move beyond simple descriptions of microplastic pollution, the authors propose a three-tiered regulatory framework involving physical, chemical and biological drivers. Particle size, shape and aging influence transport and surface reactivity. Polymer chemistry and environmental conditions control adsorption and desorption. Biological processes, including biofilm formation, ingestion and food-web transfer, determine how contaminants ultimately reach organisms.
The researchers also identify conditions under which combined chemical and biological vector effects may become particularly important. These include strong microbial selective pressure at relatively low contaminant concentrations, high extracellular polymeric substance content in biofilms, highly aged microplastics with oxygen-rich surface groups, and prolonged exposure exceeding 30 days.
The authors emphasize that future research should shift toward quantitative, environmentally realistic studies that can define ecological risk thresholds. Current toxicity experiments often rely on short-term, high-concentration exposures that poorly represent chronic environmental conditions. The review calls for long-term observations, improved exposure models, targeted removal of high-risk aged microplastics and more unified approaches to global microplastic governance.
Ultimately, the study reframes microplastics not simply as contaminants, but as dynamic platforms capable of connecting chemical pollution, microbial ecology and antimicrobial resistance across ecosystems.
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Journal reference: He Z, Zhu X, Pei R, Shi J, Zhang Q. 2026. Microplastics as pollutant shuttles: unraveling the drivers of chemical and biological vector effects. Energy & Environment Nexus 2: e023 doi: 10.48130/een-0026-0017
https://www.maxapress.com/article/doi/10.48130/een-0026-0017
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About Energy & Environment Nexus:
Energy & Environment Nexus (e-ISSN 3070-0582) is an open-access journal publishing high-quality research on the interplay between energy systems and environmental sustainability, including renewable energy, carbon mitigation, and green technologies.
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Journal
Energy & Environment Nexus
Method of Research
Literature review
Article Title
Microplastics as pollutant shuttles: unraveling the drivers of chemical and biological vector effects
What happens when a shoreline scavenger consumes microplastics?
Multi-omics analysis reveals what happens in the gut of wharf roaches when they eat polystyrene
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Wharf roaches act as “cleanup crews” of the seashore. In recent years, microplastics, such as EPS, have been washing up on beaches and subsequently consumed by these creatures. A team from Kyushu University used multi-omics analysis to investigate what occurs in the digestive tracts of wharf roaches that have ingested EPS. The results revealed that roaches that ingested EPS had elevated activation of genes related to the metabolism of foreign substances. Additionally, while there were no changes in gut microbiota, they found methane-producing archaea and viruses only in EPS-consuming roaches.
view moreCredit: Yuji Oshima/Kyushu University
Fukuoka, Japan—In a paper published in the journal Marine Pollution Bulletin, researchers at Kyushu University report on what happens when wharf roaches, a common shoreline scavenger, eat expanded polystyrene (EPS). Roaches that fed on EPS showed no significant reduction in lifespan, but their guts displayed altered expression of genes involved in chemical defense, DNA repair, and digestion. Analysis of the wharf roach gut microbiome showed little change, but several rare microbes were found only in the EPS-fed specimens.
In coastal areas, EPS—commonly referred to as Styrofoam—are one of the major components of marine plastic pollution. They are prevalent because their low density and high buoyancy allow them to drift over long distances and accumulate on beaches.
Wharf roaches (Ligia spp.) are common coastal isopods that act as scavengers, consuming organic matter and contributing to nutrient cycling in shoreline ecosystems. They have also been found to consume the plastic pollution that washes up on the shore. This makes wharf roaches useful models for investigating the biological effects of EPS ingestion and a potential sentinel species for coastal plastic pollution.
A research team led by Professor Emeritus Yuji Oshima at Kyushu University's Faculty of Agriculture conducted a laboratory exposure experiment to investigate the effect of EPS ingestion in wharf roaches. The researchers compared EPS fed wharf roaches with a starved control group and used multi-omics approaches to analyze gene expression in the gut and the composition of the gut microbiome.
