Shifts in Microbial Communities, Microbial Biomass and Organic Matter Mineralization for Three Mediterranean Soils Contaminated By Metals

Microbial communities (phospholipid fatty acid pattern, bacterial growing strategies, eco-physiological index (EPI) and total bacteria counts, as a number of heterotrophic cuhurable bacteria), substrate-induced respiration (SIR), and nitrogen mineralization were studied in three Mediterranean soils at three different depth levels (A, B and C). Soils were experimentally treated with a final concentration of 1000 ppm of trace metals (Cu²⁺, Zn²⁺, Al³⁺, Fe²⁺, Pb²⁺, Ni²⁺, Mn²⁺, Cr³⁺ and Cd²⁺). Soils were stored in 571 plastic containers for one year, and watered with 1001 during this period. Leachate was recovered through a bottom tap. Samples of the three depths were studied. Soil microbial communities showed different effects to other studies presented in the literature, but carried out on non-Mediterranean soils. Dramatic differences were found between treated soils and untreated ones, but not between soils or horizons. the treated soil displayed a decrease in CFUs, SIR N-mineralization and EPI together with a dominance of r-growing strategists. the relative moles percent of several PLFAs, especially 15:0, 16: 1ω7, cy17: 0, br18:0 and 18: 1ω7 decreased because of the pollution of soils, whereas 10Me16, 18:2ω6, cy19:0, i16:0 and br17:0 showed higher values than in untreated soils.     

The fungal colonisation of rock-art caves: experimental evidence

The conservation of rock-art paintings in European caves is a matter of increasing interest. This derives from the bacterial colonisation of Altamira Cave, Spain and the recent fungal outbreak of Lascaux Cave, France—both included in the UNESCO World Heritage List. Here, we show direct evidence of a fungal colonisation of rock tablets in a testing system exposed in Altamira Cave. After 2 months, the tablets, previously sterilised, were heavily colonised by fungi and bacteria. Most fungi isolated were labelled as entomopathogens, while the bacteria were those regularly identified in the cave. Rock colonisation was probably promoted by the dissolved organic carbon supplied with the dripping and condensation waters and favoured by the displacement of aerosols towards the interior of the cave, which contributed to the dissemination of microorganisms. The role of arthropods in the dispersal of spores may also help in understanding fungal colonisation. This study evidences the fragility of rock-art caves and demonstrates that microorganisms can easily colonise bare rocks and materials introduced into the cavity.     

圆柱体相似试件的拉裂破坏模型研究

首先简单介绍了单轴压缩试验的具体情况。对于拉裂破坏模式,提出了相应的力学计算模型,并建立了抗压强度和抗拉强度的关系式。对于由拉裂面的存在而导致试件最终破坏的计算模型,提出了4种相应的假设。其中,对4种特征的拉裂面建立了抗压强度和抗拉强度的关系式。     

Cultural Relevance for Rural Community Development in China: A Case Study in Bai, Jingpo and Huyaodai Communities of Yunnan Province

A three-year study over the Bai, Jingpo and Huayaodai communities in Yunnan Province reveals that the community development is significantly influenced in various ways by such cultural factors as the concepts of development; concepts and traditions of inter-community relationships, consumption, mar- riage and gender; patterns of decision-making and production, resource and income allocation; as well as the role of information dissemination systems, religion and ritual. Based on the analysis over the interactive relevance between each factor and community development, some strategies and methods for dealing with such a cultural relevance in development projects are recommended.     

Stabilization/solidification of ashes in clays used in the manufacturing of ceramic bricks.

This paper presents the results of the lixiviation of metals from different mixtures of fly and bottom ashes that have been stabilized and solidified in clays used in the manufacture of bricks. The ashes used for this study were obtained from a Hoffmann-type brick furnace adapted for the incineration of municipal solid waste during the manufacturing of ceramic bricks. The ashes were stabilized in clay in different proportions of clay:ash mix (99:1, 95:5, 90:10, 80:20 and 60:40). Such mixes were used to manufacture bricks that were calcined at a temperature ranging from 50 to 1100 degrees C. The clay, ashes and manufactured bricks were characterized using X-ray diffraction, fluorescent X-ray, thermogravimetry, differential thermal analysis, atomic absorption spectroscopy and scanning electronic microscopy. In addition, toxicity characteristic leaching procedure lixiviation tests were performed according to the EPA 1311 method for the determination of heavy metals. The results showed an affinity between clay and ash, and also that the bricks manufactured with these mixtures present low lixiviation levels. The tests also showed the highest decrease in the concentration of arsenic, nickel, chromium, zinc and silver for 99:1 mixtures. The 95:5 mixture was found to be the most favourable for the stabilization (greater concentration decrease) of lead and cadmium. Selenium was the metal with the lowest concentration change whereas arsenic, nickel, chromium, zinc and cadmium showed the greatest concentration change in all mixtures, with the exception of cadmium in the mixture 99:1.     

