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1.
This paper summarizes the findings obtained in a monitoring study to understand the sources and processes affecting the quality of shallow and deep groundwater near central air conditioning plant site in Trombay region by making use of physicochemical and biological analyses. All the measured parameters of the groundwaters indicate that the groundwater quality is good and within permissible limits set by (Indian Bureau of Standards 1990). Shallow groundwater is dominantly of Na–HCO3 type whereas deep groundwater is of Ca–Mg–HCO3 type. The groundwater chemistry is mainly influenced by dissolution of minerals and base exchange processes. High total dissolved solids in shallow groundwater compared to deeper ones indicate faster circulation of groundwater in deep zone preferably through fissures and fractures whereas groundwater flow is sluggish in shallow zone. The characteristic ionic ratio values and absence of bromide point to the fact that seawater has no influence on groundwater system.  相似文献   

2.
In this study, the hydrochemical characteristics of shallow groundwater were analyzed to get insight into the factors affecting groundwater quality in a typical agricultural dominated area of the North China Plain. Forty-four shallow groundwater samples were collected for chemical analysis. The water type changes from Ca·Na-HCO3 type in grass land to Ca·Na-Cl (+NO3) type and Na (Ca)-Cl (+NO3+SO4) type in construction and facility agricultural land, indicating the influence of human activities. The factor analysis and geostatistical analysis revealed that the two major factors contributing to the groundwater hydrochemical compositions were the water-rock interaction and contamination from sewage discharge and agricultural fertilizers. The major ions (F, HCO3) and trace element (As) in the shallow groundwater represented the natural origin, while the nitrate and sulfate concentrations were related to the application of fertilizer and sewage discharge in the facility agricultural area, which was mainly affected by the human activities. The values of pH, total dissolved solids, electric conductivity, and conventional component (K, Ca, Na, Mg, Cl) in shallow groundwater increased from grass land and cultivated land, to construction land and to facility agriculture which were originated from the combination sources of natural processes (e.g., water-rock interaction) and human activities (e.g., domestic effluents). The study indicated that both natural processes and human activities had influences on the groundwater hydrochemical compositions in shallow groundwater, while anthropogenic processes had more contribution, especially in the reclaimed water irrigation area.  相似文献   

3.
Groundwater quality of Enugu metropolis comprising Achara Layout, Abakpa, and Emene settlement areas has been studied and characterized using multivariate statistical techniques. Three principal components (PCs) which explain 77.93 and 88.17 % were extracted at Achara Layout and Abakpa, respectively, while two PCs which explain 83.13 % were extracted at Emene. PC 1 of all the three areas reflects weathering of the host rock minerals and constitutes the dominant controlling process for all the areas. PC 2 of the three areas and PC 3 of Achara Layout and Abakpa can be attributed to both weathering/leaching of feldspathic minerals of host rocks (giving rise to alkaline earth metals in the groundwater) and anthropogenic activities. Cluster analysis defined groups of groundwater samples with similar hydrochemical characteristics. Two groups in Achara Layout and Emene fell into the high pollution loading class, while only one group in Abakpa fell into this class. The variation in the groundwater quality within each of the three areas may be explained in terms of groundwater flow directions, land use, and well depths. Discriminant analysis showed that the discriminating parameters of the groundwater quality of Achara Layout, Abakpa, and Emene are total dissolved solids, Na and Mg, and Cl, respectively. This study has revealed that the groundwater quality of the areas is controlled by both geogenic and anthropogenic processes and activities. The generated groundwater quality spatial variation models for each area will serve as a tool in the planning and development of groundwater in that region.  相似文献   

