河川における直鎖アルキルベンゼンスルホン酸塩（ＬＡＳ）の流出特性

Abstract

Runoff loadings of linear alkylbenzensulfonates (LAS) were observed weekly from June 1990 to May 1991 in eight inflowing rivers to Lake Kasumigaura.Annual maximums and means of LAS concentration ranged from 0.047mg·l-1 in a rural river to 1.45mg·l-1 in an urban river, and from 0.012mg·l-1 in the rural river to 0.472mg·l-1 in other urban river, respectively. Seasonal means of LAS concentrations became maximum in winter and minimum in spring or summer due to the biodegradation depended on water temperature during flowing-down. Because LAS loadings were influenced by flow, both maximums and minimums among their seasonal means of loadings were dispersed in three seasons. The loadings of LAS homologue with long alkyl chain length between 13 and 14 became less in rivers of bigger catchment areas, and the isomer loadings with external phenyl position became similar to that. Annual LAS loading per capita, ranged from 24 to 528g·y-1·cap.-1, showed almost log-log linear relationship to river catchment area. Annual runoff rate of LAS loading, ranged from 0.07 to 1.45, could be expressed as a function of logarithm of river catchment area. The annual loading per capita and its runoff rate were low level in large rural rivers and high in small urban rivers.