Water depth alters the fate of estrone across the sediment–water interface in a typical inland lake

Abstract

Water depth variation alters lake sediment environments, affecting the exchange of oxygen, trace elements, and nutrients at the sediment–water interface (SWI). However, there is still limited information on the in-situ fate of refractory emerging pollutants such as estrogenic compounds (ECs) at the SWI of different water depths in lakes. In this study, we integrated active sampling and diffusive gradients in thin film (DGT) technology to in-situ investigate the distribution, diffusion, and microbial responses of estrone (E1) at the SWI from the shallow-water zone (SZ), transition-water zone (TZ), and deep-water zone (DZ) in a typical inland lake of northern China. The surface sediment of the DZ accumulated most E1 (479.57 ± 194.90 ng/kg). In the vertical profile of the sediments, for SZ and TZ, E1 concentration in the sediment, porewater, and DGT fluctuated within a certain concentration range with increasing sediment depth. For the DZ, it exhibited a fluctuating and increasing trend with increasing depth. Dynamic migration analysis of E1 indicated partial resupply in each zone, and the resupply parameter R was 0.102 to 0.416 in the SZ, 0.111 to 0.384 in the TZ, and 0.084 to 0.374 in the DZ, respectively. The resupply capacity in the upper sediment layers (−1 to −4 cm) was higher for the TZ and DZ, whereas the SZ showed higher capacity in the lower layers (−5 to −9 cm). Based on the microbial sequencing results, Sulfuricurvum (typically present in microaerophilic and anoxic conditions) was predominant in the DZ (17.99 ± 15.4 %). Achromobacter (typical E1-degrading genus distributed in oxic environments) was more abundant in the SZ, which led to a higher E1 degradation potential in this zone. The results of this study shed light on the fate of E1 in the SWI of lakes at different water depths, facilitating a more precise control of estrogenic pollution in lake sediments.