Assessing water quality using water quality index and multivariate analysis

Groundwater is increasingly gaining significance as the main solution to the water supply problems in Ghana, especially in the rural areas. This study was conducted to determine which factors play significant roles in the hydrochemistry of groundwater from the southern Voltaian formation. Conventional graphical and multivariate statistical methods were used. The study reveals three main factors controlling the hydrochemistry. Silicate mineral weathering and reverse cation exchange are the most important processes affecting the hydrochemistry of groundwater at this part of the formation. Interpolation maps created from factor scores suggest that these processes are the most pervasive, recording high scores almost everywhere in the study area. Carbonate mineral weathering is the second most important process in the hydrochemistry. This study finds that carbonate mineral weathering in the area is probably facilitated by carbonic acid rather than sulfuric acid. Chemicals from agricultural activities constitute the third most important process influencing groundwater quality in the area. Eighty samples were used to calculate water quality indices, WQI, which were in turn used to classify groundwater from the study area. Over 98% of the samples fall within the “Excellent” and “Good” categories, suggesting that groundwater from the southern Voltaian formation is generally acceptable for drinking purposes.     

Freshwater sediment quality in Spain

This study was carried out to evaluate sediment pollution related to trace elements such as Cd, Cu, Ni, Pb, Zn, Hg, As and Cr and eight polycyclic aromatic hydrocarbons (PAHs) in 127 sites located in 85 rivers in Spain. Sediment samples were classified according to similar chemical characteristics by means of statistical multivariate techniques (principal component analysis, PCA) and artificial neural networks such as self-organizing maps (SOM). Sediment sample classification provided by PCA was not as useful as the one provided by the SOM, revealing itself as a powerful tool to be incorporated in the first steps of sediment quality assessments. The use of sediment quality guidelines such as the mean-probable effects concentration quotient (m-PECQ) predicted sediment quality and gave an overall view of sediment pollution throughout Spain. Most of the samples (118 out of 127) showed m-PECQ values below 0.5 highlighting their relative low potential risk to cause adverse effects on the benthic fauna. However, some samples presented m-PECQ values higher than 0.5 suggesting a clear potential risk to these fauna. Besides, unusual high concentrations of trace elements and PAHs were related to the human activities carried out near each sampling point.     

Groundwater quality Management in China

Groundwater quality is of vital importance in groundwater safety especially for the purpose of water supply, its management becomes more and more necessary as groundwater contamination has threaten its safe use in China. The article analyzed the contamination sources of groundwater and impact of contamination on human health and water supply, the knowledge gaps were pointed and recommendations were made for groundwater quality management in China.     

Behavioural-geographical aspects of environmental quality

The behavioural approach in human geography accentuates the view of quality of the environment through man and his value orientations. The quality of environment from the point of view of human experience raises behavioural-geographical questions that are the core of the presented topic. Aspects of environmental imaginations and sensations as well as human value system are presented as variables affecting the structure of the perceived environment and human spatial behaviour. In this context, the authors present results of two behavioural studies that correspond to new models of man and environment from the viewpoint of a behavioural approach. The suggested humanistic approach in behavioural geography emphasizes above all the emotional aspect of the relationship between man and environment, which through environmental values, spatial sensations, and meanings, leads to human spatial behaviour.     

地下水水质监测与评价

地下水由于分布广、水质好且开发费用低而成为全世界重要的供水水源。中国北方生活供水的一半来自地下水,地下水也是干旱期重要的农业灌溉水源。然而,地下水水质日益面临来自农业、工业和城市污染源的威胁。地下水水质监测是评价水质状况最可靠的方法,并可作为供水水源保护的早期预警系统。它为水管理部门和水用户提供可靠的科学数据以便更好地管理和保护地下水资源。世界上正在执行两个巨大的地下水质监测和评价项目:一个是欧盟的水框架计划;另一个是美国的国家水质评价计划。文章评述了地下水水质监测的现状,介绍了地下水易污性评价、地下水污染源分级和地下水污染风险评价的方法。地下水易污性分区图是土地利用规划和供水水源保护的基础。地下水污染源分级结果为污染源治理提供了优先顺序。地下水污染风险分区图圈划出地下水污染的高风险区,为地下水资源保护和地下水污染监测提供重要的依据。     

Water quality parameters along rivers

Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries-a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. This study involves determination of physical, biological and chemical parameters of surface water at different points. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84–805μs; DO: dry- 5.52 mg/L, monsoon-5.72 mg/L; BOD: dry-1 mg/L, monsoon-0.878 mg/L; Total Solid: dry-149.4 mg/L, monsoon- 145.7 mg/L. A model study was also conducted and values of different model parameters were estimated.     

