Search

The inter-cavern containment property assessment is one of the critical issues of the underground water-sealed oil storage facility and its result determines whether the mixing of different oil products occurs or not. In this study, an inter-cavern containment property assessment method combining discrete fracture network analysis with graph theory was proposed. In the method, the discrete fracture network analysis is adopted to obtain the distribution of the hydraulic head in the rock mass and the graph theory is used to determine the hydraulic connectivity between the two adjacent caverns. The influences of cavern spacing, liquid level differences, water curtain pressures, and geometric parameters on the inter-cavern containment property were investigated based on the assessment method. The results indicated that the inter-cavern containment property could be guaranteed by increasing cavern spacing (d), water curtain pressure (P), or decreasing liquid level differences (Δh), fracture trace length, and linear density. To compare the influence of different factors on the inter-cavern containment property, a parameter p was defined to represent the connectivity of fracture networks between caverns according to the connected relations in graph theory. By comparing changed connectivity parameter p, the influences of cavern spacing, liquid level differences, and water curtain pressures on the inter-cavern containment property were ranked as follows: Δh > d > P. Based on the Huangdao underground oil storage caverns, the inter-cavern containment properties were discussed. The result showed that the cavern spacing should be greater than 40 m, the water curtain pressure should not be greater than 130 kPa and the liquid level difference should be less than 12 m to ensure inter-cavern containment properties, which can offer good guidance for the design and operation of caverns. [ABSTRACT FROM AUTHOR]

In this investigation, metals of environmental concern, Cd, Cr, Co, Pb and Cu, are identified in the feed coal of thermal power plant from eastern India. The concentrations (0.56–10.3 µg/g) of these metals are enriched (one- to twofold) in fly and bottom ash during combustion. Additionally, a noticeable presence of Cd, Cr, Co, Pb, and Cu was also observed on the surface (0.26–5.6 µg/l) and groundwater (0.12–2.65 µg/l) of the neighbouring power plant, which focuses on the contribution of combustion ashes in the water contamination of these elements. The analytical result shows that rainwater has a greater influence on the rapid transportation of these elements into the surface water than groundwater. The mobility of such metals of environmental concern from the combustion ashes into the surface and groundwater may pose a risk to the ecosystem. A regular monitoring of chemical quality of coal as well as expert dumping custom, chemical treatment before disposal and recycling of combustion residues are the essential steps for clean energy generation and safe environment. [ABSTRACT FROM AUTHOR]

An underground liquified petroleum gas (LPG) storage facility was constructed between 2003 and 2013 in Namikata, Imabari City, Ehime Prefecture, Japan, to increase domestic LPG stockpiles. The most important issue during construction and operation of this facility is gas leakage prevention. To thwart water leakage, the water curtain system was constructed according to design standards, and a large amount of deionized seawater (seal water) was continuously injected into the rock mass around the cavern to keep the water level constant during both construction and operation. It is possible to distinguish three end member waters (existing groundwater, seawater or fossil seawater, and seal water) using the salinity and isotope (δ18O) difference because seal water injected underground has almost the same δ18O value as seawater. In this study, continuous observation is carried out using the geochemical techniques for flow analysis with a mixing proportion of three end-members in the initial construction period (April 2005 to March 2006) of the LPG underground storage facility. It is determined that existing groundwater and fossil seawater originally distributed in this region are partly replaced by seal water in the cavern. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization, the degree of human influence on land use is getting increasingly deeper. To research the future land use, this paper collects 5 years of land use from 1992 to 2012 from the government, and integrates cellular automata and Markov models to predict the land use change in 2020 and in 2030 in the Idrisi software. The key findings: (1) in the period 1992–2012, significant land cover type has been changed and the rate of change for farmland, ecological land, construction land and other uses, is greater than 6%; (2) the transition areas from farmland to construction land are 778 km2, the largest among land use patterns, and they are mainly concentrated to the north, east and south of the city center; (3) according to the 2030 projection, land use change will result in a reduction in farmland, from 3633.29 km2 to 3126.21 km2 (22.14–19.05% in percentage), and an increase in construction land, from 2976.87 km2 to 3239.44 km2 (18.14–19.74% in percentage), relative to the total area in 2012. According to the urbanization process, the characteristic of land use change is from original dramatic to the late slowdown, then obtain a stable state finally. But from the results of prediction, the construction land will continue to increase while the farmland will decrease, which counteracts the ability to reach the harmony steady state, and policies related to reduced urban construction development or economic sanctions need to be introduced into land use planning. [ABSTRACT FROM AUTHOR]

