Exploring the sublethal genotoxic effects of class II organophosphorus insecticide quinalphos on freshwater fish Cyprinus carpio

The genotoxic effects of quinalphos(QP)were evaluated in the erythrocytes of Cyprinus carpio using the comet,micronucleus,and nuclear abnormality assays.The 96 h LC_(50) value of quinalphos,estimated by static renewal system,was 10.9µL/L.On the basis of the LC_(50) value,two sublethal concentrations(1.09 and 2.18µL/L)of the compound were used together with cyclophosphamide(5 mg/L)as the positive control.The fish were exposed for 35 d,and sampling was done at the end of 7,14,21,28,and 35 d.Our results reveal a significant dose-dependent increase in the frequencies of DNA strand breaks,micronucleus,and nuclear abnormalities.Similar responses were also observed in fish exposed to the positive genotoxin cyclophosphamide.The collective findings demonstrated that quinalphos exerts a genotoxic effect on C.carpio.The results further confirmed that the comet,micronucleus,and nuclear abnormality assays are useful tools in determining the potential genotoxicity of pesticides towards aquatic organisms.

Toxicity assessment of polyethylene microplastics in combination with a mix of emerging pollutants on Physalaemus cuvieri tadpoles

Studies in recent years have shown that aquatic pollution by microplastics(MPs)can be considered to pose additional stress to amphibian populations.However,our knowledge of how MPs affect amphibians is very rudimentary,and even more limited is our understanding of their effects in combination with other emerging pollutants.Thus,we aimed to evaluate the possible toxicity of polyethylene MPs(PE-MPs)(alone or in combination with a mix of pollutants)on the health of Physalaemus cuvieri tadpoles.After 30 days of exposure,multiple biomarkers were measured,including morphological,biometric,and developmental indices,behavioral parameters,mutagenicity,cytotoxicity,antioxidant and cholinesterase responses,as well as the uptake and accumulation of PE-MPs in animals.Based on the results,there was no significant change in any of the parameters measured in tadpoles exposed to treatments,but induced stress was observed in tadpoles exposed to PE-MPs combined with themixture of pollutants,reflecting significant changes in physiological and biochemical responses.Through principal component analysis(PCA)and integrated biomarker response(IBR)assessment,effects induced by pollutants in each test group were distinguished,confirming that the exposure of P.cuvieri tadpoles to the PE-MPs in combination with a mix of emerging pollutants induces an enhanced stress response,although the uptake and accumulation of PE-MPs in these animalswas reduced.Thus,our study provides newinsight into the danger to amphibians of MPs coexisting with other pollutants in aquatic environments.