Bioaccumulation and the expression of hepatic cytochrome P450 genes in marine medaka (Oryzias melastigma) exposed to difenoconazole

This study was conducted to assess the effects of difenoconazole (DFZ), a triazole fungicide, on the hepatic biotransformation system and its bioaccumulation in marine medaka (Oryzias melastigma). Fish were exposed to DFZ (1, 10, 100, 1000 ng/L) for 180 days. The results showed that: (1) The mRNA levels of hepatic CYP1A1, CYP1B, CYP1C1, CYP27B and CYP3A40 were up-regulated, but those of CYP3A38 and CYP27A1 were down-regulated. (2) The activity of ethoxyresorufin-O-deethylase (EROD) and the content of reduced glutathione (GSH) in the liver were increased in the DFZ-treated groups, and glutathione S-transferase (GST) activity was increased in the 100 and 1000 ng/L groups. (3) DFZ was accumulated in the muscle and the biological concentration factors in the 10, 100, and 1000 ng/L groups were respectively 149, 81 and 25. These results suggested that long-term exposure to DFZ at low concentrations would result in a bioaccumulation of this compound and disturb the biotransformation system.     

Mn-CeOx/钛基层柱粘土(Ti-PILCs)低温选择性催化还原催化剂的钙中毒研究

以钛基层柱粘土(Ti-PILCs)为载体,制备了Mn-Ceox/Ti-PILCs低温选择性催化还原(SCR)催化剂,采用浸溃法模拟了催化剂钙中毒,研究了不同含钙量对催化剂活性的影响,并运用NH3-程序升温脱附(TPD)、H2-程序升温还原(TPR)及X射线光电子能谱(XPS)表征,分析了钙对催化剂的失活作用.结果表明:...     

社会主义新农村建设中环境保护法律体系的改进研究

社会主义新农村建设是现代化进程中的重要任务,结合环境保护法律体系以实现无污染的高效治理是必要条件。对农村生态环境污染现状及原因进行分析,总结出当前农村生态问题有:工业点源污染、农业面源污染、饮用水和排水污染、固体废弃物超标和其他方面引起的环境污染;在新农村建设中,确定环境保护法律体系构建的指导思想,健全环境保护的监督体制、明确环境保护法的应用范围与规制领域、赋予农民生态环境保护的知情权等,为新农村建设中的环境保护提供支撑。     

城市生活垃圾生命周期分析及处理规划研究

生活垃圾处理规划是城市环境规划重要组成部分,为城市垃圾管理提供行动依据。本文以北京市为例,基于生活垃圾生命周期全过程的环境影响分析和资源化率核算,提出北京市生活垃圾优化处理框架,并纳入垃圾处理规划体系。结果表明规划方案优化了垃圾处理系统,环境影响可降低22％,资源化率可提高60％。     

污水厂曝气节能智能优化控制系统

针对国内大部分污水厂现有曝气控制中存在着溶解氧浓度波动大、曝气量冗余大、曝气单元能耗高等问题,提出曝气节能智能优化系统,该系统通过获得A/O工艺实时的在线数据不断进行模拟计算,然后按照生化池进水的污染物负荷状况,以曝气能耗最小为目标函数来获取最优的DO设定值及其PI控制器的参数Kp、Ki。该智能优化系统在沥滘污水厂的实际应用情况表明:该系统在盫こ鏊实那榭鱿拢唤鎏岣吡讼低车目垢汉沙寤髂芰Γ苯档土?曝气能耗。     

Exposure to difenoconazole inhibits reproductive ability in male marine medaka (Oryzias melastigma)

Difenoconazole(DFZ) is a triazole fungicide which has been detected in the aquatic environment, including estuaries and embayments. However, few studies addressing the reproductive toxicity and transgenerational effects of DFZ on marine fishes are available.The present study was conducted to investigate the effects of DFZ on male marine medaka(Oryzias melastigma). After exposure of the embryo to 1, 10, 100 and 1000 ng/L DFZ for180 days, the gonadosomatic index was significantly decreased in the 1000 ng/L treatment.The number of sperm was reduced while the abundances of spermatocytes and spermatogonia in the testes were increased in all the treatments. The m RNA levels of salmontype gnrh(sgnrh), the luteinizing hormone(lhβ) and the follicle-stimulating hormone(fshβ)genes in the brain all exhibited a significant down-regulation, the expression of androgen receptors(arα and arβ) was decreased and that of estrogen receptor β and cytochrome P450 aromatase(cyp19 B) was increased in the testes. The expression levels of cyp19 A and cyp19 B were increased in the liver. The decrease of ars m RNA levels might be one of the reasons causing the reduction of sperm. The down-regulation of sgnrh, lhβ and fshβ m RNA levels suggested that DFZ might impact the spermatogenesis via the brain–pituitary–gonad pathway. The decrease of the fertilization success, the hatch ability and the swim-up success in the F1 generation indicated that DFZ pollution at environmental levels might cause a decrease of wild fish populations.     

