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More than 30 organic contaminants were detected in shallow groundwaters at Wuhan, the largest city in central China. Seriously contaminated groundwaters were from densely populated, industrial and commercial areas. Abnormal concentrations were found in groundwater from Hankou, downtown Wuhan: trimethylbenzene up to 29 μg/L, tetramethylbenzene up to 866 μg/L, and trichloroethene up to 9.5 μg/L. Benzene, Toluene, Ethylene and Xylene (BTEX) contamination of groundwater is serious and widespread at Wuhan, ranging between 0.14 and 25.0 μg/L. Considering the hydrogeological conditions of most Chinese cities, DRAMIC, a modified version of the widely used DRASTIC model, was proposed by the authors for assessing vulnerability of groundwater to contamination. The factors D, R, A and I in DRAMIC model are the same as in DRASTIC. The factor topography is ignored. The factor soil media is substituted by a new factor aquifer thickness ( M) and the factor hydraulic conductivity of the aquifer by a new factor impact of contaminant ( C). The equation for determining the DRAMIC Index is: DRAMIC = 5 D R + 3 R R + 4 A R + 2 M R + 5 I R + 1 C R. The calculated DRAMIC Index can be used to identify areas that are more likely to be susceptible to groundwater contamination relative to each other. The higher the DRAMIC Index is, the greater the groundwater pollution potential. Applying DRAMIC, a GIS-based vulnerability map for Wuhan city was prepared. Interestingly, places such as downtown Hankou, where enhanced concentrations of BTEX have been detected, correspond quite well with those with higher DRAMIC ratings. [ABSTRACT FROM AUTHOR]

Total dissolved inorganic carbon (TDIC) and its stable isotope ratio δ13CTDIC are used to trace the evolution of the carbon system of groundwater in three UK Permo-Triassic sandstone aquifers. Samples were collected from multilevel piezometers, open boreholes and sewer sampling points in the British Midlands (Nottingham, Birmingham and Doncaster) to evaluate both local and regional variations in δ13CTDIC. Δ13C samples of matrix and pore water have also been analysed in each aquifer to further constrain the interpretations. Combining δ13CTDIC ratios with measurements of TDIC and pH clearly distinguishes the principal processes underlying the geochemical evolution of groundwater in Triassic sandstone aquifers, where processes can be both natural (e.g. carbonate dissolution) and anthropogenic (sewer-derived recharge). The paper shows that δ13CTDIC resolves ambiguities that arise from the interpretation of TDIC and pH measurements in isolation. Field measurements demonstrate that, under natural conditions, the carbonate system evolves similarly in each aquifer. An open-system evolution during recharge largely saturates the groundwater with carbonate depending upon its availability in the sandstone matrix. The contribution of sewer exfiltration to urban recharge is readily distinguished by lower pH and higher TDIC values without significant changes in δ13CTDIC. [ABSTRACT FROM AUTHOR]

During the planning, designing, construction, operation and maintenance of highways, groundwater can be of important environmental and constructional constraint that can significantly influence the safety operation of traffic and of big influence on the operational costs of highways. To classify and conceptualize the relation between groundwater and highways, three important groups of problems can be determined: groundwater protection from highway influences, protection of highway from groundwater and economic use of groundwater for highway operation. In the present study, groundwater management strategies are represented during all life cycles of highways. Greater emphasis is given to groundwater protection and field hydrogeological investigations for proper groundwater management related to the highway. The approach adopted in Slovenia and the role of hydrogeology is given as an illustration. [ABSTRACT FROM AUTHOR]

By combining a sewer defect database and hydrogeological information, it has been attempted to assess sewer–groundwater interaction at the scale of the city of Rastatt (SW-Germany). Comprehensive hydrochemical samplings, including a series of new marker species, have been conducted in the urban aquifer and used for validation. The iodated X-ray contrast media, amidotrizoic acid and iothalamic acid, can be considered as highly specific for wastewater influence and have been found in several groundwater observation wells. [ABSTRACT FROM AUTHOR]

