The topography of the Japan Sea is as like a pot. The depths of entrance (Tushima straits) is only 140m and its of exist (Tugalu straits) is same. The maximum depth is 3750m. The exchange of water is not so easy. The polluted material will accumulate. About 227 million people populated in the hinterland. The inflow volume of polluted material is not so clear at now. But, the partial information shown the large amount of the pollution. In this paper, the prediction of pollution in the Japan sea is tried by the comparison with the data of the Baltic Sea.