Integrating phytoremediation into treatment of pulp and paper industry wastewater: field observations of native plants for the detoxification of metals and their potential as part of a multidisciplinary strategy

Abstract This work aimed to explore the use of native herbs for the removal of heavy metals from pulp and paper industry wastewater, with the view of applying them as part of a multidisciplinary approach for detoxification. Results showed that after in-situ phytoremediation by the native herbs, the heavy metal, and metalloid contents in the wastewater were reduced to almost 60%. Heavy metal analysis of the plant tissues revealed that Fe accumulation was highest in all the tested plants. The bioconcentration factor was higher than one for all the metals, i.e., Mn and Pb in Momordica doica (255.6-168.42) and Zn in Calotropis procera (398.35 mg kg-1). Elevated translocation factor (>10) was observed in Parthenium hysterophorus>Cannabis sativa>Calotropisprocera>Tribulus terrestris for Mn (10.40), As (11.34), Fe (18.65), and Cu (41.29 mg kg-1), respectively, indicating their hyperaccumulating tendency. Transmission electron microscope analysis of plant root tissue showed a high metal deposition in the root cell wall, cytoplasm, and vacuole as strong evidence of the in-situ phytoremediation capability of these plants. Antioxidants activity of plants such as superoxide dismutase, catalase, hydrogen peroxidase, peroxidase, and ascorbate peroxidase were also noted higher than control of selected plants. These results offer evidence to support the potential of using native plants as a novel green process to be integrated into the further treatment of hazardous industrial wastewater in the polluted sites.