The ionic and isotopic compositions (δD, δ18O, and 3H) of urban groundwaters have been monitored in Seoul to examine the water quality in relation to land-use. High tritium contents (6.1–12.0 TU) and the absence of spatial/seasonal change of O–H isotope data indicate that groundwaters are well mixed within aquifers with recently recharged waters of high contamination susceptibility. Statistical analyses show a spatial variation of major ions in relation to land-use type. The major ion concentrations tend to increase with anthropogenic contamination, due to the local pollutants recharge. The TDS concentration appears to be a useful contamination indicator, as it generally increases by the order of forested green zone (average 151 mg/l), agricultural area, residential area, traffic area, and industrialized area (average 585 mg/l). With the increased anthropogenic contamination, the groundwater chemistry changes from a Ca–HCO3 type toward a Ca–Cl(+NO3) type. The source and behavior of major ions are discussed and the hydrochemical backgrounds are proposed as the basis of a groundwater management plan. [ABSTRACT FROM AUTHOR]

To investigate the urban groundwater contamination by eight trace metals and 69 volatile organic compounds (VOCs) in relation to land use in Seoul, a total of 57 groundwater samples collected from wells were examined using a non-parametric statistical analysis. Land use was classified into five categories: less-developed, residential, agricultural, traffic, and industrial. A comparison of analyzed data with US EPA and Korean standards for drinking water showed that some metals and VOCs exceeded the standards in a few localities, such as Fe ( N=5), Mn ( N=6), Cu ( N=1), TCE ( N=6), PCE ( N=8), 1,2-DCA ( N=1), and 1,2-dichloropropane ( N=1). Among the 69 investigated VOCs, 19 compounds such as some gasoline-related compounds (e.g., toluene) and chlorinated compounds (e.g., chloroform, PCE, TCE) were detected in groundwater. Non-parametric statistical analysis showed that the concentrations of most trace metals (Fe, Mn, As, Cr, Pb, Cd) and some VOCs (especially, TCE, PCE, chloroform; toluene, carbon tetrachloride, bromodichloromethane, CFC113) are significantly higher in the industrial, residential, and traffic areas ( P<0.05), indicating that anthropogenic contamination of urban groundwater by those chemicals is growing. Those chemicals can be used as effective indicators of anthropogenic contamination of groundwater in urban areas and therefore a special attention is warranted for a safe water supply in those areas. The results of this study suggest that urban groundwater quality in urban areas is closely related with land use. [ABSTRACT FROM AUTHOR]

With over 40% of the water supply of Western and Eastern Europe coming from urban aquifers, efficient and cost-effective management tools for this resource are essential to maintain the quality of life. However, the increasing concerns about the environmental impacts of water projects and their increasing economic costs mean that traditional planning concepts, which assume unlimited supplies of potable water, must be questioned. This includes the source of the water supply and its appropriate use. Urban transport systems and the provision of water have been identified as the most critical factors that determine the future of cities in this century. The objective of an interdisciplinary research project presented in this paper is to identify and develop systems and technologies and integrative processes and analytical tools, which are commercially valuable, scientifically robust and which improve the cost effectiveness of urban water services, in line with the program’s vision of ecological sustainability. As part of this program, a software tool has been developed to estimate the water flows and contaminant loads within the urban water system. This paper presents first modelling results of water and contaminant flows through the existing urban water, wastewater and stormwater systems, from source to discharge point. [ABSTRACT FROM AUTHOR]

Water quality data from 56 wells, aquifer characteristics, soil types and land use in the city suburb of Dakar were compared to assess the effects of land use on the Thiaroye groundwater quality. The study area encompassed an unsewered densely populated zone, agricultural land, low density villages, and undeveloped land located in the sand dunes. A method similar to GIS technologies was applied to evaluate the degree of vulnerability of the different parts of the aquifer in relation to urban development, land use and aquifer characteristics. The aquifer parameters (hydraulic conductivity, groundwater level depth, recharge, soil type) were re-evaluated qualitatively into three class rankings (high, moderate and low), depending on the likelihood for contaminants reaching the water table, then combined using the two matrix Boolean logic based approaches to identify the nine classes of vulnerability assessed in the aquifer domain. An attempt was made to explain the distribution of nitrate concentration with the assessed vulnerability. In the area assessed, in the densely populated zone running from Pikine, to Thiaroye and Yeumbeul, very high nitrate concentrations correspond with the highest vulnerability index (H1). Nitrate contamination in this area is a consequence of point-source seepage from individual septic systems improperly built in this area. In the eastern part of the aquifer, high nitrate concentrations at Deni B. Ndao, Mbawane and Golam localities coincide with a moderate vulnerability assessment. The major source of nitrate in these areas is induced by agricultural activities. [ABSTRACT FROM AUTHOR]