基于esp基因和JCV标记的MST方法在五大流域典型水源地中的应用

非点源污染目前已经成为影响水体环境的重要污染。微生物源示踪技术(microbial source tracking,MST)是解决非点源污染的一项新技术,它可以确定污染的宿主来源。肠球菌esp基因和多瘤病毒JCV可以作为检测水体中人源粪便污染的分子标记,其灵敏度和特异性都很高。为分析五大流域水源地是否受到人源粪便的污染,对辽河、海河、淮河、长江和黄河五大流域典型水源地水样进行采集和检测,选取人源粪便特异病原微生物肠球菌的esp基因和多瘤病毒JCV建立了相应的MST分子检测方法。结果表明,五大流域的典型水源地采样点均有可能受到了人源粪便的污染,可为当地相关部门提供技术支持和数据参考。     

鸡、猪粪便源大肠杆菌对4种抗生素耐药性的比较

以琼脂稀释法对67株鸡源大肠杆菌及61株猪源大肠杆菌进行最低抑菌浓度(MIC)测定,并以SPSS分别进行卡方检验和Probit模型估算,分析不同来源大肠杆菌耐药差异显著性及不同抗生素的半数抑菌浓度(MIC50),以期对不同畜禽粪便来源的大肠杆菌耐药差异进行详细准确的探讨。结果显示,鸡源大肠杆菌对头孢噻肟、诺氟沙星、环丙沙星和四环素耐药率分别为98.51%、68.66%、56.72%和100%,猪源大肠杆菌对头孢噻肟耐药率为88.52%,对诺氟沙星、环丙沙星和四环素则100%耐药。除四环素,鸡源、猪源大肠杆菌对诺氟沙星、环丙沙星、头孢噻肟的耐受差异显著(P0.05),51%的鸡源大肠杆菌和89%的猪源大肠杆菌均呈4重耐药。SPSS分析结果表明,Probit模型估算结果优于当前MIC50常规计算方法,头孢噻肟、诺氟沙星、环丙沙星和四环素对鸡源大肠杆菌MIC50分别为40.031μg·m L~(-1)、40.020μg·m L~(-1)、2.683μg·m L~(-1)和101.418μg·m L~(-1),对猪源大肠杆菌MIC50分别为8.724μg·m L~(-1)、56.044μg·m L~(-1)、31.214μg·m L~(-1)和130.915μg·m L~(-1)。回归方程显示环丙沙星对鸡源大肠杆菌抑制作用最强;高于40.031μg·m L~(-1)时,诺氟沙星抗菌作用弱于头孢噻肟,低于120.23μg·m L~(-1)时,诺氟沙星抗菌作用强于四环素;头孢噻肟、环丙沙星、诺氟沙星和四环素对猪源大肠杆菌的抑菌作用则呈递减趋势。同时验证了诺氟沙星和环丙沙星属同种作用机制,基于Probit模型计算更简单、快速、直观。研究结果可为畜禽养殖中大肠杆菌的耐药差异监控提供一定的数据基础。     

基于GIS的龙墩水库典型小流域面源污染氮磷负荷研究

以南京市高淳区龙墩水库流域为研究对象,运用地理信息系统(GIS)和通用土壤流失方程模型(USLE)预测氮磷的污染负荷.利用SWAT模型的子流域划分模块进行流域分区,运用等标污染负荷和等标污染强度进行面源污染评价,最后通过聚类分析完成氮磷污染负荷的分级,从而确定关键源区.结果表明,研究区总磷(TP)污染强度为4.95 t·km-2,污染负荷为124.25 t;总氮(TN)污染强度为10.96t·km-2,污染负荷为274.87 t.整个流域的等标污染负荷为2.76× 109 m3,其中TN为2.75× 108 m3,等标污染负荷比为9.96％;TP为2.48× 109 m3,等标污染负荷比为90.04％,TP为流域面源污染的主要污染物.不同土地利用方式的TP和TN污染负荷和流失模数均以旱地为最高,旱地是流域内面源污染物的主要来源.     

