MEASUREMENT OF MICROBIAL BIOMASS AND ACTIVITY IN LANDFILL SOILS

Two complementary techniques, which have been widely used to provide a general measure of microbial biomass or microbial activity in natural soils, were evaluated for their applicability to soils from the Malla rd North and Mallard Lake Landfills, DuPage County, Illinois, U.S.A. I ncluded were: (1) a potassium sulphate extraction technique with quant ification of organic carbon for measurement of microbial biomass; and (2) an arginine ammonification technique for microbial activity. Four profiles consisting of replaced soils were sampled for this study; uni ts included topsoil (mixed mollisol A and B horizons), compacted clay cover (local calcareous Wisconsinan age glacial till), and mixed soil/ refuse samples. Internally consistent results across the four profiles and good correlations with other independent indicators of microbial activity (moisture, organic matter content, nitrogen, and phosphorus) suggest that, even though these techniques were developed mainly for n atural mineral soils, they are also applicable to disturbed landfill s oils.