4.
This article discusses the generation and migration process of nitrate-N pollution in shallow groundwater caused by agricultural nonpoint source pollution in the catchment area of Shitoukoumen Reservoir in northeast China. By monitoring the shallow groundwater nitrate-N in the low-water period, the normal season, and high-flow period in the study area for a year, it was found that the nitrate-N concentration in the shallow groundwater of this area had a seasonal variation in both spatial and time distribution. In the time distribution, the peak value appeared in July, the high-flow period, and the valley value appeared in April, the low-water period, and showed a significant correlation with the time distribution of fertilization rate and rainfall. In the spatial distribution of nitrate-N pollution, when the distribution in shallow groundwater was analyzed separately in the three different periods (low-water period, the normal season, and high-flow period) and the discipline transference and enrichment of nitrate-N pollution in shallow groundwater was determined, this indicated that the region in the southeast study area where runoff conditions were better was less contaminated, and the region where runoff conditions were poor, as well as the region along the river were seriously polluted. The nitrate-N concentration in shallow groundwater was distributed mainly along the path of groundwater flow and was excreted in the drainage region. This showed that the spatial distribution of nitrate-N concentration in the shallow groundwater of the entire region was mainly controlled by the groundwater flow system. At the same time, in the middle and lower reaches of the study area, the seasonal changes in the recharged–excreted relationship between groundwater and river caused seasonal differences in the spatial distribution of nitrate-N pollution in groundwater. The combined effects of the groundwater mobility and the surface river resulted in a poor correlation between the groundwater nitrate-N concentration and land-use types. Only in the plain area where there was little influence from groundwater runoff and the surface river did the groundwater nitrate-N concentration correlate with land-use types. The spatial and time distribution of nitrate-N concentration in the shallow groundwater of the study area was impacted by agricultural nonpoint source pollution, the groundwater flow system, and the surface river and formed a concentration response system which uses basins as a unit.  相似文献   

5.
The integration of the Geographic Information System (GIS) with groundwater modeling and satellite remote sensing capabilities has provided an efficient way of analyzing and monitoring groundwater behavior and its associated land conditions. A 3-dimensional finite element model (Feflow) has been used for regional groundwater flow modeling of Upper Chaj Doab in Indus Basin, Pakistan. The approach of using GIS techniques that partially fulfill the data requirements and define the parameters of existing hydrologic models was adopted. The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient, and estimation of the groundwater budget of the aquifer. GIS is used for spatial database development, integration with a remote sensing, and numerical groundwater flow modeling capabilities. The thematic layers of soils, land use, hydrology, infrastructure, and climate were developed using GIS. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater flow modeling and integration and presentation of image processing and modeling results. The groundwater flow model was calibrated to simulate future changes in piezometric heads from the period 2006 to 2020. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The model results indicated a significant response in watertable due to external influential factors. The developed model provides an effective tool for evaluating better management options for monitoring future groundwater development in the study area.  相似文献   

6.
江苏某县地下水邻苯二甲酸酯类的检测与风险评价   总被引:4,自引:1,他引:3  
在江苏某癌症高发区对地下水进行布点,采用固相萃取与气相色谱-质谱联用方法测定深层地下水和浅层地下水中邻苯二甲酸酯类(PAEs)的浓度。检测结果表明,地下水中PAEs污染程度较严重,邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)均有超标现象,其中,丰水期深层地下水和枯水期浅层地下水中DBP超标率达到100%,最大超标10.7倍。PAEs总质量浓度均值为10 034.56~14 872.91 ng/L,丰水期总浓度均值大于枯水期,浅层地下水的总浓度均值大于深层地下水。采用优化的USEPA风险评价模型,对PAEs进行人体健康风险评价,评价结果表明,该地区52.5% 地下水的PAEs总致癌风险超过10-6的水质监控值,总非致癌风险在可接受范围内。  相似文献   

7.
Effects of Forest Management Practices on Mid-Atlantic Streams   总被引:1,自引:0,他引:1  
Agricultural and urban land use activities have affected stream ecosystems throughout the mid-Atlantic region. However, over 60% of the mid-Atlantic region is forested. A study was conducted to investigate the effects of management practices on forested stream ecosystems throughout the mid-Atlantic region. The study consisted of two phases: Phase 1 was a literature synthesis of information available on the effects of forest management practices on stream hydrology, erosion and sedimentation, riparian habitat alteration, chemical addition, and change in biotic diversity in the mid-Atlantic region. In Phase 2, data from mid-Atlantic streams were analyzed to assess the effects of forest land use on stream quality at the regional scale. Typically, it is the larger order streams in which monitoring and assessment occurs—3rd order or higher streams. The impacts of forest management practices, particularly hydrologic modifications and riparian buffer zone alteration, occur predominantly in first and second order streams with cumulative impacts translating to higher order streams. Based on the literature review and mid-Atlantic Highland streams analysis, there are short-term (e.g., 2 to 5 years) effects of forest management practices on stream quality at local scales. However, signatures of cumulative effects from forest management practices are not apparent at regional scales in the Highlands. In general, forested land use is associated with good stream quality in the region compared with other land use practices.  相似文献   

8.
Spatial and seasonal differences in water quality of drainage water and unconfined shallow groundwater were related to irrigation in Samandağ, a Mediterranean coastal region. Eighteen wells, seven drainage points and Orontes River were monitored bimonthly for one year for analyses of electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR), cations (Na, K, Ca + Mg) and anions (CO3, HCO3, Cl and SO4). Agricultural irrigation using saline groundwater decreased water quality of Orontes River during the irrigation season (May to September) more than during the non-irrigation season (October to April). Seasonal fluctuations in water quality of shallow groundwater were greater during the irrigation season than the non-irrigation season in the study area. Excessive use of groundwater resulted in a decline in the water table levels in the irrigation season. Water table level rose up to the soil surface in areas where there was a lack of drainage or poor drainage, due to the impact of precipitation in the winter. SAR and pH values of drainage water increased in the irrigation season, while the other properties of drainage water decreased. Irrigation water quality of Orontes River was classified as C3S1 in both seasons. Irrigation water quality of shallow groundwater and drainage water varied from C2S1 to C4S2 in one year. Drainage and well waters were found to be different on yearly basis in terms of Na, SAR (p<0.01) and Ca + Mg concentrations (p<0.001). Ca + Mg concentrations for both sources were different for all sampling dates (p<0.001).  相似文献   

9.
Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co, Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported by rainfall and groundwater flow.  相似文献   

10.
Water availability in arid regions is both sporadic and highly variable in quantity. If the water quality shows large variations of salinity and concentration of other chemical constituents with depth and time span, it has considerable effect on the entire hydrological set up of the area. In the Saidabad tahsil area, the deep aquifers that supply water to borewells in the alluvial plain of the Mathura region, Uttar Pradesh, have higher salinity than those of the dugwells from the shallow aquifers. The excessive drilling of tubewells and high yield tubewells are resulting in deterioration of water quality of the shallow aquifers. On the contrary, the chemical constituents such as, Na+, K +, Cl -, andHCO 3 - show higher concentration in shallow aquifers than deep aquifers. A study carried out to monitor water quality in this region reveals that the groundwater quality varies with depth and time span in shallow and deep aquifers. Factors controlling variations in salinity and concentration of chemical constituents of the water in the two types of aquifers are discussed. The relative merits of the shallow water for potability are pointed out with respect to salinity concentrations and public health.  相似文献   

11.
Groundwater samples are collected from 30 observation wells in the study area to analyze the hydrochemical quality for determining the seawater encroachment in the part of Central Godavari Delta, Bay of Bengal, India. In order to establish the baseline hydrochemical conditions and processes determining the groundwater quality, an integrated investigation coupled with multivariate statistical analysis and hydrochemical methods are used to identify and interpret the groundwater chemistry of the aquifer system. The major land use is irrigated agriculture and aquaculture in the study area. The ground waters affected by the seawater intrusion featured high levels of sodium (Na+), chloride (Ca+), and TDS, which are the simplest common indicators for seawater influence. The elevated levels of NO3–N at some monitoring wells indicate nitrate pollution of groundwater due to anthropogenic origin such as septic effluents or chemical fertilizers. Besides the major chemical compositions, it was also demonstrated that ionic ratios would be useful to delineate seawater intrusion and they include Na+/Ca2+, Mg2+/Ca2+, SO4 2?/Ca2+, Na+/(Na+?+?Cl?), and Ca?/sum of anions. This paper demonstrates the variations in hydrochemical quality of groundwater and its evolution processes in two different seasons in the coastal aquifer alluvial settings  相似文献   

