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1.
Bas Pedroli 《Journal of Hydrology》1990,120(1-4):381-404
Ecohydrology, the interdisciplinary field of research directed to the application of hydrological knowledge to landscape ecology, is introduced to evaluate a test data set of 412 analyses of groundwater samples from 60 locations in a Dutch coversand area, numerically classified into 17 water types. Three types of simple groundwater quality classification are identified: single parameter, combined parameter and multiparameter.
Single quality parameters like pH, electrical conductivity (EC) and ion concentration values, are rarely used in ecohydrology. The representation of the complex conditional relationships between groundwater and the living part of ecosystems with these parameters is unsatisfactory, as also proved with the test data set. It is difficult to differentiate groundwater types reliably on the basis of one single parameter.
Combined quality parameters which are widely used are a pH-EC plot, a plot of pHCO3 vs. (pH-pCa), after Kemmers, and an IR-EC plot after van Wirdum, where the ionic ratio (IR) is a Ca/(Ca + Cl) ratio. The latter two parameters indicate the residence time of the groundwater sampled as well as the hydrochemical conditions related to vegetation distribution and development. The IR is very popular for discriminating between atmocline (precipitation-like) and lithocline (long-residence groundwater-like) water types. In the test data set, objections to its use are discussed with regard to the conditions assumed in its application. Especially in the intermediate IR range, which should indicate potentially marked ecologic gradients, its theoretical basis is narrow. However, general relationships can be deduced from the IR-EC plot. In the test data set as well as in the general Dutch setting, the transformation of atmocline into lithocline water types determines to a large extent ecosystem diversity, although a third, metacline, pollution-induced water type increasingly interferes.
Finally, multiparameter classification of groundwater types is discussed. Statistical classification gives good results but is site specific. It is recomended that efforts be combined in the search for an internationally applicable composite classification adapted to ecohydrological research. 相似文献
2.
在用离子色谱法测定温泉水样中F~-、Cl~-、Br~-、NO_2~-、NO_3~-、SO_4~(2-)、PO_4~(2-)等阴离子和Li~+、Na~+、K~+、Mg~(2+)、Ca~(2+)等阳离子过程中,研究了用油泵超声波池内脱气法处理H_2CO_3过饱和水样以排除HCO_3~-对阴离子检测干扰的方法.研究采用青岛普仁仪器有限公司生产的PIC-8型离子色谱仪,分离柱为TSK-GEL SuperIC-CationColumn(150 mm×4.5 mm)离子分离柱,以1.9 mmol/L碳酸钠-1.8mmol/L碳酸氢钠作为阴离子淋洗液,流量为1.5 Ml/min;以2 mmol/L HNO_3为阳离子淋洗液,流量为1.0 ml/min,测定了腾冲火山区叠水河、大滚锅两个温泉水中的阴阳离子的含量.研究结果表明:该方法简便、快速、准确可靠,可在火山和地震监测中推广使用. 相似文献
3.
《Acta Geochimica》2017,(3)
The chemical composition of rainwater has been studied in a karst rural area from September 2012 to August 2013 in Guizhou Province,Southwest China.The results indicated that the VWM value of p H was 5.4,varied from 4.6 to 6.9.Ca~(2+)and NH_4~+were the major cations,and SO_4~(2-)was the dominant anion.Neutralization factors show that the acid was mainly neutralized by Ca~(2+),NH_4~+and Mg~(2+).Investigations of correlation coefficients and enrichment factors revealed that Ca~(2+)and Mg~(2+)were mainly crust origins,and NH_4~+was from agriculture and livestock manure.SO_4~(2-)and NO_3~-were mainly from anthropogenic sources. 相似文献
4.
Patrice de Caritat 《Journal of Hydrology》1995,170(1-4):47-62
Groundwater chemical data from Birkenes, southern Norway, collected during the period October 1980 to November 1993, reveal intensifying acidification in the 1990s, as evidenced by decreases in pH, acid-neutralising capacity and alkalinity, and increases in hardness/alkalinity ratio, ‘acidification’, nitrate, non-marine sulphate (SO4*), non-marine hardness (Ca* + Mg*) and dissolved aluminium. The whole monitoring period is characterised by slopes of four or more on a plot of (Ca* + Mg*) vs. alkalinity.
