RFLP技术在湖泊微生物多样性研究中的应用

文章介绍了一种不依赖于传统培养方法的限制性酶切片段长度多态性技术(RFLP),在湖泊微生物多样性研究中的应用、及其优缺点,并针对湖泊微生物基因组DNA的提取方法和16SrDNA片段的PCR优化条件等方面进行了探讨。     

北戴河近岸沉积物中微生物16S rDNA的PCR-RFLP分析

采用间接法提取了北戴河地区近岸沉积物中微生物的总DNA,以细菌的通用引物27F和1492R扩增16S rDNA片段,将扩增产物克隆到T-载体上,并转化大肠杆菌感受态细胞,构建沉积物中细菌16S rDNA克隆文库.PCR扩增基因文库中插入的16S rDNA外源片段,用两种限制性内切酶Hha Ⅰ和Rsa Ⅰ分别酶切,获得该海洋沉积物131个克隆的酶切指纹图谱.结果表明:HhaⅠ和Rsa Ⅰ联合酶切产生了41个基因分型,文库的覆盖度达74.81%,Hha Ⅰ和Rsa Ⅰ单酶切产生的基因分型分别为30和22,但文库的覆盖度高:克隆文库中存在一种优势类群,占总克隆的23%.16S rDNA测序结果表明:北戴河近岸沉积物中的细菌在分类方面主要属于α-和γ-变形杆菌亚门.     

六六六(HCHs)在小白洋淀水生植物中的分布与富集

利用GC-ECD测定了小白洋淀6个采样点的9种浮水、挺水和沉水植物中4种六六六(hexachlorocyclohexanes,HCHs)异构体的含量,分析了其分布、组成及富集特征。结果表明:1)小白洋淀水生植物中总HCHs含量范围在ND~7.47 ng·g-1(ww),浮水植物中HCHs含量最高,挺水植物各组织含量也有明显差异,根部HCHs含量明显高于茎叶2种组织。2)4种HCHs异构体中,γ-HCH的残留水平要显著高于其他3种异构体。在沉水植物和浮水植物中,均以γ-HCH占绝对比例,相对含量达60%~99%;而在挺水植物中,δ-HCHs占有较高比例,并且主要富集在挺水植物的根部,茎中次之,叶中最少。3)小白洋淀浮水植物和沉水植物HCHs含量与水体中HCHs含量呈显著的正相关关系,而挺水植物荷花、蒲草中HCHs各组分含量与水体中HCHs的相关关系不显著。4)水生植物对水中HCHs的富集系数BCF在8.7~661.2范围;浮水植物的BCF最高,沉水植物次之,挺水植物的茎对水体中HCHs的BCF最低。     

A 21-year record of methoxylated and hydroxylated polybrominated diphenyl ethers in sediments from the East China Sea

Sediments are major sinks for organic pollutants and therefore can be used as archives of pollutant history. Methoxylated (MeO-) and hydroxylated (OH-) polybrominated diphenyl ethers (PBDE) are of increasing concern because of their potential toxicity and worldwide distribution. However, there is limited information on these compounds in marine environments. Here we determined the contents of nine MeO-PBDE, ten OH-PBDE and total organic carbon in a sediment core collected from the inner shelf of the East China Sea in 2009. The historical trends of 6-MeO-BDE47, 6-OH-BDE47 and total organic carbon were reconstructed. Our results show that 6-MeO-BDE47 concentrations present no significant trend from 1987 to 2005 and then increase from 2005 to 2008. 6-OH-BDE47 concentrations generally increase slightly from 1987 to the end of the 1990s and then decrease. Comparisons between 6-OH-BDE47 and 6-MeO-BDE47 as well as total organic carbon suggest that 6-OH-BDE47 is mainly from terrigenous inputs.     

Polybrominated diphenyl ethers in plastic products,indoor dust,sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination,accumulation pattern,emissions, and human exposure

Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10^?7 to 1.2 × 10^?5 (year^?1) for total PBDEs and from 2.9 × 10^?7 to 7.2 × 10^?6 (year^?1) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10–3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities and the high degree of human exposure and suggest the need for continuous investigations on environmental pollution and toxic impacts of e-waste-related hazardous chemicals.     

