As the economies of Japan's neighboring countries have grown rapidly, problems such as red tide and eutrophication caused by the deterioration of the marine environment around Japan, including the Bohai Sea, Yellow Sea, East China Sea and the Sea of Japan, have become increasingly evident.
 In this study, pollution loads, mainly chemical oxygen demand (COD), total nitrogen (T-N) and total phosphorus (T-P), from land-based sources of pollution in Japan, China, South Korea and Russia were predicted. And a land-based pollution load simulation model and an ocean current simulation model covering Japan's coastal waters and adjacent waters were developed to evaluate the effects of those pollution loads on the marine environment.
 The newly developed land-based pollution load simulation model has made it possible to predict changes in pollutant loading during the period from 2005 to 2030, taking economic growth into consideration, and reductions in pollution loading under future scenarios that can be achieved through sewage system and other improvements.
 In this study, water quality in Japan's coastal waters and adjacent waters in the coming years from 2005 to 2030 was predicted through ocean current simulation using pollutant load predictions obtained from the pollutant load simulation model.
Pollutant load simulation and ocean current simulation succeeded to evaluate the effects of countermeasures in future scenario analyses. Simulation results showed appropriately that land-based countermeasures such as installing sewerage system or advanced wastewater treatment are effective to reduce land-based pollution loads from Japan, China, South Korea and Russia.
 Furthermore, an international workshop with Japanese, Chinese, South Korean and Russian researchers was held in Tokyo in order to solve problems associated with marine environmental deterioration and enhance the accuracy of water quality prediction. At the final session of the workshop, researchers of four countries made an agreement document which wrote down about sharing water quality monitoring data and other relevant research data. Therefore, researchers in these countries will cooperate in research continuously.

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Research on the Conservation of Northwest Pacific Marine Environments



Wastewater System Division, Water Quality Control Department,   National Institute for Land and Infrastructure Management

Chinese website

Japanese website

Update: February 1, 2013

In order to study the above, the calculation program of the land-based pollutant load from Japan, China, South Korea, and Russia, was developed. This calculation program, its operational manual, and its sample data files can be downloaded here.

Update: February 1, 2013

On this study, water quality data in the sea and the main rivers and information of measures for water quality conservation were offered by the researcher of each country. Part of these can be downloaded here.