Mepanipyrim induces visual developmental toxicity and vision-guided behavioral alteration in zebrafish larvae

Prediction of Potential Risk for Flupyradifurone and Its Transformation Products to Hydrobionts

Flupyradifurone (FPF) is considered the latest generation of neonicotinoid insecticides. Here, we investigated the toxicity and ecological risk of FPF and its aerobic transformation products (TPs) to aquatic species using the method of prediction. We found that FPF exhibited moderate or high toxicity to some aquatic species. The 5% hazardous concentration of FPF was 3.84 μg/L for aquatic organisms. We obtained 91 aerobic TPs for FPF, and almost half of FPF TPs exhibited toxicity to fish or Daphnia. Eleven of the TPs of FPF exhibited a high or moderate risk to aquatic ecosystems. All FPF TPs with high and moderate risks contained a 6-chloropyridine ring structure, indicating that the derivant of a pyridine ring exhibits potential risks to aquatic ecosystems. Our results provide insight into the potential risk of FPF to aquatic ecosystems and could be used to help set criteria to control pollution caused by FPF.

Fish to learn: insights into the effects of environmental chemicals on eye development and visual function in zebrafish

Vision is the most essential sense system for the human being. Congenital visual impairment affects millions of people globally. It is increasingly realized that visual system development is an impressionable target of environmental chemicals. However, due to inaccessibility and ethical issues, the use of humans and other placental mammals is constrained, which limits our better understanding of environmental factors on ocular development and visual function in the embryonic stage. Therefore, as complementing laboratory rodents, zebrafish has been the most frequently employed to understand the effects of environmental chemicals on eye development and visual function. One of the major reasons for the increasing use of zebrafish is their polychromatic vision. Zebrafish retinas are morphologically and functionally analogous to those of mammalian, as well as evolutionary conservation among vertebrate eye. This review provides an update on harmful effects from exposure to environmental chemicals, involving metallic elements (ions), metal-derived nanoparticles, microplastics, nanoplastics, persistent organic pollutants, pesticides, and pharmaceutical pollutants on the eye development and visual function in zebrafish embryos. The collected data provide a comprehensive understanding of environmental factors on ocular development and visual function. This report highlights that zebrafish is promising as a model to identify hazardous toxicants toward eye development and is hopeful for developing preventative or postnatal therapies for human congenital visual impairment.

Toxicity and ecological risk assessment for two AhR agonistic pesticides mepanipyrim and cyprodinil and their metabolites

Mepanipyrim and cyprodinil are widely used to control and/or prevent fungal diseases in fruit culture. They are frequently detected in the aquatic environment and some food commodities. Different from TCDD, mepanipyrim and cyprodinil are more easily metabolised in the environments. However, the risk of their metabolites to the ecological environment is unclear and needs to be further confirmed. In this study, we investigated the temporal pattern of mepanipyrim- and cyprodinil-induced CYP1A and AhR2 expression and EROD enzyme activity at different time frames during zebrafish embryonic and larval development. Then, we assessed the ecological risk of mepanipyrim, cyprodinil, and their metabolites to aquatic organisms. Our results showed that mepanipyrim and cyprodinil exposure could increase the expression level of cyp1a and ahr2 genes and EROD activity by a dynamic pattern in different developmental stages of zebrafish. Besides, their several metabolites showed strong AhR agonistic activity. Importantly, these metabolites could cause potential ecological risks to aquatic organisms and should be paid more attention to. Our results would provide an important reference value for environmental pollution control and the use management of mepanipyrim and cyprodinil.

Computer-aided toxicity prediction and potential risk assessment of two novel neonicotinoids, paichongding and cycloxaprid, to hydrobionts

Paichongding (IPP) and cycloxaprid (CYC) have been effectively used as the alternative products of imidacloprid (IMI) against IMI-resistant insects and exhibit a great market potential. However, risk assessment of IPP and CYC for non-target organisms, especially ecological risk assessment for non-target aquatic organisms, is still lacking. Here, we predicted the toxicity and potential risks of IPP, CYC, and their transformation products (TPs) to hydrobionts. The results indicated that IPP and CYC could generate 428 and 113 TPs, respectively, via aerobic microbial transformation. Nearly half of the IPP TPs and nearly 41 % of the CYC TPs exhibited high or moderate toxicity to Daphnia or fish. Moreover, we found that IPP, CYC, and 80 TPs of them posed potential risks to aquatic ecosystems. Almost all harmful TPs contained a 6-chloropyridine ring structure, suggesting that this structure may be associated with the strong toxicity of these TPs to aquatic organisms, and these TPs (IPP-TP2 or CYC-TP2, IPP-TP197 or CYC-TP71, IPP-TP198 or CYC-TP72, and IPP-TP212 or CYC-TP80) may appear in aquatic environments as final products. The risks posed by these TPs to aquatic ecosystems require more attention. This study provides insights into the toxicity and ecological risks of IPP and CYC.

Predicting and assessing the toxicity and ecological risk of seven widely used neonicotinoid insecticides and their aerobic transformation products to aquatic organisms

Neonicotinoid insecticides (NIs) are widely used worldwide, accounting for 25 % of the global insecticide market, and are easily transported into surrounding aquatic ecological environments after application. At present, >80 % of surface water is contaminated by NIs globally. Some transformation products (TPs) of NIs can exhibit greater toxicity to aquatic organism than their parent products. However, few studies have evaluated the toxicity and ecological risk of the TPs of NIs. In this study, we aimed to assess the toxicity and ecological risk of seven widely used NIs and their aerobic TPs to aquatic organisms using a prediction method. We found that partial aerobic TPs of NIs have greater toxicity to aquatic organisms than their parent products, and some of them could severely damage aquatic ecosystems. Meanwhile, acetamiprid, thiacloprid, and several other TPs of NIs with a chlorinated ring structure showed strong bioconcentration abilities, which could potentially harm aquatic organisms through the food chain. Moreover, the widespread use of NIs has certain aquatic ecological risks, which should be controlled and limited. This study comprehensively evaluated the ecological risk of seven widely used NIs and their aerobic TPs to aquatic organisms for the first time. Our results could provide an important reference for assessment of the aquatic environmental risk posed by NIs and pollution control.