长沙市不同功能区空气微生物污染与评价

利用真菌、细菌综合培养基,采用自然沉降法对长沙市5个典型功能区进行空气微生物监测。结果表明,城区内不同功能区大气微生物的浓度各异,其中市区商业区、交通枢纽区的大气细菌污染最重,其次是休闲娱乐区和居民区,文教区大气细菌含量最低。绿化情况良好的休闲娱乐区的真菌含量高于交通枢纽区。以大气细菌含量指标评价了各测点的空气质量,空气质量处于微生物污染水平。     

粪便中病原微生物快速检测方法研究进展

近年来国内乡村生态环境的保护和改善受到高度关注,其中厕所粪便的无害化处理和资源化利用是乡村居住环境改造的重点之一。粪便中的病原微生物可通过污染食物或水源感染人类,对公共健康和生态环境产生很大危害,因此针对粪便中病原微生物的快速检测方法的研究至关重要。该文综述了目前粪便中病原微生物快速检测方法的研究进展,特别是核酸检测法、免疫学检测法和生物传感器检测法这3类新兴的病原微生物快速检测方法。核酸检测法通对目标序列进行放大扩增,可以检测目标病原体的特定基因,检测准确度高;免疫学检测法利用抗原-抗体杂交反应,据此开发的试剂盒能够快速检测目标物;生物传感器检测法主要依靠光学和电化学分析技术,样品制备简单,能够实现检测系统的微型化、模块化和集成。文中对比了几种方法的检测限和检测时间,并对其优缺点和实际应用潜力进行了分析讨论。     

基于小流域尺度的目标抗生素排放量估算方法——以梅江流域为例

抗生素的大量使用和排放造成的环境污染和生态风险问题日益突出,抗生素排放量的估算是评价流域内抗生素污染程度的重要指标,但目前抗生素排放量估算方法尚不完善。本研究以梅江流域为例,建立了适合小流域尺度的典型抗生素排放量估算方法,计算了四环素类抗生素(TCs)向不同环境相的排放量并分析了其主要来源。结果表明:2016年梅江流域TCs排放量为8 558.1 kg,不同行政区抗生素排放量差异较大,其中梅江镇受人口密度及养殖密度影响,抗生素排放量最大,高达1 224.4 kg;同时流域内不同抗生素的排放量也有所不同,其大小顺序为强力霉素(DXC)土霉素(OTC)四环素(TC)金霉素(CTC);TCs受排放源、排放途径等因素影响,以进入环境水相及土壤相为主,其中进入水相中的抗生素主要来自人类及生猪粪便,进入土壤相中的抗生素主要来自生猪及三黄鸡粪便。梅江小流域抗生素具有潜在的生态风险,应加强抗生素使用管理。该研究为我国小尺度流域目标抗生素排放量的估算提供了十分有效的方法。     

洱海流域农业面源污染研究进展

农业面源污染控制是洱海水质保护必须直面的不可逃避的问题。在系统调研洱海流域农业面源污染领域研究成果的基础上,归纳了洱海流域不同农业产业、行政区域、农用地、入湖河流和入湖河口湿地农业面源污染分布及特征,介绍了洱海流域农业面源污染研究采用的技术,总结了入湖河口湿地、农田灌排沟渠和湖滨缓冲带对洱海流域农业面源污染治理产生的积极作用,阐明大蒜不合理的施肥和轮作模式,奶牛、猪和肉牛等大牲畜的养殖以及土地利用的频繁改变等是导致洱海流域农业面源污染负荷产生的主要原因。通过合理的化肥减量施用、有机肥替代化肥、水稻-蚕豆轮作以及蚕豆间作大蒜模式,既能削减农业面源污染负荷,又能保证作物优质适产。针对洱海流域农业面源污染综合防治存在的问题,提出今后应加大农村生产生活、入湖河流生态系统以及养殖业等对洱海流域农业面源污染影响的研究。     

