[Microbiological studies of ground water polluted with hydrocarbons. 1. Quantitative and qualitative distribution of bacterial populations].

The groundwater, polluted with hydrocarbons, showed large cell numbers during one year of examination: 10(3)-10(4) CFU/ml grown on N-agar after 5 days at 20 degrees C, 10(4)-10(5) CFU/ml grown on water-agar after 8 weeks at 20 degrees C and total cell numbers of 10(5)-10(7)/ml. The bacteria, which were isolated from N-agar, were chiefly Pseudomonas, Flavobacterium, Acinetobacter, and other gramnegative species, Arthrobacter and Bacillus as members of grampositive bacteria. Furthermore the following "physiological' groups were found in the groundwater: ammonium-oxidizing bacteria (MPN 10(1)-10(2)/ml), sulfur-oxidizing bacteria (MPN 10(1)-10(4)/ml), nitrate-reducing bacteria (MPN 10(3)-10(6)/ml), denitrifying bacteria (MPN 10(1)-10(4)/ml), spores of aerobe spore-forming bacteria (2-30/ml), spores of anaerobe spore-forming bacteria (0.2-0.4/ml), manganese-oxidizing bacteria (10(3)-10(4) CFU/ml) and Actinomycetes (0.1-1.0 CFU/ml).