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The aim of this study was to explore the underlying mechanism of adverse effects caused by tebuconazole (TEB) on the reproduction of aquatic organisms In the present study, in order to explore the effects of TEB on reproduction, four-month-old zebrafish were exposed to TEB (0, DMSO, 0.4 mg/L, 0.8 mg/L, and 1.6 mg/L) for 21 days. After exposure, the accumulations of TEB in gonads were observed and the cumulative egg production was evidently decreased. The decline of fertilization rate in F1 embryos was also observed. Then the changes in sperm motility and histomorphology of gonads were discovered, evaluating that TEB had adverse effects on gonadal development. Additionally, we also found the alternations of social behavior, 17β-estradiol (E2) level, and testosterone (T) level. Furthermore, the expression levels of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis and social behavior were remarkably altered. Taken together, it could be concluded that TEB affected the egg production and fertilization rate by interfering with gonadal development, sex hormone secretion, and social behavior, which were eventually attributed to the disruption of the expressions of genes associated with the HPG axis and social behavior. This study provides a new perspective to understanding the mechanism of TEB-induced reproductive toxicity.

Interactions between titanium dioxide nanoparticles (n-TiO 2 ) and pollutants in the aquatic environment may alter the bioavailability of pollutants, and thus altering their toxicity and fate. In order to investigate the bioconcentration of azoxystrobin (AZ) and its mechanism of cardiotoxicity in the presence of n-TiO 2 , the experiment was divided into control, n-TiO 2 (100 μg/L), AZ (40, 200 and 1000 μg/L) and AZ (40, 200, 1000 μg/L) + n-TiO 2 groups, and the zebrafish embryos were exposed to the exposure solution until 72 h post-fertilization. Results suggested the presence of n-TiO 2 notably reduced the accumulation of AZ in larvae compared with exposure to AZ alone, thereby significantly decreasing AZ-induced cardiotoxicity, including heart rate changes, pericardium edema, venous thrombosis, increased sinus venosus and bulbus arteriosus distance and changes in cardiac-related gene expression. Further studies showed that AZ + n-TiO 2 together restrained total-ATPase and Ca 2+ -ATPase activities, while the activity of Na + K + -ATPase increased at first and then decreased. Furthermore, there were significant changes in the expressions of oxidative phosphorylation and calcium channel-related genes, suggesting mitochondrial dysfunction may be the potential mechanism of cardiotoxicity induced by AZ and n-TiO 2 . This study supplies a new perspective for the joint action of AZ and environmental coexisting pollutants and provides a basis for ecological risk management of pesticides., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Beta-cypermethrin, a type II synthetic pyrethroid insecticide, is widely used in pest control. Several studies have demonstrated that beta-cypermethrin can affect the reproductive system of mammals. However, there is still a scarcity of information about the reproductive toxicity to fish induced by beta-cypermethrin and its molecular mechanism. Therefore, this study was conducted to address this scientific question, in which the adult zebrafish were exposed to 0 (blank control), 0 (acetone solvent control), 0.1, 0.5, and 2.5 μg/L of beta-cypermethrin for 21 days. A decrease in cumulative egg production of zebrafish was observed, indicating that beta-cypermethrin had a negative impact on reproductive capacity of zebrafish. Regarding the histomorphological analysis of gonads, the delay of gonadal development was observed after exposure for 21 days. In addition, significant changes in plasma 17β-estradiol (E2) and testosterone (T) were found in zebrafish. Further exploration showed that the transcription levels of hypothalamic-pituitary-gonadal (HPG) axis-related genes were remarkably changed, which corresponded well with the alterations of hormone levels. These results demonstrated that beta-cypermethrin might have an adverse effect on the reproduction system of zebrafish through delaying gonadal development, disturbing sex hormone secretion, and affecting HPG axis gene expression. This study suggests that beta-cypermethrin poses a potential threat to the reproduction of fish populations, and the toxicity assessment of beta-cypermethrin plays a vital role in the environmental risk assessment of pesticides., (Copyright © 2020. Published by Elsevier Inc.)

In current study, a rapid and sensitive method for simultaneous determination of 8 phenoxy carboxylic acid (PCA) herbicides in environmental water samples was established based on an octyl and amino functionalized magnetic mesoporous silica (mOAS). The mOAS sorbent was fabricated by simple modification of octyl and aminopropyl groups onto the surface of magnetic mesoporous silica. Various techniques were employed to characterize the physical and chemical properties of the mOAS sorbent. The mOAS sorbent showed good extraction capacity and selectivity for PCA herbicides owing to the mixed-mode hydrophobic and ionic exchange interaction mechanisms. Then a one-factor-at-a-time approach was utilized for the optimization of extraction, washing and eluting conditions. Under the optimum conditions, wide linearity ranges with squared correlation coefficients ranging from 0.9888 to 0.9966 were obtained, and the method detection of limits (LODs) were in the range of 0.005-0.02 ng/mL. Furthermore, recoveries ranged from 86.9 to 114.6% with intra- and inter-day relative standard deviation (RSD) of 0.8-11.0% at three concentration levels spiked in blank water sample. Finally, the as-proposed method was successfully applied to extract 8 PCA herbicides in real water samples followed by determination with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Results showed that the mOAS as adsorbent for magnetic solid phase extraction (MSPE) of acidic herbicides is an efficient alternative with simplicity and rapidity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)