Comparison of different models of water quality index in the assessment of surface water quality

The method of water quality index is widely used in evaluation of the surface water quality because of its capability to summarize a number of water quality parameters into one numeric value, along with defined scale of water quality range. The current investigation includes application of modified model for calculating water quality index values, generated using experimental data and literary models. Software was created using modular design. Fourteen physical, chemical and biological parameters representing water quality state along with the assigned weights were elected. Comparison between models generated based on Serbian and American models of water quality index was done. Selected parameters differ mutually in number of parameters used in calculation of index, as well as in values of the weighting factors. In order to enable an efficient water quality analysis and to reconcile the requirements of both Serbian and American model, two software solutions were generated and processed on the example of the water quality of the Danube River in Serbia. Danube water quality was assessed at seventeen measuring locations along the river flow. Index values obtained from the two generated software applications were compared with the results of the official Serbian online calculator. Water quality determined using new generated models shows stricter approach and one class lower water quality compared to the existing Serbian model. Therefore, modular and open-generated simulation software is of great significance for the comparison and testing of different water quality models, not just those two shown in this study.     

Effects of poor quality irrigation waters on the nutrient leaching and groundwater quality from sandy soil

Sodium (Na⁺) in poor quality irrigation water participate in ion-exchange processes results in the displacement of base cations into solution and a raised concentration in groundwater. Knowledge of the rate of decrease of nutrients from soils resulting from poor water quality application is essential for long-term planning of crop production while minimizing the impact on groundwater quality. In this study, we examined the effect of sodium adsorption ratio (SAR) of irrigation water on nutrients leaching and groundwater quality in columns of sandy soil. Three types of irrigation waters at three NaCl–CaCl₂ solutions with the following levels of SAR (5, 15, and 30) were synthesized in laboratory. With the application of solutions, exchange occurred between solution Na⁺ and exchangeable cations (Ca²⁺, Mg²⁺, and K⁺), resulting in the displacement of these cations and anions into solution. Increasing the level of SAR from 5 to 15 and 30 resulted in increase in the average exchangeable sodium percentage (ESP) of the soil from 10.4 to 20.3, and 32.5, respectively. Adverse effect of high Na⁺ concentration in the solutions on raising ESP was less pronounced in solution having low SAR. Leaching of Ca²⁺, Mg²⁺, K⁺, and P from soil with the application of solutions represents a significant loss of valuable nutrients. This sandy soil showed the high risk for nutrients transfer into groundwater in concentrations exceeding the groundwater quality standard. Irrigation with poor quality water, which is generally more sodic and saline than regional groundwater, increases the rate of sodification and salinization of shallow groundwater.     

Groundwater quality assessment in urban environment

The assessment of environmental effects generated by urban areas (with various activities as agriculture, industry, human activities) on groundwater quality became essential for the use and conservation of the water resources. The main objective was to apply a water quality index to the groundwater sources using the specific methodology, establishing the suitability for drinking for groundwater. Water resources were monitored in October 2011, the samples were collected from 22 points for groundwater, and more parameters were analyzed: pH, electrical conductivity, turbidity, oxygen regime, hardness, alkalinity, nutrients regime (nitrates, ammonium, phosphates) which were considered important and utilized for water quality index computation that reveal poor quality for groundwater. The oxidability should be included in computation formula and the final results used for water management, taking into consideration the limits of the current model. Multivariate statistical analysis was used to indicate the influence of urban area on the quality of groundwater resources. Results of the analysis highlight an influence of geology and a contamination of agricultural origin.     

随采地震数据质量定量评价

在采煤工作面布设了随采地震监测系统后,为了自动筛选实时不间断传输回地面的巨量地震数据,利用采煤机积极割煤时,各接收道收到的信号相关性强,反之则弱这一特点,提出了一种自动定量化评估随采地震数据质量的方法。对内蒙某矿随采地震数据进行了处理,结果证明该方法能有效识别出单道的相关能量峰,对数据质量定量评价的效果很好。利用此法筛选了贵州某矿随采地震监测数据,将优选数据叠加后,数据的信噪比得到了明显的改善,相关能量轴明显增强。该方法可从海量随采地震数据中快速筛选出高质量的数据,大幅缩减进一步处理的工作量,改善处理效果。      

Water quality problems of urban areas

The increases in population and building density that occur as predominantly rural catchment areas become progressively urbanised can have a far-reaching effect on the hydrological cycle, and therefore on both the quantity and quality of water resources. The success of management strategies intended to alleviate the flooding problems and to prevent the degradation of water quality within and downstream of the urban area depends upon a thorough understanding of the sources of urban runoff pollution and the mechanisms by which pollutants are transported to watercourses. Particular care is necessary to ensure that any measures taken to mitigate the adverse effects of either flooding or pollution do not conflict with others in the same overall stormwater management plan.     

