乙二胺缓冲溶液在总硬度测定中的应用

测定总硬度 ,使用氨性氯化铵缓冲溶液 ,但由于氨水易挥发 ,难以长期贮存。今提出用乙二胺配制缓冲液可以克服上述缺点。配制方法如下 :量取1 0 0ｍＬ乙二胺 ,边搅拌边缓缓注入已盛有 2 0 0ｍＬ蒸馏水的烧杯中 ,放置冷却至室温。然后在搅拌下 ,逐滴加入 5 7 5ｍＬ浓盐酸 ,如发现烧杯壁较热 ,则应冷至室温后再行滴加。此缓冲溶液ｐＨ =1 0。每次使用时 ,于 5 0ｍＬ水样中加入乙二胺缓冲溶液 5ｍＬ ,其余操作与常法相同乙二胺缓冲溶液在总硬度测定中的应用@黄莺$泰兴市环境监测站!江苏泰兴225400 @郭建$泰兴市环境监测站!江苏泰兴225400…     

水中总硬度测量不确定度的评定

采用EDTA滴定法测定水质总硬度的测量不确定度评定。充分考虑测量重复性、标准溶液的配制、滴定等过程对测量的影响,计算水中总硬度的测量相对合成标准不确定度为1·81×10-3。     

燃烧氧化-非分散红外吸收测定水中总有机碳方法的改进

总有机碳测定的方法分为差减法和直接法。现对测定方法进行改进,将差减法和直接法测定结果结合,先将样品进行酸化初步吹扫,再使用差减法测定总有机碳。试验结果显示,无论在标准曲线、精密度试验、加标回收试验还是标准样品测定方面,改进法均优于直接法测定结果,且能较好地缩短测量时间。     

测定水中总氰化物时磷酸盐缓冲溶液pH值的探讨

用异烟酸－吡唑啉酮光度法测定水中总氰化物时,对所用磷酸盐缓冲溶液ｐＨ值的使用范围进行了探讨,通过多次实验,配制了３种不同ｐＨ值的缓冲液,结果表明,ｐＨ值在６．０￣７．２之间,标准曲线的相关性和方法的灵敏度无显著差异。     

用高浓度亚硝酸盐氮贮备液省略标定过程的探讨

在对亚硝酸盐氮测定中,《水和废水监测分析方法》[1]要求配制亚硝酸盐氮标准贮备液,并经标定后才能使用,此标定过程,较为繁琐。为此经过长期的实践,改用精确称量亚硝酸钠,配制高浓度贮备液,省略标定过程的方法(简称省略法),用于测定亚硝酸盐氮。1　试验11　试剂及仪器亚硝酸盐氮标准溶液的配制:称取1232ｇ亚硝酸钠(ＮａＮＯ2)溶于水,移入500ｍＬ容量瓶中,用水稀释至标线,摇匀,配成每毫升含050ｍｇ的高浓度亚硝酸钠标准贮备液,贮于棕色瓶中,冰箱内保存,可稳定两个月(省略法)。另按文献[1]配制每毫升含025ｍｇ亚硝酸盐氮标准贮备液,并进行标定…     

永久性余氯标准色列的配制

用邻联甲苯胺测定医疗污水中的总余氯是GB 1 8466- 2 0 0 1《医疗机构污水排放要求》规定的标准方法。但该方法没有交待目视标准色列如何配制。针对医疗污水中总余氯的浓度水平,参考JIS方法和我国卫生部《生活饮用水检验规范》进行计算,应分别称取经1 2 0℃干燥至衡重的1 5 5 0 0gK2 Cr2 O7和4 65 0 0gK2 CrO4,溶解于氯化钾 盐酸缓冲溶液,并稀释至1 0 0 0ml后即为余氯储备液。其中KCl HCl缓冲液的配制:称取3 70g经1 0 5℃烘干至衡重的KCl,再加0 5 6ml浓盐酸,用纯水定容至1 0 0 0ml。永久性余氯标准色列( 0 1～1 0 0mg L)的配制:…     

测定总硬度EDTA标准溶液配制的改进

水中总硬度测定时,为提高指示剂铬黑T的灵敏性,通常在缓冲溶液中加入EDTA二钠镁,当缺少该试剂时,可用一定量的EDTA二钠和硫酸镁来替代,但是,配制操作较繁杂.今提出在ED-TA标准溶液标定之前,将此两种试剂加入其中,然后再进行标定.按此方法,可省去反复调试操作,亦不必在缓冲液中加入指示剂,而影响滴定终点.……     

KI-MIBK萃取法测定地表水中铜、镉、铅的改进

对KI-MIBK萃取火焰原子吸收法测定地表水中铜、镉、铅进行了改进,用100mL容量瓶代替分液漏斗取样、萃取和火焰原子吸收测定。改进法校准曲线的灵敏度和相关系数、精密度和准确度均优于标准法。     

