Spatial distribution and ecological risk assessment of heavy metals in surface sediments from a typical plateau lake wetland, China

Surface sediment (0-15 cm) samples were collected from 31 different grid points throughout the Yilong Lake in April 2004. Samples were subjected to a total digestion technique and analyzed for As, Cd, Cr, Pb, Ni, Cu, and Zn in order to study spatial distribution characteristics based on Kriging method and assess their ecological risks posed by these heavy metals. Results showed that the mean concentrations of these heavy metals were lower than potential effect levels. Patches of higher heavy metal concentrations occurred in the inflow area of the Cheng River and northeast area nearby the road and railway. The higher concentrations of As and Cr also appeared in the east area (lake outlet), while the patches of lower concentrations were uniformly distributed at the southwest corner between Luosewan and Xiaoguoxi. The heavy metal loads such as As, Cd and Pb might come from the common sources due to industrial sewage and traffic pollution, while higher concentrations of Ni, Cr, and Zn in these sediments were dominated by parent rocks. However, Cu originated from both sources. Sediments with respect to As, Cd and Cu were grouped below the effect range low (ERL) at all sites, and with respect to Cr and Pb were grouped into the range from ERL to the effect range median (ERM) at more than 50% of sampling sites. The mean heavy metal toxic units in the Yilong Lake decreased following the order Pb > Cr > As > Ni > Zn > Cd > Cu, with higher contributions to the sum of toxic units of Pb, Cr and As.     

Evaluation of soil microbial toxicity of waste foundry sand for soil-related reuse

The relationship between the chemical con- taminants and soil microbial toxicity of waste foundry sand （WFS） was investigated. Five different types of WFS from typical ferrous, aluminum, and steel foundries in China were examined for total metals, leachable metals, and organic contaminants. The soil microbial toxicity of each WFS was evaluated by measuring the dehydrogenase activity （DHA） of a blended soil and WFS mixture and then comparing it to that of unblended soil. The results show that the five WFSs had very different compositions of metal and organic contaminants and thus exhibited very different levels of soil microbial inhibition when blended with soil. For a given WFS blended with soil in the range of 10wt.%-50wt.% WFS, the DHA decreased almost linearly with increased blending ratio. Furthermore, for a given blending ratio, the WFSs with higher concentrations of metal and organic contaminants exhibited greater microbial toxicity. Correlation analysis shows that the relationship between ecotoxicity and metal and organic contaminants of WFSs can be described by an empirical logarithmic linear model. This model may be used to control WFS blending ratios in soil-related applications based on chemical analysis results to prevent significant inhibition of soil microbial activity.     

Dense Polyacrylic Acid-Immobilized Polypropylene Non-woven Fabrics Prepared Via UV-Induced Photograft Technique for the Recovery of Rare Earth Ions from Aqueous Solution

Journal of Polymers and the Environment - In this work, a novel and easy-separating rare earth adsorbent (PAA/PPNWF) was successfully synthesized by generating dense polyacrylic acid (PAA) on the...     

天然Na基膨润土吸附处理高浓度PAM废水的研究

研究了PAM在天然钠基膨润土上的吸附行为,将其应用于含高浓度PAM（100～200 mg/L）的生产废水处理。静态条件下,膨润土的吸附平衡时间为1.5 h,最有效的吸附材料投加量为100 mg/100 mL水样。实验证明,低温度变化范围和弱酸、弱碱条件对PAM的吸附行为不产生显著影响。在最佳吸附动力学条件下,以活性炭做参比,利用实验的结论对化工厂中PAM生产废水进行吸附处理,结果表明,在对PAM废水中对PAM的吸附量分别可达到30.1和22.4 mg/g,膨润土是性价比较高的吸附处理材料。     

Cu-Mn-O制备条件对其催化燃烧甲苯性能的影响

以甲苯催化燃烧为模型反应,考察了Cu-Mn-O催化剂共沉淀制备方法中沉淀剂、滴加方式和焙烧温度对其催化活性的影响.结果表明,以Na2CO3为沉淀剂、反滴(金属离子溶液滴加到碱液)、500℃焙烧所制得的催化剂具有较高的活性,其甲苯完全燃烧(甲苯转化率98%以上)温度为220℃.多晶粉末衍射(XRD)和比表面积(BET)表征发现,在Cu1.5Mn1.5O4晶相中掺杂少量的CuO晶相可以有效地提高催化剂活性,催化剂的比表面积(BET)越大,活性越高.     

土壤生态毒性测试方法综述

土壤生态毒性测试在化学品管理和污染土壤评价等方面具有重要作用。传统的测试方法通常是利用生物个体、种群等水平上的存活、繁殖等测试终点来评价化学品或污染土壤对生态系统的影响。微宇宙等模拟生态系统和一些野外试验方法更接近生态系统的实际情况,但耗时更长、花费更高。与传统的测试方法相比,生物标志物敏感性高、响应速度快,有可能作为土壤污染的快速诊断工具。近年来,新技术的应用进一步促进了土壤生态毒理学的发展,如组学技术有助于理解有毒物的致毒机制,发现新的分子生物标志物。本文综述了目前土壤生态毒性测试的主要方法及其标准化和应用现状,同时对土壤生态毒性测试方法今后的研究方向及在我国环境管理中的应用提出展望。     

国内城市生活垃圾焚烧飞灰研究现状及进展

随着我国经济快速发展及城市化水平提升,城市生活垃圾产量越来越大,焚烧逐渐成为城市生活垃圾处理的主要方式.但焚烧会产生大量的垃圾焚烧飞灰(以下简称飞灰),飞灰属于危险废物.论述了飞灰的来源、成分、特性及危害,介绍了飞灰的处理处置技术:水泥固化技术、化学药剂稳定化技术、熔融固化技术、水热稳定化技术和水泥窑协同处理技术,并分...     

国内外油田污水处理技术发展概况

随着国内外油田开发,各种采油废水处理技术在油田得到了应用和发展。但由于采油废水的复杂性,导致在选择合适的水处理技术时难度加大,文章将当前众多采油废水处理技术进行综述,以期为选择有针对性的采油废水处理技术提供依据。     

混凝法处理丙烯腈-丁二烯-苯乙烯树脂废水

以聚合氯化铝铁为混凝剂、阴离子型聚丙烯酰胺为助凝剂,采用混凝法处理丙烯腈-丁二烯-苯乙烯树脂（ABS）废水（简称废水）,考察了聚合氯化铝铁加入量、沉降时间、搅拌转速、搅拌时间、废水pH和混凝温度对废水处理效果的影响。实验结果表明,在聚合氯化铝铁加入量50mg／L、阴离子型聚丙烯酰胺加入量2mg／L、废水pH6．0～8．0、快速搅拌1min、慢速搅拌6min、沉降时间25min、混凝温度20～25℃的条件下,废水的SS去除率达97％以上,COD去除率达77％以上。