Effect of different detergent concentrations on the soil microorganisms number.

As poorly bio-degradable substances chemical in nature, detergents may be discharged into watercourses and arable land areas uncontrollably and so have adverse ecological and economic effect on the biological production of such ecosystems. The researches to determine permissible chemical load limits in the environment are believed to be of an outstanding importance. The paper was aimed at studying the effects of different detergent (Meril, Merima, Krusevac) concentrations, introduced into the nutritive medium, on the total number of soil microorganisms, fungi and oligonitrophiles. The research was performed at the Microbiology Laboratory of the Faculty of Agronomy in Cacak. The medium for total number (Torlak, Belgrade) was used for determining the total number of bacteria, Capek agar was used for soil fungi and Fjodorov agar for oligonitrophiles. The results obtained show that the lowest possible toxic effect on the microorganism groups studied was produced by the lowest detergent concentration (0.001%), whereas the concentrations of 0.1% and, particularly of 1% solution, inhibited microorganism growth nearly utterly. In this sense, oligonitrophilous bacteria appeared to be the most sensitive and soil fungi the most resistant group of microorganisms.