The sanitary significance of coliform bacilli in soil

Abstract

Coliforms were readily obtained from many soils. In samples taken from sites exposed to animal contamination Bact. coli type I occurred predominantly. A large number of samples taken from grassy banks, only remotely exposed to contamination, were found to contain intermediates. It was found that the greater the probable degree of contamination of the soil the higher was the proportion of Bact. coli type I, and that the less the probable degree of contamination the higher was the proportion of intermediates. It is difficult to explain this merely on the basis of the prolonged survival of intermediates in soil, and it would appear obvious that the source of these intermediates lay elsewhere than in animal faeces. The numbers in which they were found in soil, however, were not of the order expected of bacteria living in their natural environment, and consequently it was equally difficult to conclude that these intermediates were actively established in soil.