12.
通过系统整理分析自然资源、水利、生态环境等部门已有地下水监测网,针对广东地下水监测存在的问题和未来地下水环境管理需求,提出较大空间尺度和水质监控的地下水环境监测网建设框架及广东省"三层七级"共237个网点的层级化地下水环境监测网建设方案,并与水文地质单元、浅层地下水功能区划进行了空间叠加分析。结果表明,广东省三大部门监测网在空间上分布总体较为分散,相互补充性好,提出的监测网方案总体上与广东省地下水本底条件、地下水资源开发利用现状、地下水环境功能分区、重点污染源空间分布特征等相匹配,契合地下水饮用水源保护和重点污染源监控两大管理需求,构建的地下水环境监测网框架可为其他地区提供参考,提出的地下水环境监测网建设方案可为广东省地下水环境管理和污染防控提供决策支持。  相似文献   

13.
Groundwater from 33 monitoring of peripheral wells of Karachi, Pakistan were evaluated in terms of pre- and post-monsoon seasons to find out the impact of storm water infiltration, as storm water infiltration by retention basin receives urban runoff water from the nearby areas. This may increase the risk of groundwater contamination for heavy metals, where the soil is sandy and water table is shallow. Concentration of dissolved oxygen is significantly low in groundwater beneath detention basin during pre-monsoon season, which effected the concentration of zinc and iron. The models of trace metals shown in basin groundwater reflect the land use served by the basins, while it differed from background concentration as storm water releases high concentration of certain trace metals such as copper and cadmium. Recharge by storm water infiltration decreases the concentration and detection frequency of iron, lead, and zinc in background groundwater; however, the study does not point a considerable risk for groundwater contamination due to storm water infiltration.  相似文献   

14.
Soil salinization is an important worldwide environmental problem, especially in arid and semi-arid regions. Knowledge of its temporal and spatial variability is crucial for the management of oasis agriculture. The study area has experienced dramatic change in the shallow groundwater table and soil salinization during the 20th century, especially in the past two decades. Classical statistics, geostatistics and geographic information system (GIS) were applied to estimate the spatial variability of the soil salt content in relation to the shallow groundwater table and land use from 1983 to 2005. Consumption of reservoir water for agricultural irrigation was the main cause of a rise in the shallow groundwater table under intense evapotranspiration conditions, and this led indirectly to soil salinization. The area of soil salt accumulation was greater in irrigated than in non-irrigated landscape types with an increasing of 40.04% from 1983 to 2005 in cropland at ∼0.43 t ha−1 year−1, and an increase at ∼0.68 t ha−1 year−1 in saline alkaline land. Maps of the shallow groundwater table in 1985 and 2000 were used to deduce maps for 1983 and 1999, respectively, and the registration accuracy was 99%.  相似文献   

15.
Many developing and threshold countries rely on shallow groundwater wells for their water supply whilst pit latrines are used for sanitation. We employed a unified strategy involving satellite images and environmental monitoring of 16 physico-chemical and microbiological water quality parameters to identify significant land uses that can lead to unacceptable deterioration of source water, in a region with a subtropical climate and seasonally restricted torrential rainfall in Northern Argentina. Agricultural and non-agricultural sources of nitrate were illustrated in satellite images and used to assess the organic load discharged. The estimated human organic load per year was 28.5 BOD(5) tons and the N load was 7.5 tons, while for poultry farms it was 9940-BOD(5) tons and 1037-N tons, respectively. Concentrations of nitrates and organics were significantly different between seasons in well water (p values of 0.026 and 0.039, respectively). The onset of the wet season had an extraordinarily negative impact on well water due in part to the high permeability of soils made up of fine gravels and coarse sand. Discriminant analysis showed that land uses had a pronounced seasonal influence on nitrates and introduced additional microbial contamination, causing nitrification and denitrification in shallow groundwater. P-well was highly impacted by a poultry farm while S-well was affected by anthropogenic pollution and background load, as revealed by Principal Component Analysis. The application of microbial source tracking techniques is recommended to corroborate local sources of human versus animal origin.  相似文献   

16.
Advancing land degradation in the irrigated areas of Central Asia hinders sustainable development of this predominantly agricultural region. To support decisions on mitigating cropland degradation, this study combines linear trend analysis and spatial logistic regression modeling to expose a land degradation trend in the Khorezm region, Uzbekistan, and to analyze the causes. Time series of the 250-m MODIS NDVI, summed over the growing seasons of 2000–2010, were used to derive areas with an apparent negative vegetation trend; this was interpreted as an indicator of land degradation. About one third (161,000 ha) of the region’s area experienced negative trends of different magnitude. The vegetation decline was particularly evident on the low-fertility lands bordering on the natural sandy desert, suggesting that these areas should be prioritized in mitigation planning. The results of logistic modeling indicate that the spatial pattern of the observed trend is mainly associated with the level of the groundwater table (odds?=?330 %), land-use intensity (odds?=?103 %), low soil quality (odds?=?49 %), slope (odds?=?29 %), and salinity of the groundwater (odds?=?26 %). Areas, threatened by land degradation, were mapped by fitting the estimated model parameters to available data. The elaborated approach, combining remote-sensing and GIS, can form the basis for developing a common tool for monitoring land degradation trends in irrigated croplands of Central Asia.  相似文献   

17.
A base line study into the environmental quality of soils in the rural areas of the province of Zeeland, the Netherlands, was performed. The polder-landscape in this area was developed in a complex history of floodings and land-reclamation. Samples from 67 sites, at a density of roughly one per 25 km2, were analyzed for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in addition to a physicochemical characterization by pH(KCl), dry solids, organic matter, and clay content. At about 2/3 of the sites samples were taken at more than one depth. Fluoride and pesticides were determined in partly overlapping selections of 30 samples. Four land use classes were distinguished (arable land, grass land, orchards, uncultivated), and samples were labelled by region within the province. Data evaluation was aided by a recursive statistical approach, whereby statistical tests confirm and strengthen geochemical reasoning. Single- and multivariate statistics were used both as exploratory tools and as a measure of significance and relevance of conditions and processes. In general the environmental quality of the soils is satisfactory. Exceedence of the legal standards for natural background values at more than one site occurs for Cd, Cu, Hg and the pesticides DDT/DDE, dieldrin and HCH, at most by a factor of three. High levels of Hg appear related to arable land use; enhanced levels of Cu are found in orchards. High Cd levels primarily seem to follow a regional or geological pattern; yet, a relation with arable land use and clayey soils cannot be excluded. Pesticides are not detected in grass land, incidence is highest in orchards as well as in uncultivated areas. DDT levels appear to be generally inherited from the past. Variation in soil type as described by the macro physico-chemical characteristics is essential in explaining the variation in concentration level of the potential contaminants. Variations with depth also appear largely related to concurrent variation in soil properties. For As redox conditions and hydrological regime seem of importance, in addition to the geologic history. The influence of atmospheric input is inferred for Pb. The available data do not fully resolve the causes for the regional pattern that remains when the influences of soil type, geology, and land use have been taken into account. In addition to current concentration levels, the base line study offers general insight as to what degree variations in potential contaminants are of natural or anthropogenic origin. A succession of similar studies at suitable time intervals, each with a new selection of sampling sites, may constitute an evolving, flexible monitoring system. When putting up a monitoring system, authorities should weigh the advantages and disadvantages of a network composed of fixed sites against this alternative.  相似文献   

18.
The Mid-eastern Inner Mongolia of China, a typical agro-pastoral transitional zone, has undergone rapid agricultural land use changes including land reclamation and cropland abandonment in past decades due to growing population and food demand, climatic variability, and land use policy such as the "Grain for Green" Project (GFG Project). It is significant to the regional ecology and sustainability to examine the pattern and its rationality of land use change. The processes of land reclamation and cropland abandonment were accessed by using land use change dataset for four periods of 1990, 1995, 2000, and 2005, derived from the interpretation of Landsat TM images. And then the rationality of land reclamation and cropland abandonment was analyzed based on the habitat suitability for cultivation. The results indicated that: (1) land reclamation was the dominant form of agricultural land use change from 1990 to 2005, the total cropland area increased from 64,954.64 km(2) in 1990 to 76,258.51 km(2) in 2005; However, the speed of land reclamation decreased while cropland abandonment increased around 2000. The Land Reclamation Degree decreased from 1995-2000 to 2000-2005, meanwhile, Cropland Abandonment Degree increased. (2) As for the habitat suitability levels, moderately and marginally suitable levels had largest areas where cropland was widespread. Pattern of agricultural land use trended to become more rational due to the decrease of land reclamation area in low suitable levels and the increase of cropland abandonment in unsuitable area after 2000. (3) The habitat suitability-based rationality analysis of agricultural land use implicated that the GFG Project should take cultivation habitat suitability assessment into account.  相似文献   

19.
Untreated sewage and agriculture are the most important sources of contamination. The study was carried out by conducting a short-term surface water and groundwater pollution survey of the Owerri Urban area and its environs, in order to establish the current levels of pollution. An attempt has been made to show the relationships between pollution levels, population density, industrial and agricultural activities. The spatial distribution of pollutants due to a poor land use system and to human activities was investigated. This emphasises integrated planned development as a preventive measure for arresting pollution levels in fast growing urban centres. The total groundwater stored in the area amounts to 7.87 × 109 m3. Twenty five percent of this is released as base flow into the adjacent rivers (Otamiri and Nworie). The annual groundwater recharge is 3.4 × 109 m3. The enormous volume of groundwater stored and the comparatively low cost of development makes groundwater an excellent alternative supply source for the area (Uma et al., 1984).  相似文献   

20.
Groundwater is connected to the landscape above and is thus affected by the overlaying land uses. This study evaluated the impacts of land uses upon groundwater quality using trilinear analysis. Trilinear analysis is a display of experimental data in a triangular graph. Groundwater quality data collected from agricultural, septic tank, forest, and wastewater land uses for a 6-year period were used for the analysis. Results showed that among the three nitrogen species (i.e., nitrate and nitrite (NOx), dissolved organic nitrogen (DON), and total organic nitrogen (TON)), NOx had a high percentage and was a dominant species in the groundwater beneath the septic tank lands, whereas TON was a major species in groundwater beneath the forest lands. Among the three phosphorus species, namely the particulate phosphorus (PP), dissolved ortho phosphorus (PO 4 3?? ) and dissolved organic phosphorus (DOP), there was a high percentage of PP in the groundwater beneath the septic tank, forest, and agricultural lands. In general, Ca was a dominant cation in the groundwater beneath the septic tank lands, whereas Na was a dominant cation in the groundwater beneath the forest lands. For the three major anions (i.e., F?, Cl?, and SO 4 2?? ), F? accounted for <1 % of the total anions in the groundwater beneath the forest, wastewater, and agricultural lands. Impacts of land uses on groundwater Cd and Cr distributions were not profound. This study suggests that trilinear analysis is a useful technique to characterize the relationship between land use and groundwater quality.  相似文献   

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