A research team has revealed that microplastics can substantially alter how cadmium affects crops, generally reducing cadmium uptake and some forms of plant damage compared with exposure to the metal alone. Drawing on 4,243 pairwise observations across multiple plant species, the researchers found that cadmium severely suppressed growth, photosynthesis, and protein content while increasing oxidative damage and tissue contamination. Although co-exposure to microplastics moderated many of these effects, the outcome varied with plastic properties and environmental conditions, highlighting the complexity of assessing agricultural soils contaminated by multiple pollutants.
Cadmium is a persistent and highly toxic heavy metal that can accumulate in agricultural soils through mining, metal processing, wastewater irrigation, and natural geological processes. Plants readily absorb it even at relatively low concentrations, allowing the contaminant to enter the food chain while disrupting crop growth and physiology. Microplastics are also widespread in farmland, where they originate from plastic mulches, fertilizers, irrigation, sewage sludge, and fragmented agricultural products. Their large surface area and reactive chemical groups allow them to bind metals and alter their movement through soil. Individual experiments, however, have produced conflicting results: some suggest that microplastics restrict cadmium uptake, whereas others show that certain polymers or doses increase its mobility and toxicity.
A study (DOI: 10.48130/newcontam-0026-0013 ) published in New Contaminants on 09 May 2026 by Wei Wu's team, Hainan University, provides critical evidence for improving risk assessment and management of microplastic–cadmium co-contamination to protect crop productivity, food safety, and agricultural sustainability.
The researchers synthesized evidence covering plant morphology, photosynthesis, biochemical responses, nutrient balance, cadmium accumulation, and soil microbial diversity. Across the compiled studies, cadmium exposure reduced plant biomass by 29%, photosynthetic performance by 28%, and protein content by 49%. It also increased oxidative damage by 191% and raised cadmium concentrations in plant tissues by as much as 12-fold. Rice, maize, wheat, and Brassica crops were among the species showing pronounced reductions in root development, shoot growth, and photosynthetic traits. When plants were exposed to cadmium and microplastics together, the average damage was less severe than under cadmium alone. Biomass declined by 21% and photosynthetic activity by 24%, while oxidative damage rose by 92% and cadmium accumulation increased 3.8-fold. More specifically, cadmium alone produced a 19-fold increase in root cadmium and a 5.6-fold increase in shoots; with microplastics present, these increases were limited to 4.5-fold and 1.6-fold, respectively. The apparent antagonistic interaction may arise because plastic surfaces adsorb cadmium, lowering its availability to roots. Microplastics attached to root surfaces may also form physical barriers, promote lignin or suberin deposition, and restrict the movement of cadmium from roots to shoots. The analysis additionally indicated that microplastics partly moderated cadmium-related changes in antioxidant defenses and microbial diversity. However, this response was not universal. Particle size, polymer composition, dose, exposure duration, plant species, growth medium, and soil pH all influenced the outcome. Smaller particles produced stronger average modulation than larger particles but could also enter root tissues or disrupt nutrient balance. Polyethylene sometimes intensified toxicity, while other polymers produced different patterns of cadmium retention and transport. Alkaline soil generally reduced cadmium availability through metal–plastic complex formation and precipitation.
The findings show that conventional assessments of cadmium-contaminated farmland may be incomplete if they overlook microplastics. Incorporating plastic size, polymer type, contamination level, and soil chemistry into environmental models could improve predictions of crop exposure and food-safety risks. The results may also support targeted soil monitoring, remediation planning, and management strategies for co-contaminated agricultural land. Microplastics should not, however, be interpreted as beneficial soil amendments. They remain persistent pollutants and can independently inhibit plant growth, disturb nutrient homeostasis, and affect soil organisms.
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References
DOI
Original Source URL
https://doi.org/10.48130/newcontam-0026-0013
Funding information
This study was financially supported by Postdoctoral Research Projects in Hainan Province (Grant No. RZ2500009203).
About New Contaminants
New Contaminants (e-ISSN 3069-7603) 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.
New Contaminants
Not applicable
Microplastic-mediated modulation of Cd toxicity: evidence from a global meta-analysis
9-May-2026
The authors declare that they have no competing interests.