中压加氢裂化装置危险和可操作性研究

针对中压加氢裂化生产过程存在很大的火灾、爆炸、毒害等危险性的特点，以加氢裂化反应器出口至冷高压分离器进口之间管线为分析节点，对工艺参数流量可能发生的各种偏差进行了危险和可操作性研究，找出了偏差发生的原因及可能导致的后果，提出了相应的控制措施，对提高装置的安全可靠性，预防和减少事故发生具有重要作用。     

我国农村环境污染问题及成因分析

详细阐述了我国农村环境污染的具体表现,并综合分析了污染造成的危害及产生污染的原因,针对具体情况从促进农业生产方式转型、增强环保意识、统筹城乡发展防止污染转嫁、完善农村环境监督法律体系四个方面提出了治理环境污染、推进农村生态文明建设的可行性措施,以期为我国农村环境的综合治理提供参考。     

Arsenic toxicity in mice and its possible amelioration

Oral administration of arsenic trioxide(3 and 6 mg/kg body weight/d) for 30 d caused, as compared with vehicle control, dose-dependent significant reductions in body weight, absolute weight, protein, glycogen, as well as, total, dehydro and reduced ascorbic acid contents both in the liver and kidney of arsenic-treated mice. Succinic dehydrogenase(SDH) and phosphorylase only in the liver activities were significantly reduced in a dose-dependent manner. Acid phosphatase activity was significantly decreased in the liver of low dose arsenic-treated animals;however, significant rise in its activity was observed in high dose group. As compared with vehicle control, treatment also caused significant dose-dependent reductions in SDH, alkaline phosphatase and acid phosphatase activities in the kidney of mice. Vitamin E cotreatment as well as, 30 d withdrawal of arsenic trioxide treatment with or without vitamin E caused significant amelioration in arsenic-induced toxicity in mice. Administration of vitamin E during withdrawal of treatment also caused significant amelioration as compared from only withdrawal of the treatment. It is concluded that vitamin E ameliorates arsenic-induced toxicities in the liver and kidney of mice.     

Toxicity of cypermethrin to Daphnia magna HB

The acute toxic effect of the pesticide cypermethrin to Daphnia magna HB was examined. D. magna HB was exposed to cypermethrin at concentrations of 0, 1, 3, 5, 7, and 9 mg/L for 24 h. Data showed that the 24 h-LG50 of cypermthrin on D. magna HB was 4.81 mg/L. In contrast, the 24 h-LC50 of K2Cr2O7 (the national standard toxicant) to Daphnia magna was 0.38 mg/L in the current study. Results indicated that the Daphnia magna was very sensitive to pesticides. In addition, the effects of the culture condition(such as hardness, temperature and DO etc. ) on Daphnia magna HB was also studied.     

氰戊菊酯和锐劲特对原生动物群落的联合毒性试验研究

氰戊菊酯和锐劲特两种农药被广泛用于茶树、果树、水稻、蔬菜等的病虫害防治,它们同时出现在同一环境中的机会非常多,但有关两种农药对生态系统的复合毒性效应却未见有研究报道.与单种生物毒性试验相比,群落级生物毒性试验对毒物胁迫的反映更具环境真实性.以PFU在天然淡水中采集到的原生动物群落为靶生物,研究了氰戊菊酯和锐劲特2种农药对淡水原生动物群落的毒性效应,对于水生生态环境的保护有特殊的意义.研究结果表明,2种农药单独存在时对原生动物群落的48h半数致死浓度分别为15 93mg·L-1和35 83mg·L-1;2种物质以等毒性比(单一LC50的比值)混和,进行联合毒性试验研究,用Marking相加指数法进行评价,其AI值为0 9,表现为协同作用.氰戊菊酯和锐劲特进入水环境后,将使水环境中原生动物群落的结构和组成发生变化,原生动物种类数减少,群落结构变得简单.在所有种类中,纤毛虫受损最大,水生生态系统的物质循环和能量流动将会受到一定程度的影响.     

植物铝胁迫发生机制及其内在缓解途径研究进展

本文总结了土壤中铝的存在形式及其化学行为,分析了以针叶人工林为例的诱发植物铝胁迫效应的内外部机制,以及铝胁迫在不同生态水平上对植物生长的影响。比较了环境铝胁迫下,植物体自身缓解环境铝威胁的不同途径。     

城市生活垃圾填埋场渗滤液生化处理过程中重金属离子问题

我国对城市生活填埋场渗滤液处理技术的研究主要集中在COD与NH4 -N的去除上,对渗滤液中重金属离子的专项研究几乎未见报道.本文首先总结了国内外城市生活垃圾渗滤液中重金属的种类及浓度,在渗滤液中的存在状态,渗滤液中重金属与其他成分(有机物、氨氮)的相互作用关系,辨证分析了重金属在渗滤液生化处理过程中的有益作用和毒性,归纳了重金属在渗滤液生化处理过程中的变化规律,同时总结分析了重金属的去除技术.     

运用主成分分析法评价北京市代表性河流的水质与毒性状况

以北京市3条具有不同功能的代表性河流(清河:纳污排洪;京密引水渠:供水水源;小月河:景观用水)作为研究对象,分析测定了33个水质指标,采用内梅罗指数法与大型蚤急性毒性测试法对3条河流的水质与毒性状况进行了评价,同时运用主成分分析法对毒性产生的原因和影响水质的因素进行了初步探讨.结果表明,1)3条河流已受到不同程度的污染,水质和毒性状况均不容乐观.作为纳污排洪的清河大部分采样点水质较差,生物毒性极高;作为景观用水的小月河水质一般,具有一定的生物毒性;作为供水水源的京密引水渠水质一般,但毒性较低.2)水样生物毒性与Cl-、Ca、K、Li、Mn、Na、Cr、Ni等指标有关;内梅罗水质指数与NO2-、Cl-、K、Na、Ni等指标有关.3)某些指标(如NO2-)超标会对水质分级产生较大影响,但对生物毒性贡献不大,而低浓度的重金属,不会对水质分级产生贡献,却会对生物的生理活动产生影响,综合化学指标和毒性指标共同评价水质更为合理.     

Relationships Between Toxicity and Concentrations of Chemical Contaminants in Sediments from Sydney Harbour, Australia, and Vicinity

Correlation analyses between measures of toxicity and concentrations of chemical contaminants were conducted for 103 surficial sediments from Sydney Harbour, Australia, and vicinity. Toxicity tests consisted of amphipod survival and reburial tests of whole sediments (Corophium colo), sea urchin fertilisation and larval development tests of pore waters (Heliocidaris tuberculata) and microbial bioluminescence (Microtox) tests of solvent extracts and pore waters. Toxicity in most tests correlated with concentrations of metallic contaminants, in particular, zinc, lead and copper. Organic contaminants did not correlate as significantly with toxicity. However, Heliocidaris tuberculata showed relationships with organochlorine compounds in samples with low to moderate metals contamination. Toxicity in the Microtox solvent extract test appeared to be primarily influenced by the presence of sulfur. This study has no precedent in Australia and the results support the validity of using local indigenous species in toxicity tests of field-collected sediments. This toxicity/chemistry dataset may be used in evaluations of sediment quality guidelines recently introduced to Australia.     

Toxicity Testing of Leachate from Waste Landfills Using Medaka (Oryzias Latipes) for Monitoring Environmental Safety

To investigate the environmental safety of waste disposal landfill sites and of land reclaimed from such sites, we evaluated the toxicity of leachate from these sites by a combination of bioassays in the Japanese killifish medaka Oryzias latipes. We tested for lethal toxicity in adult and larval medaka and for hatching inhibition of embryos from eggs. As biochemical evidence of the effects of leachate exposure, CYP1A (EROD activity) and vitellogenin (Vtg) were induced. We also bioassayed water-treated leachate and downstream river water. Leachate solution was lethal to larval and adult medaka. Embryo hatchability was inhibited, and abnormal hatching, spinal deformity and anisophthalmia occurred in embryos exposed to leachate solution. CYP1A was induced by exposure to leachate solution diluted to 1.0%, and EROD activity was significantly higher than in control. Vtg and unknown proteins were induced in the sera of male medaka exposed to the diluted leachate solution. Conventional water treatments worked effectively to remove toxic compounds but did not work well to remove element ions, including heavy metals. Treated leachate produced neither lethal toxicity nor hatching abnormalities during the exposure period. Fish toxicity tests for leachate would be useful for monitoring the environmental safety of landfill sites.