Variability in the chemistry of private drinking water supplies and the impact of domestic treatment systems on water quality

Tap water from 497 properties using private water supplies, in an area of metalliferous and arsenic mineralisation (Cornwall, UK), was measured to assess the extent of compliance with chemical drinking water quality standards, and how this is influenced by householder water treatment decisions. The proportion of analyses exceeding water quality standards were high, with 65 % of tap water samples exceeding one or more chemical standards. The highest exceedances for health-based standards were nitrate (11 %) and arsenic (5 %). Arsenic had a maximum observed concentration of 440 µg/L. Exceedances were also high for pH (47 %), manganese (12 %) and aluminium (7 %), for which standards are set primarily on aesthetic grounds. However, the highest observed concentrations of manganese and aluminium also exceeded relevant health-based guidelines. Significant reductions in concentrations of aluminium, cadmium, copper, lead and/or nickel were found in tap waters where households were successfully treating low-pH groundwaters, and similar adventitious results were found for arsenic and nickel where treatment was installed for iron and/or manganese removal, and successful treatment specifically to decrease tap water arsenic concentrations was observed at two properties where it was installed. However, 31 % of samples where pH treatment was reported had pH < 6.5 (the minimum value in the drinking water regulations), suggesting widespread problems with system maintenance. Other examples of ineffectual treatment are seen in failed responses post-treatment, including for nitrate. This demonstrates that even where the tap waters are considered to be treated, they may still fail one or more drinking water quality standards. We find that the degree of drinking water standard exceedances warrant further work to understand environmental controls and the location of high concentrations. We also found that residents were more willing to accept drinking water with high metal (iron and manganese) concentrations than international guidelines assume. These findings point to the need for regulators to reinforce the guidance on drinking water quality standards to private water supply users, and the benefits to long-term health of complying with these, even in areas where treated mains water is widely available.     

The influence of acidic mine and spoil drainage on water quality in the mid-Wales area

The many abandoned base metal mines of the mid-Wales ore field are sources of extensive pollution. Some of the mineralised veins contain large amounts of pyrite and marcasite and oxidative weathering of these produces sulphuric acid resulting in very acidic mine drainage waters. In addition, the spoil tips associated with these mines can contain abundant iron sulphides. Drainage waters from these sources have pH values as low as 2.6 and are heavily contaminated with metals such as Al, Zn, Cd and Ni.Two of the main rivers of the area, the Rheidol and Ystwyth, intercept heavily contaminated acidic drainage which has a marked effect on water quality. The Rheidol contains over 100 g L^–1 Zn for 16 km downstream of the acid water influx. This level is over three times the recommended EEC limit for Zn in salmonoid waters of low hardness.     

Some effects of langmuir circulation on the quality of water resource systems

The quantitative extent to which the large-scale organized water motion in the surface waters of lakes and reservoirs, known as Langmuir circulation, affects the distribution and settling of algae and other suspended particles is not known and has thus been ignored in conventionally used water-quality models. Since the distribution and settling of these particles is important in determining water quality, this study set out to investigate these effects. Current literature which discusses this problem is reviewed and a mathematical model is developed based on the two-dimensional advection-diffusion mass transport describing the temporal and spatial distribution of suspended particles in a typical Langmuir cell; the Langmuir circulation flow field and turbulent diffusion coefficients are empirically modelled by relating them to environmental parameters.The results show that Langmuir circulation does affect particle distribution and settling. For particles with small sinking speeds, such as the lighter algae, the circulation causes intense mixing, resulting in essentially uniform distribution of particles over the cell (as assumed in the ‘well-mixed compartment model’). For particles with high sinking velocities, however, aggregation can occur, giving rise to significant reduction in sinking loss when compared with that predicted by conventional models. For diatoms, reductions of 6% and higher can occur depending on which conventionally used model is being considered, while for silt and sand particles in a cell of large width-to-depth ratio a reduction of more than 60% is possible.     

