PCBs污染土壤的CaO诱导低温热处理脱氯研究

研究了低温热处理脱氯技术对废弃电容器封存点附近污染土壤中多氯联苯脱氯的效果,考察反应温度、反应时间及CaO添加比例对PCBs去除率、脱氯率的影响以及反应前后土壤中污染物的组分变化.实验土样中PCBs浓度为107.7 mg/g,属于罕见高浓度PCBs污染土壤.当反应温度为400℃、停留时间4h、CaO添加比例为10%,PCBs的去除率为87.7%,脱氯率为85.3%.土壤样品中五氯联苯和四氯联苯反应后含量降低或未检出,部分反应后样品检出一氯联苯和联苯,说明在CaO诱导PCBs低温热处理脱氯反应中存在逐步脱氯/加氢反应途径.     

水泥窑共处置废物过程中重金属的流向分布

为了探索水泥窑共处置危险废物过程中重金属流向分布规律,研究了不同温度条件下Cr、As、Pb在煅烧熟料、颗粒物和尾气中的残留率.在900、1 000、1 100、1 200、1 300和1 450℃温度条件下,将添加Cr、As和Pb化学试剂的生料分别进行煅烧,模拟重金属在水泥窑内不同温度带的煅烧过程.结果表明,6个温度条件下,Cr主要分布在熟料中并且呈现不规则变化;颗粒物中的Cr在1 200℃条件下分布量最大,所占比例为32.79%(w);在900℃和1450℃条件下,烟气中的Cr分布量最大,所占比例为0.24%(w).6个温度条件下As主要分布在熟料中并且1 000~1 450℃条件下稳定在81%~83%之间;在900℃条件下,As在熟料中的残留率最大,所占比例为97%(w);在1450℃条件下,As在尾气中的分布达到最大值,所占比例为0.0023%(w).6个温度条件下,Pb在熟料中的残留率随着温度升高而逐渐减少,挥发颗粒物中的含量呈现相反的趋势;尾气中Pb的含量随着温度的升高逐渐增加.     

Involvement of abscisic acid in regulating antioxidative defense systems and IAA-oxidase activity and improving adventitious rooting in mung bean [Vigna radiata (L.) Wilczek] seedlings under cadmium stress

In vitro experiments were conducted to investigate the effects of abscisic acid (ABA) and Cd on antioxidative defense systems and indole-3-acetic acid (IAA) oxidase during adventitious rooting in mung bean [Vigna radiata (L.) Wilczek] seedlings. The exogenous ABA significantly enhanced the number and fresh weight of the adventitious roots. CdCl₂ strongly inhibited adventitious rooting. Pretreatment with 10 μM ABA clearly alleviated the inhibitory effect of Cd on rooting. ABA significantly reduced superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT) activities, as well as the levels of glutathione (GSH) and ascorbic acid (ASA) during adventitious rooting. ABA strongly increased IAA-oxidase activity during the induction (0–12 h) and expression (after 48 h) phases and increased the phenols levels. Cd treatment significantly reduced the activities of SOD, APX, POD, and IAA oxidase, as well as GSH level. Cd strongly increased ASA levels. ABA pretreatment counteracted Cd-induced alterations of certain antioxidants and antioxidative enzymes, e.g., remarkably rescued APX and POD activities, reduced the elevated SOD and CAT activities and ASA levels, and recovered the reduced GSH levels, caused by Cd stress. Thus, the physiological effects of the combination of ABA and Cd treatments were opposite of those obtained with Cd treatment alone, suggesting that ABA involved in the regulation of antioxidative defense systems and the alleviation of wounding- and Cd-induced oxidative stress.     

Distribution of antibiotic-resistant bacteria in chicken manure and manure-fertilized vegetables

Veterinary manure is an important pollution reservoir of antibiotics and antibiotic-resistant bacteria (ARB). However, little is known of the distribution of ARB in plant endophytic bacteria and the number/types of ARB in chicken manure. In this study, 454-pyrosequencing was used to investigate the distribution and composition of ARBs in chicken manure and fertilized vegetables. The prevalence of ARB in the samples of the chicken manure compost recovered from farms on which amoxicillin, kanamycin, gentamicin, and cephalexin were used was 20.91–65.9 % for ARBs and 8.24–20.63 % simultaneously resistant to two or more antibiotics (multiple antibiotic resistant bacteria (MARB)). Antibiotic-resistant endophytic bacteria were widely detected in celery, pakchoi, and cucumber with the highest rate of resistance to cephalexin. The pyrosequencing indicated that the chicken manure dominantly harbored Firmicutes, Bacteroidetes, Synergistetes, and Proteobacteria and that Bacteroidetes was significantly enhanced in farms utilizing antibiotics. In the total cultivable colonies, 62.58–89.43 % ARBs and 95.29 % MARB were clustered in Bacteroidetes with the dominant species (Myroides ordoratimimus and Spningobacterium spp., respectively) related to human clinical opportunistic pathogens.     

稀土作业者外周血淋巴细胞姊妹染色单体互换的观察

本文报告了 5 0例稀土作业工人外周血淋巴细胞姊妹染色单体互换 (SCE)的观察结果 ,其 SCE频率为 5 .49± 1.2 1(SCE/ cell,X SE) ,与 2 0例对照组相比 ,差异显莉 (P<0 .0 1)。随工令的延长 ,SCE频率为增高的趋势 ,但各工令组之间 ,经统计学处理 ,差异不显著 (P<0 .0 5 )。男工 SCE率高于女工 ,这可能与男工吸烟人数多于女工有前。我们认为 :SCE可作为稀土作业人员早期危害观察指标     

膜生物反应器运行中的膜污染问题

这了各国研究者针对膜生物反应器中的膜污染问题所作的工作，认为膜本身的性质以及废水组成和工艺条件都是造成膜污染的主要原因，利用反冲洗和清洗手段，可以有效地改善膜的性能，以提高膜的寿命，膜生物反应器技术的改进是避免膜污染的新思路。     

溶剂萃取--蒸汽蒸馏法处理含油污泥

为了实现含油污泥的资源化和无害化，对含油污泥进行了室温下的三氯甲烷溶剂萃取，然后在温度３２０～４８０℃、压力０．２ＭＰａ下进行水蒸汽蒸馏０～９０ｍｉｎ的掊油实验，结果表明含油污泥中加入３倍的萃取溶剂进行萃取，再按１ｇ油泥加０．５ｍＬ的水在４００℃下蒸馏，４５ｍｉｎ效果较好，脱油率达８０％～９５％。     

Chemical composition of precipitation and its sources in Hangzhou, China

To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH??, Ca2?, Mg2?, Na?, K?, SO?2?, NO??, F?, and Cl?). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO?2?/NO?? ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO?2?, Ca2?, and Mg2? and 33.7% of K? were of non-sea origins, while all Na? and Cl? and 66.3% of K? originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources.     

Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau

In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements(Ca and Mg), and nutrient(NO $_{3}^{-})$ were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007?C2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1?C22) and anthropogenic action (sites 23?C76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO $_{3}^{-}$ and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively.     

遥感调查方法在河北省省级自然保护区生态环境变化评估方面的应用研究

河北省省级自然保护区以自然生态系统类型为主,人类活动较为频繁,将遥感评估方法应用于河北省省级自然保护区生态环境变化评估具有重要意义。本文通过分析高分辨率遥感卫星影像的特点,结合河北省省级自然保护区的实际情况,优先选取分辨率为2m的民用卫星,提出了遥感调查方法在自然保护区人类活动和开发建设活动中自动监测、生态系统格局变化、生态系统质量变化以及人类活动干扰程度四方面的评估应用。