No description available.

No description available.

A discussion is presented to illustrate the relationships among landform, soil, vegetation and water chemistry in the intermittent permafrost zone of the Mackenzie Valley, Northwest Territories. Two study areas were examined in this region, one in the vicinity of Wrigley and the other in the vicinity of Fort Simpson, N.W.T. A catenary sequence of soils and vegetation occurring as a transect on five distinctive landforms were examined in the Wrigley area. The transect extended from 1170 m above sea level downslope to 500 m above sea level. The five landforms were: an alpine meadow, an area of stone stripe and stone ring formation, a colluvial slope, a coalescing fan and an area of polygonal bog formation. Information on chemical water quality is presented for each of these areas for the parameters pH, O₂, Ca, Mg, Na, K, Cl, F and NO₃. Chemical water quality presented for the Fort Simpson study area allows for the differentiation of different types of organic terrain based on the dissolved load of the saturated organic materials. The polygonal bog landform initially examined in the Wrigley area formed one of the differentiated types of organic terrain. The results are discussed with reference to organic terrain morphology and the distribution of permafrost in the study area. / Land and Food Systems, Faculty of / Graduate

The equilibrium equations relating dissolved CO2 , HC03- CO3-, H+, solid phase CaC03 , exchangeable H+ and ionic strength were programmed for simultaneous solution on a 7072 IBM digital computer. This routine was combined with an eXisting program which had been successfully used to relate the equilibrium of soluble and exchangeable Ca+ + ,Mg+ + ,Na+; dissolved Cl - , S04- ' and N03-; and solid phase CaS04 •2H20. The final systems analysis model thus developed accounted for most of the dissolved substances normally present in significant quantities in ground waters and soil solutions. This model made possible calculation of the equilibrium concentrations which would result if the concentration of one or more of these constituents were to be arbitrarily changed. This systems analysis model was used to predict the equilibrium concentrations of ionic species in soil solutions obtained from soils at moisture and carbon dioxide levels different from those prevailing in the original analysis. The soils used in this study were vastly different in chemical characteristics, texture, and genesis. Included were soils which were both acid and basic in reaction, calcareous and noncalcareous, gypsiferous and nongypsiferous, and both high and low in organic matter. In general, the chemical predictions obtained were of about the same level of accuracy as the experimental methods used to determine these chemical constituents. Soil cores from strata underlying an irrigated area were collected, and the 1: 1 soil-water extracts of these cores were analyzed for chemical constituents. The systems analysis model developed in this study was then used to estimate the concentrations of the chemical constituents which would have been in solution in the cores at the time they were sampled. The soil solutions calculated to be in most strata were similar to the underlying ground water, thus indicating a probable common origin for the water above and below the water table. It is believed that this systems analysis approach can, with minor modification, be used to predict changes in ground water quality as water percolates through strata of known chemical characteristics.

No description available.

No description available.

No description available.

No description available.

No description available.

Scaling is a major problem in cooling water circuits as it reduces water flow and therefore affects the efficiency of the circuit. The natural organic matter has been suggested in earlier studies to limit the formation of calcium carbonate scaling by complexing the calcium ion. It was therefore the aim of this study to characterize the natural organic matter in the cooling water circuits at Lethabo power station (Vereeniging) and to investigate its potential to complex with calcium. The cooling water and raw water samples were comprehensively analyzed for major metal ions, anions and dissolved organic carbon using AAS, ICP-OES, IC and TOC analyzer and the results entered into MINTEQA2 speciation program to determine the precipitation potential of aragonite and calcite in the water samples. The natural organic matter from the cooling water and raw water were isolated initially through the cross-flow ultrafiltration using a polysulfone membrane with a molecular weight cut-off of 45 kDa. The collected isolates were characterized by ultraviolet-visible spectrophotometer, Fourier transform-infrared spectroscopy and (carbon, hydrogen and nitrogen) elemental analysis. The natural organic matter was also fractionated on ultrafiltration stirred cells using membranes with molecular weight cut-off of 1 kDa, 10 kDa and 100 kDa and then characterized using high performance size-exclusion chromatography. The isolated fractions were also titrated with sodium hydroxide and with calcium chloride to determine the amounts of carboxylic and phenolic groups available for complexation and the extent of the complexation of the fractions with calcium respectively. The speciation results from MINTEQA2 indicated that the raw water had a potential to be corrosive and the cooling water had a potential to scale. Higher concentrations of the natural organic matter were detected in the permeate from the cross-flow ultrafiltration process which suggested that it had predominantly a low molecular weight fraction. This low molecular weight fraction was further confirmed by the results from the high performance size-exclusion chromatography analysis of the fractions obtained from the fractionation process using ultrafiltration stirred cells. The specific ultraviolet absorbance and ratios of 465 to 656 nm absorbances results indicated that the organic compounds were mostly aliphatic in character. Titration of the concentrated organic isolates with sodium hydroxide solution revealed that the fractions had a high content of titratable acidic groups and titrating with calcium chloride showed that there is considerable complexation with calcium to affect calcium carbonate precipitation. / Dr. M. Shumane