Ecotoxicological effects of triclosan on Lemna minor: bioconcentration, growth inhibition and oxidative stress.

Abstract

Triclosan (TCS), an emerging pollutant, is a notable contributor to adverse impacts on aquatic organisms due to its widespread use during COVID-19 and hydrophobic properties. There is extensive documented literature on TCS toxicity in commercially important fish species; however, studies on aquatic plants remain limited. In this prelude, the present study aims to evaluate the effect of TCS on Lemna minor, a commercially important aquatic plant species for 7days. The results showed dose-dependent significant alterations in growth, pigments and stress enzymes of L. minor at varied concentrations of TCS (1 to 8mg L-1). Median inhibitory concentration (IC50) was found to be 4.813mg L-1. Total chlorophyll and carotenoid levels decreased 73.11 and 81.83%, respectively after 7days of TCS exposure. A significant increase in catalase and superoxide dismutase activity was observed in TCS exposed groups as compared to the control. Bioconcentration factor was found to be in the range of 5.855 to 37.129 signifying TCS ability to accumulate and transfer through the food chain. Scanning electron microscopy (SEM) analysis showed deformation in the cell surface and alteration of stroma morphology of TCS exposed groups. Furthermore, the Fourier transform infrared spectroscopy (FTIR) study also revealed that higher concentrations of TCS could cause alteration in the functional groups in the plant. This study demonstrates that TCS negatively impacts the growth and metabolism of primary producers, offering crucial insights into its interactions with aquatic plants and establishing baseline information essential for crafting effective mitigation strategies for TCS contamination in aquatic environments.