Formation process and mechanism of humic acid-kaolin complex determined by carbamazepine sorption experiments and various characterization methods

To explore the formation process and mechanism of organic matter and organic-mineral complex under humification and mineralization conditions, a series of samples including humic acid, kaolin, and humic acid-kaolin complex were prepared using a subcritical water treatment method(SWT) under specific temperature, pressure and reaction time conditions. HA was used as a surrogate for natural organic matter because it has a similar abundant pore structure,variety of carbon types, and chemical components. These samples were used in carbamazepine(CBZ) sorption experiments and characterized by a variety of techniques. The polymerization of humic acid under the conditions of increased temperature and pressure resulted in an increase in specific surface area and molecular quantity. In addition, the degree of aromaticity rose from59.52% to 70.90%. These changes were consistent with the transformation from ‘soft carbon' to‘hard carbon' that occurs in nature. The results of sorption experiments confirmed the interaction between humic acid and kaolin from the difference between the predicted and actual Qevalues. The conceptual model of humic acid-kaolin complex could be deduced and described as follows. Firstly, the aromatic components of humic acid preferentially combine with kaolin through the intercalation effect, which protects them from the treatment effects.Next, the free carboxyl groups and small aliphatic components of humic acid interact on the surface of kaolin, and these soft species transform into dense carbon through cyclization and polymerization. As a result, humic acid-kaolin complex with a mineral core and dense outer carbonaceous patches were formed.     

微波辅助酸预处理玉米秸秆水解条件研究

玉米秸秆由叶子、皮和髓组成, 这些组分含有不同的纤维素、半纤维素和木质素, 因而可以成为生产燃料乙醇的原料. 采用微波辅助的酸水解来脱除与纤维素和木质素紧密结合的半纤维素, 使得纤维素结构发生变化有利于后续酶解是值得探讨的. 本研究通过将玉米秸秆叶子、皮和髓分离, 分别对它们进行了微波(2450MHz, 1000W)酸预处理, 确定了玉米秸秆不同部分的最优水解条件, 并对其进行了生产燃料乙醇的潜力对比, 以选出最适合做燃料酒精原料的部分. 同时, 在实验中, 选取硫酸浓度、温度、处理时间、料水质量体积比及搅拌速度5个因素分别进行单因素试验和正交试验. 结果表明, 5个因素对微波酸预处理玉米秸秆叶子的影响顺序依次为: 硫酸浓度>温度>料水质量体积比>时间>搅拌速度, 最佳条件是硫酸浓度5.0%, 温度75 ℃, 时间30min, 料水质量体积比1∶15, 搅拌速度800 r·min-1; 对玉米秸秆髓的影响顺序依次为: 硫酸浓度>搅拌速度>预处理时间>料水质量体积比>预处理温度, 最佳条件是硫酸浓度4.0%, 温度75 ℃, 时间25min, 料水质量体积比1∶20, 搅拌速度1000 r·min-1; 对玉米秸秆皮的影响顺序依次为: 硫酸浓度>预处理时间>料水质量体积比>预处理温度>搅拌速度, 最佳条件是硫酸浓度9.0%, 温度72 ℃, 时间30min, 料水质量体积比1∶17.1, 搅拌速度2000 r·min-1. 通过实验可以进一步得出, 玉米秸秆叶子和髓更适合用于生产燃料乙醇. 该研究结果对玉米秸秆的燃料化利用有一定的指导意义.     

Phosphorus adsorption by sediment considering mineral composition and environmental factors

Environmental Science and Pollution Research - Sediment, composed of a complex assemblage of minerals, controls the fate and behaviour of P in aqueous environments and affects trophic status. In...