PREPARATION OF LOW-ASH HUMIC ACIDS, AND THE ACCOMPANYING LOSSES OF ORGANIC MATERIAL, FROM CANADIAN LAKE SEDIMENTS AND A GLEYSOL

Abstract

Treatment with dilute hydrofluoric acid, acid precipitation and washing, dialysis and subfractionation with ultrafiltration membranes were used to prepare humic acids and 2 subfractions of them with barely detectable ash content. A soil and sediments from 9 lakes [including lakes Ontario and Erie and lakes from The Experimental Lakes Region, Canada] in different areas and with different chemistry and trophic levels were so treated. Total losses of organic matter averaged 57%, with a range of 47-67% percent. Losses at each step were determined, the greatest being during ultrafiltration.