纳米银与银离子对土壤微生物及酶活性的影响

为研究纳米银和银离子对土壤微生物的影响,采用土壤培养方式,对不同剂量纳米银(10、50、100 mg·kg~(-1))和银离子(1、5、10 mg·kg~(-1))暴露下黄褐土、砖红壤中可培养微生物数量及土壤酶活性(脲酶、荧光素二乙酸酯水解酶、蔗糖酶、过氧化氢酶)进行研究,并采用纯培养方法对纳米银和银离子暴露下的大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)凋亡情况进行检测,对纳米银释放的银离子毒性进行评估。结果表明,随着纳米银剂量的增加,土壤可培养微生物数量显著减少,脲酶和过氧化氢酶活性降低,蔗糖酶、荧光素二乙酸酯水解酶(FDA酶)活性没有显著变化;银离子处理中微生物数量明显减少,但土壤酶活性被激活。10 mg·L~(-1)纳米银暴露1 h后大肠杆菌、金黄色葡萄球菌凋亡率、死亡率增高;随着培养时间的延长,纳米银缓慢释放银离子,并促进大肠杆菌的凋亡。综上分析,纳米银能够抑制土壤可培养微生物生长和酶活性,其中脲酶、过氧化氢酶对纳米银较为敏感,蔗糖酶、FDA酶受纳米银的影响较小;纳米银的毒性一方面是其本身的特异抗菌性,也有部分来自缓慢释放的银离子。     

新疆盐渍土3种植被类型土壤微生物碳源利用

研究了新疆天山以北三工河流域自然生境下梭梭(Haloxylon ammodendron)、琵琶柴(Reaumuriasoongonica)、隐子草(Cleistogenes chinensis)3种植被群落的土壤微生物碳源利用差异,分析了土壤理化性质与微生物总体活性、功能多样性的相关关系.采用BIOLOG生态板检测了各微生物群落对31种单一碳源的利用情况,结果表明,3种群落的微生物总体活性(AWCD)(F=41.877,P<0.001)、功能多样性(Shannon指数)(F=164.680,P<0.001)、丰富度(R值)(F=20.818,P=0.02)差异显著,其中梭梭植被下微生物群落的AWCD值、Shannon多样性指数、R值明显高于其他两种植被的微生物群落.土壤pH(相关系数=0.958,P<0.001)、土壤总碳相对含量(相关系数=0.718,P<0.05)与微生物总体活性(AWCD)呈显著相关,对微生物碳源利用有重要影响,而土壤可溶盐总量、含水率则与AWCD相关性不显著,微生物群落碳源利用功能多样性和丰富度与土壤理化性质均无显著相关关系.对于所研究的31种单一碳源,梭梭植被下微生物群落的利用情况也好于其他两种植被类型,对11种单一碳源利用情况较好,而琵琶柴、隐子草植被微生物群落分别则仅能对其中6种和5种碳源有较好的利用能力.     

不同源类型农业非点源负荷特征研究——以新田小流域为例

以珠江三角洲北部新田小流域为研究对象,采用源类型法,在流域范围内建立林地、果园、旱地和水田四个全封闭的农业用地单元,并对四个单元出口处的径流量进行同步采样,分析COD、BOD、氨氮、总氮和总磷等污染物的负荷特征.结果表明:(1)流域地表水存在着明显非点源污染现象,不同源类型,地表径流的污染程度不同.(2)不同源类型农业非点源污染负荷强度不同,其中水田、旱地单位面积非点源负荷强度较大,果园、林地各项污染物的负荷强度相对最小.受地表扰动、施肥等人类活动影响,流域内水田、旱地是农业非点源污染发生的关键源区.(3)流域范围内,不同源类型农业非点源负荷总量不同,其中,果园各项污染物非点源负荷总量最大,其次是林地,水田、旱地非点源负荷输出总量较小,流域范围内,源面积成为影响非点源负荷总量的主要因素.(4)相应的非点源污染治理不仅是关键源区,同时应关注大面积流失区.     

