RESUMO
The sorption coefficients of estrone (E1), 17ß-estradiol (E2), and estriol (E3), 17α-ethinylestradiol (EE2), and diethylstilbestrol (DES) on four sediments (BS1-4) collected downstream of agricultural, domestic, and industrial discharges were determined. The objective was to investigate the effect of sediment origin on the sorption affinity of natural and synthetic estrogens on sediments. Experimental results indicate that the sediment samples from different origins had differing estrogen sorption affinities. Organic materials in sediment samples collected from downstream of agricultural and domestic discharge, i.e., BS1 and BS2, respectively, were readily biodegraded and biotransformed during sediment diagenesis, which enhanced the sorption capacity for estrogens. Sediment samples BS3 and BS4, which were obtained downstream of domestic and industrial discharges, respectively, may contain complex compositions, including hydrophilic substances that resulted in lower log K(oc) values. The estrogen sorption on sediments was reasonably regressive with linear models. The log K(oc) values for individual estrogens in individual sediments showed variation: 2.82-4.21 for E1; 2.73-4.14 for E2; 2.19-3.76 for E3; 3.24-3.94 for EE2; and, 4.07-5.25 for DES. Nevertheless, the relationship between log K(ow) and log K(oc) of individual estrogens in individual sediments was linear. The mean log K(oc) values for target estrogens followed the trend of DES (4.68) > EE2 (3.71) > E2 (3.52) > E1 (3.44) > E3 (2.99), corresponding to the trend of log K(ow) values. These analytical results suggest that sorption of estrogens on sediments varied with sample origin. Therefore, evaluations of the fate and transport of estrogens in river environments must consider surrounding agricultural, domestic, and industrial sources.