Controlling various contaminants in wastewater effluent through membranes and engineered wetland

For effective wastewater reclamation and water recovery, the treatment of natural and effluent organic matters (NOM and EfOM), toxic anions, and micropollutants was considered in this work. Two different NOM (humic acid of the Suwannee River, and NOM of US and Youngsan River, Korea), and one EfOM from the Damyang wastewater treatment plant, Korea, were selected for investigating the removal efficiencies of tight nanofiltration (NF) and ultrafiltration (UF) membranes with different properties. Nitrate, bromate, and perchlorate were selected as target toxic anions due to their well known high toxicities. Tri-(2-chloroethyl)-phosphate (TCEP), oxybenzone, and caffeine, due to their different K _ow and pK _a values, were selected as target micropollutants. As expected, the NF membranes provided high removal efficiencies in terms of all the tested contaminants, and the UF membrane provided fairly high removal efficiencies for anions (except for nitrate) and the relatively hydrophobic micropollutant, oxybenzon. Through the wetlands, nitrate was successfully removed. Therefore, a fair process of combining membranes with an engineered wetland could be proposed for sustainable wastewater reclamation and optimum control of contaminats.     

火焰原子吸收光谱法测定工作场所空气中锰含量的不确定度评定

目的建立并运用火焰原子吸收光谱法测定工作场所空气中锰的不确定度评定方法。方法应用测量不确定度评定方法分析测定过程中不确定度的来源,识别出其中的主要来源。结果不确定度的主要来源：①标准溶液配制引入的不确定度;②样品消解定客引入的不确定度：③采样引入的不确定度;④仪器量化引入的不确定度。结论运用该不确定度评定方法对测定过程中关键环节的识别,将有助于检测人员重点关注关键环节的质量控制,以更为有效地提高检测工作的质量。     

脱氮除磷组合技术在美国的专利申请分析

针对1998-2008年间在美国专商局提交的有关污水脱氮除磷组合技术的专利申请进行了检索及统计分析,从量化角度展示了相关专利申请的年度分布状况、技术分类情况、申请人国别及类型,并对主要申请人的专利申请情况进行了初步分析。结果表明,污水脱氮除磷组合技术在美国已进入技术成熟期,好氧和厌氧是相关技术的热点和增长点。     

氟化工行业循环经济模式构建研究

氟化工是化工行业中发展最快、最具高新技术和最有前景的行业之一。如何使该行业持续健康发展,走循环经济是其根本出路。文章中论述了氟化工企业目前存在的主要问题,提出了氟化工企业实施循环经济的基本途径,并以青海某氟化工企业为实例,论述了该氟化工企业从延长产业链、采用清洁生产工艺、能源回收利用、水资源利用、固废资源综合利用、工艺尾气资源利用等方面构建循环经济模式,为同类型氟化工企业循环经济建设提供参考。     

柔性垂直防渗技术膨润土-黏土密封材料防渗性能研究

以长沙某厂区内天然黏土为主要原料,采用水溶液聚合法,在室温条件下,通过聚丙烯酰胺改性膨润土与黏土混合,制备密封材料,用于柔性垂直防渗墙建设工程底部区域密封,以防止地下水从高密度聚乙烯(HDPE)土工膜底绕流。通过室内试验研究3种不同改性剂以及膨润土添加量对密封材料渗透系数的影响以及密封材料对六价铬的阻滞吸附作用。结果表明：聚丙烯酰胺改性膨润土能够减小密封材料的渗透系数,而羟丙基甲基纤维和聚乙烯醇在一定程度上导致密封材料渗透系数增大;随着改性膨润土掺入量的增加,密封材料的渗透系数逐渐减小。在模拟柱迁移试验中,密封材料对污染物的截留率可达68.5%。基于长沙某柔性垂直防渗墙工程,对建成防渗墙区域进行示踪剂弥散迁移试验,在下游接收井中均未检测到示踪剂,说明该密封材料在工程应用上能有效防止底部地下水绕流。