不同EPS组成生物膜对Cu2+吸附的研究

采用自行设计的反应器,通过调节培养液的配比对载体进行挂膜,得到蛋白质和多糖含量比分别为7:1、5:1和10:1的3种生物膜作为吸附剂,用其对Cu2+进行吸附试验,同时对吸附机理进行探讨.结果表明,培养8d后,生物膜可挂膜成熟,在C/N=12时,生物膜上的菌落数较C/N=4和C/N=37条件下多.PN/PS值越小,生物膜对铜的吸附量越高,EPS3对Cu2+的吸附量分别高出EPS1 7.37 %, EPS2 7.62%.在生物膜吸附Cu2+后,溶液中Ca2+、Mg2+、K+含量明显升高,表明离子交换对生物膜吸附Cu2+起主要作用,且Cu2+更易与Ca2+和Mg2+产生离子交换作用.当KNO3浓度在0.1~0.6mol/L之间,随着离子强度的增加,生物膜吸附Cu2+的量迅速减少,当KNO3浓度大于0.6mol/L时,生物膜对Cu2+吸附量的变化趋于平缓,说明生物膜对Cu2+的吸附同时包括离子交换吸附和化学吸附.     

虫螨腈对斑马鱼的急性毒性及生物富集性研究

以斑马鱼(Brachydanio rerio)为试验生物,采用半静态法测定虫螨腈对斑马鱼的急性毒性和生物富集系数。试验结果表明,虫螨腈对斑马鱼96 h-LC50为0.015 mg·L-1,其95%的置信限为0.011 mg·L-1~0.12 mg·L-1,属于高毒。在两个处理浓度2.0×10-4mg·L-1和2.0×10-3mg·L-1下,连续暴露8 d,斑马鱼对虫螨腈的生物富集系数(BCF8d)分别为1 211.6和1 549.7,属于高富集性农药。     

某湿地生态保护区水体中铜的生态风险评价及管理限值研究

铜是生物必需的微量元素,但过量暴露会对生物产生毒害效应。针对我国南方城市某湿地生态保护区水体重金属污染问题,参照《澳大利亚和新西兰淡水和海水水质指南》,应用物种敏感度分布(speeies sensitivity distribution,SSD)方法和联合概率曲线(joint probability curve,JPC)方法评价水体中铜的生态风险评价,在此基础上提出水体中铜浓度的管理限值。根据该湿地生态保护区生物调查历史数据以及其他文献数据,整理了415个本地物种的清单,通过美国环境保护署ECOTOX数据库以及其他文献共获取了13个物种的毒性数据,构建了Weibull分布、对数正态分布、正态分布、对数Logistic分布、Logistic分布、BurrⅢ型分布和Gumbel分布等7个SSD模型。结果表明,利用13个本地物种铜毒性数据构建的SSD模型具有合理性,不同模型计算得到的湿地生态保护区水体中铜的总体风险期望值为0.054~0.121。其中,BurrⅢ型分布模型的拟合效果最好,据此推导得到以保护水生生态系统为目标的铜的高可靠性与中等可靠性触发值分别为2.55μg·L~(-1)和1.41μg·L~(-1)。考虑到管理目标的可达性和现状的生态风险水平,提出该湿地生态保护区水体中铜浓度的管理限值为3μg·L~(-1)。     

Identification of pakchoi cultivars with low cadmium accumulation and soil factors that affect their cadmium uptake and translocation

The selection and use of low-Cd-accumulating cultivar （LCAC） has been proposed as one of the promising approaches in minimizing the entry of Cd in the human food chain. This study suggests a screening criterion of LCACs focusing on food safety. Pot culture and plot experiments were conducted to screen out LCACs from 35 pakchoi cultivars and to identify the crucial soil factors that affect Cd accumulation in LCACs. Results of the pot culture experiment showed that shoot Cd concentrations under the three Cd treatments significantly varied across cultivars. Two cultivars, Hualv 2 and Huajun 2, were identified as LCACs because their shoot Cd concentrations were lower than 0.2 mg. kg-1 under low Cd treatment and high Cd exposure did not affect the biomass of their shoots. The plot experiment further confirmed the consistency and genotypic stability of the low-Cd- accumulating traits of the two LCACs under various soil conditions. Results also showed that soil phosphorus availability was the most important soil factor in the Cd accumulation of pakchoi, which related negatively not only to Cd uptake by root but also to Cd translocation from root to shoot. The total Cd accumulation and translocation rates were lower in the LCACs than in the high-Cd cultivar, suggesting that Cd accumulation in different cultivars is associated with the Cd uptake by root as well as translocation from root to shoot. This study proves the feasibility of the application of the LCAC strategy in pakchoi cultivation to cope with Cd contamination in agricultural soils.     

