of water must be inoculated onto the nutrient medium of Tauson, into which 

 a sterile solution (sterilization is carried out in sealed ampules by re- 

 peated boiling) of diesel oil, kerosine, or drop of mineral oil is added 

 as the main source of carbon. After adjusting of pH to the neutral value, 

 the medium is poured into test tubes. Into each, hydrocarbon and dilutions 

 of the tested water are added. The test tubes are placed into an incubator 

 at 26 °C for 5-10 days. At that time, the dilution may be determined in 

 which the film of bacteria was formed or in which the medium became cloudy. 

 In clean water the bacteria will either fail to grow, or will develop in 

 the 1st or 2nd dilution, while in polluted waters they will grow in the 

 3rd - 5th, sometimes in the 6-7th dilution. 



In some cases instead of titer, a time consuming process, the intensity 

 of bacterial development may be determined. For this, the medium is poured 

 into 3-5 ml serum bottles and to each a drop of hydrocarbon and 0.1 ml of 

 the suspect water are added. The bottles are then incubated. In 5-10 

 days they are examined, and the intensity of bacterial development (forma- 

 tion of the film, turbidity) is noted. The water is considered to be 

 clean if negative, or poor development is observed. When the pollution of 

 the water by petroleum products is significant, a thick skin-like film 

 with a white or pink tint rapidly develops, and occasionally the medium 

 becomes turbid. 



Content of Cellulose Degrading Aerobic Bacteria (Pollution of Water With 

 Cellulose-- 



At the present time, many wood processing plants discharge wastes into 

 natural waters. Often wood fibers, lignin, and the like are found in them. 

 As a rule, cellulose degrading bacteria develop in enormous quantities in 

 the places of accumulation of wood fibers. They may isolated by inocu- 

 lating specific nutrient media, e.g., medium of Hatchinson (Romanenko, 

 1971). This medium contains the principal mineral salts required with 

 cellulose (filter paper) as the sole carbon source, with this medium, the 

 inoculum must be used from the 1st to the 6th dilution. Development of 

 bacteria in the l-2nd dilution indicates the presence of a relatively 

 small number, while development in subsequent dilutions shows the presence 

 of pollution with cellulose. 



Presence of Sulphides and Thiosu1phates --The presence in water of re- 

 duced compounds of sulphur may be estimated by the presence of thionic 

 bacteria. These may be grown on the liquid or solid phase medium of 

 Beiering. The colonies often have a milky coloration owing to liberated 

 sulphur. Colonies can be quantified with a help of autoradiography 

 (Romanenko, at al., 1975). This method utilizes 14 c-carbonate added to 

 the agar medium. Bacteria are grown on membrane filters. After incuba- 

 tion, the filters are removed, treated with a weak solution of hydrochloric 

 acid, dried and glued to strip of compact paper equal in size to photo- 

 graphic film. In a light-free environment, the paper is applied to the 

 film, and both are rolled. In 2-5 days the film is developed in a contrast 

 developer. Colonies of thionic bacteria are counted as dark spots on the 

 f i lm. 



63 



