复极性三维电极法处理硝基苯废水的实验研究

以铁板为阴极,石墨为阳极,吸附饱和的活性炭粒子为填充材料,研究了复极性三维电极法处理硝基苯废水时各因素对处理效率的影响。通过单因素实验确定了复极性三维电极法处理硝基苯废水的最佳操作条件为：电解电压20V,反应时间60min,活性炭填充量25g／L,电极板间距4cm,废水初始pH值6～7,电解质的投加量0．8g／L。此条件下废水的硝基苯去除率达到80％以上,COD去除率达到50％以上,显示出良好的处理效果。     

间二硝基苯清洁生产工艺研究

根据清洁生产原理、间二硝基苯生产工艺及废水产生情况,提出了重结晶废水直接回用于精制,精制废水蒸馏后回用于精制洗涤和重结晶的清洁生产工艺;经小试4次和中试3次废水循环套用后产品均为优等品,证明清洁生产工艺对产品质量无不良影响,可实现工艺废水零排放。     

环境规制和农业科技进步的关系分析——基于波特假说的研究

波特假说主要从动态的角度论证了环境规制和农业科技进步之间的正向变亿关系.而在安徽省1990 -2008年的农业生产数据的基础上,选择合适的环境规制和农业科技进步的指标变量,运用Johansen协整分析方法验证了安徽省农业生产中的环境规制和农业科技进步的关系也符合这一假说,Granger因果关系检验说明了安徽省环境规制是农业科技进步产生的原因,脉冲响应分析和方差分析则更深入地从定量的角度分析了环境规制对农业科技进步影响滞后的趋势和影响程度.由实证分析可以看出,只是从静态角度来分析,环境规制是不利于农业的科技进步的;但从长期效益来看,环境规制有利于农业的科技进步.因此,在农业生态环境恶化的形势下,严格对农业废弃物的排放限制,制定较严格的农产品生产标准和产品质量标准,提高农民的环境意识和科技意识,通过强化环境规制来促使农业生产者提高农业生产技术,提高农产品品质和产品的市场竞争力就显得尤为重要.     

Increased urinary 8-hydroxy-2��-deoxyguanosine levels in workers exposed to di-(2-ethylhexyl) phthalate in a waste plastic recycling site in China

Background

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.

Methods

The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender?Cage matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2??-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.

Results

Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 ??g/l; well water: 14.20 vs. 0.79 ??g/l, pond water: 135.68 vs. 0.37 ??g/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p?p?p?Conclusions The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.     

MAP法处理高浓度氨氮废水技术研究进展

MAP法(磷酸铵镁沉淀法)是去除废水中高浓度氨氮的一种有效技术。本文叙述了MAP法去除废水中氨氮的反应机理,分析pH值、物质摩尔比,反应时间等影响因素。该方法具有去除率高、反应速度快、受外界环境影响小等特点,同时还实现了对氮的有效回收,具有较好的应用前景。     

基于灰色关联投影的四川省生态环境质量定量研究

生态环境系统是一个包括自然、经济和社会等多个方面,具有信息不确知性和不完全性因素的灰色系统。以四川省为研究区,在构建生态环境评价指标体系的基础上,基于灰色系统理论和矢量投影原理,建立了生态环境质量评价的灰色关联投影模型,并运用所建模型对四川开展生态省建设前后3年的生态环境质量进行评价。结果表明,四川省自开展生态省建设以来,生态环境质量逐步提高,但仍然有进一步提高的空间。     

北京市交通道路空气中NOx的污染现状及时空变化规律研究

基于2008年及2009年分4个季节对北京市3种类型道路（开阔型、交叉路口型和峡谷型）空气中的NOx的现场监测结果,分析了3种类型道路空气中NOx的污染现状和时空变化规律及影响因素。实验结果表明,昼间北京市各类型街道空气中NOx浓度呈早晚浓度高、中午浓度低的变化规律,NOx浓度随季节和车流量变化较明显。交通道路空气中NO占NOx的分担率高,且有较好的相关性,而NO2分担率较低,与NOx相关性较差。     

Biological detection and analysis of mercury toxicity to alfalfa (Medicago sativa) plants

Mercury has become one of the major causes of toxic metal pollution in agricultural lands. Accumulation of mercury by plants may disrupt many cellular functions and block growth and development. To assess mercury toxicity, we performed an experiment focusing on the responses of alfalfa (Medicago sativa) to Hg(2+)-induced oxidative stress. Alfalfa plants were treated with 0-40microM HgCl(2) for 7d. The concentrations of Hg(2+) were positively correlated with the generation of O2- and H(2)O(2) in leaves. Treatment with Hg(2+) increased the activities of NADH oxidase and lipoxygenase (LOX) and damaged the biomembrane lipids. To understand biochemical responses under Hg stress, activities of several antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were assayed. Analysis of SOD activity by non-denaturing polyacrylamide gel electrophoresis revealed five isoforms in leaves, but they showed different patterns. Also, eight isoenzymes of APX and seven of POD in leaves were detected. However, only one isoform of CAT was visualized. The total activities of APX, POD and CAT were generally enhanced. We also measured several antioxidative metabolites such as ascorbate and glutathione (GSH), and found that both differentially accumulated in leaves. These results indicate that the increased levels of O2- and H(2)O(2) under Hg stress were closely linked to the improved capacity of antioxidant enzymes. The data not only provide the important information for better understanding of the toxic and tolerance mechanisms, but as well can be used as a bio-indicator for soil contamination by Hg.     

土壤中六六六和滴滴涕的堆肥生物修复研究

采用堆肥生物修复法对土壤中六六六(HCH)和滴滴涕(DDT)的降解效果进行了研究.试验结果表明,六六六和滴滴涕的降解先后经历了快速降解阶段和缓慢降解阶段;堆肥第21天后,六六六和滴滴涕降解率均达60%以上;γ-HCH降解效果最好,其次为β-HCH,α-HCH和δ-HCH的降解效果差别较大;p,p'-DDE的降解效果要好于p,p'-DDD,初始质量浓度为0.03 mg/kg的p,p'-DDT未得到降解;微生物对六六六和滴滴涕的降解作用均较明显.     

酸雨胁迫对水稻和高粱种子萌发的影响

酸雨对作物种子萌发的生态效应是影响农业生产的重要问题,为揭示酸雨影响种子的萌发机理,本文以水稻(Oryzasatival)"宁梗1号"和高粱(Sorghum vulare)"黄土高粱"为试验种子,采用不同酸性强度的模拟酸雨处理两类种子.定时测定酸雨胁迫强度对种子的发芽率、发芽势、发芽指数、活力指数、异状发芽率、呼吸速率和呼吸商的影响.结果表明,当酸雨胁迫强度pH=2.0～2.5时,因胁迫强度过高.水稻和高粱种子皆不萌发;当酸雨胁迫强度pH≥3.0时,两类抗性种子5项萌发指标的变化幅度均为高粱大于水稻;高粱的酸雨伤害阈值为pH=3.5～4.0,水稻为pH=3.0～3.5;当胁迫强度pH≥2.5时,两类抗性种子呼吸速率和呼吸商2项生理指标的变化幅度为高粱大于水稻、水稻和高粱种子的生理反应阈值为pH≥2.0,萌发反应阈值为pH≥3.0,说明水稻对酸雨的抗性强于高粱;2类抗性种子对酸雨胁迫强度的耐受性差异是其抗性分异的根本原因.