北京市4种不同污水处理系统中病原菌变化研究

采用定量PCR技术,对北京市4种不同污水处理系统中大肠杆菌、军团菌和沙门氏菌随工艺及四季的数量变化进行了追踪研究,以评估病原菌的去除效果及污水回用的健康风险.结果发现,大肠杆菌在夏季进水和出水中的浓度分别在107~108copies·m L-1和105copies·m L-1左右;G-A/O系统对大肠杆菌的去除率最高,平均去除率达99.88%.军团菌在4个污水处理系统中进水浓度为104~105copies·m L-1,出水浓度约为104copies·m L-1,其在剩余污泥样品中浓度较高,达到105~106copies·m L-1.沙门氏菌进水浓度较低,为102~103copies·m L-1,且其在多个工艺段样品中未检出.季节变化对于病原菌的去除具有较大影响.研究表明,大肠杆菌在各污水处理系统中均可检出,且其分布具有一定的季节性,夏季的进出水中浓度相对较高;而军团菌和沙门氏菌浓度在各工艺中则并未呈现出明显的季节性变化.G-A/O系统对3种细菌的整体去除效果最为稳定,去除率较高.大肠杆菌在污水处理厂的出水及剩余污泥中浓度仍然较高,此外,冬季出水中也能检测到沙门氏菌的存在,因此,污水处理厂的出水和污泥排放仍存在一定的生态和健康风险.     

过氧化氢对铜绿微囊藻的损伤效应研究

采用室内培养的方法研究了不同浓度H2O2对铜绿微囊藻(Microcystic aeruginosa)藻细胞的损伤效应.结果表明,H2O2浓度越大,对藻细胞的毒害作用越大.24 h之后,铜绿微囊藻藻细胞数、叶绿素a、类胡萝卜素和蛋白质含量及总抗氧化能力(T-AOC)都快速下降,而MDA含量显著增加,同时培养基中的H2O2含量也迅速降低;随着处理时间的增加,毒性效应逐渐增强;72 h之后,藻细胞各指标值都降得很低,MDA含量也增加到最大,培养基中H2O2也逐渐被消耗和分解,藻细胞的损伤效应也达到最大.其中,H2O2浓度为50 mg·L-1时,能够有效的去除藻细胞,并且对藻细胞的生理指标及抗氧化能力都有很强的损伤效应.     

四氯丙烯对稀有鮈鲫的急性毒性及安全浓度评价

采用半静态试验方式测试了四氯丙烯对稀有鮈鲫(Gobiocypris rarus)的急性毒性,试验浓度分别设定为0.25 mg·L~(-1)、0.30mg·L~(-1)、0.36 mg·L~(-1)、0.42 mg·L~(-1)、0.50 mg·L~(-1)和0.60 mg·L~(-1),同时进行空白对照(试验用水)和分散剂对照(体积分数为0.006%的吐温-80水溶液)试验。采用气相色谱法对试验溶液进行浓度分析,实测浓度分别为0.19 mg·L~(-1)、0.25 mg·L~(-1)、0.34 mg·L~(-1)、0.40 mg·L~(-1)、0.51 mg·L~(-1)和0.64 mg·L~(-1),试验结果以实测浓度表示和统计。结果表明:四氯丙烯致稀有鮈鲫无死亡发生(EC0)的最高浓度为0.25 mg·L~(-1),导致稀有鮈鲫100%死亡(EC100)的最低浓度为0.51 mg·L~(-1)。根据实测浓度,用SPSS(17.0)概率单位法求得四氯丙烯对稀有鮈鲫的半数致死浓度96 h-LC50为0.347 mg·L~(-1),95%置信区间为0.328 mg·L~(-1)~0.361 mg·L~(-1)。     

胎盘内多环芳烃分布及源解析研究

探讨多环芳烃在胎盘中的分布,并对其进行源解析。从2012年6月—2013年6月在云南省第一人民医院产科分娩的产妇中随机抽取30例,利用气相色谱-质谱联用仪(GC-MS)检测其胎盘中多环芳烃的含量;比较胎盘的中央部分和边缘部分多环芳烃含量的差异;对多环芳烃进行源解析,探讨其主要来源。胎盘中检测到多种多环芳烃成分;其中2~4个苯环的多环芳烃占总量的90%以上,尤其是萘、苊、芴、菲、蒽、芘、荧蒽的含量较高;萘、苊烯、苊、茚并(1,2,3-c,d)芘、二苯并(a,h)蒽5种多环芳烃在胎盘中央的含量高于边缘,具有显著性差异(P0.05),其他多环芳烃在胎盘中央和边缘的含量无显著性差异(P0.05)。多环芳烃源解析提示80%研究对象体内的多环芳烃主要来自石油产品的燃烧或暴露于石油产品。