Owing to its proximity to the sea, the Birkenes catchment receives seasalt-influenced precipitation, which results in episodic, natural acidification of the groundwater via cation exchange of marine Na+ with soil-bound H+ and/or Al3+. However, it is uncertain whether all of the recent groundwater acidification can be attributed to intensifying seasalt deposition alone: the steep slopes on the (Ca* + Mg*) vs. alkalinity plot and the increase in groundwater SO4* suggest that strong acids, of possible anthropogenic origin, may be involved. Additionally, seasalt deposition appears not to have increased during the 1990s: Cl− content in precipitation has not increased significantly and river water pH has not decreased significantly over the period 1990–1993. The suggestion is made that the observed intensification in groundwater acidification at Birkenes partly results from the exhaustion or weakening of an acid buffering system caused by soil acidification, under persisting, even if abating, anthropogenic acid loading. 相似文献
5.
Factors contributing to nitrate contamination in a groundwater recharge area of the North China Plain 总被引：4，自引：0，他引：4 
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下载免费PDF全文 Shiqin Wang Changyuan Tang Xianfang Song Ruiqiang Yuan Zhiwei Han Yun Pan 《水文研究》2016,30(13):2271-2285
Nitrate contamination is a common problem in groundwater of the North China Plain (NCP) owing to overuse of fertilizers and discharge of wastewater. Accordingly, it is important to investigate nitrate contamination in recharge areas to understand the fate of nitrate in the plains area. In this study, the spatial and temporal distribution characteristics of nitrate and factors contributing to its sources and transformation in shallow groundwater of the Beiyishui River watershed, NCP, were analysed by a combination of multiple regression and multi‐tracer methods. The nitrate concentration of 79% of the samples exceeded the natural environmental standard of 13.3 mg l?1, while that of 23% of the samples exceeded the World Health Organization (WHO) drinking water standard of 50 mg l?1. Groundwater age estimation of the hill regions based on chlorofluorocarbons (CFCs) revealed a mix of young water from 1982 to 1990 and old, low CFC water. The analysis based on the variations in land use in past years revealed that part of the grassland was converted into woodland between 1980 and 1995; therefore, the land use at the recharge time was used to determine which surface conditions influence groundwater nitrate concentrations. Multiple regression analysis showed that point source pollution contributed to the high concentration of nitrate in the hill region. Fertilizer application associated with land use change from grassland to woodland was also related to the present nitrate concentration. In the plains area, the contribution of fresh water from fault fractures and denitrification led to 31 to 72% and 6 to 51% reductions in nitrate concentrations, respectively. Our results suggested that controlling point source contamination and fertilizer input to hilly regions of the study will prevent groundwater of the plains area from deterioration in future years by mixing fresh water into the aquifers and decreasing denitrification, and therefore nitrate concentrations. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
Increasing groundwater salinity and depletion of the aquifers are major concerns in the UAE. Isotopes of oxygen, hydrogen, and carbon concentrations in groundwater were used to estimate evaporation loss using the isotopes of oxygen and hydrogen, and using a carbon isotope to trace inorganic carbon cycling in two main aquifers in the eastern part of the United Arab Emirates. The δD‐δ18O of groundwater samples plotted on a line given by: δD = 4 δ18O + 4 ·4 (r2 = 0·4). In comparison, the local meteoric water line (LMWL) has been defined by the line: δD = 8 δ18O + 15. In order to better understand the system investigated, samples were separated into two groups based on the δD‐δ18O relationship. These are (1) samples that plot above the LMWL (δD = 6·1 δ18O + 12·4, r2 = 0·8) and which are located predominantly in the north of the study area, and (2) samples that plot below the LMWL (δD = 5·6 δ18O + 6·2, r2 = 0·8) and which are mostly distributed in the south. Slopes for both the groups are similar and lower than that for LMWL indicating potential evaporation of recharging water. However, the y‐intercept, which differs between the two groups, suggests evaporation of return flow and evapotranspiration in the unsaturated zone to be more significant in the south. This is attributed to intense agricultural activities in the region. Samples from the eastern Gravel Plain aquifer have δ13C and dissolved inorganic carbon (DIC) values in the range from ? 10 to 17‰, and 12–100 mg C/l, respectively, while the range for those from the Ophiolite aquifer is from ? 11 to ? 16.4‰, and 16–114 mg C/l respectively. This suggests the control of C‐3 and C‐4 plants on DIC formation, an observation supported by the range δ13C of soil organic matter (from ? 18·5 to ? 22·1‰.) Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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8.
