PARENT SESSION
57 - Chemical Policy Approaches
8:30 AM to 12:20 PM, Wednesday, 15 May 2002
Session Chair: Witzani, Helmut ¹, Jakl, Thomas ², Bornatowicz, Norbert ³, Schindler, Ilse ⁴, ^{1 2 3 4} .
Stolz A

(57-05) Ecological Risk-Benefit Analysis of DDT Regulation.

Nakamaru, Mayuko^*,1, Iwasa, Yoh², Oka, Toshihiro³, Nakanishi, Junko⁴, ¹ Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA² Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan³ Fukui Prefectural University, Fukui, Japan⁴ Institute of Environmental Science and Technology, Yokohama National University7, Yokohama, Japan

ABSTRACT- Here we report the ecological risk-benefit analysis of DDT based on the enhanced extinction risk of a wild bird population. We take sparrowhawk and herring gull, for instance. We evaluated the mean extinction time based on the canonical model, which is a kind of the stochastic differential equation models, and calculated the risk equivalent, i.e. the decrease in the carrying capacity causing the same enhancement of the population extinction risk as the chemical exposure. The equivalent habitat losses in the sparrowhawk population with 100 females were50.5% when the DDTs concentration in eggs was 11.9 ppm. We also calculated the benefit of DDT by evaluating economical cost of an alternative policy of preventing malaria by using pyrethroid-impregnated bednets. Combining these two, we are able to carry out the ecological risk-benefit analysis.

Key words: Ecological risk/benefit analysis of DDT, mean extinction time of bird population, risk equivalent, economical cost of preventing malaria