Comparative study of heavy metal and pathogenic bacterial contamination in sludge and manure in biogas and non-biogas swine farms

The objective of this study is to determine and compare the heavy metal (Zn, Cu, Cd, Pb) and bacterial (E. coli, coliform and Salmonella spp.) contamination between swine farms utilizing biogas and non-biogas systems in the central part of Thailand. Results showed that average levels of E. coli, coliform, BOD, COD, Zn, Cu and Pb in sludge from the post-biogas pond were higher than the standard limits. Moreover, the levels of E. coli, coliform, Cd and Pb were also higher than the standard limits for dry manure. The levels of E. coli, coliform and BOD on biogas farms were lower than on non-biogas farms. Following isolation of Salmonella spp:; it was found that Salmonella serovars Rissen was the most abundant at 18.46% (12/65), followed by Anatum 12.31% (8/65), and Kedougou 9.23% (6/65). The pathogenic strains of Salmonella serovars Paratyphi B var. java and Typhimurium were present in equal amounts at 4.62% (3/65) in samples from all swine farms. This study revealed that significant reduction in E. coli and coliform levels in sludge from covered lagoon biogas systems on swine farms. The presence of Salmonella as well as Cd and Pb, in significant amount in dry manure, suggests that there is a high probability of environmental contamination if it is used for agricultural purposes. Thus, careful waste and manure disposal from swine farms and the regular monitoring of wastewater is strongly recommended to ensure the safety of humans, other animals and the environment.     

Evaluation of adsorption capacities of humic acids extracted from Algerian soil on polyaniline for application to remove pollutants such as Cd(Ⅱ), Zn(Ⅱ) and Ni(Ⅱ) and characterization with cavity microelectrode

The adsorption capacities of new humic acids isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils (Algeria) and commercial humic acid (PFHA) on polyaniline emeraldine base (PEB) were studied at pH 6.6. Also the adsorption of heavy metals such as Cd2+, Zn2+ and Ni2+ on humic acid-polyaniline systems (HA-PEB) was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy (SEM), infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd2+, Zn2+ and Ni2+ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities (qmax) of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that qmax of Cd2+, Zn2+ and Ni2+ on HA-PEB followed the order: THA-PEB > YHA-PEB > PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.     

重金属离子快速检测技术研究与应用进展

在突发环境污染事件和区域生态风险筛查中迫切需要环境样品中重金属离子的快速检测技术手段。环境样品中重金属离子的快速检测技术有电化学方法和生物学方法。电化学检测方法主要是阳极溶出伏安法(AnodicStripping Voltammetry,ASV),可以同时检测多种重金属离子,有标准化认证的产品,但是检测成本相对较高。随着纳米粒子技术(Nanoparticles,NPs)和石英微天平分析技术(Quartz Crystal Microbalance,QCM)的引入,ASV法的检测成本将不断降低;生物检测方法包括免疫检测(Immunoassay,IA)和功能DNA(Functional DNA)检测技术。重金属离子的免疫检测技术样品通量大,检测成本低,已经广泛用于食品行业,其中汞离子的免疫检测方法已经成为环境样品标准检测方法之一。免疫检测传感器技术将拓展重金属离子的快速检测的应用空间。功能DNA传感器检测的研究为重金属离子的快速检测提供了新的技术手段,但是这些仅限于实验室研究,还没有达到实际应用的水平。     

福州城市边缘区森林土壤重金属污染特征及评价

为掌握福州城市边缘区森林土壤重金属污染特征,选取10个典型区域作为研究对象,分析森林土壤中Zn、Mn、Cr、Pb、Cu 5种重金属的含量及分布特征,并采用单项污染指数和综合污染指数法对土壤进行质量评价,结果表明:Cr、Pb是该区土壤重金属污染最主要的元素;Zn、Cu、Pb、Cr含量随土层深度增加而减少,Mn则相反;Zn...     