EDTA滴定法测定水中总硬度的几点体会

在环境监测分析中 ,总硬度为常规分析项目。测定地下水和地表水中的总硬度 ,一般常用EDTA滴定法 ( GB7477— 87) ,该法虽具仪器价廉、步骤简单、操作方便、准确可靠的优点 ,但就其某些具体操作而言 ,尚有待进一步完善。为此 ,特在日常例行监测实践中 ,对具体操作中的有些问题留心探索 ,并进行对比试验 ,得出了较为可靠的分析结果。1　试剂与仪器试剂配制均按文献 [1]进行 ,其中氯化铵、氨水、硫酸镁、二水合 EDTA二钠和三乙醇胺等试剂均为分析纯。钙标准溶液的配制 :预先将碳酸钙在 15 0℃干燥 2 h,称取 1.0 0 1g置 5 0 0 ml锥形瓶中 ,…     

土壤中总铬测定方法改进

采用《土壤质量总铬的测定火焰原子吸收分光光度法》(GB/T 17137-1997)测定土壤中总铬时,需用硫酸、硝酸、氢氟酸消解,再用盐酸溶液定容.由于硫酸的共沸最高温度为317 ℃[1],在熔样时要将硫酸产生的SO3完全赶尽较困难,现用硝酸-氢氟酸-高氯酸消解土壤的标准样品和实际样品,同时消解并绘制工作曲线(简称工作曲线法),再通过标准加入法测定样品,可取得较为满意的结果.     

基于多元统计方法的某地浅层地下水污染来源分析

为查明某地农田灌溉水井水质污染致使作物生长受损事件的污染来源,对研究区10眼水井进行了水质检测分析,并采用多元统计方法判断污染来源。结果表明:研究区水样中全盐量普遍超过农田灌溉水质标准,总硬度、硫酸盐、氨氮和氰化物等也存在不同程度的超标;水样中全盐量、氨氮与氰化物的含量之间存在显著正相关,具有共同的来源,且与河流A补给关系密切;地下水中盐分过高是造成作物受损的主要原因;地下水中全盐量、氨氮及氰化物等主要污染物来源于上游的焦化企业。基于多元统计方法的地下水污染来源分析结果可为当地地下水污染防治及管控提供环境管理依据。     

陕北石油勘探开发区地表水污染特征分析

研究了陕北主要石油勘探开发地区地表水的水质状况,分析了pH、矿化度(全盐量)、硬度、六价铬、砷、镉、铅、氨氮、挥发酚、石油类、化学需氧量(COD)、氯化物、硫酸盐、硝酸盐氮、总磷、氰化物、氟化物等17个指标,结果显示砷、镉、铅、氟化物、硝酸盐、氰化物、氟化物的P_i值均小于1;挥发酚、总磷、石油类、氨氮、COD、六价铬、硫酸盐、矿化度、氯化物、硬度均超标。研究区东部和西部地表水呈现出不同的污染特征,通过分析不同区域污染物来源,提出了污染防治对策与建议。     

Prevalence of certain inorganic constituents in groundwater samples of Erode district, Tamilnadu, India, with special emphasis on fluoride, fluorosis and its remedial measures

A total of 60 drinking water samples collected from Erode district, Tamilnadu, India were analysed for fluoride contamination, besides water quality parameters such as pH, electrical conductivity, total dissolved solids, total alkalinity, total hardness, fluoride, bicarbonates, calcium, magnesium, nitrate, sulphate, phosphate, sodium and potassium. The results obtained were found to exceed the permissible limits. The concentration of fluoride in the water samples ranged between 0.5 and 8.2 mg/l and revealed that 80% of the water samples contain fluoride above the maximum permissible limit. Similarly, the concentrations of nitrate, hardness, calcium and magnesium in some samples were also more than the permissible level. Pearson’s correlation coefficient among the parameters showed a positive correlation of fluoride with total hardness and calcium. It is inferred from the study that these water sources can be used for potable purpose only after prior treatment.     

Evaluation of anthropogenic effects on water quality and bacterial diversity in Rawal Lake,Islamabad

Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant.     

氯化铵-火焰原子吸收光谱法测定地表水中的总铬

应用原子吸收法测定水样中的总铬，在不同条件下对空白样品、标准样品和实际样品进行试验分析，进一步验证了方法的准确度和精密度，加标回收率在96.8%-103%之间，相对标准偏差为2.1%。试验表明，该方法准确可靠，实际操作具有可行性，适用于工业废水和受污染地表水中总铬的测定。     

Deterioration of coastal groundwater quality in Island and mainland regions of Ramanathapuram District, Southern India