厦门后溪流域沿城乡梯度浮游细菌多样性及其与环境因子的关系

为研究城市化对河流浮游细菌的影响,选取厦门后溪流域沿城乡梯度采集样品,并利用变性梯度凝胶电泳(Denaturing gradient gel electrophoresis,DGGE)和多元统计方法对浮游细菌群落空间分布格局进行分析.结果表明,Shannon-Weiner多样性指数和DGGE条带数随着采样站点和城市中心距离的减小呈现先升高后下降的趋势.聚类分析(Cluster)和多维尺度分析(Multidimensional scaling,MDS)将12个站点的浮游细菌群落分为4组,测序结果显示β-变形菌(Betaproteobacteria)是优势类群,占40.0%.统计分析表明,pH和总氮(Total nitrogen,TN)是影响后溪浮游细菌群落组成最主要的环境因子,他们共同解释了47.6%的群落组成变化.总之,沿城乡梯度随着水体理化指标的变化,浮游细菌群落也发生明显转变,表明后溪浮游细菌受到城市化的强烈影响.此外,结果也提示DGGE可以作为监测与评价河流生态系统健康的重要工具.图6表2参33     

Septic tank and agricultural non‐point source pollution within a rural watershed

This investigation addresses the problem of Non‐Point Source (NPS) pollution in the rural Lake Weatherford watershed in Parker County, Texas. This reservoir is the primary municipal water supply for the City of Weatherford, Texas. The principal method of wastewater disposal is the on‐site system or septic tanks for the small residential areas surrounding the reservoir.

Sources of NPS pollution of interest in this watershed include agricultural operations as well as the residential areas. These sites were identified with the aid of aerial photography and field investigation. Suspected NPS problems were substantiated through a sampling program involving chemical and biological testing of the reservoir. Results indicate that there is significant NPS pollution contamination of Lake Weatherford from agricultural sources and seepage from on‐site wastewater disposal systems. Excessive fecal coliform and fecal streptococcus counts (>500 bacteria/100 ml) were generally associated with rainfall events and several samples showed values > 100000 bacteria/100 ml. The fecal coliform/fecal streptococcus ratios indicated contamination from human sources, animal sources, and a combination of both. Nutrient concentrations fluctuated from quite low to high with ammonia as the most consistent problem. High ammonia values were also associated with rainfall events.     

Population dynamics of vibrio species in the river Narmada at Jabalpur

Several studies on the presence and ecology of various Vibrio sp have been reported in coastal and estuarine waters throughout the world, but there is trifling information available on the distribution of this organism of colossal pathogenic potential in the fresh water riverine environment. Thus, we conducted a multiyearenvironmental study to scrutinize the occurrence of members of genus Vibrio in the largest west flowing river of the Indian subcontinent, which is also the largest river of central India, the Narmada. Statistical analysis was done to reveal major environmental factors controlling the presence of Vibrio sp in the river Narmada. Monthly field samplings were conducted between January 2002 and December 2003 at four different sites in Jabalpur (MP), India. At each site, water samples were taken and physicochemical and bacteriological parameters were measured. The identity of the isolates was confirmed by employing 16S rRNA analysis. The organisms were found to be widely distributed in the river with regular seasonal variations. The density of Vibrio was found to be correlated with temperature, coliforms and other heterotrophic bacteria. Water temperature accounted for most of the variability in the concentration of Vibrio spAs typical fecal pollution indicators may not access public health risk from potential pathogens such as vibrios, hence special monitoring programme for vibrios may adequately be included in the water quality management.     