Comparative study on the efficiency and environmental impact of two methods of utilizing polyvinyl chloride waste based on life cycle assessments

Two processes of utilizing polyvinyl chloride （PVC） waste, an incineration process and a vacuum pyrolysis process, for energy conversion were compared to determine their efficiency and environmental perfor- mance. We carried out a life cycle assessment with each of the two processes to evaluate their environmental impact and defined the goals and limits of our remit. As well, we established an inventory of PVC waste from incineration and vacuum pyrolysis based on process analysis, data collection and calculations. The results show that electrical power output per unit mass of PVC waste in the incineration process was twice as high as that of the vacuum pyrolysis process. Incineration had a larger total environmental impact potential than vacuum pyrolysis. The total environmental impact potential of PVC waste from incineration was three times higher than that from vacuum pyrolysis. Incineration of PVC disposed 300 ng. 100 kgI of dioxins and vacuum pyrolysis 98.19 ng- 100 kgI of dioxins. As well, we analyzed the data for their uncertainty with results quantified in terms of three uncertainties： basic uncertainty, additional uncertainty, and computational uncertainty. The coefficients of variation of the data were less than 25% and the quality of the inventory data was acceptable with low uncertainty. Both PVC waste disposal processes were of similar quality and their results comparable. The results of our life cycle impact assessment （LCIA） showed considerable reliability of our methodology. Overall, the vacuum pyrolysis process has a number advantages and greater potential for development of PVC disposal than the incineration process.     

The role of supervisor political skill in mentoring: Dual motivational perspectives

Drawing on self‐determination and self‐concept‐based theories, this study investigated the mediating effects of psychological empowerment and organization‐based self‐esteem on the relationship between supervisory mentoring and employee performance and the moderating effect of supervisor political skill on the direct and first stage of the indirect effects. Data were obtained from a sample of 330 subordinate–supervisor dyads from the People's Republic of China. Using PROCESS of conditional indirect effect, we found support for the moderated direct and indirect effects of supervisory mentoring. First, supervisor political skill moderates the direct effect of supervisory mentoring on employee promotability. Second, supervisor political skill moderates the indirect effect of supervisory mentoring on the following: (i) employee promotability via both psychological empowerment and organization‐based self‐esteem and (ii) contextual performance only via psychological empowerment. These direct and indirect effects of supervisory mentoring are stronger when supervisors demonstrate a higher level of political skill. Copyright © 2013 John Wiley & Sons, Ltd.     

氧化铝熟料窑粉尘的特性和电收尘技术的应用

分析了氧化铝熟料粉尘的特性,介绍了中国铝业公司山尔分公司氧化铝熟料窑窑尾电收尘的改造情况及电收尘本体的结构特点。     

强夯法加固软土地基的设计与施工工艺初探--以孟加拉吉大港软基处理为例

孟加拉吉大港新锚地集装箱码头位于孟加拉国Karnaphuli River河边,基底地层主要以填土、淤泥质土和粉细砂为主。对地基处理前集装箱堆放区和龙门轨道处的地基沉降量进行估算,总沉降量分别为462．2mm和562.4mm,均不满足设计要求,同时结合地基的加固要求。提出采用强夯法加固地基的各项技术参数,并进行综合评价,认为利用此方法进行强夯的计算设计方便快捷、有效、减少计算量,值得推广。     

爆炸危险环境防雷安全措施探讨

针对当前爆炸危险环境建筑物的防雷措施存在的漏洞,探讨了合理可行的安全措施和解决对策.     

板坯火焰清理机烟气治理技术

介绍了国产板坯火焰清理机烟气的治理系统及湿式电除尘器的结构和技术特点.结果表明,该烟气治理系统及湿式电除尘器能够满足火焰清理机工况和烟气排放的环保要求,完全可以替代同类进口设备.