●Research Trends and Results
Links with overseas research institutes
regarding conservation of theNorthwest Pacific marine environment
SAKAKIBARA Takashi, Research Coordinator for Water Quality Control Water Quality Control Department
YOKOTA Toshihiro, Head Wastewater System Division
SHIGEMURA, Hiroyuki, Senior Researcher Wastewater System Division
FUJIWARA Hiromichi, Researcher Wastewater System Division

Research Trends and Results(Key words) Ocean environment, pollution load, simulation, sewerage system
1. Introduction
In countries near Japan, rapid population growthand industrial growth seen in recent years have notbeen accompanied by adequate development of theirsewage systems and other infrastructures, resulting in
an increasingly serious problem of water pollution in
major rivers and Northwest Pacific. The Wastewater
System Division has studied methods of conserving
the future marine environment in Northwest Pacific(Bohai Sea, Yellow Sea, East China Sea, Japan Sea),and in particular, has attempted to clarify the pollutant
load runoff reduction effects of providing seweragesystems in neighboring countries. And because weoften cannot obtain overseas data or documents inside
Japan in sufficient quantities for our survey, we haveundertaken survey research in cooperation withresearchers in the concerned countries (Japan, China,Korea, Russia).
2. Contents of recent surveys and challenges
In order to clarify the future effectiveness ofmeasures to reduce pollutant loads in Northwest
Pacific achieved as a result of the construction ofsewerage systems in neighboring countries, theWastewater System Division built a simulation modelof the runoff of pollutant loads from watersheds inconcerned countries and set future economic growth(increasing pollutant loads) scenarios and seweragesystem installation scenarios (reducing pollutantloads), verifying the effectiveness of pollutant loads
reduction measures. We also built a hydrodynamic andwater quality model, and entering the results ofcalculations by a pollutant load model, used it toperform flow and water quality model calculations,clarifying the way that the pollutant load (COD, T-N,T-P) behaves on the surface of Northwest Pacific(Fig. 1).
On the other hand, it was extremely difficult tocollect water quality data from each country in orderto perform the above simulation calculations. We
think that in the future, as one challenge to be
overcome to take marine environment conservation
measures in Northwest pacific, it will be vital thateach country continues sustained monitoring of water
quality in major rivers and in Northwest pacific.

(1)
Pollutant load runoff simulation①汚濁負荷流出シミュレーション
Fareastern Russia
ロシア極東
Calculation of pollutant load runoff originatingon日中韓露における陸域起源のdry land in Japan, China, Korea, and汚濁負荷流出量を計算
Russia渤海
BohaiSea
黄海Sea
Yellow(2)
Hydrodynamic & Water Quality simulation②海洋海流シミュレーション
Prediction of behavior of pollutant load on
日本近海（渤海・黄海・東シナ
Northwest
Pacific ( Bohai Sea, Yellow Sea,
East
China Sea, and Japan Sea)
海・日本海）上での汚濁負荷の挙動を予測）

中国・黄河流域
China/Yellow
River Basin

China/Huai
River Basin
中国・淮河流域

日本
Japan
Japan
Sea
日本海

China/ChangjiangRiver Basin
中国・長江流域

Korea
韓国

East
China Sea
東シナ海

Figure 1. Outline of Contents of Surveys in PreviousYears

合意文書署名Signing
the agreement

Participants at the international
meeting
国際会議出席者

Signing
the agreement
合意文書署名Figure 2. The International Conference with Overseas
Researchers and Signing the Agreement
3. Future links with overseas research institutes
In February 2011, we held an international meetingfor researchers invited to Tokyo from Japan, China,Korea, and Russia, countries which had already been
cooperating with our survey research (Fig. 2 left). At
the conference venue, reports were given on theresults of the past surveys, confirming the importanceof continuing relationships with research institutes andsharing water quality monitoring data possessed byeach country. At the same time, the participants signed
an agreement stating that researchers from Japan,
China, Korea, and Russia would share water quality
monitoring data for major rivers in the various
countries and for Northwest Pacific (Fig. 2 – right). In
the future, based on the knowledge already obtained,
we will continue to collect information concerning
pollutant unit load etc. and water quality monitoringdata from each country, and also actively provide such

●Research Trends and Results
information to them.
http://www.nilim.go.jp/lab/ebg/(Wastewater System Division)