Evaluation of genotoxicity and physicochemical variations of Eichhornia crassipes (Mart.) Solms exposed to paper-mill-contaminated wastewater

Abstract

The pulp and paper industry is a major global concern, as it consumes vast amounts of water during various stages of paper production and may discharge toxic effluents into the environment. This study aimed to determine the impact of pulp and paper mill effluents on Eichhornia crassipes (Mart.) Solms—a free-floating, invasive hydrophyte famous for its phytoremediation potential and grows extensively in wastewater—by assessing its morphological, physicochemical, and genomic deterioration. Wastewater analysis showed higher values of electrical conductivity (EC) (1.8 ± 0.69 S m⁻¹), turbidity (332.9 ± 45.18 NTU), salinity (0.85 ± 0.39 ppt), and total dissolved solids (TDS) (1.14 ± 0.39 g L⁻¹) as compared to the control sample. Morphological characters such as root length (7.19 ± 1.19 cm), leaves per plant (6.60 ± 1.53), and leaf area (627.75 ± 28.03 mm²) were reduced as compared to the control sample. Biochemical parameters like relative water content (RWC) (50%), total chlorophyll content (TCH) (0.41 mg g⁻¹), and pH (6.12) were reduced and increased the ascorbic acid content (AA) (26.08 mg g⁻¹) compared to control. The modified cetyltrimethylammonium bromide (CTAB) method was used to extract genomic DNA, and DNA damage was detected by comet assay. Genomic analysis revealed that wastewater caused significant DNA damage, as evidenced by increased comet tail intensity. The highest breaking frequency was observed in tail percentage DNA and tail moment, reaching 48.2% and 17.35 µm, respectively. These results indicate that pulp and paper mill effluents impact the morphological traits and biochemical processes of E. crassipes and cause genotoxicity, highlighting the urgent need to develop effective wastewater remediation strategies.