温度、时间对不同方法检测地下水中总大肠菌群的影响

分别以温度和时间为变量,比较了滤膜法、酶底物法检测地下水中总大肠菌群的数量。研究表明,2种方法的检测结果随温度变化趋势基本一致,在35、36、37℃时,大肠菌群生长最快,3个温度下的检测结果基本无差异（P <0.05）,而与28、32、40℃下的检测结果相比差异明显。滤膜法和酶底物法的培养时间在22、24、28 h时总大肠菌群基本无差异（P <0.05）,而16、18、20、32 h的总大肠菌群数差异明显。因此为保证实验数据真实准确,2种检测方法都应严格控制培养温度和时间。培养温度为36±1℃,培养时间为22～28 h。     

矿井水地下回灌过程中主要污染组分迁移转化规律研究

为了研究矿井水地下回灌过程中主要污染组分迁移转化规律,以神府矿区浅埋煤层为对象,开展了矿井水地下回灌实验,结果表明:研究区矿井水中超标的项目有TDS、CODcr、Cl、F、总大肠菌群、大肠埃希氏菌以及肉眼可见物,SO_4、NH_4、NO_3等指标的浓度也较高。回灌出水中含盐量在前期逐渐增大,后期基本稳定;氧化还原反应使TOC浓度减少超过50%,其中大分子有机物在包气带环境中被优先去除。回灌过程中NH_4的去除主要发生在包气带,主要发生氧化反应,去除率可达73.1%;NO_3去除主要发生在饱和带,平均去除率为85.7%,主要发生了还原反应。     

离子色谱法检测饮用水中的草甘膦

建立了离子色谱法直接测定饮用水中草甘膦的分析方法。水样加入抗坏血酸除去余氯,微孔滤膜过滤后直接进样测定。用IonPac AS11-HC阴离子交换柱为分析柱,淋洗液为20 mmol/L KOH溶液,流速为1.00mL/min,进样量100μL进行检测。方法的线性范围0~1.5 mg/L,检出限为0.1 mg/L,加标回收率为95%~106%,相对标准偏差为5.08%~7.09%。方法操作简便快捷,灵敏度高,结果准确可靠。     

紫外可见分光光度法测定地表水和地下水的高锰酸盐指数

用分光光度法测定水中高锰酸盐指数。方法检出限为0.05mg/L。对实际水样进行连续5次测定,方法精密度为1.01%～1.20%,回收率为95.0%～100.5%。经国家标准容量法验证,结果与标准方法测定值相符。方法简便快速,灵敏度高,精密度好,试剂试样量少,成本低,适用于测定氯化物低于300mg/L、清洁或污染轻微的水样高锰酸盐指数的分析。     

ICP-OES法和ICP-MS法测定不同环境水体中重金属铅的方法比较

重金属铅不仅造成了严重的水环境污染,更会对人体健康产生不可逆转的影响。本研究采用ICP-OES和ICPMS两种不同的检测方法,同时检测不同环境水体中的重金属铅,结合实际水样情况,通过检出限、精密度、准确度及加标回收率的对比,得出两种方法的优缺点和适用范围。通过研究结果得出以下结论：一般水质样品推荐使用ICP-MS法;针对铅元素含量较高,或者污染严重、基体复杂的样品推荐使用ICP-OES法。该研究可为测量不同水体中重金属铅的方法提供有效思路,为环境污染防治过程中水环境的检测提供技术指导与数据支持。     

新疆平原区浅层地下水水质评价

本文利用2003年4～8月间386个浅层地下水水样测试结果,以流域与地(州、市)交并划定基本评价单元,选用pH、矿化度、总硬度、NH3-N、C6H5OH、CODMn和总大肠菌群7个项目作为评价因子,以为评价标准,采用一票否决法对各基本评价单元的地下水质量进行分类,并对水质成因作了简要分析.     

