Studies on the Survey of Sea Water Pollution along the Seashore of Kei-Yo Industrial Area. I. Variations of Pollution Indicators with the Lapse of Year

Abstract

Survey was made of sea water pollution along the seashore of Kei-Yo industrial area (Chiba prefecture) for the 12 years, 1965 to 1976. The values of chemical oxygen demand (COD), NH₄-N, and NO₂-N were examined with the lapse of time. The peak of COD value was found from 1971 to 1973, and then the value showed the tendency to decrease a little. The value of NH₄-N at Station 1 and Station 2 tended to increase remarkably from 1965 to 1976, and thereafter, to reach a plateau. The value of NO₂-N at Station 1, Station 2, Station 3, and Station 7 showed the tendency to increase slowly from 1965 to 1976.