江戸都市圏の社会・環境分析

—— 物質フローモデルによる評価 ——

抄録

Edo is the former name of Tokyo, and the Edo period was from 1603 to 1868. In 1603 the Shogunate Government of Edo was formed by Ieyasu Tokugawa, and the Edo period was ruled through a feudal system for all of its 265 years. Edo had high levels of consumption as the center of politics and there were many samurai that were a non-laboring class. Though Edo had the largest population and the highest density in the world in the late Edo period, it appeared to have the most unpolluted water environment because of human waste recycling and the circulation system in the Edo society. Hence, the target period of this study was the end of the Edo period during the 1800's.
In the early part of the Edo period, Edo was not clarified as a spatially-governed area because it was ruled by feudal policies such as land-owning and class systems. In 1818 the city area of Edo called “Shubiki” was spatially defined by the conference chamber of the Edo government. In this study, based on the “Shubiki” map announced by the Edo government in 1818 and other materials on land-use in Edo, we delimited the spatial area of Edo and analyzed the land-use patterns of the city by digital mapping using GIS. The land use patterns of the city area of Edo were classified into 11 categories, and the area of each category was estimated. The delimited city area of Edo was assumed as the land area discharging water pollutants flowing into the Tokyo bay in the 19th century.
Next, the socio-economic activities and environmental impacts of Edo city were quantitatively estimated based on documents about the population and the production data of the 19th century. On the basis of collected data such as the delimited area of Edo city, population, economic activity and area of land use, the environmental impacts on Tokyo bay were estimated by the inflow of total nitrogen (T-N) using the material flow model applied to Edo city, taking into account the recycling system of human wastes as an organic fertilizer for farming in the suburbs of Edo city.
Results of the model showed the T-N inflow into Tokyo bay from the household sector and industry sector of Edo city was 540 tons and 13 tons, taking into consideration the recycling system of human and livestock wastes for farming. The amount of T-N inflow from non-point generation sources was estimated at 156 tons. On the other hand, the total amount of T-N inflow from the Tokyo bay area in 2000 was approximately 87,000 tons, 123 times that during the Edo period.
In conclusion, this study shows that a quantitative method such as the material flow model for Edo is useful to analyze the historical situation from the viewpoint of socio-economic and environmental aspects. Especially, the estimation of favorable conditions of the water environment in the past should be reflected on as a concrete example of the ideal sea environment and a future vision of marine environment revitalization, for instance in the Tokyo Bay Renaissance Project.

JEL classification: N95, Q51, Q53, Q56