用差示分光光度法测定高浓度皮革废水中铬的方法探讨

介绍了应用差示分光光度法直接测定高浓度皮革废水中Cr的方法，通过与原实验方法分析结果的对比，获得了满意的结果，能基本满足环境监测的要求。     

2,2′-二硝基联苄生产废水的处理研究

对十六烷基三甲基溴化铵改性凹凸棒土、凹凸棒土负载TiO2采用XRD、FTIR以及TG等手段进行了分析和表征,对比了改性凹凸棒土、活性炭、大孔树脂等不同吸附剂和凹凸棒土负载TiO2对二硝基联苄生产废水的处理效果。结果表明:十六烷基三甲基溴化铵改性凹凸棒土的废水中污染物的去除率比凹凸棒土提高了2.5倍;凹凸棒土负载TiO2在波长λ=254 nm下光照0.5 h,对废水中污染物的去除率是凹凸棒土的2.0倍;投加量为3%活性炭在pH为2.0⁵.0时,对该类废水中污染物的去除率可达80%以上。     

凹凸棒石基复合材料处理印染废水的研究

以凹凸棒石为载体,钛酸四丁酯为原料,通过溶胶-凝胶法,制成TiO2/凹凸棒石基复合材料(TiO2/ATT),并对所制得的复合材料进行了XRD和BET表征。在波长为254 nm的16 W紫外灯光照下,以活性黑KN-B印染废水为脱色对象,分别探讨了TiO2/凹凸棒石复合材料的煅烧温度、投加量、活性黑KN-B染料的初始浓度、溶液的pH值和反应温度等因素对印染废水脱色率的影响。实验结果表明:用煅烧温度500℃的TiO2/凹凸棒石基复合材料处理活性黑KN-B印染废水,催化剂的投加量为15 g/L、活性黑KN-B的初始浓度为10 mg/L、pH小于7、反应温度为20℃时,光催化反应4 h内即能达到较高的去除率,对活性黑KN-B的脱色率可达95%以上。     

TiO2光催化降解水中内分泌干扰物17β-雌二醇

以低压汞灯为光源,采用间歇式光氧化反应器,研究了17β-雌二醇(E2)在纳米TiO₂(Degussa P-25)悬浆体系中的光催化降解.考察了溶液pH、E2初始浓度、TiO₂光催化剂投加量、UV光强、H₂O₂、O₂对E2光催化降解的影响.结果表明,TiO₂光催化工艺可以有效地去除水中的E2,E2的光降解过程符合一级反应动力学模型;TiO₂投加量为200　mg/L时,在14 W低压汞灯照射下,初始浓度为400 μg/L 的E2在自来水中的光降解一级反应速率常数为0.018 min^-1,E2的光催化降解速率常数与其初始浓度、TiO₂光催化剂的用量、溶液的pH值、UV光强等因素有关;外加H₂O₂、O₂可以影响催化剂的光降解效率.     

土壤呼吸与土壤有机碳对不同秸秆还田的响应及其机制

以黄豆、玉米、水稻这3种农业秸秆为原料,崇明东滩围垦土地为试验样区,以景观植物地肤草为目标植物,研究土壤呼吸和土壤有机碳对不同秸秆还田的响应及其可能的机制.结果表明,不同秸秆直接还田的土壤呼吸和地上植物量均高于对照组;黄豆秸秆还田后土壤呼吸相对最低,土壤有机碳最高,因此黄豆秸秆还田的土壤碳封存能力高于玉米和水稻秸秆.秸秆还田显著促进土壤微生物活性,增加了土壤微生物量以及β-糖苷酶、脱氢酶活性,脱氢酶活性与土壤呼吸相关性最显著.黄豆秸秆还田脱氢酶活性最低,相应的土壤呼吸也最低.黄豆秸秆纤维素、木质素和C/N含量最高,可降解性最低,表明黄豆秸秆难以被微生物降解利用,因而还田后其土壤微生物活性最低,最终导致最低的土壤呼吸和较高的土壤有机碳.     