Mobility of free surface in different liquids and its influence on water striders locomotion

Dynamics of the surface layer in different liquids is examined by means of infrared thermography of the surface and simultaneous velocity fields measurements using surface and infrared Particle Image Velocimetry. This technique allows measurements and comparison of two velocity fields—at the surface and at small depth about 50–200 μm. In distilled water the velocity fields at the surface and at small depth exhibit significant dissimilarity. The flow field below the surface is essentially 3D, whereas the surface flow is characterized by vanishing 2D divergence of velocity, indicating predominantly planar motion. In contrast, in ethanol–butanol mixture two velocity fields are well correlated, both corresponding to 3D flow with continuous surface renewal. Thermal patterns, observed at the surface, and the flow field structure in different liquids are associated with different boundary conditions for velocity at the surface. Water surface is seldom renewed, which inhibits heat and mass exchange between the liquid and atmosphere. However, absence of vertical advection also enables organisms to live within the surface layer, to stand and walk on the free surface. This is illustrated by the difficulties a water strider faces on the surface of ultrapure water, which exhibits Marangoni convection.     

Qualitative assessment of the impact of waste littering and dumping on surface water quality in NigeriaOA

Water resources are vital for all living beings and should be managed properly to ensure the safety and well-being of humankind. Surface water bodies are constantly faced with serious contamination risks generated primarily by human activities and urbanization. The problem of waste littering and dumping in developing countries like Nigeria is increasingly affecting environmental resources such as air and water. Several studies have revealed alarming levels of heavy metals that exceed the World Health Organization(WHO) standards. Plastic waste represents a substantial portion of litter, affecting water quality. Pollution results in the depletion of aquatic ecosystems and an increase in water-related diseases. This review aims to assess the impact of waste littering and dumping on surface water quality in Nigeria. In this review, the findings of various studies on surface water bodies in Nigeria, particularly those under the influence of urbanization and waste disposal, were compiled. This review compared numerous physical and chemical parameters like p H, dissolved oxygen, and heavy metals, and microbiological properties such as total coliforms. The water quality index(WQI) was also computed in these studies to ascertain the suitability of the water samples for human consumption. Review results showed that numerous water bodies in Nigeria have significantly diverse water quality levels, with some samples meeting or exceeding the WHO guidelines for microbiological, chemical, and physical characteristics. Notably, levels of heavy metals, turbidity, and p H frequently exceeded permissible limits, pointing to contamination from agricultural and industrial sources. The WQI results for multiple locations revealed that the majority of surface water sources were classified as “bad” to “very bad”, meaning they were unfit for human consumption. The results emphasized the critical need for immediate action to prevent further harm and deterioration of surface water bodies in Nigeria. Recommendations include strengthening waste management policies, promoting recycling initiatives, fostering collaborations among stakeholders, developing littering penalties and enforcing fines to curb the challenge, and raising educational awareness from the primary level. This review emphasizes the need for proactive measures to protect the environment and surface water quality in Nigeria.     

Life cycle assessment and environmental improvement of residential and drinking water supply systems in Hanoi,Vietnam

In many Asian cities the public water supply is characterised by low pressure, frequent interruptions and occasional contamination. Hence, private households have to store water and increase pressure individually to ensure an uninterrupted supply at sufficient pressure and water for drinking has to be boiled or supplied separately in bottles. In this study the present water supply system in Hanoi and a number of modification options were analysed from an environmental point of view through life cycle assessment (LCA) in order to identify the most sustainable solutions for future water supply. It was found that the boiling of water for drinking was the largest source of impacts in the present system. Impacts could be reduced significantly if the public supply network was improved and private pumping and storage could be avoided and if the water could be used directly for drinking. It was also found that impacts could be reduced if consumers used bottled water for drinking instead of boiling tap water. Finally, it was demonstrated that even if drinking water cannot be supplied directly through the public network, a reliable public water supply at high pressure is environmentally advantageous. Sensitivity analyses revealed that the conclusions of this study are likely to be applicable to other cities with similar water supply systems.     

The influence of individuals in forming collective household preferences for water quality

Preference for water quality and its nonmarket valuation can be used to inform the development of pricing policies and long term supply strategies. Tap water quality is a household concern. The objective status quo of water provision varies between households and not between individuals within households, while charges are levied on households not individuals. Individual preferences differ from collective preferences. In households where there are two adults, we examine the preferences of each separately and then as a couple in collective decisions. We show the level of influence each has in developing the collective decision process. We use discrete choice experiments to model preference heterogeneity across three experiments on women, men and on both. We propose a random utility model which decomposes the error structure in the utility of alternatives so as to identify the individual influence in collective decisions. This approach to choice data analysis is new to environmental economics.     

