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Risks of microplastics from polyurethane and polyethylene-polycarbonate coated fertilizers to soil-crop system

Journal of Hazardous Materials 2025 Score: 48 ? 0–100 AI score estimating relevance to the microplastics field. Papers below 30 are filtered from public browse.
Junsuo Li, Dongru Wang, Tao Chen, Wenhui Zhou, Xinhua Zhan

Summary

Microplastics derived from polyurethane and polyethylene-polycarbonate coated fertilizers significantly reduced tomato seed germination rates (by 12–22%) and inhibited early seedling growth, while also altering soil enzyme activity in ways that could affect long-term soil health.

Body Systems

The widespread use of polymer-coated fertilizers raises concerns about microplastics (MPs) pollution, yet their impacts on soil-crop systems remain unclear. This study evaluated the effects of MPs derived from polyurethane (PU) and polyethylene-polycarbonate (PE-PC) coated fertilizers on tomato growth and soil enzyme activity. Results showed that PU and PE-PC MPs significantly reduced 7-day germination rates by 12.5-17.5 % and 12.5-21.7 %, respectively, and inhibited early seedling growth. Interestingly, during the 45-day stage, neither PU nor PE-PC MPs exhibited apparent phytotoxicity, and in some cases even enhanced the total fresh weight of tomato plant. Chlorophyll analysis revealed that 1 % PU MPs slightly promoted chlorophyll content, whereas high PE-PC concentrations reduce it. Soil enzyme analysis revealed increases in β-glucosidase and acid phosphatase activity but no significant change in urease activity. Furthermore, distance-based redundancy analysis (db-RDA) indicated that MPs type and concentration jointly influenced plant physiological traits and soil enzyme activities. These findings suggest that coated fertilizer-produced MPs pose potential risks at germination stages, but their adverse effects appear negligible during the vegetative growth stage. These results can provide a support for scientific application and security risk assessment of coated fertilizers.

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