Bacteriophages in water pollution control: Advantages and limitations

•Phages can be better indicators of enteric viruses than fecal indicator bacteria. •Multiple phages should be added to the microbial source tracking toolbox. •Engineered phage or phage cocktail can effectively target resistant bacteria. •In phage use, phage-mediated horizontal gene transfer cannot be ignored. •More schemes are needed to prevent phage concentration from decreasing. Wastewater is a breeding ground for many pathogens, which may pose a threat to human health through various water transmission pathways. Therefore, a simple and effective method is urgently required to monitor and treat wastewater. As bacterial viruses, bacteriophages (phages) are the most widely distributed and abundant organisms in the biosphere. Owing to their capacity to specifically infect bacterial hosts, they have recently been used as novel tools in water pollution control. The purpose of this review is to summarize and evaluate the roles of phages in monitoring pathogens, tracking pollution sources, treating pathogenic bacteria, infecting bloom-forming cyanobacteria, and controlling bulking sludge and biofilm pollution in wastewater treatment systems. We also discuss the limitations of phage usage in water pollution control, including phage-mediated horizontal gene transfer, the evolution of bacterial resistance, and phage concentration decrease. This review provides an integrated outlook on the use of phages in water pollution control.     

Ecological risk assessment from the perspective of soil heavy metal accumulations in Xiamen city,China

Contamination of soils by heavy metals is of rising concern in many cities in China undergoing rapid urbanization. Here, we evaluate the severity of soil contamination by four heavy metals (arsenic, chromium, copper, and lead) at 146 urban and suburban sites within the city of Xiamen, Fujian, China. A multivariate regression model was proposed and developed to simulate heavy metals accumulation in urban and suburban soils, to identify the concentration and spatial distribution of heavy metals in soils, and to assess ecological risks by 2020. Results showed that, overall, Xiamen soils should be subject to low ecological risks due to heavy metals contamination by 2020, the ecological risks for urban soils were greater than suburban soils, nearly half of Xiamen soils are at moderate ecological risks, and many suburban soils experience low ecological risks. The methods demonstrate the potential to predict future ecological risks from heavy metals contamination which could inform pollution prevention and control measures.     

Chemical and bacterial quality monitoring of the Nile River water and associated health risks in Qena–Sohag sector,Egypt

The River Nile is the primary source of freshwater for drinking, irrigation, and industrial purposes in Egypt. Thus, the water quality in this river concerns the health of local inhabitants. The present study reveals seasonal variations of various physicochemical and heavy metals parameters and microbial load of water at 15 sites from Qena to Sohag cities, Egypt. The water is fresh with TDS?≤?270 and 410 mg L^?1 in summer and winter, respectively. Fe, Mn, Cd, Cr, Cu, Ni, and Zn concentrations were within drinking water specification in both seasons except Cr and Cd in summer. Viable numbers of total coliform, fecal coliform, and fecal streptococci were recorded in both seasons with fecal streptococci's disappearing in winter. The concentrations of salts and ions in winter were higher than summer due to decreased water quantity and flow rate in this season. On the other hand, heavy metals and bacteria were higher in summer owing to the rain and weathering of upstream rocks and increasing of human activities during the summer. The calculated water quality index (WQI) depicted that the chemical quality of water was poor for drinking and treatment, especially biological treatment, which is required before the water is supplied for drinking. Human health risk assessment factors such as probable daily intake, hazard quotient, and carcinogenic risk indicated high risks of Cr, Cd, and Ni for adults and children in both seasons. The non-carcinogenic and carcinogenic risks are mainly posed by Cr. The WQI values for the other water uses indicated the marginal quality for aquatic life, fair for irrigation, and fair in summer to good in winter for livestock consumption. The irrigation water quality parameters indicated that the water could be used to irrigate all soils and crops except the hazard of biological contamination. The water–rock interaction controls water chemistry besides the contribution of human activities. The agricultural, industrial, and municipal wastewaters were the main contributors to water pollution and should be treated before discharge into the Nile River. Source and drinking water should be monitored continuously to prevent related human waterborne diseases.

