ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01505.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTAs more and more cases of ground‐water contamination are reported, the public has become increasingly aware of the importance of preserving the quality of this limited resource, especially in areas totally dependent on ground‐water sources. Although most of the attention is focused on pollution by organic chemicals, these compounds are responsible for a relatively small percentage of ground‐water‐related disease outbreaks. The majority of waterborne disease outbreaks are caused by bacteria and viruses present in domestic sewage. Septic tanks contribute the largest volume of waste water, 800 billion gallons per year to the subsurface, and are the most frequently reported cause of ground‐water contamination associated with disease outbreaks. The U.S. Environmental Protection Agency has designated areas with septic tank densities of greater than 40 systems per mi2(1 system per 16 acres) as regions of potential ground‐water contamination. Numerous cases of ground‐water contamination have been reported in areas of high septic tank density; lot sizes in these areas range from less than one‐quarter acre to three acres. The single most important means of limiting ground‐water contamination by septic tanks is to restrict the density of these s

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01506.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTConcentrations of HCO3and δ13C values of dissolved inorganic carbon change along the hydrologic gradient of the Aquia aquifer. In the outcrop area, meteoric recharge rapidly dissolves carbonate shell material (δ13C ∼ 0.0 per mil) in the presence of soil‐gas CO2(δ13C∼–26 per mil). HCO3concentrations in this area range from 150‐200 mg/1 and δ13C values of dissolved HCO3are approximately –13.0 per mil. Concentrations of HCO3decrease gradually (to about 130 mg/1) and δ13C values become slightly heavier (to about –11.4 per mil) as water flows away from the outcrop area. These trends reflect progressive dissolution of metastable carbonate shell material and subsequent precipitation of secondary calcite cement. At about 40 miles downgradient in the flow system, HCO3concentrations increase sharply (to about 400 mg/1), and δ13C values become significantly heavier (δ13C ∼–6.2 per mil). The observed 1:1 molar ratio of Na+to HCO‐3in this downgradient water shows that dissolution of isotopically heavy carbonate shell material cannot by itself explain the observed δ13C trend. Rather, the Na:HCO‐3ratio demonstrates that shell material dissolution must take place in the presence of CO2. Because the aquifer in this area is closed to both soil‐gas and atmospheric CC>2, an aquifer‐generated source of isotopically heavy (δ13C ∼–5.3 per mil) CO2is implied. Possible sources of aquifer‐generated CO2include bacterially‐mediated fermentation of lignitic aquifer materia

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01507.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTA hydraulic trap in the form of a purge well is proposed for the Forwell collector well K‐71. The trap, which will protect well K‐71 from contamination by contaminants migrating downgradient from the old Breslube waste disposal site, is based on a qualitative flow net obtained from a finite‐element model of the Forwell Aquifer. The trap constitutes pumping at the position of observation well OW 9‐80 at a continuous rate of at least 6.1 X 10‐3m3/s. The uniqueness of the trap lies in its simplicity and relatively

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01508.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTWaters from 91 springs in a 130 X 140 km area of west‐central Arkansas were analyzed for all the major ions. The yearly flux of these ions in the rain and pure‐water extract of the dry deposition 180 km north of this area was measured and assumed to represent the composition of the recharge to the ground water feeding the springs. Cation/Cl‐flux ratios were used as a norm for the concentration of ions in the spring waters by evapotranspiration. Ratios above the norm were interpreted as ion exchange or rock dissolution into the ground waters. Ratios below the norm were interpreted as ion adsorption or, for Ca2+, CaCO3precipitation processes. Na+and Mg2+are invariably above the norm. K+, NH+4 and H+are invariably below the norm; whereas Ca2+values are about equally divided between above and below the norm. Equivalents of cations above the norm and below the norm were compared for a number of springs to determine the main ground‐water processes for each spring. The Na+/Cl‐and K+/Cl‐norms for the rain water form near‐perfect minimum and maximum envelopes, respectively, of the Na+vs Cl‐plots of the spring‐water compositions. This is due to the adsorption affinities of the soil for Na+being low, and