超高效液相色谱-串联质谱法直接进样测定水样中8种有机污染物

2011年我国实施了新的生活饮用水卫生标准,卫生指标扩展至106项,并配套了相关的检测方法,其中微囊藻毒素、莠去津采用液相色谱紫外检测器的检测方法;丙烯酰胺、灭草松、2,4-D采用气相色谱-电子捕获检测器的检测方法;呋喃丹、草甘膦采用液相色谱荧光检测器的检测方法。这些检测方法均有前处理程序繁琐、工作量大、可操作性差的缺点,在实际工作中应用较为困难。本文采用超高效液相色谱-串联质谱技术（UPLC-MS/MS）,建立了水样过0.22 μm滤膜,直接进样测定自来水、地下水及地表水中8种有机污染物（草甘膦、呋喃丹、灭草松、莠去津、2,4-滴、丙烯酰胺、微囊藻毒素-RR和微囊藻毒素-LR）的分析方法。8种化合物在各自的线性范围内线性关系良好,相关系数均不低于0.993,定量下限为0.07~5 μg/L,低、中、高三个加标水平的回收率为94.2%~103.7%,相对标准偏差为1.1%~7.8%。本文建立的方法操作简便,可以实现在6 min内一次性分析8种目标化合物,与国家标准方法相比,显著提高了分析效率;与文献报道的均是单一类化合物检测方法相比,本检测方法具有相似的灵敏度和检测限,但是目标化合物覆盖更全面,分析时间更短。     

气相色谱—串联质谱技术检测水中安眠酮残留量

本实验建立水中安眠酮残留量的气相色谱-串联质谱联用(GC-MS/MS)分析方法。方法样品采用乙酸乙酯提取,浓缩后甲醇定容待测。采用GC-MS/MS分析时,安眠酮在15 mins内流出。对采集的水样进行两种浓度的加标质控,回收率均在70%以上,相对标准偏差(RSD)在3.0%以内。在0.05~1.00 mg/L的浓度范围内呈线性关系,相关系数大于0.999。检出限为0.50μg/L。该方法可准确用于环境水样中安眠酮残留的定量分析,灵敏度、精密度和准确度均满足残留检测的分析要求。     

自动电位滴定仪应用于地下水六项指标的连续滴定

地下水中六项指标(pH、总碱度、氯离子、钙离子、镁离子及硫酸根)的分析需要对每个指标单独进行取样检测,步骤繁琐且效率较低。同时总碱度、氯离子、钙离子、镁离子及硫酸根通常采用手动目视滴定,检测结果存在人为操作误差,精密度和准确度相对较差。本文建立了准确快速测定地下水中六项指标的分析方法,只需2次取样,采用自动电位滴定仪自动判定终点,加液器可精确控制标准溶液加入量至0. 1μL,并且通过调整检测顺序、溶液酸度和加入掩蔽剂的方法消除相互干扰。本方法的加标回收率为93. 5%～120. 0%,相对标准偏差(RSD,n=10)为0. 18%～11. 33%。电位滴定法得到的数据相比标准方法的平行性更好,尤其是当所测定水样较为浑浊或者有颜色时测定数据更稳定。     

气动雾化进样-微波等离子体炬质谱法快速测定水样中的钙离子

环境水样中金属元素的分析通常采用电感耦合等离子体质谱法(ICP-MS),检出限低、线性范围宽,但仍存在使用功率高、耗气量大、分析成本高以及不适用于现场分析等不足。本文为降低金属元素分析成本,建立了微波等离子体炬(MPT)与有机质谱耦合的方式检测水样中钙离子的新方法。详细探究了载气流速和维持气流速对钙离子响应信号的影响,方法检出限为224.56 ng/L,相对标准偏差(RSD)为1.2%~9.8%,加标回收率在86.3%~110.4%之间。本方法无需样品预处理,分析速度快、灵敏度和精确度高,为环境水样中金属离子的测定提供了新途径,有望应用于金属离子的实时在线分析。     

Potency of constructed wetlands for deportation of pathogens index from rural,urban and industrial wastewater

Pathogen removal is essential for wastewater treatment and its potential reuse in agriculture. Three field-scale wastewater treatment systems consisting of free surface flow were operated around 1.5 years receiving water from urban domestic, rural domestic and industrial sources. The study was conducted to evaluate seasonal performance of constructed wetland systems in removing Escherichia coli, Enterococci and total coliforms under continuous hydraulic flow. Results displayed that all three wetlands gain recognition in removing pathogen load with high removal efficacy till water reaches output ports. Removal efficiencies were even higher, 66–93, 78–92 and 80–94% for E. coli, Enterococci and total coliforms, respectively, within constructed wetlands. Remarkably at shorter temporal scales in CW-A, greater homogeneity of pathogen concentrations was assessed at wetland outlet sites. In outlet ports, results displayed a highly effective removal of E. coli concentration 80–90% (June 2015), 86–92% (October 2015) and 79–92% (February 2016), Enterococci 80–94% (June 2015), 83–94% (October 2015) and 80–94% (February 2016) and total coliforms 85–93% (June 2015), 87–95% (October 2015) and 88–96% (February 2016). Positive correlation was observed between bacterial indicators (E. coli–Enterococci, r = 0.038; p < 0.01 and E. coli–total coliforms, r = 0.142; p < 0.01). Removal of bacterial indicators in constructed wetland was also displayed by PCA in which three-component analysis of variance was 98.39% and showed a clear decrease in measured parameter gradients toward samples from outlet ports. Constructed wetlands provide cost-effective treatment systems for reducing the pathogen load in wastewater in variable agro-climatic conditions and thus improve water quality.     