Groundwater resources with high salinity content are found in some parts of the lower Shire River valley (Malawi). This paper discusses the geochemistry of minor elements with regards to the prevailing salinity. Hierarchical clustering and principal component analyses were used to identify factors which relate to both minor elements and samples and were interpreted as reflecting the influence of prevailing saline/brackish groundwater. Concentrations of lead (Pb), boron (B), strontium (Sr) and chromium (Cr) were associated with groundwater with high content of total dissolved solids (TDS). Speciation calculations indicated that dissolved Sr, barium (Ba) and lithium (Li) were mainly in the form of free aqueous ions whereas hydrolysed species were significant for aluminium (Al) and Cr, and carbonate complexes for Pb. Chloride complexes were prevalent for silver (Ag). Solubility of cerussite (PbCO3) and barite (BaSO4) was shown to act as a control on the levels of Pb and Ba, respectively. Thus, Ba concentrations were very low in saline groundwater owing to their high sulphate content. A relatively variable B concentration in the groundwater samples was explained using a binary mixing model of saline and fresh groundwater. The mixing of fresh groundwater with saline groundwater was concomitant with high Na+/Ca2+ ratios and enrichment of B, probably by desorption from clays. The WHO drinking water guidelines for Ba, B, Cr and Pb were exceeded in 6.5%, 9.7%, 16.1% and 64.5% of all the samples, respectively. However, all samples were below the Malawian specification of B in borehole and shallow well water quality (MS 733:2005) of 5.0 mg/L. 相似文献
9.
Located at southern coast of China, the Pearl River Delta (PRD) is facing serious water problems in both quantity and quality after its rapid urbanization in the last decade. Most remarkably, the local groundwater, that was used to be the source of drinking water before the urbanization was polluted due to poor management of the septic tanks. In order to study the effects of suburban development on local groundwater flow and water quality in the PRD region, Fengcun of Guangzhou has been chosen as the study area. In Fengcun, drinking water was groundwater before the 1990s, but now piped reservoir water is used by each family because the groundwater has been polluted. This study clarifies the source and process of the groundwater pollution from septic tanks using isotopic and geochemical characteristics, especially nitrate (NO3?) concentrations. Water samples were collected from the wells and ponds in Fengcun in March and July 2005 and in July 2006. Based on the pe–pH diagram, NO3? and ammonium of groundwater are from the effect of human activities, rather than from nitrification and ammonification of N2. NO3? pollution of groundwater is from point sources, and NO3? concentrations decrease from northeast to southwest. Groundwater is polluted rapidly by the leakage of septic tanks. NO3? concentrations of pollution sources were lower than 20 mg l?1 in March 2005, but had increased to about 120 mg l?1 in July 2006. This implies that groundwater protection should be strengthened in rural areas of the PRD. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
10.