兰州银滩湿地5种植物对重金属吸附能力的分析

利用原子吸收分光光度法测定兰州银滩湿地5种植物及其生长土壤(表层)中Cu、Pb、Zn的含量,结果表明,采样区域表层土壤存在轻度Cu、Zn、Pb污染,其中Cu、Pb的来源或污染途径可能相同,且Cu、Zn、Pb的生物可利用性较低,TCLP生态风险评价显示均小于国际标准值;采样区域表层土壤Cu、Zn、Pb总量与TCLP提取量...     

北方某钢铁厂部分厂区土壤重金属污染的初步调查

对北方某即将搬迁钢铁厂的部分厂区土壤重金属进行了初步调查,主要利用SPSS相关和变异分析、Surfer空间分析及归一化处理对重金属污染的空间分布特征进行了描述。一区污染最为严重,有Hg、Mn、Zn、As、Cr和Cu;二区污染物主要为As、Pb和Zn;三区污染主要有As、Cr和Co;四区污染物有Cr、Co、Mn、Cu和Pb,污染相对较低。研究为调查区域搬迁后的土地规划提供了科学依据。     

Arbuscular mycorrhizal fungal phylogenetic groups differ in affecting host plants along heavy metal levels

Arbuscular mycorrhizal fungi（AMF） are important components of soil microbial communities,and play important role in plant growth. However, the effects of AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） and host plant functional groups（herbs vs. trees, and non-legumes vs. legumes） at three heavy metal levels. In the meta-analysis, we calculate the effect size（ln（RR）） by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels.Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment.     

Mo-modified Pd/Al2O3 catalysts for benzene catalytic combustion

Mo-modified Pd/Al2O3catalysts were prepared by an impregnation method and tested for the catalytic combustion of benzene. The catalysts were characterized by N2 isothermal adsorption, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, temperatureprogrammed desorption of NH3（NH3-TPD）, H2temperature-programmed reduction（H2-TPR）, and high-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM）. The results showed that the addition of Mo effectively improved the activity and stability of the Pd/Al2O3catalyst by increasing the dispersion of Pd active components, changing the partial oxidation state of palladium and increasing the oxygen species concentration on the surface of catalyst. In the case of the Pd-Mo/Al2O3catalyst,benzene conversion of 90% was obtained at temperatures as low as 190°C, which was 45°C lower than that for similar performance with the Pd/Al2O3catalyst. Moreover, the 1.0% Pd-5% Mo/Al2O3catalyst was more active than the 2.0% Pd/Al2O3catalyst. It was concluded that Pd and Mo have a synergistic effect in benzene catalytic combustion.     

探讨适用于河流沉积物重金属污染程度的评价方法

本文使用地累积指数法和潜在生态危害指数法两种方法对同一区域五条河流的沉积物中重金属的测定结果进行了评价和比较,提出了将河流沉积物中重金属的监测纳入我国地表水常规监测的意见和建议.     

伊犁河流域土壤重金属环境地球化学基线研究及污染评价

采用标准化方法建立伊犁河流域黑钙土、栗钙土、灰钙土和盐碱土Cu、Zn、Pb、As、Hg环境地球化学基线模型,并计算其理论基线值.采用基线因子污染指数评价法、环境背景值评价法和重金属环境洁净度评价法对流域土壤进行对比污染评价.结果表明:①基线因子污染评价显示流域内4种典型土壤类型以As的污染最为突出,黑钙土、栗钙土、灰钙土分别有7.14%、9.76%、7.50%的样点达重度污染;其次为Pb,栗钙土有7.32%的样点达重度污染,且As和Pb的变异度最大,表明人为扰动大.②环境背景值评价显示,土壤主要污染元素为As,其次为Cu、Zn、Pb;③土壤重金属环境洁净度评价显示,Cu、Zn、Pb在4种土类中均优于二级洁净度,Hg为一级洁净度,As在灰钙土中为中度污染,黑钙土、栗钙土、盐碱土为二级或优于二级.比较3种评价体系,基线因子污染评价较为充分地体现了元素地球化学迁移特性及土壤发育过程,且可将污染评价定位到样点;而背景值污染评价因建立于区域背景值,忽视了重金属元素在土壤中自然迁移、淀积过程;重金属环境洁净度评价则以土壤环境安全度为主要评价目的.