Influence of topsoil of pyroclastic origin on microbial contamination of groundwater in fractured carbonate aquifers

The aim of the research was to analyse the influence of a topsoil of pyroclastic origin on microbial contamination of groundwater in a carbonate aquifer and verify the reliability of thermotolerant coliforms and fecal enterococci as bacterial indicators. The research was carried out through hydrogeological and microbiological monitoring at an experimental field site in Italy during two hydrologic years and through column tests in a laboratory. The taxonomic classification of fecal indicators detected in spring water samples was performed using API20 galleries. Fecal enterococci were also identified by means of 16S rRNA gene sequencing. The topsoil of pyroclastic origin significantly retains both thermotolerant coliforms and fecal enterococci. Results of column tests carried out in soil blocks collected randomly within the test site suggest that Escherichia coli was more retained than Enterococcus faecalis, even though this difference is statistically significant in only two out of six soil samples. Thus, a non-uniform difference in retention is expected at field scale. This suggestion is in agreement with the results of the microbiological monitoring. In fact, fecal enterococci were a more reliable indicator than thermotolerant coliforms for detecting contamination at both seasonal springs of the aquifer system, while no significant differences were observed at the perennial spring.     

Groundwater chemical and fecal contamination assessment of the Jerba unconfined aquifer,southeast of Tunisia

Located in the southeast of Tunisia, on the Mediterranean Sea, Jerba Island has a semiarid climate condition. The surface water scarcity has made groundwater the main source to supply the domestic, touristic, and agricultural water demand. Unconfined aquifer is a vulnerable costal aquifer system that undergoes several phenomena. This work aims at assessing the geochemical and bacteriological groundwater quality, defining groundwater pollution sources and promoting sustainable development and effective management of groundwater resources in Jerba Island. Data were collected after the wet season in 2014 from 79 wells. Electric conductivity, pH, TDS, and major and fecal tracers (total coliforms, thermotolerant coliforms, Escherichia coli, and Salmonella) were analyzed. Geochemical modeling including the relationships between geochemical tracers Na⁺ vs. Cl^?, Ca²⁺ vs. Cl^?, K⁺ vs. Cl^?, representative ionic ratios (Br^?/Cl^?, Na⁺/Cl^?, Mg²⁺/Ca²⁺), and statistical analysis were used to specify major process contributing to groundwater pollution and main factors controlling groundwater mineralization in the island. Groundwater varieties were hydrochemically classified into three types in terms of salinity values: group 1 (8.86%) to fresh water, group 2 (27.84%) to brackish water, and group 3 (63.29%) belongs to saline water. In addition, groundwater quality revealed high concentrations in chemical pollution tracers (Na⁺, Cl^?, SO₄ ^2?, and NO₃ ^?) and fecal tracers. Besides, most of the sampled wells were contaminated with nitrate (50.63%). Also, thermotolerant coliforms and E. coli were detected in all groundwater samples (96.2% of wells). Results indicated that the Jerba shallow aquifer was under serious threat from both natural and anthropogenic contamination. However, the wild discharge of domestic effluents, septic tanks, and sewage were the main origins of underground water contamination in Jerba Island. The reduction of fecal sources, through constructing normalized latrines is thus recommended.     