Abstract The catchment-scale groundwater vulnerability assessment that delineates zones representing different levels of groundwater susceptibility to contaminants from diffuse agricultural sources has become an important element in groundwater pollution prevention for the implementation of the EU Water Framework Directive (WFD). This paper evaluates the DRASTIC method using an ArcGIS platform for assessing groundwater vulnerability in the Upper Bann catchment, Northern Ireland. Groundwater vulnerability maps of both general pollutants and pesticides in the study area were generated by using data on the factors depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity, as defined in DRASTIC. The mountain areas in the study area have “high” (in 4.5% of the study area) or “moderate” (in 25.5%) vulnerability for general pollutants due to high rainfall, net recharge and soil permeability. However, by considering the diffuse agricultural sources, the mountain areas are actually at low groundwater pollution risk. The results of overlaying the maps of land use and the groundwater vulnerability are closer to the reality. This study shows that the DRASTIC method is helpful for guiding the prevention practices of groundwater pollution at the catchment scale in the UK. Citation Yang, Y. S. & Wang, L. (2010) Catchment scale vulnerability assessment of groundwater pollution from diffuse sources using the DRASTIC method: a case study. Hydrol. Sci. J. 55(7), 1206–1216. 相似文献
11.
Principal component analysis (PCA) was applied to hydrochemical and isotopic data of 34 groundwater samples. This allowed the reduction of 20 variables to four significant PCs that explain 81.9% of the total variance; F1 (47.1%) explains the groundwater mineralization, whereas F2 (17%) shows isotopic enrichment and nitrate pollution. Based on an iso-factor scores map of F1, three water zones were delineated: Zone A (F1 < ?1), with fresh groundwater from the unconfined aquifer; Zone B (1 > F1 > ?1), with moderate mineralization from the confined–unconfined aquifer boundary; and Zone C (F1 > 1), with the most mineralized hot water from the confined aquifer. The iso-factor scores map of F2 delineates positive values representing samples from the unconfined aquifer, with freshwater and nitrate contamination associated with stable isotope enrichment, whereas negative values represent samples from the confined aquifer. The results clearly demonstrate the usefulness of PCA in groundwater hydrochemistry investigations. 相似文献
12.
The groundwater regime in the north‐western part of the Visakhapatnam urban area was polluted as early as 1981 by discharge of untreated industrial effluent from a Hindustan Polymers Limited (HPL) plant. A total dissolved solids (TDS) concentration of surficial effluent up to 6500 mg/l and of groundwater in the range 3000–4200 mg/l has been reported in the environs of the HPL plant during May 1992. Groundwater occurs under water table conditions. The groundwater flow model was simulated as a single layer aquifer, using MODFLOW and FLOWPATH computer models. Aquifer parameters were estimated and the value of effective porosity assumed. The water table configuration was mapped in May 1981 using 33 observation wells. The calibrated hydraulic head distribution was used to compute the velocity field using the effective porosity values. The flow paths of groundwater migration from the source locations up to 2002 AD were predicted. Pathlines of particles in the groundwater indicated a predominant north‐east and south‐west migration of groundwater pollution in the area. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
13.
Surface water is a scarce resource in Namibia with about sixty percent of Namibia's population dependent on groundwater for drinking purposes. With increasing population, the country faces water challenges and thus groundwater resources need to be managed properly. One important aspect of Integrated Water Resources Management is the protection of water resources, including protection of groundwater from contamination and over-exploitation. This study explores vulnerability mapping as a basic tool for protecting groundwater resources from pollution. It estimates groundwater vulnerability to pollution in the upper Niipele sub-basin of the Cuvelai-Etosha in Northern Namibia using the DRASTIC index. The DRASTIC index uses GIS to estimate groundwater vulnerability by overlaying different spatially referenced hydrogeological parameters that affect groundwater contamination. The study assesses the discontinuous perched aquifer (KDP) and the Ohangwena multi-layered aquifer 1 (KOH-1). For perched aquifers, point data was regionalized by a hydrotope approach whereas for KOH-1 aquifer, inverse distance weighting was used. The hydrotope approach categorized different parts of the hydrogeological system with similar properties into five hydrotopes. The result suggests that the discontinuous perched aquifers are more vulnerable than Ohangwena multi-layered aquifer 1. This implies that vulnerability increases with decreasing depth to water table because contaminants have short travel time to reach the aquifer when they are introduced on land surface. The nitrate concentration ranges between 2 and 288 mg/l in perched aquifers while in Ohangwena multi-layered aquifer 1, it ranges between 1 and 133 mg/l. It was observed that perched aquifers have high nitrate concentrations than Ohangwena 1 aquifer, which correlates well with the vulnerability results. 相似文献
14.