Impacts of land use changes and groundwater management actions on groundwater quality were evaluated at the island scale with spatiotemporal trends of NO-N and Cl concentrations in groundwater of Jeju Island, Korea. The temporal trends from 1993 to 2012 in the concentrations of NO-N and Cl from more than 3900 wells were estimated using the Mann-Kendall trend test and Sen's slope analysis and compared with the land use change trend for the period 1995-2009. The results indicate that the upward trends in NO-N were associated with the expansion of agricultural lands, whereas Cl trends were considered to be affected by other factors in addition to the land use changes. In the mid-mountainous region, the deterioration in the groundwater quality by the both NO-N and Cl was expected due to the continuous expansion of agricultural lands. In the lowland area, the NO-N and Cl components showed different trends depending on the regions. In the eastern area, increasing trends in NO-N were observed due to the development of new agricultural areas, while the Cl concentration was observed to decrease as a result of the regulation on groundwater extraction to reduce seawater intrusion. Our study highlights that a comprehensive interpretation of trends in NO-N and Cl and land use changes for long-term periods can provide useful insights to prepare for suitable groundwater management plans in the whole island perspective. [ABSTRACT FROM AUTHOR]

The weathering of pyrite-rich andesite in the southeastern part of Korea has led to acid rock drainage, creating severe environmental problems in the region. In this study, the mineral compositions and geochemical mobility of heavy metals in the bedrock, in addition to the weathering products, are investigated. Samples of bedrock and weathering products were collected from two sites in the Yangsan area. Site 2 shows considerably more weathering than site 1, due to the longer duration of weathering. The mineral compositions show that the bedrock at site 2 was more heavily altered by hydrothermal activity. The weathering products at site 2 contain jarosite and goethite with lower pH values than site 1, in which the samples are buffered by calcite. This indicates that the mineral compositions and pH values of the weathering products at the two sites are influenced by the primary mineral compositions of the bedrock and the duration of weathering. With the exception of Pb, the concentrations of heavy metals at site 1 are higher than those at site 2, probably due to higher concentrations in the bedrock. Moreover, the labile and acid-soluble fractions, which can be more readily released into the environment, are higher at site 1, mainly due to the shorter duration of weathering. Accordingly, the weathering process at site 1 carries more potential hazards to the environment than that at site 2. However, chemical weathering is locally impeded by calcite buffering at site 1. Although the concentrations of heavy metals at site 2 are lower than those at site 1, they are being continuously released due to the lower pH and longer and more and extensive weathering. [ABSTRACT FROM AUTHOR]

Changes in the hydrochemical conditions of groundwater were evaluated following the construction of a large-scale underground facility at the Mizunami Underground Research Laboratory (MIU), Japan. The facility was constructed to a depth of 500 m in sedimentary and granitic rocks. Drawdown of the groundwater level in the range of several tens to hundreds of meters was observed up to hundreds of meters away from the shafts during the first ten years of facility construction and operation. Subsequent changes in groundwater chemistry occurred due to upconing of high-salinity groundwater from the deepest part of the shaft and the infiltration of low-salinity shallow groundwater. We predict that future deep groundwater chemistry in the vicinity of the MIU facility will resemble that of the present-day shallow groundwater. Multivariate statistical analysis provides fundamental insights into such a site. We found that the extent of hydrochemical variability related to MIU construction and operation was dependent on the distance from the facility shafts and galleries and on hydrogeological compartmentalization resulting from lithological boundaries (such as permeable conglomerates vs. more compact lithological units) and other features (such as faults or clay layers). We conclude that hydrochemical impact assessment of groundwater in low-permeability rock is essential prior to the construction of such a facility. This should include characterization of hydrogeological structures and compartments to propose suitable location of shafts and galleries. [ABSTRACT FROM AUTHOR]

