Abstract
The taste and odor problem causing by cyanobacteria has been occurred in Kamafusa dam reservoir. However, the increasing of musty-odor substance (2-MIB) concentration has been also observed, although cyanobacteria were absent in surface water column. As one of the hypotheses to explain this phenomenon, the influx of cyanobacteria or/and 2-MIB from paddy fields located on the upstream basin was considered. We investigated the amount of cyanobacteria biomass and that of 2-MIB of the paddy fields located in the upstream basin, and estimated the influx of them into the dam reservoir through the following agricultural streams and inflow rivers. The results of this study, in process flowing from paddy fields to the dam reservoir, both cyanobacteria biomass and 2-MIB concentration has been diluted in stages. Therefore, we concluded that the impact of cyanobacteria occurred in upstream basin may be very low on development of 2-MIB concentration in the dam reservoir.