Impact of fertilizer plant effluent on water quality

The impact of National Fertilizer Company of Nigeria outfall effluent on the physicochemistry and bacteriology of Okrika creek was investigated during the sampling period from May to December, 1998. The National Fertilizer Company of Nigeria outfall effluent, the Okrika creek water and the Ikpukulubie creek (control) water samples were collected. The physico-chemical parameters analyzed for all the samples included temperature, pH, total chloride, total dissolved solids, dissolved oxygen, conductivity, free ammonia, total phosphate, urea, zinc and iron, while the bacteriological determinations were total culturable aerobic heterotrophic bacteria count and identification of representative isolates. The Okrika creek recorded higher concentrations for all the physico-chemical parameters and bacteria load than the control creek. The higher values of pH, Free NH₃, urea, TDS and the conductivity of the National Fertilizer Company of Nigeria outfall effluent above the FEPA standards reflect the poor effluent quality generated by National Fertilizer Company of Nigeria. The bacteria species isolated from the samples include Aerococcus viridans, Alcaligenes faecalis, Bacillus cereus, Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens and Staphylococcus aureus. In general, the investigation revealed that there was an extremely adverse impact on the physico-chemical and bacteriological water quality characteristics of the Okrika creek as a result of the discharge of poor quality effluent from National Fertilizer Company of Nigeria operations.     

Conjunctive use of surface water and groundwater via the bank infiltration method

The bank infiltration (BI) technique may be a viable option if the local climate, hydrological, and geological conditions are conducive. This study was specifically conducted to explore the possibility of using BI to source the polluted surface water in conjunction with groundwater. Three major factors were considered for evaluation: (1) investigation on the contribution of surface water through BI, (2) input of local groundwater, and (3) water quality characteristics of water supply. Initially, the geophysical method was employed to define the subsurface geology and hydrogeology, and isotope techniques were performed to identify the source of groundwater recharge and interaction between surface water and groundwater. The physicochemical and microbiological parameters of the local surface water bodies and groundwater were analyzed before and during water abstraction. Extracted water revealed a 5 %–98 % decrease in turbidity, as well as HCO₃ ⁺, SO₄ ^?, NO₃ ^?, Al, As, and Ca concentration reduction compared with those of Langat river water. However, water samples from test wells during pumping show high concentrations of Fe²⁺ and Mn²⁺. In addition, amounts of Escherichia coli, total coliform, and Giardia were significantly reduced (99.9 %). Pumping test results indicate that the two wells (DW1 and DW2) were able to sustain yields.     

Drinking water quality in Nepal’s Kathmandu Valley: a survey and assessment of selected controlling site characteristics

Water was sampled from over 100 sources in Nepal’s Kathmandu Valley, including municipal taps, dug wells, shallow-aquifer tube wells, deep-aquifer tube wells, and dhunge dharas (or stone spouts, public water sources that capture groundwater or surface water). Information was gathered on user preference and site and well characteristics, and water was examined for indicators of contamination from sewage, agriculture, or industry. Most problematic were total coliform and Escherichia coli bacteria, which were present in 94 and 72% of all the water samples, respectively. Contamination by nitrate, ammonia and heavy metals was more limited; nitrate and ammonia exceeded Nepali guidelines in 11 and 45% of the samples, respectively. Arsenic and mercury exceeded WHO guidelines in 7 and 10% of the samples, respectively, but arsenic never exceeded the less strict Nepali guideline. Significant differences existed in contamination levels between types of sources; dug wells and dhunge dharas, being the shallowest, were the most contaminated by bacteria and nitrate; deep-aquifer tube wells were the most contaminated by arsenic. Whereas E. coli concentrations decreased with depth, iron and ammonia concentrations increased with depth. These relationships account for people choosing to drink water with higher levels of bacterial contamination based on its superior (non-metallic) taste and appearance.     

Surface water quality contamination source apportionment and physicochemical characterization at the upper section of the Jakara Basin, Nigeria

The present study investigates the surface water quality of three important tributaries of Jakara Basin, northwestern Nigeria to provide an overview of the relationship and sources of physicochemical and biological parameters. A total of 405 water samples were collected from 27 sampling points and analyzed for 13 parameters: dissolved oxygen (DO), 5-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), suspended solids (SS), pH, ammonia-nitrogen (NH₃NL), dissolved solids (DS), total solids (TS), nitrates (NO₃), chloride (Cl), phosphates (PO₄), Escherichia coli (E. coli) and fecal coliform bacteria (FCB). Pearson’s product–moment correlation matrix and principal component analysis (PCA) were used to distinguish the main pollution sources in the basin. Four varimax components were extracted from PCA, which explained 84.86, 83.60, and 78.69 % of the variation in the surface water quality for Jakara, Tsakama, and Gama-Kwari Rivers, respectively. Strong positive loading included BOD₅, COD, NH₃NL, E. coli, and FCB with negative loading on DO attribute to a domestic waste water pollution source. One-way ANOVA revealed that there was no significant difference in the mean of the three water bodies (p?>?0.05). It is therefore recommended that the government should be more effective in controlling the point source of pollution in the area.     

