ABSTRACT

Selenium in natural waters was chemically specified at 16 stations from Lake Biwa to Osaka Bay. The concentrations of selenium (IV), selenium (VI) and organic selenium in Lake Biwa ranged from 0.04 to 0.36, from 0.00 to 0.36, and from 0.00 to 1.97 nM, respectively. The concentration of organic selenium was highest at the depth of the maximal of chlorophyll a concentration in the Lake Biwa water. The concentrations of selenium (IV), selenium (VI) and organic selenium in the Yodo River ranged from 0.12 to 0.37, from 0.02 to 0.32, and from 0.32 to 0.18 nM, respectively. In coastal Osaka Bay, the concentrations of selenium (IV), selenium (VI) and organic selenium ranged from 0.05 to 0.31, from 0.09 to 0.50, and from 0.14 to 0.77 nM, respectively.