Genotoxic and mutagenic effects of chlorothalonil on the estuarine fish Micropogonias furnieri (Desmarest, 1823)

Genetic damage in elasmobranchs: A review

DNA integrity is crucial for organismal health, and assessing DNA damage in aquatic organisms is essential for identifying environmental threats and informing conservation efforts. Pollutants such as metals, hydrocarbons, agrochemicals, pharmaceuticals, and climate change are linked to genetic damage, oxidative stress, and mutagenesis in several species, such as elasmobranchs (sharks and rays). Most studies focus on bivalves, crustaceans, and bony fish, with fewer assessments being carried out in cartilaginous fish. Concerning elasmobranchs, studies employing the micronucleus test and nuclear anomaly assays have aided in understanding how this group responds to contamination by organic and inorganic pollutants. Notably, each species deals differently with these contaminants, presenting varied DNA damage levels, including low levels of response, probably associated to feeding habits, trophic position, maturation stage, sex and metabolism. Further investigations should be conducted in elasmobranchs to elucidate these variations and better understand DNA damage in this important ecological group.

The toxicity and health risk of chlorothalonil to non-target animals and humans: A systematic review

Chlorothalonil (CTL), an organochloride fungicide applied for decades worldwide, has been found to be present in various matrixes and even accumulates in humans or other mammals through the food chain. Its high residue and diffusion in the environment have severely affected food security and public health. More and more research has considered CTL as a possible toxin to environmental non-target organisms, via influencing multiple systems such as metabolic, developmental, endocrine, genetic, and reproductive pathways. Aquatic organisms and amphibians are the most vulnerable species to CTL exposure, especially during the early period of development. Under experimental conditions, CTL can also have toxic effects on rodents and other non-target organisms. As for humans, CTL exposure is most often reported to be relevant to allergic reactions to the skin and eyes. We hope that this review will improve our understanding of the hazards and risks that CTL poses to non-target organisms and find a strategy for rational use.

Triazoles and Strobilurin Mixture Affects Soil Microbial Community and Incidences of Wheat Diseases

Pesticides are widely used in agriculture as a pest control strategy. Despite the benefits of pesticides on crop yields, the persistence of chemical residues in soil has an unintended impact on non-targeted microorganisms. In the present study, we evaluated the potential adverse effects of a mixture of fungicides (difenoconazole, epoxiconazole, and kresoxim-methyl) on soil fungal and bacterial communities, as well as the manifestation of wheat diseases. In the fungicide-treated soil, the Shannon indices of both fungal and bacterial communities decreased, whereas the Chao1 indices did not differ compared to the control soil. Among bacterial taxa, the relative abundances of Arthrobacter and Sphingomonas increased in fungicide-treated soil due to their ability to utilize fungicides and other toxic compounds. Rhizopus and plant-beneficial Chaetomium were the dominant fungal genera, with their prevalence increasing by 2-4 times in the fungicide-treated soil. The genus Fusarium, which includes phytopathogenic species, which are notably responsible for root rot, was the most abundant taxon in each of the two conditions but its relative abundance was two times lower in fungicide-treated soils, consistent with a lower level of disease incidence in plants. The prediction of metabolic pathways revealed that the soil bacterial community had a high potential for degrading various pollutants, and the soil fungal community was in a state of recovery after the application of quinone outside inhibitor (QoI) fungicides. Fungicide-treated soil was characterized by an increase in soil microbial carbon, compared with the control soil. Collectively, the obtained results suggest that the application of difenoconazole, epoxiconazole, and kresoxim-methyl is an effective approach for pest control that does not pose a hazard for the soil ecosystem in the short term. However, it is necessary to carry out additional sampling to take into account the spatio-temporal impact of this fungicide mixture on the functional properties of the soil.

Toxicity assessment of SARS-CoV-2-derived peptides in combination with a mix of pollutants on zebrafish adults: A perspective study of behavioral, biometric, mutagenic, and biochemical toxicity

The dispersion of SARS-CoV-2 in aquatic environments via the discharge of domestic and hospital sewage has been confirmed in different locations. Thus, we aimed to evaluate the possible impacts of zebrafish (Danio rerio) exposure to SARS-CoV-2 peptide fragments (PSPD-2001, 2002, and 2003) alone and combined with a mix of emerging pollutants. Our data did not reveal the induction of behavioral, biometric, or mutagenic changes. But we noticed an organ-dependent biochemical response. While nitric oxide and malondialdehyde production in the brain, gills, and muscle did not differ between groups, superoxide dismutase activity was reduced in the "PSPD", "Mix", and "Mix+PSPD" groups. An increase in catalase activity and a reduction in DPPH radical scavenging activity were observed in the brains of animals exposed to the treatments. However, the "Mix+PSPD" group had a higher IBRv2 value, with NO levels (brain), the reduction of acetylcholinesterase activity (muscles), and the DPPH radical scavenging activity (brain and muscles), the most discriminant factors for this group. The principal component analysis (PCA) and hierarchical clustering analysis indicated a clear separation of the "Mix+PSPD" group from the others. Thus, we conclude that exposure to viral fragments, associated with the mix of pollutants, induced more significant toxicity in zebrafish adults than in others.

Risk Assessment of Chlorothalonil as a Probable Human Carcinogen on Selected Vegetables in an Eastern China Province

Objectives

This study aimed to provide an assessment of chlorothalonil's possible carcinogenic risk posed to the public. In combination and comparison with the non-carcinogenic risk, the results hopefully could provide useful insights, early warning, and references for policy formulation.

Methods

This study firstly investigated the occurrence of chlorothalonil on selected key vegetables for different scenarios, and then conducted an exposure assessment with officially published data. Lastly, both the non-carcinogenic and carcinogenic risk of chlorothalonil were calculated by using Monte-Carlo simulation.

Results

Even though mean non-carcinogenic risks of chlorothalonil for all scenarios were below threshold value, the mean carcinogenic risks for maximum-risk scenario and most-likely risk scenario were mostly above threshold value. High probabilities of exceedance of threshold value existed for carcinogenic risk under all scenarios.

Conclusion

Potential threat to public health existed for conventionally 'safe' pesticide if considering the possible carcinogenicity. Extra caution should be taken and the potential carcinogenic effects should be included into consideration for better protection of public health during the policy formulation process.