Lactose-positive intestinal protozoa in objects under construction soil cover of the Samara Region

Samara Region is one of the largest industrial and agricultural centers of the Russian Federation. It is characterized by a high level of urbanization. Soil degradation, its chemical and bacteriological pollution as well as declining fertility are the result of versatile economic activity in the region. The rate and level of soil pollution are actively monitored however only very scarce data on its sanitary-epidemiological condition are available. At present Samara Region is facing a boost of residential, administrative and industrial constriction which requires sanitary-epidemiological testing of soil at construction sites. The paper deals with the above mentioned problem. It has been determined that the most reliable criteria in estimating the sanitary-epidemiological condition of soil are sanitary-significant microorganisms, a group of coliform bacillus in particular. The causes and effects of urban soil pollution by microbiological contaminants have been analyzed. The role of lactose-positive intestinal protozoa as sanitary-significant microorganisms has been studied. A quantitative evaluation of lactose-positive intestinal protozoa index has been carried out for the soils below residential buildings, administrative buildings, industrial constructions as well as the utility systems area. In particular, it has been measured that the level of soil pollution by lactose positive intestinal protozoa depends on the period they have been in human use. An aggravated level of soil pollution in certain areas can be observed due to uncontrolled littering as well as pet walking or an increasing number of stray animals. Industrialized areas (oil plants) are characterized by the lowest level of lactose positive protozoa contamination which is explained by the fact that those industries use modern technologies which are able to minimize ecological risks. However, such areas are polluted in a different way. Dangerous level of soil contamination by lactose positive protozoa is registered at several large automotive plants.