A study was carried out in the Island and mainland regions of Ramanathapuram District to characterize the physico-chemical characteristics of 87 groundwater samples in Island and 112 groundwater samples in mainland which include pH, EC, TDS, salinity, total alkalinity, calcium hardness, magnesium hardness, total hardness, chloride and fluoride. Heavy inorganic load in majority of the groundwater samples has been estimated due to the salinity, TDS, TH and chloride beyond the threshold level which substantiates the percolation of sea water into the freshwater confined zones. Although the groundwater sources are available in plenty, the scarcity of potable water is most prevalent in this coastal area. The Water Quality Index (WQI) and Langeleir Saturation Index (LSI) have also been calculated to know the potable and corrosive/incrusting nature of the water samples. The statistical tools such as principal component analysis, box plots and correlation matrix have also been used to explain the influence of different physico-chemical parameters with respect to one another among the groundwater samples. The percentage of groundwater samples in mainland was more than that in Island with respect to the acceptable limit of WHO drinking standard, especially in TDS, CH, TH and chloride but the converse is observed in the case of fluoride. About 8 % of the mainland aquifers and 42 % of Island aquifers were identified to have fluoride greater than 1.5 mg/l. The signature of salt-water intrusion is observed from the ratio of Cl/CO ₃ ^2? ?+?HCO₃ and TA/TH. A proper management plan to cater potable water to the immediate needs of the people is to be envisaged.     

Evaluation of groundwater quality in and around Peenya industrial area of Bangalore, South India using GIS techniques

Groundwater resource forms a significant component of the urban water supply. Declining groundwater levels in Bangalore Urban District is generally due to continuous overexploitation during the last two decades or more. There is a tremendous increase in demand in the city for good quality groundwater resource. The present study monitors the groundwater quality using geographic information system (GIS) techniques for a part of Bangalore metropolis. Thematic maps for the study area are prepared by visual interpretation of SOI toposheets on 1:50,000 scale using MapInfo software. Physicochemical analysis data of the groundwater samples collected at predetermined locations form the attribute database for the study, based on which spatial distribution maps of major water quality parameters are prepared using MapInfo GIS software. Water quality index was then calculated by considering the following water quality parameters--pH, total dissolved solids, total hardness, calcium hardness, magnesium hardness, alkalinity, chloride, nitrate and sulphate to find the suitability of water for drinking purpose. The water quality index for these samples ranged from 49 to 502. The high value of water quality index reveals that most of the study area is highly contaminated due to excessive concentration of one or more water quality parameters and that the groundwater needs pretreatment before consumption.     

A hydrochemical profile for assessing the groundwater quality of Jaipur City

A study was conducted to evaluate the water quality of Jaipur City. Groundwater samples from hand pumps and tube wells of eleven sampling stations were analyzed during monsoon session with the help of standard methods of APHA. The analytical results shows higher concentration of total dissolved solids, electrical conductivity, total hardness and nitrate, which indicate signs of deterioration but values of pH, calcium, magnesium, sulphate and fluoride are within permissible limit as per WHO standards. From the Hill-Piper trilinear diagram, it is observed that the majority of ground water from sampling stations are calcium-magnesium-chloride-sulphate type water. The values of sodium absorption ratio and electrical conductivity of the ground water were plotted in the US salinity laboratory diagram for irrigation water. Most of the samples fall in C3S1 quality with high salinity hazard and low sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation (in meq/l) is in order magnesium > sodium > calcium > potassium while for the anion (in meq/l) it is chloride > bicarbonate > sulphate > nitrate > carbonate > fluoride.     

Dynamics of phytoplankton in relation to physico-chemical factors of Almatti reservoir of Bijapur District, Karnataka State

The present investigation deals with limnobiotic status of the Almatti reservoir from February, 2003 to January, 2005. The study revealed that there exists a fluctuations of the physical factors viz., rainfall, humidity, air and water temperature, pH and electrical conductivity (EC), and chemical factors viz., dissolved oxygen (DO), free carbon dioxide, total alkalinity, total hardness, calcium, magnesium, chloride, nitrate, phosphate, sulphate, bicarbonate and total dissolved solids (TDS). From the data it was also apparent that correlations between the physico-chemical factors and dynamics of phytoplankton could be seen. The simple correlation coefficient test revealed that the cyanophytes number was positively correlated with DO, nitrate, phosphate and negatively significant with total hardness, total alkalinity, EC, calcium, magnesium, sulphate, bicarbonate and TDS. They are inversely correlated with pH, chloride, rainfall and humidity. Bacillariphyceae are correlated with total alkalinity, bicarbonates, magnesium and TDS, whereas inverse correlation was found with rainfall, humidity, pH and phosphate. Desmids showed positive correlation with nitrates, while it was inversely correlated with chloride, rainfall and humidity. Dinophytes density was positively correlated with total alkalinity, EC, total hardness, calcium, bicarbonate, while it showed inverse correlation with rainfall, humidity and phosphate. However, it is obvious that the absence of significant difference between sampling stations for all these parameters in the Almatti reservoir indicated fairly homogeneous conditions and the water quality is also found to be homogeneous.     

奎屯市一水厂水质现状及趋势分析

利用1996 - 2005年的地下水质监测数据,对奎屯市饮用水源地进行了现状评价,选择奎屯市一水厂作为研究目标,对总硬度、硝酸盐氮和硫酸盐三项指标的变化趋势进行分析,并对其变化成因进行了探讨.