Benefit from improvement of organic contamination of Tokyo Bay

Benefit from improving organic contamination by reducing nitrogen load is measured for Tokyo Bay by using the travel cost method (TCM). Among recreational activities grouped by access to the water, Recreation 1 (viewing, walking, nature study, photography and sketching) attains the largest demand, followed by Recreation 2 (clam-digging, paddling and shore fishing). The benefit or difference in consumersʹ surplus before and after improving chemical oxygen demand amounts to 458.3 bn yen. The contingent valuation method (CVM) is also used to directly estimate the benefit, which amounts to 2.8 times as large as the benefit by TCM. The cost for reducing nitrogen load by installing a denitrification system is merely 10.7% of the benefit by TCM. Improving organic contamination for Tokyo Bay is considered to produce large net benefits.