“Our earlier fieldwork showed that wharf roaches chew EPS and excrete it as much smaller fragments, suggesting that these animals can help turn large pieces of foam into microplastics. However, the biological effects of ingesting EPS in the animals themselves remain unknown,” says Oshima. “We wanted to find out whether swallowing foam comes at a biological cost for these shoreline scavengers”
The researchers first examined whether EPS ingestion affected the lifespan of wharf roaches. Field-collected wharf roaches were divided into two groups: one group was given only pieces of a commercially available polystyrene foam board for one week, while the control group was given no food. EPS exposure did not significantly affect survival. Foam-fed wharf roaches lived for an average of 27.8 days, compared to 31.6 days for the unfed controls. However, this 3.8-day difference was not statistically significant, suggesting that EPS ingestion did not measurably reduce lifespan under the experimental conditions.
Gene expression in the digestive tract of EPS-fed wharf roaches showed higher expression of several genes involved in chemical defense. These include three key detoxification enzymes: cytochrome P450, UDP-glucuronosyltransferase, and sulfotransferase. This together represents both major phases of the conventional detoxification pathway: the initial chemical modification of foreign compounds and their subsequent conversion into forms that can be more readily excreted. A gene involved in DNA repair also showed higher expression, whereas several genes encoding digestive enzymes, including one involved in breaking down plant fibers, were expressed at lower levels.
Next, the researchers examined whether EPS ingestion changed the gut microbiome of the wharf roaches. Surprisingly, microbial diversity within individual animals and overall community composition did not differ across the four microbial domains examined. However, several rare organisms showed group-specific patterns. Three archaeal taxa—including Methanospirillum, a genus of methane-producing archaea—and one family of bacteriophages were detected in all three EPS-fed specimens but not in the controls.
“The foam-fed animals appeared healthy and had lifespans similar to those of the controls; however, their guts showed differences in the expression of genes involved in chemical defense. This tells us “no visible harm” does not necessarily mean “no biological effect.” Further work is needed to determine whether these gene expression differences lead to functional changes in the animals,” explains Oshima.
EPS is inexpensive, lightweight, and widely used in the fishing and packaging industries, and it can fragment quickly once exposed to the environment. The team’s findings provide another reason to manage EPS waste more carefully: shoreline animals do not simply live alongside stranded foam—they ingest it, fragment it into microplastics, and now we know it changes their gut microbiome. This highlights the importance of improving the design, recovery, and disposal of EPS products, as well as prioritizing coastal cleanup efforts.
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For more information about this research, see "Changes in dysbiosis and gene expression in the gut of wharf roach (Ligia spp.) fed with expanded polystyrene,”
Seokhyun Lee, Hirokuni Miyamoto, Yuki Takai, Wataru Suda, Hiroshi Ohno, Yohei Shimasaki, Yuji Oshima. Marine Pollution Bulletin, https://doi.org/10.1016/j.marpolbul.2026.120200
Wharf roach consuming EPS [VIDEO]
About Kyushu University
Founded in 1911, Kyushu University is one of Japan's leading research-oriented institutes of higher education, consistently ranking as one of the top ten Japanese universities in the Times Higher Education World University Rankings and the QS World Rankings. The university is one of the seven national universities in Japan, located in Fukuoka, on the island of Kyushu—the most southwestern of Japan’s four main islands with a population and land size slightly larger than Belgium. Kyushu U’s multiple campuses—home to around 19,000 students and 8,000 faculty and staff—are located around Fukuoka City, a coastal metropolis that is frequently ranked among the world's most livable cities and historically known as Japan's gateway to Asia. Through its VISION 2030, Kyushu U will “drive social change with integrative knowledge.” By fusing the spectrum of knowledge, from the humanities and arts to engineering and medical sciences, Kyushu U will strengthen its research in the key areas of decarbonization, medicine and health, and environment and food, to tackle society’s most pressing issues.
Journal
Marine Pollution Bulletin
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Changes in dysbiosis and gene expression in the gut of wharf roach (Ligia spp.) fed with expanded polystyrene
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