Menglan Su,Rongkai Bao,Bo Gao,Xiaobin Liao,Peng Xiao,Wenhua Li
Diafenthiuron is a novel derivative of thiourea and is highly toxic to non-target organisms, necessitating its efficient removal from wastewater before discharge. This study compared diafenthiuron removal efficiencies at a target concentration of 1 µM using three methods: a 4 mg/L ozone (O3) treatment; an ultraviolet (UV) light treatment, applying UV254radiation with a fluence of 60 mJ/cm2for 10 min; and a combined O3/UV treatment utilizing ozone and ultraviolet light. An acute toxicity assessment was conducted using a modeled zebrafish embryo (Danio rerio). The diafenthiuron removal efficiencies were 49.59%, 54.51%, and 68.90% for the UV light, O3, and O3/UV treatments, respectively. The treatments showed additional benefits of exerting no negative impacts on the survival rate, heart rate, or body length of the zebrafish larvae posttreatment. The survival and heart rates at 120 hpf, as well as the body length at 96 and 120 hpf, showed significant differences between the advanced oxidation and 1 μM diafenthiuron treatment groups. However, these parameters remained consistent with those of the control group. The three treatments alleviated the spatiotemporal downregulation of the liver-specific markerfabp10acaused by diafenthiuron exposure. The UV light and O3/UV treatments were efficient at degrading diafenthiuron, causing decreased reactive oxygen species levels and increasedpomcandprlexpression levels. The O3-treated diafenthiuron and 1 μM diafenthiuron treatments increased the reactive oxygen species levels and decreased thepomcandprlexpression levels. The combined O3/UV treatment showed the highest removal efficiency and the least toxicity, making it the most effective method for diafenthiuron degradation. This study provides valuable insights into the treatment of diafenthiuron-laden wastewater.
The diamondback moth (DBM), Plutella xylostella (L.), is a major pest affecting cruciferous vegetables, and seriously affects the quality and yield of these vegetables. Diafenthiuron is a traditional thiourea-based insecticide , but it is rarely used to control pests on cruciferous vegetables due to its phytotoxicity on these vegetables under high temperature and light conditions. Thus, there is an ongoing need for more effective pesticides that can be used on cruciferous vegetables, possibly including new formulations of diafenthiuron. A new thiourea insecticide, methylthio-diafenthiuron, is intended to optimize the structure of diafenthiuron not only to preserve its insecticidal bioactivity but also to overcome its phytotoxicity to cruciferous vegetables, aiming to control insect pests on cruciferous vegetables. In this study, we compared the toxicity of methylthio-diafenthiuron to some frequently used insecticides on the third-instar larvae of DBM. The parental pupal duration was significantly longer under the treatment than in the control, but the pupal weight, fecundity, and hatching rate significantly decreased. By studying the changes in three detoxifying enzymes within 72 h after treatment with a sublethal concentration, the activity of CarE and ODM in the treatment group significantly increased at first and then decreased. In addition, methylthio-diafenthiuron clearly inhibited three kinds of ATPases in the DBM and significantly reduced the eclosion rate of the pupae . This research provides valuable information for the assessment and rational application of methylthio-diafenthiuron for the control of pests on cruciferous vegetables.
危险品化学品经营许可证（带存储）