Presents a combined hydrogeological and microbiological analysis of landfill leachate and soils in Essex County, Ontario, to study the vertical and horizontal flow rates of groundwater Addresses two aspects of landfilling: the factors controlling the maintenance of a large and vigorous microbial population actively involved in biodegradation, and the retention of potentially pathogenic bacteria within the drainage borders of the landfill site Possible movement of the predominant population of bacteria through leachate and groundwater was determined by a cluster 2 analysis of the matrix of similarity coefficients of each strain compared to every other strain which was generated from their responses to 63 tests The responses reflected the physiological profile of the organisms and provided, in part, the information needed to identify the bacterial isolates The same database was also analysed for the principal components of the variance which were theninterpreted ecologically 12