Study of Correlation Between Microbial Pollution and Physicals and Chemicals Factors (Temperature, BOD5) in some Parts of Zayandehrood River in Isfahan

Since Zayandehrood of Isfahan is an important source of water in central part of Iran, therefore an investigation was under taken for identification, enumeration and isolation of pathogenic bacteria, and their correlation with physicals and chemicals factors such as biochemical oxygen demand (BOD) and temperature. In this study two sites were chosen for sampling. They are as follows: 1) Shahrestan Bridge, 2) the distance between Sharestan Bridge and “Bozorgmehr “Bridge.Total bacteria, fecal coliform and fecal streptococci were counted using MPN standard methods. B.O.D and temperature were determined. The results showed that the gram positive cocci (Streptococcus faecalis) were is isolated in the all of seasons, while staphylococcus aureus isolated only in spring, summer and autumn. The gram negative bacilli isolated were Escherichia coli, Salmonella typhi, klebsiella pneumoniae, Shiglla sonnei, Proteus morganii, Serratia marcescens and pseudomonas aeruginosa. The measurement of B.O.D and temperature revealed the temperature have the direct correlation with increasing of number and type of pollutant bacteria, because these microorganismes were maximum during hot season and were found minimum in cold season. But increasing B.O.D had relative direct correlation with increasing number of bactria. In this study the M.P.N of coliform (Fc) and faecal streptococci (Fc) and their ratio (Fc/Fs) determined that the pollution of Zayandehrood river is human base origin.