Molecular characterization of microbial communities and quantification of <Emphasis Type="Italic">Mycobacterium immunogenum</Emphasis> in metal removal fluids and their associated biofilms

A number of human health effects have been associated with exposure to metal removal fluids (MRFs). Multiple lines of research suggest that a newly identified organism, Mycobacterium immunogenum (MI), appears to have an etiologic role in hypersensitivity pneumonitis (HP) in case of MRFs exposed workers. However, our knowledge of this organism, other possible causative agents (e.g., Pseudomonads), and the microbial ecology of MRFs in general, is limited. In this study, culture-based methods and small subunit ribosomal RNA gene clone library approach were used to characterize microbial communities in MRF bulk fluid and associated biofilm samples collected from fluid systems in an automobile engine plant. PCR amplification data using universal primers indicate that all samples had bacterial and fungal contaminated. Five among 15 samples formed colonies on the Mycobacteria agar 7H9 suggesting the likely presence of Mycobacteria in these five samples. This observation was confirmed with PCR amplification of 16S rRNA gene fragment using Mycobacteria specific primers. Two additional samples, Biofilm-1 and Biofilm-3, were positive in PCR amplification for Mycobacteria, yet no colonies formed on the 7H9 cultivation agar plates. Real-time PCR was used to quantify the abundance of M. immunogenum in these samples, and the data showed that the copies of M. immunogenum 16S rRNA gene in the samples ranges from 4.33?×?10⁴ copy/ml to 4.61?×?10⁷ copy/ml. Clone library analysis revealed that Paecilomyces sp. and Acremonium sp. and Acremonium-like were dominant fungi in MRF samples. Various bacterial species from the major phylum of proteobacteria were found and Pseudomonas is the dominant bacterial genus in these samples. Mycobacteria (more specifically MI) were found in all biofilm samples, including biofilms collected from inside the MRF systems and from adjacent environmental surfaces, suggesting that biofilms may play an important role in microbial ecology in MRFs. Biofilms may provide a shield or sheltered microenvironment for the growth and/or colonization of Mycobacteria in MRFs.     

石化综合污水生化处理中有机污染物的分析

运用GC-MS、紫外光谱及三维荧光光谱扫描技术考察了石化污水处理厂“水解酸化—厌氧处理—好氧处理”工艺的各单元出水中有机污染物的变化情况。总进水中检出84种主要有机污染物,主要含有烃类27种,酚类5种,醛、酯、醇和酮类化合物共24种,胺类4种,腈、有机酸及其他杂环化合物14种,另有10种物质未定性;该工艺的COD累积去除率达87.66%, 64种有机污染物被完全去除,17种有机污染物去除率可达90%以上,接触氧化池出水中主要含杂环化合物和少量醛、醇、酯类化合物。     

The effect of structural compositions on the biosorption of phenanthrene and pyrene by tea leaf residue fractions as model biosorbents

To enhance the removal efficiency of polycyclic aromatic hydrocarbons (PAHs) by natural biosorbent, sorption of phenanthrene and pyrene onto raw and modified tea leaves as a model biomass were investigated. Tea leaves were treated using Soxhlet extraction, saponification, and acid hydrolysis to yield six fractions. The structures of tea leaf fractions were characterized by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The amorphous cellulose components regulated the sorption kinetics, capacity, and mechanism of biomass fractions. The adsorption kinetics fit well to pseudo-second-order model and isotherms followed the Freundlich equation. By the consumption of the amorphous cellulose under acid hydrolysis, both the aliphatic moieties and aromatic domains contributed to total sorption, thus sorption capacities of the de-sugared fractions were dramatically increased (5–20-fold for phenanthrene and 8–36-fold for pyrene). All de-sugared fractions exhibited non-linear sorption due to strong specific interaction between PAHs and exposed aromatic domains of biosorbent, while presenting a relative slow rate because of the condensed domain in de-sugared samples. The availability of strong sorption phases (aromatic domains) in the biomass fractions were controlled by polar polysaccharide components, which were supported by the FTIR, CHN, and SEM data.     

Influence of the composition and removal characteristics of organic matter on heavy metal distribution in compost leachates

Compost leachates were collected to investigate the influence of the composition and removal of volatile fatty acids (VFAs), humic-like substances (HSs), and dissolved organic nitrogen (DON) on heavy metal distribution during the leachate treatment process. The results showed that acetic and propionic acids accounted for 81.3 to 93.84 % of VFAs, and that these acids were removed by the anaerobic-aerobic process. Humic- and fulvic-like substances were detected by excitation–emission matrix spectroscopy coupled with parallel factor analysis, and their content significantly decreased after the anaerobic and membrane treatments. DON in compost leachates ranged from 26.53 mg L^-1 to 919.46 mg L^-1, comprised of dissolved free amino acids and the protein-like matter bound to humic- and fulvic-like substances, and was removed by the aerobic process. Correlation analysis showed that Mn, Ni, and Pb were bound to VFAs and protein-, fulvic-, and humic-like substances in the leachates. Co was primarily bound to fulvic- and humic-like matter and inorganic sulfurs, whereas Cu, Zn, and Cd interacted with inorganic sulfur.     