Wetlands on the Vecht river plain in the Netherlands are threatened by pollution of ground water on the adjacent ridge ‘Het Gooi’. To assess the impact of this pollution, information is needed on the present groundwater flow pattern and hydrochemical processes occurring during flow. In the determination of hydrochemical processes past changes in flow patterns must be taken into consideration.
Over the past 600 years impoldering and groundwater extraction have induced important hydrological changes in the study area. Exercises with a two-dimensional finite difference groundwater model were used to study the effects of these changes on regional groundwater flow patterns. Steady-state simulations along a vertical section were carried out for four different points in time, namely, the 14th century, 1885, 1941 and 1985. Changes in flow patterns are inferred from a comparison of the steady-state simulations. The results indicate that groundwater flow changed from a simple pattern under natural conditions to a complex flow pattern dominated by artificially man-controlled hydraulic heads at present.
The computer simulations are used to estimate the effect of changes in flow patterns on regional groundwater composition. Data on the distribution of chloride and oxygen-18 in ground water provide a verification of the estimated effects and information on the present position of the fresh-brackish groundwater interface in the study area. Isochrones calculated by the model are used to estimate the position of this front where data on water composition are absent. The future displacement of the fresh-brackish groundwater front is inferred from the position of successive isochrones, assuming that the present flow pattern will remain in steady state.
The computer simulations provide a general framework for the determination of hydrochemical processes in future studies addressing the impact of groundwater pollution on wetlands in the river plain. 相似文献
15.
Elevated nitrate concentrations in groundwater are a common challenge for water management. One important factor in this context is higher frequencies and intensities of wet-dry cycles that may cause increased nitrate concentrations in groundwater due to nitrate flushes after drought termination. Yet systematic studies on regional-scale impacts of droughts on groundwater nitrate concentrations are missing so far. Here we analyzed time series of 44 shallow groundwater wells and 41 springs all across the German Federal State Baden-Wuerttemberg from 2000 to 2018 to characterize patterns of post-drought nitrate increase in groundwater. In general, half of the exceptional nitrate concentrations, which exceeded the 80th percentile of long-term nitrate measurements, could be related to droughts in the research timeframe. The 2003 drought event stood out in terms of drought severity and post-drought nitrate concentration increases in our data. The great majority (91%) of all monitoring sites showed at least one exceptionally high nitrate concentration in the 4 years following the 2003 drought event. Springs were mainly located in forests of steep low mountain ranges and wells in cropland of flat river valleys. Therefore, delay times between drought intensity and nitrate concentration increases as well as magnitudes of nitrate concentration increase were diverse among wells and springs. We derived two distinct nitrate response patterns: (i) nitrate increases immediately following drought events (more common for springs and fractured rock aquifers) and (ii) delayed nitrate increases (more common for wells and porous aquifers). Springs generally showed quicker (median of 101 days) but weaker (median of +1.3 mg/L) post-drought nitrate increases than wells (185 days, +3.4 mg/L). Only few sites exhibited no post-drought nitrate increase and post-drought mean-nitrate concentrations of groundwater reservoirs were extraordinarily high in 2006. Overall, we demonstrate that post-drought nitrate increase in groundwater is omnipresent, while different landscapes and hydrogeological characteristics create a diverse regional pattern. As severe droughts become more frequent in a changing climate, post-drought nitrate increase may intensify problems regarding water quality and supply. 相似文献
16.
Principles of zoning a territory by the pollution hazard to groundwater depending on the pollution sources and their position in the environment are considered. Pollution hazard classifications are proposed for groundwater, pollutants (by their chemical and hydrochemical properties), and groundwater pollution risks, depending on the degree of hazard and the type of pollutant. A procedure is proposed for mapping the hazard and risks of groundwater pollution by various pollutants on the basis of the performed zoning. 相似文献
17.
