41 Study of the Impact to the water Quality by Marine Engine Exhaust Emissions

Starting with the laboratory study, the amount of exhaust emission compound dissolved in water was measured, and the divergence of exhaust emission compounds was reviewed. Measurements were taken for hydrocarbon (HC), especially benzene, toluene, m-Xylene, p-Xylene, and o-Xylene. It was verified that the amount of exhaust emission compounds dissolved in water has positive correlation with the volume of exhaust gas introduced into the water. The dissolved amount was smaller with the low emission engine model. Volatile Organic Compound (VOC) decreased sharply at the beginning, but the decrement got smaller after a certain period of time. Next research was performed on the actual river where PWC are being used. We looked into the possible correlation between the VOC's concentration in water and the distance to the water where a lot of PWC's are running. In addition the MTBE (Methyl Tertiary-Butyl Ether) concentration was measured. Based on the findings from this research and study, PWC industry in Japan voluntarily restricted the operation hours on the water where VOC was detected first. The area for racing crafts training was moved upstream. VOC was reduced successfully as the restriction was implemented. The accumulated value of VOC per day reduced as much as 85%.