多摩川における大腸菌群,大便性大腸菌群および有機汚濁量

抄録

Total coliform (TC) and fecal coliform (FC) organisms were enumerated and isolated from water samples from several stations on the Tamagawas River and its tributaries in Tokyo. The level of these indicator bacteria and biochemical oxygen demand(BOD) markedly increased from the upper streams towards the lower reaches of this river system. There were statistically significant positive correlations (p<0.01) among TCs, FCs, and BOD. Also the FC/TC ratios were highly correlated with BOD (p<0.01). The proportion of thermotolearant coliforms and Escherichia coli constituting the TC population increased with increasing BOD levels. whereas the relative concentration of E. coli to the FC population decreased with increasing BOD levels. These results suggest that the population densities of FCs or thermotolearnt coliforms in the river environment are directly proportional to the degree of sewage and human waste pollution, which is reflected by BOD levels, but their occurrence in polluted river and esturay waters is due in part to regrowth of some FC members such as Klebsiella pneumoniae.