The relationships of urbanization to surface water quality in four lakes of Hanyang,China

By converting rural land into urban land, urbanization impacts on surface water quality, because cities produce more pollutants than farmlands, especially heavy metals. Ways to reduce urbanization impacts on water quality are now being highlighted worldwide. Considering that land use can be a source or sink in pollution runoff, an understanding of the relationship between urbanization and surface water quality, as well as effects of specific land uses on water quality, is crucial. Corresponding management and controlling steps can then be put forward towards non-point source (NPS) pollution control and urban sustainable development. China has experienced rapid urbanization, especially since the 1980s. However, the environmental impacts of this process are not fully investigated. Hanyang, Hubei Province was selected as a typical city to study the impacts of urbanization on lake water quality. Pearson's correlation analysis was performed to elucidate the correlation between different land uses and water quality indicators at both whole lake watershed and small catchment scales. The results indicated that land uses play different roles, either source or sink, in pollution flow processes. Bottomland had a negative and residential land a positive correlation to most water quality indicators, especially heavy metals. These proved to be indicative and crucial land uses in NPS pollution control. Finally, a strategy for regulating urban land uses is proposed for improving surface water quality in cities similar to Hanyang, in southern China.     

Large scale systems approach to estuarine water quality modelling with multiple constituents

A matrix model for simulating concentration distributions of water quality constituents with coupled reactions in an estuary is developed from a large scale systems approach. The model is an approximation to the set of coupled partial differential equations describing the process. This steady state approximation is formulated as a large algebraic system consisting of coupled subsystems. The large algebraic system is solved by an efficient iterative method. Results utilizing actual field data are presented for the nitrogen cyle with five constituent forms of nitrogen for Corpus Christi Bay, Texas. Simulated and observed concentrations are compared.     

Analysis and prediction of the influence of energy utilization on air quality in Beijing

This work evaluates the influence of energy consumption on the future air quality in Beijing, using 2000 as the base year and 2008 as the target year. It establishes the emission inventory of primary PM₁₀, SO₂ and NO_x related to energy utilization in eight areas of Beijing. The air quality model was adopted to simulate the temporal and spatial distribution of each pollutant concentration in the eight urban areas. Their emission, concentration distribution, and sectoral share responsibility rate were analyzed, and air quality in 2008 was predicted. The industrial sector contributed above 40% of primary PM₁₀ and SO₂ resulting from energy consumption, while vehicles accounted for about 65% of NO_x. According to the current policy and development trend, air quality in the eight urban areas could become better in 2008 when the average concentrations of primary PM₁₀, SO₂ and NO₂ related to energy utilization at each monitored site are predicted to be about 25, 50 and 51 μg/m³, respectively.     

综合水质标识指数法在浑河水质评价中的应用

综合评价水环境质量,全面把握流域水环境污染特征是水环境污染防治中的重要基础性工作。水质标识指数可以完整标识水质评价指标的类别、水质数据、功能区目标值等重要信息,在单因子水质标识指数法基础上建立的综合水质标识指数法能完整表达河流总体的综合水质信息,既不会因个别水质指标较差就否定综合水质,又能对综合水质做出合理的评价;既可以在Ⅰ到Ⅴ类中比较水质的优劣,亦可以对劣Ⅴ类进行评价。为系统全面地研究浑河流域各不同河段水环境特征,将浑河流域划分为3个控制单元,根据2001—2010年间水质监测数据,采用综合水质标识指数法,识别出各控制单元主要污染因子,并阐明了浑河流域水环境质量时空变化规律,本研究即体现了全流域统筹考虑的系统思想,又体现了分区研究的针对性特点,并首次将综合水质标识指数法应用于浑河流域水质综合评价,其研究结论对水质监测数据的评价有一定的借鉴作用,亦对流域水污染防治对策的提出有一定的指导意义。     

The development of a multi-species algal ecodynamic model for urban surface water systems and its application

