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Retention processes of cadmium and zinc relevant in acid sandy soils affected by diffuse pollution
17A 941128 Acidisation: borehole development and rehabilitation Banks, D; Cosgrove, T; Harker, D; Howsam, P; Thatcher, J P Q J Engng Geol V26, N2, 1993, P109-125 Acidisation is used to improve the performance of or rehabilitate water supply boreholes or oil production wells in carbonate rocks. Treatment should be designed according to the primary aim, deep penetration of fissures or removal of slurry or encrustation. Laboratory studies and pumping tests indicate drilling slurry removal is the dominant effect in newly drilled bores in chalk. Calliper logging demonstrates greatest effects will be around the injection zone, which should coincide with major producing zones. It is suggested that significant savings are possible in the amount of acid used to obtain desired improvement.
941132 Retention processes of cadmium and zinc relevant in acid sandy soils affected by diffuse pollution Wilkens, B J; Loch, J P G Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 VI, P453-456. Pub/ Rotterdam: A A Balkema, 1992 Atmospheric deposition of Cd and Zn from a nearby smelter has led to fears of groundwater pollution by leaching from the sandy soils of the Kempen region of the Netherlands. A study of the metal-binding (retention) processes specific to this kind of soil under existing acidifying conditions has been carried out. Iron oxides and organic matter are the dominant binding components and sorption is strongly pH-dependent. Relative importance of these factors has been evaluated and is used in prediction of future potential for groundwater contamination.
941129 Occurrence of abnormal acidity in granular soils. Technical note Sandover, B R; Norbury, D R Q J Engng Geol V26, N2, 1993, P149-153
941133 Geochemistry of water and chemical weathering rates under a humid tropical climate Benedetti, M; Menard, O; Noack, Y
During site investigation for a road in Hampshire, routine samples of groundwater, made ground, alluvium, terrace gravels, and Bracklesham beds were taken, pH and sulphate determination showed over two thirds of samples with pH It 5.5, with a low of 2.3. Because this implied problems with cement and pipework, repeat testing was carried out, without the ageing of the original samples. Results showed much reduced acidity. The need to take care when dealing with sulphidebearing soils is emphasised.
Rotterdam: A A Balkema, 1992
941130 Leaching characteristics of heavy metals from three historical Pb-Zn mine tailings heaps in the United Kingdom Merrington, G; Alloway, B J Trans Inst Min Metall (Sect A Min lnd) V102, May-Aug 1993, PA75-A82 Tailings from three historical mining areas in the UK were subjected to accelerated weathering tests simulating periods of l and 2 years at 3 different ambient temperatures. Only limited correlation was seen between total concentrations of Cd, Ca, Pb, and Zn in the primary ore minerals and in the leachate. Effects of temperature on leachate ionic concentration and pH are described. Leachate concentration depends on type of gangue mineral, presence of other sulphide minerals, and formation of secondary iron minerals. Laboratory simulated concentrations agree reasonably well with field measurements. 941131 Soil-pollution effects on geotextile composite walls Fang, H Y; Pamukcu, S; Chancy, R C Proc Symposium on Slurry Walls: Design, Construction and Quality Control, Atlantic City, 27-28 June 1991 P103-116. Publ Philadelphia: ASTM, 1992 (ASTM Special Technical Publication Nl129) The grain size distribution of the surrounding soil is one factor taken into account when selecting the type or porosity of a geotextile for use in a composite barrier. This distribution can be changed by the effects of soil contaminants. Laboratory studies on the effect of pore fluid pH, soil adsorption of particulate matter, and particle swelling or shrinkage on grain size distribution are described. The distribution shifts to finer scales for non-dispersive and dispersive clays as pore water pH respectively increases or decreases.
Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P545-548. Publ
Much laboratory work has been carried out using pure minerals under carefully controlled conditions to study erosion rates and dissolution of rock-forming minerals. Under natural conditions, however, many minerals will react simultaneously, together with soil constituents. Dissolution and erosion rates have been computed based on the geochemistry of natural waters percolating through basaltic rocks and their weathering products in the Parana Basin of Brazil. Computed rates are 12 orders of magnitude less than those predicted from experimental studies. 941134
Experimental study of salt rock-water interactions Silberschmidt, V G; Silberschmidt, V V Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 VI, P673-675. Publ Rotterdam: A A Balkema, 1992 Long term investigations of the interaction of salt rock with water are described, using data from the Verkhnekamskoya deposits in Russia. Salt massif moisture content and its influence on strength characteristics of the rock have been investigated. Dissolution rate depends on leaching surface inclination. Initiation and growth of water-conducting fractures is associated with decrease in rock strength. Dissolution rates have been calculated for carnallite, sylvite and halite. Physical and mathematical models of accidental flooding of potash mines and its prevention have been investigated.