The Tabriz area is one of the most industrialized areas in northwest of Iran. The heavy industrialization and the increasing urbanization are responsible for the rapidly increasing stress on the groundwater of the area. The objective of this study was to evaluate heavy metals such as Fe, Mn, Al, Zn, As and Cr in groundwater and their spatial distribution in Tabriz plain aquifer. The concentrations of Fe, Cr, Mn, As, and Al in some of the groundwater samples exceed the maximum admissible concentration (MAC). Correlation matrix (CM) and principal components analysis (PCA) methods were employed to identify source apportionment of contamination parameters in groundwater. There are two types of aquifers, with different quality of water, in the plain; an unconfined aquifer with saline water and a confined aquifer with fresh water quality. Arsenic concentrations in the unconfined aquifer and in the recharge areas of the plain boundary are low, with an average of 25.8 µg/L, while in the confined aquifer and deep wells the concentrations are high, with an average of 122.5 µg/L. The arsenic occurring in groundwater resources of the area originates from geological formations such as alluvial tuffs of Sahand mountain and its concentration is highly dependent on hydrogeological and environmental reducing conditions, residence time of water and depth of the sampling wells. [ABSTRACT FROM AUTHOR]

The concentration of trace elements such as As, Ba, Co, Cu, Ni, Pb, Rb, Sr, V, Y, and Zr was studied in soils around Zaheerabad Town, Medak District, Andhra Pradesh, India. The soil type in the study area is clayey and lateritic. The application of fertilizers and pesticides for agriculture has contributed to the continuous accumulation of trace elements in soils. The contamination of the soils was assessed by comparing trace element concentration with natural background values for clayey and lateritic soils. Fifty soil samples have been analyzed using X-ray fluorescence spectrometer. The concentration ranges of Cu (76.4-213.1 mg/kg) and Pb (4.2-50.1 mg/kg) are exceeding natural background limit and other trace element concentration like Co (44.4-85.7 mg/kg), Cr (138.8-348.5 mg/kg), Ni (12-50.1 mg/kg), V (56.3-779.3 mg/kg) and Zn (71.2-133.7 mg/kg) are within permissible limit. The soil contamination was estimated on the basis of Index of geoaccumulation ( I), enrichment ratio (ERn) [or enrichment factor (EF)], contamination factor (CF) and degree of contamination ( C). The concentration of above-mentioned elements was similar to the levels in the earth's crust pointed to metal depletion in the soil as the EF was <1. Cu and Pb showed high EF in the soil samples indicating that there is a considerable heavy metal pollution, which could be correlated with the agricultural activity in the area. A contamination site poses significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects on terrestrial, groundwater and aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The kinetics of sulfur-utilized autotrophic denitrification of groundwater was evaluated in batch tests to obtain kinetic parameters. Experiments were performed in media bottles containing varying NO-N concentrations (20, 44, and 77 mg/L) with 4.0-4.75 mm-sized sulfur particles. Alkalinity was set as a constant in all experimental containers at 850 mg/L as CaCO. The half-order kinetic model was found to adequately describe the process efficiently, yielding denitrification rate constants of 4.36, 5.51, and 6.91 mg-N/L · h in the presence of NO-N at 20, 44, and 77 mg/L, respectively. The rate of denitrification increased with the increasing initial NO-N concentrations. [ABSTRACT FROM AUTHOR]

Operation of underground oil (gas) storage cavern in coastal area can induce seawater intrusion because excavation of underground storage cavern causes the groundwater level decrease of coastal aquifer. Seawater intrusion has the potential to cause the corrosion of underground cavern facility and leakage of gas and oil from the storage caverns, therefore, seawater intrusion into the underground storage caverns should be evaluated carefully to avoid unexpected operation problems. In this study, the extent of seawater intrusion into underground oil storage cavern in Yeosu, Korea, was assessed through field monitoring and numerical modeling to evaluate the storage cavern sustainability against seawater intrusion. The mean values of seawater mixing ratios of seepage water in each cavern, estimated through modeling, range from 0.01 to 8.70 %, which are less than the measured mixing ratio (2.3-12.8 %) based on the Cl concentrations. This result indicates that other source of Cl may have contributed to the observed salinity in the cavern seepage water. Spatial and temporal variations in monitoring data and numerical modeling demonstrate that the location of storage, seepage water flow rate, and the fracture zones are important factors controlling seawater mixing ratio. Seawater intrusion barrier wells located along the coastline were shown to be important to prevent seawater intrusion into the storage caverns significantly. The predicted seawater mixing ratio after 100 years of cavern operation is 0.06-12.7 % varying depending on the caverns' location. [ABSTRACT FROM AUTHOR]

The geochemistry of major and trace elements (including heavy metals and rare earth elements) of the fresh and weathered black shales, and the soils derived from black shales in the Ganziping mine area in western Hunan province (China) were studied using the following techniques: X-ray fluorescence (XRF), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray diffraction (XRD). The results show that the black-shale soils are significantly enriched with AlO and FeO, and depleted of mobile elements CaO, NaO and KO. The soils are also highly enriched with heavy metals U, V, Ni, Ba, Cu, Zn and Pb, that may cause potential heavy-metal contamination of the soils. Composition of the soils is homogeneous compared to the weathered black shales, for which the concentrations of major elements except CaO and NaO, and trace elements except heavy metals (U, V, Ni, Ba, Cu, Zn and Pb) as well as the mobile Sr, show lower variations than in the weathered black shales. Ratios of Zr/Hf, Ta/Nb, Y/Ho, Nd/Sm, and Ti/(Ti + Zr), of the soils are also less variable, with values constantly similar to that of the fresh and weathered black shales correspondingly. Thus, components of the soils are believed to be contributed from the parent black shales through weathering and pedogenesis. It is concluded that the soils were formed by at least two stages of geochemical processes: the early stage of chemical differentiation and the later stage of chemical homogenization. The chemical differentiation that was taken during black-shale weathering might have caused the depletion of CaO and NaO, and the enrichment of AlO and FeO; while the chemical homogenization that was taken during pedogenesis led to the depletion of SiO and KO, and to the further enrichment of AlO and FeO. The heavy-metal enrichment (contamination) of the soils was then genetically related to the enrichment of AlO and FeO in the soils. [ABSTRACT FROM AUTHOR]

The adsorption of Cs, Sr, Ni, and Co radioactive substitutes onto Yesan clay and zeolite was studied through batch and column tests using Cs, Sr, Ni, and Co as substitutes for radioactive isotopes. Adsorption values of 0.189-1.865 μg/g onto Yesan clay and 0.595-9.055 μg/g onto zeolite were observed, with the radioactive substitutes being almost 100 % adsorbed from the onset of column testing. Adsorption was achieved through ionic bonding. These materials demonstrated suitability for use as backfill or foundation materials for nuclear power plants, radioactive waste disposal facilities, and other radioactive facilities. [ABSTRACT FROM AUTHOR]