Characterizing the heavy metal-complexing potential of fluorescent water-extractable organic matter from composted municipal solid wastes using fluorescence excitation–emission matrix spectra coupled with parallel factor analysis

To investigate the effect of organic matter evolution on heavy metal sorption, fluorescence excitation–emission matrix (EEM) spectra combined with parallel factor (PARAFAC) analysis were employed to characterize the evolution and metal-complexing potential of fluorescent water-extractable organic matter (WEOM) from composted municipal solid wastes (MSWs). The WEOMs examined comprised humic-, fulvic-, tryptophan-, and tyrosine-like substances. Composting treatment increased the content of humic- and fulvic-like matter, and changed the existence pattern of tryptophan- and tyrosine-like substances (i.e., the tryptophan- and tyrosine-like substances from uncomposted MSWs were mainly bound in protein-like matter, whereas those from composted MSWs were primarily bound in humic- and fulvic-like substances). Furthermore, composting treatment increased the polar functional group, aromaticity, and humification degree of the WEOMs, but decreased the aliphatic and hydroxyl group. These evolutions decreased the Cu(II) affinities of fulvic- and humic-like substances and the Pb(II) affinities and complexing capacities of fulvic-like substances, but increased the Cu(II) complexing capacities of fulvic- and humic-like substances. These results reveal that mature composts from the MSWs can be used for the remediation of Cu- and Pb-contaminated soils in situ, whereas immature composts can enhance the metal transferability from soil to plant.     

巢湖入湖河流沉积物中有机磷的形态分级研究简

为识别巢湖流域污染物的特征、来源及其沉积物有机磷各形态分布与富营养化的关系,测定了7条巢湖入湖河流沉积物中有机磷各形态的含量,分析不同污染类型入湖河流沉积物中有机磷各形态分布的差异及与其他因素间的相关性。研究发现,不同污染类型入湖河流沉积物中水土保持控制型河流沉积物中有机磷各组分的相对含量顺序为残渣态P_o >富里酸-P_o >HCl-P_o >胡敏酸-P_o >NaHCO₃-P_o,平均的相对比例为7.5：3.1：1.9：1.5：1.0,而城市污染控制型和面源污染控制型河流沉积物中有机磷各组分的相对含量顺序恰好相同,面源污染控制型河流沉积物P_o各形态含量低于城市污染控制型和水土保持控制型河流。中活性P_o和OM、TP、P_i、P_o、TN、NaHCO₃-P_i、NaOH-P_i呈正相关,非活性P_o与P_o、NaOH-P_i呈显著正相关关系,反映了中活性P_o很容易转化为生物可利用磷和非活性P_o,且非活性P_o仍然具有潜在的生物活性。     

空速和二氧化碳对沼气脱硫剂硫容确定的影响

为了弄清空速与二氧化碳含量对氧化铁脱硫剂硫容确定的影响,分别在实验气源为纯硫化氢,空速为40、80、120和160 h-1以及实验气源为二氧化碳含量分别在0%、20%、40%和80%,其余为硫化氢,空速为80 h-1条件下,对T502(粗脱硫剂)和HXT-2(精脱硫剂)2种氧化铁脱硫剂进行了不同测试条件对氧化铁硫容确定影响的研究。研究结果表明,T502和HXT-2氧化铁脱硫剂硫容测试结果随着空速和二氧化碳含量增加而减少,结果显示了在空速较低条件下(120h-1),二氧化碳含量在40%以下时对氧化铁脱硫剂硫容测试结果影响不大,但二氧化碳含量在40%以上时,对氧化铁脱硫剂硫容测试结果影响显著。     

三峡对长江中下游干流汛末水位影响——2006~2011年实例模拟

为了阐明三峡水库调节对长江中下游汛末水位的影响,基于2006～2011年三峡试验性蓄水实例,采用长江中游江湖耦合模型定量解析了近6年因三峡水量调节直接引起的长江中下游水位变化分量。结果表明,三峡使长江中下游汛末水位提前快速消落,枯水提前约半月余;螺山、汉口和大通三站汛末水位因三峡的水量调节而分别下降07,06和041 m。水位频率分布有明显变化,汛末中高水位区间内频率有所下降,而低水位频率则升高。三峡工程建成运行后每年汛末将集中蓄水,长江中下游供水量减少必成为常态。汛末水位的这些趋势性变化可能会对水资源利用和湿地生态造成影响,值得关注     

我国碳排放区域差异性分析

在对我国各地区的碳排放总量、人均碳排放和碳排放强度进行计算的基础上,运用Theil系数等方法对我国碳排放区域差异性进行分析。Theil系数分析结果表明我国碳排放强度呈现区域差异性,区域内差异是总体差异的主要原因,而东部和中部地区内部差异是导致区域内差异的主要原因;变异系数分析结果表明：碳排放总量东部地区差异最大、中部最小,人均碳排放西部地区差异最大、东部最小,碳排放强度中部地区差异最大、东部最小;基尼系数分析结果表明：西部地区碳排放差异最大,中部次之,东部最小;运用聚类分析将全国各省碳排放现状分为优、良、中、差四大类。针对研究结果,提出了转化经济发展方式、优化产业结构等节能减排建议