Land-use-mediated <Emphasis Type="Italic">Escherichia coli</Emphasis> concentrations in a contemporary Appalachian watershed

A high-spatial resolution study design was used to investigate the relationship between land use practices, stream physicochemistry, hydroclimate, and stream Escherichia (E) coli concentrations in a mixed-land-use watershed in the Appalachian region. Stream samples were collected daily from six monitoring sites and analyzed for total E. coli counts using an enzyme metabolism indicator method. Statistical comparison of E. coli concentration time series showed significant (p?<?0.05) differences between study sites. Although highest average E. coli concentrations were observed at two agricultural sites (534 and 582 colony-forming counts (CFU) per 100 mL, respectively), highest total loadings were observed within the receiving stream, with values increasing downstream (2?×?10¹² and 4.2?×?10¹² study total CFU for bracketed upstream and downstream sites, respectively). No single physical variable displayed a significant correlation (p?<?0.05) with observed E. coli concentration at every site. However, sites displayed different patterns of significant correlations (p?<?0.05) between E. coli concentration and both physicochemical (e.g. pH, dissolved oxygen saturation) and hydroclimate variables (e.g. streamflow and precipitation). Percent agricultural land cover was the only land use category that showed significant (p?<?0.04) correlation with study average E. coli concentrations, thereby emphasizing the importance of land use practices to stream pathogen regimes. Results validate the analytical method and provide high-resolution, detailed, quantitative characterizations of stream E. coli regimes, thereby supplying land and water resource managers with science-based information to advance management decisions and improve public health.     

Antibiotic resistance and genetic diversity in water-borne Enterobacteriaceae isolates from recreational and drinking water sources

A total of 240 water-borne bacteria including 72 Escherichia coli, 83 Enterobacter, 30 Klebsiella, 36 Salmonella and 19 Shigella spp. isolates from drinking and recreational water sources were assessed for antibiotic resistance and genetic diversity. Escherichia coli (88.89 %) and species of Enterobacter (86.75 %), Klebsiella (83.33 %) and Salmonella (100 %) were resistant to cefadroxil, while >94 % Shigella spp. were resistant to cefaclor and cefuroxime. Ofloxacin was the most effective antibiotic against isolates of all the genera. Multiple antibiotic resistance index identified dug well, pond and piped water supplies as high risk sources of enteric pathogens. Random amplified polymorphic DNA analysis and restriction fragment length polymorphism of amplified 16S rRNA gene were studied for genetic relatedness of Enterobacteriaceae isolates. Primer P1254 identified 10, 16, 4, 4 and 1 distinct random amplified polymorphic DNA group(s) of E. coli, Enterobacter, Klebsiella, Salmonella and Shigella species, respectively. Unlike random amplified polymorphic DNA, restriction fragment length polymorphism using AluI and HaeIII could not segregate isolates in different genetic profiles. 16S rRNA gene of three Enterobacter spp. strains from different sources with similar restriction fragment length polymorphism but different random amplified polymorphic DNA patterns was sequenced, and identified as Enterobacter hormaechei strains skg0061, 0062 and 0063. The sequence information has been submitted to GenBank (HQ322393-95). Biochemically similar but genetically diverse Enterobacteriaceae members from drinking and recreational water sources exhibited varying antibiotic sensitivity. Contamination of water sources with such multiple antibiotic-resistant enteric pathogens poses threat to human health.     

Analysis of support requirements for a shallow diversion tunnel at Guledar dam site, Turkey

Engineering geological properties and support design of a planned diversion tunnel at Guledar dam site, which was located at the North of Ankara, Turkey were studied in this article. The main purpose of the construction of the planned tunnel is to regulate, drainage and to provide water for irrigation purposes. The diversion tunnel runs mainly through formations of limestone, sandstone and diabase. Rock masses at the site were characterized using Rock Mass Rating (RMR), Rock Mass Quality (Q), Rock Mass Index (RMi) and Geological Strength Index (GSI). RMR, Q, RMi and GSI were determined by using field data and mechanical properties of intact rock samples, measured in the laboratory. Support requirements for the planned diversion tunnel were determined accordingly in terms of the rock mass classification systems. Recommended support systems by empirical methods were also analyzed using 2D Finite Element method. Calculated parameters based on empirical methods were used as input parameters in the finite element models. The results from both methods were compared with each other. This comparison suggests that more reliable support design could be achieved by using the finite element method together with the empirical methods.