This paper reports a geochemical study of trace metals and Pb isotopes of sediments from the lowermost Xiangjiang River, Hunan province (P. R. China). Trace metals Ba, Bi, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, Mo, Cd, Sn, Sb, Pb, Tl, Th, U, Zr, Hf, Nb and Ta were analyzed using ICP-MS, and Pb isotopes of the bulk sediments were measured by MC-ICP-MS. The results show that trace metals Cd, Bi, Sn, Sc, Cr, Mn, Co, Ni, Cu, Zn, Sb, Pb and Tl are enriched in the sediments. Among these metals, Cd, Bi and Sn are extremely highly enriched (EF values >40), metals Zn, Sn, Sb and Pb significantly highly (5 < EF < 20), and metals Sc, Cr, Mn, Co, Ni, Cu and Tl moderately highly (2 < EF < 5) enriched in the river sediments. All these metals, however, are moderately enriched in the lake sediments. Geochemical results of trace metals Th, Sc, Co, Cr, Zr, Hf and La, and Pb isotopes suggest that metals in the river sediments are of multi-sources, including both natural and anthropogenic sources. Metals of the natural sources might be contributed mostly from weathering of the Indosinian granites (GR) and Palaeozoic sandstones (PL), and metals of anthropogenic sources were contributed from Pb-Zn ore deposits distributed in upper river areas. Metals in the lake sediments consist of the anthropogenic proportions, which were contributed from automobile exhausts and coal dusts. Thus, heavy-metal contamination for the river sediments is attributed to the exploitation and utilization (e.g., mining, smelting, and refining) of Pb-Zn ore mineral resources in the upper river areas, and this for the lake sediments was caused by automobile exhausts and coal combustion. Metals Bi, Cd, Pb, Sn and Sb have anthropogenic proportion of higher than 90%, with natural contribution less than 10%. Metals Mn and Zn consist of anthropogenic proportion of 60-85%, with natural proportion higher than 15%. Metals Sc, Cr, Co, Cu, Tl, Th, U and Ta have anthropogenic proportion of 30-70%, with natural contribution higher than 30%. Metals Ba, V and Mo might be contributed mostly from natural process. [ABSTRACT FROM AUTHOR]

The occurrence of fluoride in groundwaters can be influenced by many factors. In Korea, the fluoride-rich groundwaters are normally associated with rock types, especially granite and gneiss. In Gimcheon, high-fluoride groundwaters (up to a maximum of 2.15 mg/L) were observed with bimodal distribution of concentrations. The groundwater in this area showed relatively high concentrations of anthropogenic chemicals such as nitrate, chloride, and sulfate. Statistical analysis showed that fluoride is positively correlated with pH, alkalinity, sodium, and lithium, indicating that the interaction with granite is the main cause enriching its concentration. In Gimcheon, δO data of groundwater showed a negative correlation with nitrate and can be used as an indicator of groundwater age. The four samples of fluoride-rich groundwater were plotted in the light δD and δO region, showing that they were the result of long water-rock reaction. However, other groundwater with a low-fluoride concentration was evenly distributed throughout all δD and δO ranges and did not show a statistically significant correlation with nitrate, indicating possible mixing with another source of fluoride. Considering the influence from the surface on the geochemical characteristics of groundwater in this area, anthropogenic sources including phosphate fertilizer containing fluoride and pesticides may also have partly contributed to the concentrations of fluoride in the low-fluoride groundwater. The scattered distribution of fluoride-rich groundwater and the significant correlation with lithium suggest that pegmatite is the main rock type increasing fluoride concentration in this area. [ABSTRACT FROM AUTHOR]

In most countries of the world, groundwater and surface water are at a serious risk of pollution due to chemicals used in agricultural activities. The present study examined whether such a risk exists in Eskipazar, Turkey and the surrounding area, which covers a surface area of 696 km2. Nitrate pollution (NO3) was observed in waters discharging from the Örencik Formation, consisting of loose conglomerate, sandstone, mudstone, siltstone, and claystone levels; from the Yörük member of the Örencik Formation consisting of limestone, from areas where the Örencik Formation and Yörük member are located together, and from alluvium. Agricultural is practiced in these areas, and the waters discharging from these formations are used as drinking water and for domestic purposes. In particular, periodically varying levels of pollutants, such as B, Pb, Hg, Se were detected in wells drilled in Örencik Formation featuring a high NO3 concentration. The concentrations of S, Cr, Mn, Fe, Cu, Zn, Ga, Br, Sr, Y, I, Ba, and U in these waters are also slightly higher than other cold waters in the study area. In addition to the NO3 pollution, high levels of Ca and SO4 pollution was observed at a well drilled in alluvium. In addition, some trace element concentrations identified in the wells drilled in the Örencik Formation were higher than the average values at geothermal and/or mineral springs in the study area. The study area has an adequate sewage system and has no sources of pollution, such as mineralization, industrial center, waste disposal area, etc. Therefore, it is believed that the main causes of NO3 and trace element pollution are fertilizers and pesticides used in agricultural activities. Water–rock interaction, usage period of fertilizers and pesticides, amount of precipitation, groundwater level, usage of elements by plants, mobility of elements, pH value of the environment, redox potential, adsorption/desorption, biochemical processes, etc. are thought to be the causes of the periodical variation of some trace element concentrations observed in these waters. [ABSTRACT FROM AUTHOR]