An ecodynamic model that can simulate four phytoplankton species has been developed to deal with the unique characteristics of urban river systems which has manmade river profile, flow controlled by gates, severe eutrophication status, and fragile aquatic ecosystem. The ecodynamic model was developed referencing two typical models: the water quality simulation model WASP and ecological model CAEDYM. The model can simulate 11 state variables: dissolved oxygen, carbonaceous biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, organic nitrogen, inorganic phosphorus, organic phosphorus and four phytoplankton species with zooplankton as a boundary condition. The ecodynamic model was applied to Sihai section of the Beijing urban river system, where serious algal blooms broke out in recent years. The dominant phytoplankton species are Cyanophyta, Chlorophyta, Bacillariophyta, and Cryptophyta. Site-specific data on geometry, meteorology, pollution sources, and existing ecosystem parameters were collected and used for model calibration and verification The model results mimic observed trends of water quality and phytoplankton species succession and can be used for forecasting algal blooms as well as assessment of river management measures.     

镉在土壤-植物系统中的迁移转化及其影响因素

重金属镉(Cd)被列为环境污染物中最危险的五种物质之一。因其极易通过食物链在人体内积累并危害人体健康的特性，环境Cd污染尤其是土壤系统的Cd污染已成为国内外环境污染研究的热点，Cd在土壤一植物系统中迁移转化规律备受关注。本文概述了国内外土壤Cd污染研究现状；在已有研究的基础上，总结并阐述了影响Cd在土壤一植物系统中迁移转化的几个重要因素：土壤基本理化性质(pH值、有机质等)、Zn元素、P元素、陪伴阴离子Cl^-和SO4^2-，其中包括尚未被普遍认识的P元素和陪伴阴离子Cl^-和SO4^2-；并详细论述了各因子对Cd在土壤一植物系统中迁移转化的影响及其可能机理。     

On the role of entropy in water quality modelling

The use of the entropy principle in phenomenological water quality models is not only necessary, but also of great advantage. A deterministic ecosystem model must obey the 2nd law of thermodynamics. Gibb's equation is a constraint additional to the balances of mass, energy and momentum. The entropy principle supports the unified treatment of physical, chemical and biological processes in water bodies, offers stability criteria and controls the further development of the aquatic ecosystems. Thermodynamic criteria also allow the determination of the bifurcation points of the model equations. Especially near these points the state and structure of the ecosystem can be strongly changed by fluctuations of the variables and parameters of the ecosystem.Results of the thermodynamic theory of selforganizing systems (Glansdorff and Prigogine, 1971; Nicolis and Prigogine, 1977) are of very great importance for water quality modelling. Furthermore, the entropy principle bridges the phenomenological, stochastic and cybernetic approaches to water quality modelling.While the paper deals with general aspects of the role of entropy in water quality modelling, the basic system of equations, taking the entropy principle into account, can be found in a previous paper (Mauersberger, 1978).     

A comparison of the water management systems in France and China

This paper compares legal systems for water management in France and China, with a focus on integrated water resources management and regarding in particular the formulation of policies and their implementation. The research shows that China has committed itself to the efficient management of water resources through the development of various policy tools during the current period. This commitment, however, has often been interrupted and distorted by politics, resulting in the neglect of socioeconomic and environmental priorities. France has developed a legislative framework and practical instruments to apply integrated water resources management at the river basin level since the 1960s. This experience and the current implementation of the European Water Framework Directive brings elements that can contribute to Chinese society meeting its water challenges.     

Trihalomethane formation in ozonated and chlorinated surface water

The relatively recent discovery of disinfection by-products has driven the main regulatory organisms to set maximum contaminant levels for certain substances in drinking water. Trihalomethanes can be deemed as the most important group of by-products in chlorinated surface waters. The present work has focused on trihalomethane formation in a full-scale water treatment plant. We studied the effect of several factors, including ozonation, on trihalomethane levels in chlorinated treated water. The treatment scheme also includes an ozonation step. Electronic Publication     

