増水時の河川における微量有機汚染物質の挙動

抄録

During a storm event (49mm/12hr), riverine suspended solid samples (Nogawa River) and street run-off samples were taken and analyzed for two micro organic pollutants, polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs). The former is mainly originated by combustion of fossil fuels and the later is supplied to rivers by domestic consumption of synthetic detergents. PAHs and LABs concentration in the river water was 10ng/l and 13ng/l before rising stage and 310ng/l and 210ng/l in rising stage, respectively. There were correlations between the flux of river water and the flux of PAHs and LABs. The total flux of PAHs and LABs during this storm event was 72 and 22 times greater than those for the normal river stage, indicating that vast amounts of pollutants are transported downstream by storm event. It is estimated that direct input of urban run-off waters and resuspended bottom sediments contribute to the increase in flux of PAHs at rising river stage. Although both contributions varied with time, the contribution of resuspended sediments to the total increase was predominant.