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01509.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTA numerical model was developed to simulate the behavior of two‐phase immiscible fluids in ground‐water systems for specific application to hydrocarbon spills and leaks. The model is a two‐dimensional areal flow model using the finite‐element method. A verification of the numerical model was performed using both an approximate analytical solution and a laboratory investigation. The verification results show that the numerical model adequately describes the behavior of immiscible two‐phase flow within a coarse porous

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01510.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTWater samples were collected from 34 wells in the Claiborne aquifer in southwest Georgia. Land use/cover is principally forest, wetland, or agriculture. The aquifer is exposed surficially to the northwest but dips beneath confining beds to the southeast. The Claiborne aquifer is generally a fine‐ to medium‐grained quartz sand becoming more calcareous downdip and to the east. Well water was analyzed in the field for pH, electrical conductivity, alkalinity, hardness, and temperature, and in the laboratory for Cl, NH4, NO3, total N, total P, ortho‐P, SO4, K, Na, Ca, Mg, and Fe. Hardness gradually increases from 5 mg/1 updip to 162 mg/1 downdip and bicarbonate alkalinity follows the same trend reflecting variations in the aquifer lithology. Higher than normal nitrate concentrations (4‐6 mg/1) are found in ground water in the exposed updip portion of the aquifer in areas where agricultural land use for cropland is high. However, in forest‐covered areas, ground water in the exposed portion of the aquifer contains nitrate concentrations similar to the confined areas of the aquifer: less than 1 mg/1. Other chemical constituents measured do not show a discernible pattern of variation. One well near a fertilizer storage facility contains nitrate concentrations exceeding the Safe Drinking Water Standards, and other wells in the agricultural portion of the outcrop belt may seasonally exceed the

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01511.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTChemical analyses of wells penetrating the coastal aquifer of Israel indicate that the relative concentrations of sodium, calcium, magnesium, bicarbonate, and hydrogen species deviate considerably from the ideal mixing line between fresh water and sea water, as represented by the concentration of chlorides. Furthermore, deviation patterns were found to be distinctly different for areas of present sea‐water intrusion, and areas from which ancient brines are still flushed. These differences, explainable in major part as the combined effects of cation exchange and carbonate equilibria, can in turn be utilized to distinguish between invading and retreating saline‐water bodies, and identify their existence at the very beginning of the salinization process. Observed patterns are verified here in major part, with the aid of a single‐cell simulation

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01512.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTUnsteady flow to a large‐diameter well in a confined aquifer during recovery has been analyzed by discrete kernel approach. A family of type curves has been presented for different durations of pumping. These type curves provide a fairly accurate means of determining aquifer parameters from data of pump tests conducted in a large‐diameter well. The replenishment of well storage at various times has been estima

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01513.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe behaviors of five chlorophenols and three chloro‐phenoxyphenols (CPPs) have been investigated at the chemical waste disposal site at Alkali Lake, Oregon. All of the compounds demonstrated similar trends in areal distribution hydraulically downgradient from the site. The transport distances for the di‐ and trichlorophenols were influenced greatly by their ionization in the high pH (˜10) ground water. In batch equilibrium experiments, these compounds were found to have Kpvalues of ˜0.0 for the soil and ground water taken from the site. While also largely ionized at pH ∼ 10, a tetrachlorophenol, pentachlorophenol, and the CPPs demonstrated substantial sorption in the batch equilibrium experiments as well as retardation relative to the di‐ and trichlorophenols at the site. The retardations observed relative to 2,6‐dichlorophenol were less than predicted based on the batch equilibrium results. Possible reasons include cosolvent effects due to the plume itself, nonuniform contaminant distributions at the time of the original burial, the fractures which are present in the aquifer, and a decreasing ground‐water velocity with distance westward of the site. Evidence is presented to support the last reason. These results show, for the first time, well‐behaved concentration contours embodying compound‐dependent retardation in the transport of sorbing and nonsorbing organic compounds from an existing wa

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1985.tb01514.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY