0
Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Sign in to save

Synergistic Toxicity of PVC Microplastic and Methyl Thiophanate in Common Carp

Journal of Applied Toxicology 2026
Javad Kharkan, Mohammad Hossein Sayadi

Summary

Scientists found that when fish were exposed to both plastic particles (from PVC, a common plastic) and a fungicide used on crops, the combination caused significantly more blood damage, organ stress, and tissue injury than either pollutant alone. This matters because our rivers and lakes often contain mixtures of plastic waste and agricultural chemicals together, not just one at a time, and this study suggests these combos could be more harmful to fish (and potentially other animals, including humans who eat fish or drink from these water sources) than we'd expect from studying each pollutant separately.

Polymers
Body Systems

ABSTRACT Little is known about how microplastics (MPs) interact with other environmental pollutants. In light of this, the present work investigated the individual and combined toxicity of polyvinyl chloride (PVC) MPs and the fungicide methyl thiophanate (MT) in common carp. A total of 90 fish were randomly assigned to nine experimental groups. Following a 28‐day exposure period, hematological indices, antioxidant responses, serum biochemical parameters, and tissue alterations were evaluated to determine the biological effects of PVC and MT, both separately and in combination. The data were analyzed using the ANOVA test at a significance level of p < 0.05. Red blood cell counts (RBCs, millions/mm 3 ) declined noticeably in all treated groups compared with the control fish. Values recorded for Groups F, G, H, and I were 1.83 ± 0.14, 1.77 ± 0.21, 1.41 ± 0.17, and 1.37 ± 0.12, respectively, whereas the control group showed a value of 2.37 ± 0.21. Groups B, C, D, and E also had a decrease compared to the control group, but it was not significant. A similar pattern appeared for superoxide dismutase activity (SOD, ꓴ/mL), an important antioxidant defense enzyme. Enzyme activity in Groups F–I ranged from 101.14 ± 9.10 to 113.13 ± 13.56, considerably lower than the control level of 129.61 ± 19.44. Biochemical disturbances were also evident. Serum triglyceride concentrations remained altered in exposed fish, with measured values of 73.48 ± 10.28, 69.58 ± 11.52, 61.82 ± 8.03, and 54.37 ± 8.15 mg/dL for Groups F–I, compared with 83.01 ± 9.13 mg/dL in the control group. In addition, alkaline phosphatase (ALP) activity increased significantly ( p < 0.05) across all experimental groups relative to untreated fish, suggesting physiological stress and possible tissue dysfunction. Histopathological observations added another layer to these findings. Fish exposed simultaneously to PVC MPs and MT exhibited more severe damage in the gill and intestinal tissues than fish subjected to either contaminant alone, and the extent of injury became more pronounced as exposure concentrations increased. In other words, the combined presence of MPs and chemical pollutants may produce stronger toxic effects than would be expected from single‐compound exposure. The data also reinforce the need for more careful environmental monitoring, especially in waters receiving mixtures of plastic debris and agrochemical contaminants.

Share this paper