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A modified DRASTIC model, named DRASTLZ, has been proposed to better assess the sensitivity of groundwater systems to pollution by replacing the vadose zone media type (I) and hydraulic conductivity of the aquifer (C) with land use type (L) and groundwater quality (Z) indicators. First, a scoring system for the DRASTLZ model was established, assigning different weights to seven influencing factors. Using the ArcGIS platform, collected data were processed and statistically analyzed. Evaluation score maps were constructed for seven assessment indicators: groundwater depth (D), net recharge of groundwater (R), aquifer media (A), soil media (S), surface slope (T), land use type (L), and groundwater quality (Z). These maps were then overlaid, and the composite vulnerability index of Juxian County was calculated according to the assigned weights. The natural breaks classification method was employed to divide the area into five vulnerability zones: low vulnerability, relatively low vulnerability, moderate vulnerability, relatively high vulnerability, and high vulnerability. The groundwater vulnerability assessment for Juxian County was thereby completed. The calculated results indicate that the overall vulnerability of groundwater in Juxian County is relatively high, with the highest proportion (approximately 38%) falling in the high vulnerability zone, followed by moderate vulnerability (36%) and high vulnerability (15%) zones. The proportions of relatively low and low vulnerability zones are smaller, accounting for 10% and 1%, respectively. There is a positive correlation between groundwater vulnerability assessment results and the exceedance of water quality sampling points, suggesting the applicability of the developed DRASTLZ model in Juxian County closely reflects actual conditions. The successful application of the DRASTLZ model provides valuable experience and guidance for future groundwater vulnerability assessment studies in similar regions. [ABSTRACT FROM AUTHOR]

Objective: To investigate the molecular mechanism of trichloroethylene (TCE) cardiac developmental toxicity on zebrafish embryos and to try to provide experimental data for related intervention., Methods: Zebrafish embryos were purchased from the National Zebrafish Resource Center. The embryos were divided into DMSO(control group), DMSO+CHIR, DMSO+XAV, TCE, TCE+CHIR and TCE+XAV groups(TCE at the concentration of 1, 10 and 100 ppb, with the DMSO as control; DMSO: Dimethyl suldoxide; CHIR: CHIR-99021, Wnt agonist; XAV: XAV-939, Wnt antagonist), 60 embryos per group. Zebrafish embryos were fed in systematic aquaculture water, 28℃. The water was replaced every 24 h and drugs were added according to the grouping scheme. The cardiac tissues were dissected and analyzed by transcriptome microarray after RNA extraction. The expressions of Wnt signaling pathway related genes were verified by q-PCR. Wnt atagonist XAV and activator CHIR were used alone or in combination to further evaluate the possibility of the Wnt signaling participating in the cardiac developmental toxicity induced by TCE., Results: Compared with control, Zebra fish embryos exposed to TCE showed a significant increase in heart defects, and the main phenotypes were abnormal atrioventricular ratio, looping defects and pericardial edema. The results of microarray profiling showed that the expressions of genes related to Wnt signaling pathway were affected significantly. The results of qPCR further confirmed that TCE inhibited the expressions of Wnt pathway target genes Axin2, Sox9b and Nkx2.5(P＜0.05). Wnt agonist CHIR reduced the TCE-induced cardiac malformation rate significantly, while the addition of Wnt antagonist XAV markedly enhanced the cardiac developmental toxicity of TCE., Conclusion: Exposure to TCE leads to heart malformation in zebrafish embryos. Wnt signaling pathway may be involved in the cardiac developmental toxicity induced by TCE.

Primary extracted MCLR (Microcystin-LR) from Taihu Lake degradation by UV/H2O2 and ozone process were investigated. The effects of intensity of UV radiation, initial concentration of MCLR, dosages of H2O2 and ozone, initial pH value of the solution and anions on degradation of MCLR were studied. The pH value and carbonate (or bicarbonate) concentration varieties during the reaction were discussed. A concise model based on the first order model was raised. The results reveal that in UV/H2O2 system (including UV alone), the average value of the pseudo first and second order kinetics correlation coefficient R2 are 0.927 and 0.827 respectively. In the ozone treatment process, the average valve of the first and second order kinetic correlation coefficient R2 are 0.911 and 0.925 respectively; at the same time, the accuracy of modified model was proved to be better, the average value of R2 in UV/H2O2 (including UV alone) and ozone system are up to 0.982 and 0.985 respectively. Meanwhile, it can be concluded from the model that: when the initial UV radiation, H2O2 dosage and the ozone dosage were set, pH value and carbonate (or bicarbonate) concentrations were the two main aspects which influenced the reaction rate.

The degradation of bispehnol A (BPA) in aqueous suspension by interaction of photocatalytic oxidation and ferrate (VI) oxidation was investigated under different conditions. The results indicate that the formation of Fe (V) and Fe (IV) is in the photoreduction of Fe (VI) by electron (e(cb)-) on the surface of TiO2. The oxidation efficiency of the photocatalytic oxidation in the presence of Fe (VI) is much greater than that without Fe (VI). In addition, the decomposition of Fe (VI) under different conditions was also investigated. The results indicate that the Fe (VI) reduction is enhanced by photocatalytic oxidation and the adsorption capacity of Fe (VI) at TiO2 surface decreases with pH increase. When the photocatalytic oxidation is used to degrade BPA, Fe (VI) could increase the degradation rate about 2.5 times.

The degradation of MC-LR in water by UV/H2O2 process was investigated. The effects of intensity of UV radiation, initial concentration of MC-LR, dosages of H2O2, initial pH value and anions on degradation of MC-LR by UV/H2O2 process were studied. The results show that the removal of MC-LR only by H2O2 is nearly zero, and UV process can degrade MC-LR to a certain extent. However, the degradation efficiency of UV/H2O2 process is much higher than UV and H2O2 process due to the synergetic effect between UV and H2O2. The removal of MC-LR increases with the enhancement of intensity of UV radiation, but decreases gradually with the increase of initial concentration of MC-LR. When the dosages of H2O2 change from 1 mmol/L to 3 mmol/L, the constant of degradation rate rises from 0.0844 to 0.1664. The optimum pH value is 3.13. The added anions have adverse effect on the degradation of MC-LR, especially carbonate and nitrate ions have the biggest influence among the studied anions.