Impact of coal industries on the quality of Damodar river water

Increasing demand for water in domestic, agricultural, and industrial sectors necessitates exploitation of water either in the form of groundwater or from natural resources. To safeguard the long-term sustainability of water resources and their utilization, the quality of water has to be periodically monitored and determined for various characteristics, especially when the sources are polluted, such as Damodar river. Central Institute of Mining and Fuel Research (CIMFR), Dhanbad, is carrying out research work on coal and its utilization and associated environmental concerns. The blood stream of life for the whole Jharia Coalfield is none other than the river Damodar. CIMFR's campus also depends exclusively on river Damodar for meeting its demand of drinking water. This study is a general survey toward the characteristics of Damodar river water, with special emphasis on the pollutant parameters, and evaluation of the treatment process being carried out at the institute for potability. Damodar river water is indeed affected by the disposal of the wastes without any pre-treatment by different coal-based industries established in its basin. The quantity of dissolved and suspended solids, total hardness, chemical oxygen demand, and coliform bacterial count are higher in Damodar water due to the disposal of the waste/effluents from coal-washing plants, coke ovens, cement, and other industries, but well within the permissible limit which is probably attributable to the high-carrying capacity of the river. The river is still not that much affected as it is usually apprehended, and it can be well utilized for potable and domestic purposes after simple treatment.     

Applications of nanotechnology in agriculture and water quality management

Due to their small size and unique physico-chemical characteristics, nanomaterials have gained importance in the agri-food sector, notably in preservation and packaging. Future applications will focus on shelf life, food quality, safety, fortification and biosensors for contaminated or spoiled food, irrigating water and drinking water. Different types and shapes of nanomaterials are being used depending upon the needs and nature of the work in agriculture and water quality management. Here we review the application of nanotechnology in agriculture. The major points discussed are: (1) Nanomaterials for agriculture and water quality management. (2) Research interests such as nanoscale carriers, fabricated xylem vessels, nanolignocellulosic materials, clay nanotubes, photocatalysis, bioremediation of resistant pesticides, disinfectants, agricultural wastewater treatment, nanobarcode technology, quantum dots for staining bacteria and nanobiosensors. (3) Nanotechnological applications for agriculture, which includes nanolignodynamic metallic particles, photocatalysis, desalination, removal of heavy metals and wireless nanosensors.     

The influence of pH and household plumbing on water lead concentration

The water lead concentrations measured in the homes of children who were part of the Edinburgh Lead study are related to the characteristics of the water supply and the household plumbing. At the time of the study one of the City of Edinburgh's two water supplies was lime treated to reduce plumbosolvency but in the second supply this treatment had not yet become effective. This allows us to estimate the extent to which this type of water treatment reduces water lead concentrations, in houses with lead plumbing, to comply with existing and proposed limits for lead in water. The kitchen cold water was supplied from a lead storage tank in 69 (15%) of the houses. These houses had the highest lead concentrations and water treTo whom correrspondence should be addressed.     

Individual- and Assemblage-Level Effects of Anthropogenic Sedimentation on Snails in Lake Tanganyika

Abstract:  Human impacts on aquatic biodiversity are often measured at the assemblage or community level, although it has been suggested that individual-level measures are more sensitive. We evaluated the effects of anthropogenic sedimentation on endemic snails in Lake Tanganyika, East Africa, by comparing assemblage-level (i.e., species richness, evenness, and abundance) and individual-level (i.e., frequencies of predation and parasitism, fecal organic content, life history) data between sediment-disturbed and reference sites. Previous studies have indicated that sedimentation kills snails and reduces mollusc diversity in this system, but we found little evidence of changes in species richness, evenness, or snail abundance at the levels of sedimentation recorded. In contrast, individual-level data revealed a variety of differences associated with sedimentation. Frequencies of shell scarring by predatory crabs and castration by parasitic trematodes were significantly lower at disturbed sites, indicating shifts in interspecific interactions. Snails ingested large amounts of inorganic sediments at disturbed sites, suggesting a reduction in food quality. In addition, sedimentation was associated with a large downward shift in size distribution within some species and reproduction at smaller size. These strong patterns in individual-level data contrast with the lack of effects at the assemblage level. We argue that incorporating individual-level measures will often enhance the sensitivity of impact surveys and may reveal effects of disturbance on important interspecific interactions.