Water hyacinth derived biochar for polycyclic aromatic hydrocarbons removal and oxidative stress study

Polycyclic aromatic hydrocarbons (PAHs), highly concerned emerging contaminant, are priority persistent organic pollutants (POPs) adversely affect the ecological health of marine sediments. These pollutants have attracted widespread attention because of their potential toxicological effects on aquatic organisms and subsequent threats to human health. In this study, an advanced oxidation process for the remediation of PAH-contaminated sediments was developed by the activation of calcium peroxide (CaO2; CP) using a green catalyst prepared from water hyacinth biochar (WHBC), and the associated biochar-driven cellular oxidative stress was highlighted. The catalytic capacity of WHBC was determined at pyrolysis temperature between 300 and 900 degrees C. WHBC prepared 700 degrees C (WHBC700) and CP removed 74% of PAHs from the sediment matrix. Results of antioxidant activity evaluation after exposure to WHBC at doses between 400-4000 and 1000-4000 mg L-1 in human hepatocarcinoma cell lines (HepG2) for 24 h showed en-hanced glutathione peroxidase (GPx) and catalase (CAT) activities, respectively. Increase in mRNA levels of superoxide dismutase (SOD) genes was also observed after WHBC exposure (400-4000 mg L-1), implying that the oxidative damage caused by reactive oxygen species (ROS) was inhibited by elevating the cellular antioxidant activity. This study attempted to demonstrate an effective waste-to-resource strategy for remediating PAH-polluted sediment in addition to understanding the potential environmental effects of antioxidant activity and gene expression of carbon-based catalysts on HepG2.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).