Enrichment and toxic effects of triclosan on aquatic macrophytes Eichhornia crassipes and Hydrilla verticillata exposed to triclosan in sediments

Clarifying the enrichment and response processes of triclosan (TCS) in hydrophytes is crucial for assessing the ecological risk of TCS in aquatic environments. This study delves into the chronic toxic effects of TCS in floating plant Eichhornia crassipes (Mart.) Solms and submerged plant Hydrilla verticillata (L. f.) Royle exposed to TCS sediments through hydroponic experiments. The absorption abilities of hydrophytes to TCS were species-dependent. The concentration of TCS in the roots of E. crassipes was significantly higher than that in its leaves, while the absorption capacities of the leaves of H. verticillata to TCS were stronger than that in its roots. Furthermore, the physiological indexes, including chlorophyll concentration, soluble protein concentration, and antioxidant enzyme activities, showed a significant decrease with the exposure concentration and time of TCS. Although the chlorophyll and soluble protein concentrations and the antioxidant enzyme activities in the leaves were initially increased at a low concentration of TCS (at 7 days of exposure), they decreased significantly over time. Compared to the leaves, the physiological indexes of the roots were more sensitive to the ecotoxicological effects of TCS. The inhibition effects of TCS on H. verticillata were significantly higher than those on E. crassipes, which may be associated with the absorbing abilities of TCS and the growth characteristics of the plants. Pearson’s correlation analysis found a significant negative correlation between the TCS concentrations and the antioxidant enzyme activities in the plants. This study highlighted the differences in the uptake and enrichment process and toxic effects of TCS by different aquatic plants. Compared with E. crassipes, H. verticillata is more sensitive to TCS toxicity.