个人规范对农户亲环境行为的影响分析——基于拓展的规范激活理论框架

农户的亲环境行为可在一定程度上缓解农业环境污染,为改善农业环境,探寻农户实施亲环境行为的原因所在,将农户环境污染感知、环境关心和社会规范加入规范激活理论框架对其进行拓展,在此基础上,通过构建结构方程模型和层次回归模型,利用陕西、山西、甘肃、安徽和江苏5省的实地调查数据,对农户的亲环境行为进行分析。结果表明:农户的亲环境个人规范、环境污染感知和环境关心均可对其亲环境行为产生直接的正向影响,且个人规范对行为的影响程度最大;结果意识、责任归属、农户的环境污染感知和环境关心均可对其亲环境的个人规范产生直接的正向影响,且其影响程度从高到低依次为:结果意识、责任归属、环境污染感知和环境关心;农户的环境污染感知和环境关心可同时对其亲环境行为产生直接和间接影响作用,而结果意识和责任归属仅可对其亲环境行为产生间接影响作用;社会规范可正向调节个人规范对农户亲环境行为的影响。     

铜管模拟输配系统中氯胺衰减过程与模拟

研究了氯胺在铜管模拟输配系统中的衰减过程,并利用一级反应动力学模型对氯胺衰减规律进行了模拟;考察了pH、初始氯胺浓度等水质条件与流速等水力条件对氯胺衰减速率的影响.结果表明,pH值是影响氯胺衰减速率与金属铜溶出的重要因素,pH越低氯胺衰减越快;提高氯胺初始浓度可加快氯胺衰减速度,也可增加金属铜的溶出量;流速对氯胺衰减速率的影响不大.此外,衰减动力学过程模拟结果表明,采用一级反应动力学模型可以较好地拟合不同条件下的氯胺衰减规律.从而对于工程中不同条件下消毒剂浓度预测具有重要意义.     

Toxicity assessing for chlorpyrifos-contaminated soil with three different earthworm test methods

Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In the present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.     

浮桥河水库浮游植物的多样性及其演变

1997年4月至1998年1月对浮桥河水库浮游植物状况进行了调查,结果表明:该水库常见浮游植物约189种,隶属于8门92属,其中硅藻门25属64种,绿藻门39属79种,蓝藻门17属30种,甲藻门、隐藻门、裸藻门、黄藻门及金藻门种类较少。其个体密度年平均为44.9×104ind/L;生物量年平均为6.439mg/L,其中蓝藻占33.37%,硅藻和绿藻分别占20.68%和20.16%,甲藻占16.31%。浮游植物现存量的季节变化表现为从春季开始平稳上升,至秋季达到最大值。蓝藻、硅藻、绿藻等主要种类的季节变化按生物量大小依次为:秋季夏季春季冬季。浮游植物现存量的水平分布为上游最高,中游次之,下游最低,库汊低于中游而略高于下游。群落的相似性表现为上、中游相近,下游和库汊相近。群落的物种多样性根据计算Shannon-Weiner指数为上游最大,其次为中游,下游再次,库汊最低。与1980年的调查结果相比较,浮桥河水库浮游植物种类小型化明显,生物量增加2.5倍。     

Decline in Endangered Species as an Indication of Anthropic Pressures: The Case of European Mink Mustela lutreola Western Population

Populations of threatened species, especially predators at the top of the food chain, may be affected by anthropic pressures. The endangered western population of European mink Mustela lutreola has shown a large decline over 50% of its natural range. M. lutreola disappeared from northwestern France between 1984 and 1997, and the decline was associated with an increase in mustelid trapping, changes in watercourse quality, and habitat modifications due to agricultural practices. The pattern of decline showed a fragmentation restricting the minks into very small areas. Trapping was the first known cause of mortality. Although feral American mink Mustela vison may compete with autochthonous carnivores, M. lutreola had disappeared from streams before the introduction of the American species, suggesting that competitive interactions were not responsible. Furthermore, American mink has never been found or has remained rare in 62.4% of the area from which M. lutreola has disappeared. During the past 25 years, permanent grassland surfaces were reduced by 40%, whereas fodder culture increased by 470%, causing considerable habitat changes. Furthermore, 55.7% of water courses were classified as being of bad quality or polluted. Therefore, our data suggests that a conjunction of intensive trapping, alterations in water quality and habitat modification was critical for the European mink's decline. Although there are difficulties in ascribing specific cause to distribution changes in a top predator, this decline can be regarded as an indication for anthropic pressures on natural habitats.