The Applications of Chemical Analyses of Sediments and Soils in ...

Ignition loss at 350-400°C has been found to give a good indication of organicmatter content analyzed by the Walkley-Black method (Smith et al 1974) as discussedearlier. Brydges (1970) found correlations between LOI at 600EC and total Kjeldahl Nand dry weight of sediment per unit volume in some northern Ontario lakes. It isplanned to evaluate LOI at 600°C vs 350°C to determine the contribution of carbonate.Chemical Oxygen Demand (COD) tests are also conducted on sediments usinga modified Walkley-Black chromic acid procedure. There has been little success to datewith evaluation of Total Organic Carbon (TOC) at MOE by high temperaturecombustion, such as the Carlo-Erba method used at the Canadian Centre for InlandWaters.Measurements are made of other solubles as required for the disposal of dredgespoil. Little progress has been made with the characterization of organic matter andorgano-metallic complexes. A Organo-Metallics laboratory is currently being equippedat the MOE Central Laboratory to investigate the role of these compounds in sedimentsand soils.There have been few requests for Acid Potential and Carbonate analysesalthough the importance of these tests in northern Ontario mining areas is recognized.Carbonate can be analyzed by the Chittig method. More rapid methods are beinginvestigated. Extractable phosphorus is normally analyzed by shaking with 0.5 Nsulphuric acid in 1:5 ratio for 30 minutes.39