A. P. Belousova 《Water Resources》2006,33(2):219-232
Definitions of hazard and risk of groundwater pollution are given. A deterministic method for the assessment of groundwater pollution risk using estimates of groundwater protection against and vulnerability to pollution and stability indicators of groundwater quality is considered. Also presented are the principal methodological approaches to the assessment of groundwater protection against pollution and the formation of the structure of indicators and indices characterizing the stability of groundwater quality. The structure of hazard, risks, and damages associated with groundwater pollution is shown. Expert appraisal method is used for the assessment of groundwater pollution risks. 相似文献
18.
《Acta Geochimica》2021,(1)
Trace elements(and their isotopes) in carbonates are commonly used to reconstruct paleoenvironment and paleoclimate.Understanding the processes and mechanisms of element incorporation into carbonates is thus crucial for using such geochemical parameters as paleoclimate proxies.In contrast to laboratory-based experimental results,the partitioning of trace metals between solid and solution phases in natural carbonate precipitation systems has rarely been reported.In this study,we investigated the partition coefficients of metal ions between solid and solution in the channel of the natural Baishuitai travertine system,Yunnan,China.Our results show that the partition coefficients of Li~+,Na~+,Mg~(2+),Sr~(2+) and Ba~(2+)are 1,that of Ni~(2+) is approximately 1,and those of Co~(2+),Mn~(2+),Zn~(2+) and Cu~(2+) are 1,consistent with the results found in previous experimental studies.Although the substitution for Ca~(2+) is likely the main uptake process of these metals into calcite,depending on their ionic radius and charge,trace elements may also be incorporated by adsorption or physical entrapment.Our study shows that unlike laboratory experiments performed under specific conditions,the partitioning of metals between two phases in the natural travertine system could be controlled by several,even multiple,environmental factors(e.g.,carbonate deposition rate,temperature,and pH),which should be taken into account when using trace metals(and their isotopes) in carbonate archives as a paleoclimate proxy. 相似文献
19.
Arsenic and other water‐quality issues affecting groundwater,Indus alluvial plain,Pakistan 下载免费PDF全文
下载免费PDF全文 Groundwater beneath the alluvial plain of the Indus River, Pakistan, is reported to be widely polluted by arsenic (As) and to adversely affect human health. In 79 groundwaters reported here from the lower Indus River plain in southern Sindh Province, concentrations of As exceeded the WHO guideline value for drinking water of 10 μg/L in 38%, with 22% exceeding 50 μg/L, Pakistan's guideline value. The As pollution is caused by microbially‐mediated reductive dissolution of sedimentary iron oxyhydroxides in anoxic groundwaters; oxic groundwaters contain <10 μg/L of As. In the upper Indus River plain, in Punjab Province, localized As pollution of groundwater occurs by alkali desorption as a consequence of ion exchange in groundwater, possibly supplemented by the use for irrigation of groundwater that has suffered ion exchange in the aquifer and so has values >0 for residual sodium carbonate. In the field area in southern Sindh, concentrations of Mn in groundwater exceed 0.4 mg/L in 11% of groundwaters, with a maximum of 0.7 mg/L, as a result of reduction of sedimentary manganese oxides. Other trace elements pose little or no threat to human health. Salinities in groundwaters range from fresh to saline (electrical conductivity up to 6 mS/cm). High salinities result from local inputs of waste water from unsewered sanitation but mainly from evaporation/evapotranspiration of canal water and groundwater used for irrigation. The process does not concentrate As in the groundwater owing to sorption of As to soils. Ion exchange exerts a control on concentrations of Na, Ca, and B but not directly on As. High values of Cl/Br mass ratios (most ?288, the marine value) reflect the pervasive influence on groundwater of sewage‐contaminated water from irrigation canals through seepage loss and deep percolation of irrigation water, with additional, well‐specific, contributions from unsewered sanitation. 相似文献