Ultraviolet absorbance of waters Tokyo Bay, Sagami Bay and off-shore waters in the western North Pacific was examined with a 1-cm cell, with reference to distilled water.
Neither maximum nor minimum was found in absorption spectra. Regional variation in absorbance was found and coastal water had higher absorbance than off-shore water. No apparent tendency of change in absorbance was observed with depth. E230/E220 value of sea water may be useful for indicating the degree of pollution by land drainage. Higher absorbance coincided with the decreases in chlorinity and transparency, and increase in COD, indicating the mixture of land drainage.
During 30 days' storage of sea water, little change in absorbance was observed in surface water, while a little increase was found in deep water.