Groundwater quality assessment using entropy weighted water quality index (EWQI) in Lenjanat,Iran

Human health is strongly influenced by water quality which is threatened by the poor quality of polluted groundwater. In this study, the groundwater quality and its suitability for drinking have been studied in Lenjanat plain aquifer, Iran. Fifty-nine groundwater samples from study area were evaluated based on WHO and Iranian standards for drinking water. Groundwater samples from selected monitoring sources were sampled seasonally during 2009–2010. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solids, Ca²⁺, Na⁺, K⁺, Mg²⁺, HCO₃ ^?, SO₄ ^2?, Cl^?, F^? and NO₃ ^? were determined. During the water quality index calculating process, the weight of each parameter is usually given by experts according to their practical experience, which is subjective, so much useful and valuable information about the water quality gets lost. In order to avoid personal judgments about the weight of parameters, an information entropy method was used to assign weight to each parameter. Calculation of entropy weighted water quality index (EWQI) for groundwater samples showed that in the wet season, over 57 and 74 % of samples were in the range of “excellent” to “medium” quality based on WHO and Iranian standards, respectively. Due to groundwater quality reduction during dry season, 42 and 62 % of samples were in the range of “excellent” to “medium” quality based on WHO and Iranian standards, respectively. The results indicate that application of the EWQI is very useful to help the public and decision-makers will be able to identify and to evaluate groundwater quality in Lenjanat, Iran.     

Water quality in Lemoa, Guatemala

A variety of water supply sources are used in the rural Guatemalan Highlands. Formal municipal systems are rare, but villagers frequently form local water committees that construct spring-based supply systems. Recent work has indicated that groundwater may be a viable water supply source. The water quality from these two sources was characterized as well as water from other common sources including surface water and precipitation collection systems. Typically, all of the water sources contained unacceptable levels of coliform bacteria except for groundwater from a drilled well. Water monitoring indicated that not only did the water contain coliforms at the actual sources, but the infrastructure used to transmit the water to points of use may also be a source of coliforms. A cost comparison indicates that groundwater may be a cost-competitive, higher quality alternative to traditional spring-fed water systems.     

质量文化建设综述

介绍了质量管理的新发展,论述了质量文化的结构、内涵及其主要作用,树立新的质量管理观念,积极开展质量文化建设,     

西北地区地下水质量评价

本文以地下水调查的水质分析资料和动态监测资料为基础,参照我国地下水质量标准和生活饮用水卫生标准,对西北地区地下水质量状况进行综合评价。结果表明西北地区地下水质量状况为全国较差的地区,不可直接利用的地下水多分布于该区内陆盆地中心地带;地下水污染多发生在主要城市、工矿企业及其周边地区,水污染主要呈点状、线状分布,主要超标项目为溶解性总固体、总硬度、硝酸盐、亚硝酸盐、硫酸盐、氯化物和氟化物等。     

Assessing quality in Earth Science Education

Quality is an elusive concept — hard to define, but you recognise it when you come across it. This paper reviews the meaning of quality as applied in Higher Education and shows that there are, of necessity, a number of workable definitions of quality in Higher Education. The assessment of quality in Earth Science Higher Education in England during 1994–1995 is described. A number of general features of quality in Earth Sciences Education are drawn from this case study and the future direction of quality assurance is mapped. Three principles drawn from the definitions of quality and from the English teaching quality assessment exercise are applied to Earth Science Education in Africa. It is argued that different definitions of quality will apply in different societal contexts in Africa and that these may be used to shape the relevance of Geoscience Education. Increasing mobility of labour means that comparability of academic standards between African countries within a region is desirable and should be worked for. Finally, research in the UK shows that teaching quality is not necessarily dependent upon the size or research potential of a department, indicating that Africa can deliver high quality Earth Science Education.     

天津市近海水质预测方法研究

针对中国近海水质污染呈现的年周期性和自相似性特点,通过对分形理论的研究,提出了一种新的完全基于环境监测数据的近海水质污染变化的分形预测方法。以天津市近岸海域为例,根据分形拼贴定理,由基于仿射变换的分形插值方法求取各历史时间阶段水质变化的迭代函数系,根据近海水质变化的年周期性,对上述求得的迭代函数系加权求和,得到预测年份水质变化的统计意义上的迭代函数系,建立分形预测模型,应用随机迭代算法求得预测年份水质变化曲线的吸引子,对近海水质进行预测,预测结果显示枯水期、丰水期、平水期的平均预测误差分别为29.6%、27.5%、16.1%,3个水期的平均预测误差为24.4%。应用表明,该方法预测精度较高、实用性强,能够为近海水环境管理提供决策支持。     

GPS-RTK在农村宅基地调查中的运用及质量控制

以镇江市丹徒区农村宅基地调查项目为例,分析了影响GPSRTK测点平面精度和可靠性的因素,并提出了RTK测点质量控制的措施。指出GPSRTK测量必须提高可靠性,只要多检验,多比较,特别是和已有控制点的比较检验,就能提高可靠性。     

高质量连续取土技术研究

简要介绍了国内常规的取土技术。阐述了土样扰动对工程设计的经济性和合理性的影响,介绍了高质量连续性取土器的构成及其取样过程中的特点,即适用土层类型广可以获取粉细砂原状样。通过室内模拟试验,根据土体的变形、贯入力的变化以及孔隙水压力的比较分析进行研究,结果表明,连续性取土器能获取高质量的土样,效率较高,可以成为地层调查的重要工具。