This study examined the natural and anthropogenic pollution of groundwater at a national groundwater monitoring station (NGMS) in a dyeing industry complex, Korea. The arsenic contamination of a shallow well at the NGMS was noticed, starting from 22 months after the well installation. Possibilities of several mechanisms for As pollution of the groundwater were examined. The arsenical pyrite oxidation as a source mechanism in the shallow aquifer may be disregarded because of deficiency of pyrite in the shallow sediments, concomitant with depleted dissolved oxygen and very low levels of redox potentials of the As-polluted groundwater. The effect of wastewater from the general industrial area through a covered sewer stream was also considered as a possible source. Even though occurrence patterns of phenol and volatile organic hydrocarbons were very similar to those of the polluted shallow groundwater, As was not detected in the wastewater. One of the most plausible sources of the arsenic pollution was believed to be the reductive dissolution of Fe hydroxide. The As-polluted shallow groundwater had also very high levels of pH, HCO3, COD and very low levels of DO and NO3, which support the possibility of As pollution by the reductive dissolution. Consequently, the shallow groundwater in and around the NGMS has been polluted with various contaminants including As, phenol, chlorinated solvents, and petroleum hydrocarbons through multiple sources of contamination, such as natural reductive dissolution, dyeing wastewater, industrial wastewater, and municipal sewage. [ABSTRACT FROM AUTHOR]

In this study, the total concentration and speciation of trace elements (As, Cr, Cu, Cd, Pb, Zn, and Ni), in sediments of the Maharlu saline Lake, SW Iran are investigated. Comparison with sediment quality guidelines, calculation of the enrichment factors, and trace metal profiles in the Khoshk River inflow point indicate that Maharlu Lake is in the threat of contamination, especially with respect to Ni and Cd. Sequential extraction analysis reveals that elemental speciation in this lake is strongly affected by oxidizing condition of the lake water. The studied elements (except Cr) are mainly associated with oxide phases, as a result of prevailing oxidizing conditions of the lake and also probably due to the source of elements. The ratio of metals in mobile fractions to sum of fractions in lake sediments is very low. However, metal ratios (except for Cr) in mobile fractions are much higher in surface sediments, indicating the impact of anthropogenic loading of trace metals in the recent years. [ABSTRACT FROM AUTHOR]

Water quality evaluation is critically important for the protection and sustainable management of groundwater resources, which are variably vulnerable to ever-increasing human-induced physical and chemical pressures (e.g., overexploitation and pollution of aquifers) and to climate change/variability. Preceding studies have applied a variety of tools and techniques, ranging from conventional to modern, for characterization of the groundwater quality worldwide. Recently, geographic information system (GIS) technology has been successfully integrated with the advanced statistical/geostatistical methods, providing improved interpretation capabilities for the assessment of the water quality over different spatial scales. This review intends to examine the current standing of the GIS-integrated statistical/geostatistical methods applied in hydrogeochemical studies. In this paper, we focus on applications of the time series modeling, multivariate statistical/geostatistical analyses, and artificial intelligence techniques used for groundwater quality evaluation and aquifer vulnerability assessment. In addition, we provide an overview of salient groundwater quality indices developed over the years and employed for the assessment of groundwater quality across the globe. Then, limitations and research gaps of the past studies are outlined and perspectives of the future research needs are discussed. It is revealed that comprehensive applications of the GIS-integrated advanced statistical methods are generally rare in groundwater quality evaluations. One of the major challenges in future research will be implementing procedures of statistical methods in GIS software to enhance analysis capabilities for both spatial and temporal data (multiple sites/stations and time frames) in a simultaneous manner. [ABSTRACT FROM AUTHOR]