Permeability and capillarity See also: 941025 941135 Effect of freeze-thaw on the hydraulic conductivity and morphology of compacted clay Othman, M A; Benson, C H Can Geotech J 1/30, N2, April 1993, P236-246 When compacted clays are subject/~d to freeze-thaw, cracks are formed by ice lensing and shrinkage, and hydraulic conductivity increases. Photographs of thin frozen sections show similar ice structures form in ID and 3D freezing experiments, which explains the similar hydraulic conductivities found. Significant cracking occurs in a single cycle and new cracks occur on
941132 Retention processes of cadmium and zinc relevant in acid sandy soils affected by diffuse pollution Wilkens, B J; Loch, J P G Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 VI, P453-456. Pub/ Rotterdam: A A Balkema, 1992 Atmospheric deposition of Cd and Zn from a nearby smelter has led to fears of groundwater pollution by leaching from the sandy soils of the Kempen region of the Netherlands. A study of the metal-binding (retention) processes specific to this kind of soil under existing acidifying conditions has been carried out. Iron oxides and organic matter are the dominant binding components and sorption is strongly pH-dependent. Relative importance of these factors has been evaluated and is used in prediction of future potential for groundwater contamination.
941129 Occurrence of abnormal acidity in granular soils. Technical note Sandover, B R; Norbury, D R Q J Engng Geol V26, N2, 1993, P149-153
941133 Geochemistry of water and chemical weathering rates under a humid tropical climate Benedetti, M; Menard, O; Noack, Y
During site investigation for a road in Hampshire, routine samples of groundwater, made ground, alluvium, terrace gravels, and Bracklesham beds were taken, pH and sulphate determination showed over two thirds of samples with pH It 5.5, with a low of 2.3. Because this implied problems with cement and pipework, repeat testing was carried out, without the ageing of the original samples. Results showed much reduced acidity. The need to take care when dealing with sulphidebearing soils is emphasised.
Rotterdam: A A Balkema, 1992
941130 Leaching characteristics of heavy metals from three historical Pb-Zn mine tailings heaps in the United Kingdom Merrington, G; Alloway, B J Trans Inst Min Metall (Sect A Min lnd) V102, May-Aug 1993, PA75-A82 Tailings from three historical mining areas in the UK were subjected to accelerated weathering tests simulating periods of l and 2 years at 3 different ambient temperatures. Only limited correlation was seen between total concentrations of Cd, Ca, Pb, and Zn in the primary ore minerals and in the leachate. Effects of temperature on leachate ionic concentration and pH are described. Leachate concentration depends on type of gangue mineral, presence of other sulphide minerals, and formation of secondary iron minerals. Laboratory simulated concentrations agree reasonably well with field measurements. 941131 Soil-pollution effects on geotextile composite walls Fang, H Y; Pamukcu, S; Chancy, R C Proc Symposium on Slurry Walls: Design, Construction and Quality Control, Atlantic City, 27-28 June 1991 P103-116. Publ Philadelphia: ASTM, 1992 (ASTM Special Technical Publication Nl129) The grain size distribution of the surrounding soil is one factor taken into account when selecting the type or porosity of a geotextile for use in a composite barrier. This distribution can be changed by the effects of soil contaminants. Laboratory studies on the effect of pore fluid pH, soil adsorption of particulate matter, and particle swelling or shrinkage on grain size distribution are described. The distribution shifts to finer scales for non-dispersive and dispersive clays as pore water pH respectively increases or decreases.
Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P545-548. Publ
Much laboratory work has been carried out using pure minerals under carefully controlled conditions to study erosion rates and dissolution of rock-forming minerals. Under natural conditions, however, many minerals will react simultaneously, together with soil constituents. Dissolution and erosion rates have been computed based on the geochemistry of natural waters percolating through basaltic rocks and their weathering products in the Parana Basin of Brazil. Computed rates are 12 orders of magnitude less than those predicted from experimental studies. 941134
Experimental study of salt rock-water interactions Silberschmidt, V G; Silberschmidt, V V Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 VI, P673-675. Publ Rotterdam: A A Balkema, 1992 Long term investigations of the interaction of salt rock with water are described, using data from the Verkhnekamskoya deposits in Russia. Salt massif moisture content and its influence on strength characteristics of the rock have been investigated. Dissolution rate depends on leaching surface inclination. Initiation and growth of water-conducting fractures is associated with decrease in rock strength. Dissolution rates have been calculated for carnallite, sylvite and halite. Physical and mathematical models of accidental flooding of potash mines and its prevention have been investigated.
Permeability and capillarity See also: 941025 941135 Effect of freeze-thaw on the hydraulic conductivity and morphology of compacted clay Othman, M A; Benson, C H Can Geotech J 1/30, N2, April 1993, P236-246 When compacted clays are subject/~d to freeze-thaw, cracks are formed by ice lensing and shrinkage, and hydraulic conductivity increases. Photographs of thin frozen sections show similar ice structures form in ID and 3D freezing experiments, which explains the similar hydraulic conductivities found. Significant cracking occurs in a single cycle and new cracks occur on