Pentachlorotoluene and pentabromotoluene: results of a subacute and a subchronic toxicity study in the rat

Pentachlorotoluene (PCT) and pentabromotoluene (PBT) are environmental contaminants detected in the Great Lakes ecosystem. In view of the paucity of toxicity data and the potential for human exposure, a subacute (28 day) and a subchronic (91 day) study were conducted in the rat. In the subacute study, groups of 10 male and 10 female rats were fed the diet containing PCT or PBT at 0, 0.5, 5.0, 50 or 500 ppm for 28-days. In the subchronic study, the group size was increased to 15, the dose levels were 0, 0.05, 0.5, 5.0, 50 and 500 ppm in the diet and the exposure period was 91 days. Growth rate and food consumption were not affected by exposure to either chemical in the subacute and subchronic study. Clinical observations revealed no abnormalities. Decreased hemoglobin was observed in female rats fed 5.0 ppm PCT and higher levels in the subacute (28 day) study. In the same study the hematocrit value and erythrocyte numbers of females fed 5.0 or 500 ppm PCT diets were significantly lower than the control. In both subacute and subchronic studies mild dose-dependent histopathological changes were observed in the thyroid, liver and kidney of rats fed PCT and PBT diets. In general male rats were more susceptible than females to the treatment of PCT and PBT. Based on these data, it was concluded that the no observable adverse effect level for PCT was 50 ppm in the diet (3.5 mg/kg b.w./day) and that of PBT was 5.0 ppm (0.35 mg/kg b.w./day).     

苯甲酰苯胺光化学行为的共振拉曼光谱

采用共振拉曼光谱技术和量子化学计算研究了苯甲酰苯胺在甲醇和乙腈溶液中的短时光化学动力学行为.结果表明,苯甲酰苯胺的非平面反式结构为最稳定结构;在Frank-Condon区域内,苯甲酰苯胺主要由9个活性振动模组成;其中v24(苯环上C=C不对称伸缩振动和CCH的面内弯曲振动,NH面内弯曲振动)振动模在甲醇溶剂中的强度远远大于其在乙腈的强度;与脂肪酰胺类化合物和苯甲酰胺的研究结果比较发现,苯基取代-NH2上的H原子使得C=C不再具有明显的溶剂效应.     

A Marine Pollution Study of Northeast Coastal Water Off Taiwan Island

The coastal water of northeast Taiwan island, called 'Yin-Yang Hai' for its distinct yellow colour compared with blue offshore water, was investigated from 1989 to 1990 by the authors. Biological study showed the dominant species of plankton to be Copepoda, Cladocera, planktonic eggs and Diatoma. Dominant species of benthos were young crabs, Amphipoda and Annelida, with Amphipoda usually occurring in heavily polluted areas. Heavy metal data showed that the concentration of copper was high. the copper and iron concentration in algae of the intertidal zone was also high. the concentrations of iron and copper in inshore water were also higher than in offshore water. By comparison of the pH and salinity distribution of this area, we conclude that this coastal water has been polluted by acid waste water from coastal industry. the suspended solids concentration in sea water is high. Flocculation occurring at the boundary of fresh and saline water might be a reason for the distinct yellow colour of the water of this area. Further study is required.     

家庭中水利用装置系统的设计

结合我国家庭中水的利用现状,设计了一套具有广泛应用性的家庭中水利用装置系统,并实现了相应的自动化控制方案。同时,详细介绍了系统的设计思路与实现的主要功能,并对装置系统的有关问题进行了深入的探讨。     

玉溪市中心城区酸雨变化趋势分析

以1991年至2000年实测数据为依据，揭示了玉溪市中心城区10年来酸雨的变化规律及其发展趋势。     

政策干预对提高煤矿职工素质影响探讨

煤矿井下作业人员素质低,是煤矿事故多发的重要原因之一.建议从大幅度提高煤矿井下人员工资待遇,吸引高素质人才从事煤矿工作;全方位开展煤矿职业培训工作,坚持先培训后就业,实行煤矿从业准入制;对现在岗的煤矿从业人员分期分批进行培训,实现煤矿从业人员持证上岗;政府出台政策,强制煤矿企业开展职工岗位技术培训和安全培训等4个方面着手,切实提高煤矿从业人员的整体素质,减少煤矿事故的发生.     

道路交通安全管理措施比较研究

根据近五年来我国道路交通安全状况的实际,针对目前我国道路交通安全管理的现状,本文就道路交通法规建设、道路交通安全宣传教育、道路交通执法、道路事故紧急救援措施等相关内容与日本、美国、欧洲交通发达国家进行了对比分析,以图找出我国现行的道路交通安全管理对策中的薄弱环节及完善的途径.     

树脂吸附-Fenton试剂氧化法处理水杨醛生产废水

采用树脂吸附-Fenton试剂氧化法处理水杨醛生产废水。XF-01树脂和XF-02树脂静态吸附水杨醛生产废水时,COD去除率均在85％以上,挥发酚去除率均高于90％。XF-02树脂对水杨醛生产废水的处理效果更佳。动态吸附随废水流量增大,吸附出水的COD和挥发酚质量浓度均增加。适宜的废水流量为15BV,树脂的最佳脱附温度为80℃。在连续4批的吸附-脱附实验中,吸附出水的平均COD约为1200mg／L,平均挥发酚质量浓度小于10mg／L。在Fenton试剂氧化中,铁屑和铁粉的催化效果差别很小,都好于FeSO4·7H2O。以铁屑为催化剂、H2O2溶液加入量为1％时,氧化出水的COD小于150mg／L,挥发酚质量浓度小于0．5mg／L。     

淀山湖沉积物的污染特征及其风险评价

对上海淀山湖代表性表层沉积物中的重金属、磷、PAHs及OCPs等典型污染物质进行了分析和风险评价。其中总磷含量范围为1 072~1 229 mg/kg,以无机磷为主,生物可利用磷含量较高,对水体富营养化具有潜在的威胁。重金属Cu、Cr、Zn、Pb的平均含量分别为25.5、34.1、244.5、32.2 mg/kg,污染程度大小依次为ZnPbCuCr,潜在生态风险程度依次为PbCuZnCr。∑PAHs、∑OCPs含量范围分别为617.1~843.2 ng/g以及22.03~28.94 ng/g,风险结果表明PAHs和大部分OCPs均未超出ERL值,生态风险水平低。     

不同温湿度条件下微米硼的氧化过程研究

目的 探究不同温湿度条件下微米硼的氧化层结构特征。方法 利用高温水浴浸泡处理去除原料微米硼的表面氧化层,然后在恒温恒湿条件下对微米硼进行加速氧化,利用扫描电子显微镜、透射电子显微镜和X射线光电子能谱对加速氧化后硼颗粒的氧化层厚度及组成进行分析,总结表面氧化层结构及成分组成变化规律,揭示温湿度条件下微米硼的氧化机制。结果 微米硼经高温水浴浸泡处理后,表面氧化层去除率达到50%。随着加速氧化时间的延长,硼颗粒氧化层的厚度逐渐增大,由内向外硼颗粒表面可以用B-BxOy-B2O3三层结构来表示,BxOy总是伴随着B2O3同时出现的,且随着氧化反应的进行,颗粒表面BxOy的含量将超过B的含量。结论 不同温湿度条件下微米硼的氧化机制为O2向B颗粒内部单向扩散的反应机制,B先与O2反应,形成低氧化物BxOy,BxOy进而与O2反应生成B2O3。随着氧化层厚度的增加,O2向B颗粒内部扩散的阻力增大,氧化反应速率随之降低。相比湿度的影响,温度的升高可显著加快硼表面氧化层的形成;温度一定时,湿度的增加可促进硼氧化层的形成。