Laboratory experiments were carried out to study the effects of anionic surfactant sodium dodecylbenzenesulfonate (SDBS) on the uptake of pyrene by fish gills. The uptake (including adsorption) of pyrene by gills of the color carp (C. carpio var. color) exposed to 20-100 microg/L pyrene in the presence or absence of 0.2-6.0 mg/L SDBS were determined. The sorption of pyrene by mucus was preliminary studied using a four-step sequential extraction procedure. Fish gills were extracted with H(2)O, 0.01 M CaCl(2), CH(3)OH and a mixture of 1:1 n-C(6)H(14)/CH(2)Cl(2) in sequence. Results showed that SDBS significantly affected these accumulation or adsorption on the fish gills (not in gills). SDBS could affect the bioavailability of pyrene in aquatic systems.