90Sr CONDITION IN THE EAST CHINA SEA AND NORTH PACIFIC

Abstract

The condition of ⁹⁰Sr concentration in the East China Sea and North Pacific closed to the Japanese island has been measured from 3 – 31 July 2000. There were differences condition of ⁹⁰Sr concentration in the those locations. The concentration of ⁹⁰Sr detected in the surface East China Sea and North Pacific ranged 0.44–1.32 mBq/ℓ and 0.66-1.38 mBq/ℓ respectively. Generally, the condition ⁹⁰Sr concentration in the East China Sea was lower than in the North Pacific. The highest ⁹⁰Sr concentration occurred in the off shore of North Pacific, because the ⁹⁰Sr in the open sea is dominantly from nuclear weapon testing and nuclear power plant accident (Chernobyl) rather than other resources, and it take long time to precipitate into the bottom. Kuroshio and Taiwan-Tsushima warm current systems influenced importantly in distribution of ⁹⁰Sr concentration in the East China Sea beside other physical factors such as fishing activity. These currents were not strong enough to stimulate increasing ⁹⁰Sr concentration in the coastal region of North Pacific close to the Japanese islands.