Distribution and geochemical behaviour of anionic surfactants determined as ethyl violet active substances in Lake Biwa, Japan

摘要

The distribution and geochemical behaviour of anionic surfactants (AS) determined as ethyl violet active substances (EVAS) were studied in Lake Biwa, Japan. We determined the vertical distributions of dissolved EVAS (DEVAS), suspended particulate EVAS (PEVAS), particulate organic carbon (POC) and the PEVAS/POC ratio. Statistical analyses conducted using plots of PEVAS versus POC and PEVAS/ Chlorophyll-a (Chl-a) versus POC/Chl-a revealed that the distributions of DEVAS and PEVAS were affected by the concentrations of freshly produced POC and aged POC and by the pH of the lake water. Adsorption and desorption of EVAS onto the POC phase were found to be important mechanisms regulating the distribution and environmental/geochemical behaviour of EVAS in the lake. The organic carbon-normalized particle–water-partitioning coefficient, Koc, for EVAS was also estimated and compared with that for nonylphenol.