An integrated physicochemical and hydrogeochemical assessment was carried out at an automobile junk market in Obosi and in residential areas in Anambra State, south-eastern Nigeria to examine the concentration of heavy metals in the groundwater and determine the quality of the water for drinking and other domestic purposes. Forty groundwater samples were collected from boreholes and hand-dug wells (three samples from Obosi and the rest from Onitsha). They were subjected to atomic absorption spectrometry using standard field and laboratory techniques and analysed for physicochemical and hydrogeochemical parameters. Results show that the groundwater in the study area is slightly acidic to neutral, soft to moderately hard when compared with the World Health Organization maximum allowable concentration values and the Nigerian Standards for Drinking Water Quality. The electrical conductivity, dissolved oxygen and biochemical oxygen demand ranged from 58 to 1796 μS/cm, 6.78 to 8.76 and 0.17 to 1.50 mg/L, respectively. Heavy metal concentrations measured (in ppm) in the water included nickel, manganese, copper and zinc and varied from 0 to 1.82, 0 to 0.195, 0 to 0.325 and 0 to 0.09, respectively, while heavy metal concentrations in the soil measured (in ppm) included iron, lead and cadmium and varied from 0 to 3.87, 0 to 1.80 and 0 to 7.38 mg/kg, respectively. Statistical results gave significant correlation (at 0.05) between electrical conductivity and total hardness, biochemical oxygen demand and dissolved oxygen, and several others elements. The study helps in the understanding of the chemistry of groundwater for long-term monitoring and management for the local community. [ABSTRACT FROM AUTHOR]

Concentrations of major and trace elements in sediments from the Xiangjiang and Yuanjiang River inlets to Dongting Lake (China) were analyzed using XRF and ICP-MS methods, respectively. The results show that sediments from both rivers show comparable major element compositions and a similar distribution of high strength field elements (Zr, Hf, Nb, Ta, Th and U), large ion lithophile elements (Ba, Sc, Ga, Ge, Rb, Y, Cs), and rare earth elements (REE). However, the distribution of heavy metals V, Cr, Co, Ni, Cu, Zn, Pb, Cd, Tl and Bi varies significantly in sediments between the two rivers. The Xiangjiang River sediments are characterized by having a distinctly higher enrichment of the heavy metals Cr, Mn, Ni, Cu, Zn, Pb, Tl, Bi and Cd, and they are mostly contaminated by these heavy metals. That leads to the formation of heavy-metal contaminated (HMC) sediments. Sediments from these two rivers can be coincidentally divided into three groups by their REE patterns and factor load plots of principle component analyzing on major elements of 173 samples. The HMC sediments can further be separated from those of less contaminated sediments by plots of (Eu/Eu)NS* against the synthetic enrichment index values, and the HMC sediments are found to be significantly higher enriched in the major elements Al2O3, Fe2O3, MnO, P2O5 and LOI, and depleted in SiO2 and Na2O. Therefore, the distribution of the major elements Al2O3, Fe2O3, MnO, CaO, P2O5, LOI, SiO2 and Na2O in the river sediments can be used as indicators for identifying the HMC sediments. Thus, the ‘aluminium-iron index’ (AF), the ‘silicate index’ (SI), the ‘grain size index,’ and the Al2O3/SiO2, Fe2O3/SiO2 and Al2O3/Na2O ratios are then established as chemical indices for the use of identifying the HMC sediments. River sediments that have values of AF > 25.6, SI < 67.5, Al2O3/SiO2 > 0.29, Fe2O3/SiO2 > 0.12 and Al2O3/Na2O > 43.0 are then identified to be the HMC sediments in the study area. [ABSTRACT FROM AUTHOR]