     

Validation of Bacteroidales-based microbial source tracking markers for pig fecal pollution and their application in two rivers of North China

• Pig feces is the predominant excrement produced by animal husbandry in China. • The PF, Pig-1-Bac^TaqMan, and Pig-2-Bac^TaqMan MST assays showed better performance. • The pig-specific MST assays can contribute to managing the pig fecal pollution. In China, pig feces is the predominant source of excrement produced by animal husbandry. Improper use or direct discharge of pig feces can result in contamination of natural water systems. Microbial source tracking (MST) technology can identify the sources of fecal pollution in environmental water, and contribute to the management of pig fecal pollution by local environmental protection agencies. However, the accuracy of such assays can be context-dependent, and they have not been comprehensively evaluated under Chinese conditions. We aimed to compare the performance of five previously reported pig-specific MST assays (PF, Pig-Bac1^SYBR, Pig-Bac2^SYBR, Pig-1-Bac^TaqMan, and Pig-2-Bac^TaqMan, which are based on Bacteroidales 16S rRNA gene markers) and apply them in two rivers of North China. We collected a total of 173 fecal samples from pigs, cows, goats, chickens, humans, and horses across China. The PF assay optimized in this study showed outstanding qualitative performance and achieved 100% specificity and sensitivity. However, the two SYBR green qPCR assays (Pig-Bac1^SYBR and Pig-Bac2^SYBR) cross-reacted with most non-pig fecal samples. In contrast, both the Pig-1-Bac^TaqMan and Pig-2-Bac^TaqMan assays gave 100% specificity and sensitivity. Of these, the Pig-2-Bac^TaqMan assay showed higher reproducibility. Our results regarding the specificity of these pig-specific MST assays differ from those reported in Thailand, Japan, and America. Using the PF and Pig-2-Bac^TaqMan assays, a field test comparing the levels of pig fecal pollution in rivers near a pig farm before and after comprehensive environmental pollution governance indicated that pig fecal pollution was effectively controlled at this location.     

Microbial quality and physical–chemical characteristics of thermal springs

Microbial quality and physical–chemical properties of recreational spas were surveyed to investigate the health aspect of the spas’ water. A total of 195 samples were collected from pools and springs of the spas in five sites from Ardebil Province of Iran. The effects of an independent factor defined as ‘condition’ and its component sub-factors (i.e., sampling point, location, and sampling date) on microbial quality and physical–chemical properties of the spas were studied by applying path analysis. The influence of physical–chemical properties on microbial quality was also considered. The percentage of samples exceeding the ISIRI (Swimming pool water microbiological specifications (vol 9412), Institute of Standards and Industrial Research of Iran, Tehran, 2007) limits for Staphylococcus (spp.) was up to 55.8 in the springs and 87.8 in the pools, 58.1 and 99.2 for HPC, 90.7 and 97.8 for total coliform and fecal coliform, and 9.3 and 34.4 for Pseudomonas aeruginosa, respectively. There were significant differences between the pools and springs for both physical–chemical properties and microbial quality. From the path analysis, sampling point was the most effective sub-factor of ‘condition’ on both the physical–chemical properties and microbial quality. Among the physical–chemical properties, water color had the most enhancing or additive influence on microbial pollution, while EC indicated a reducing or subtractive effect.     

Microbial pathogens of public health significance in waste dumps and common sites

Microbial pathogens of public health significance found in waste and common sites were collected from four different dumping sites and assessed for pathogenic agents. The modified methods employed were based on the classical methods and basic principles of the reactions followed by biochemical enzymatic standards described for gram negative non fermenting bacteria. The results have shown presence of bacterial species including Pseudomonas, Mirococcus, Actinomyces, Neisseria, Bacillus and Klebsiella. These pathogens can infect wounds and cause sepsis and mortality and can even occur with such organisms to cause secondary infection. These groups of organisms are almost impossible to control since they are ubitiquous. Public health may be ensured from pathogenic agents at waste sites by prompt removal of waste and proper management (mechanical sorting and excavating) methods.