Environmental Biogeology of Aquatic Ecosystem:In the Case of the Rivers in Kanazawa

Water and clay minerals of sediments in rivers around Kanazawa were
twice analyzed during two years to assess water pollution and the role
of microbial remediation.For both Saigawa and Asanogawa, the average
pH was 7.6, whereas 8.3 for Morimotogawa and Kanakusarigawa. Water
temperature, pH and NO2-N concentration increased from upstream to
downstream whereas Eh decreased contrastly. DO, NH4-N, PO4-N and EVAS
changed largely during two years. Besides the effects of human daily
life drainage from the residence areas, the geological environments,
underground water and microorganisms had a considerable impact on the
quality of river water. Rapidexploitation of soils caused the
oxidation of underground water from Omma formations which contained
high concentrations of Mn, Fe, Ca and K ions, resulting in a larg
edevelopment of microbial mat. Smectite gradually decreased with the
increasing ofkaolin minerals from upstream to downstream, suggesting
that these clay minerals could have reacted with drainage water by
cations exchange and affected partially the pH of river
water.Contributions of bacteria and clay minerals in the remediation
of polluted riverwater have been proved through this study.