At the end of phytoremediation, its validation by appropriate bioassay using suitable indicator species is pertinent. Very few works on validation of phytoremediation have been carried out to date (Vaseem and Banerjee, 2015). In India, where effluents are often used in irrigation water in the rice-paddy system, catfish (Clarias batrachus) can serve as an excellent indicator species (Lakra et al., 2019). Such types of efforts will not only establish and validate phytoremediation efforts but also test the suitability of rearing this catfish in semi-treated effluents.

Question

Centella asiatica (L) Urban, also known as pennywort, belonging to the family Apiaceae, is a perennial, medicinal herb of Asia that demonstrates neuroprotection and modulates mitochondrial and antioxidant pathways to improve cognition and possess wound healing properties (Prasad et al., 2017). Apart from its medicinal properties, C. asiatica has been reported to take up metals/metalloid from soil such as Cd (Li et al., 2018), Fe (Bhat et al., 2016), Ni (Madjos, 2018), Cu (Mokhtar et al., 2011), As (Tripathi et al., 2012), Zn, Cu and Pb (Manan et al., 2015). However, reports of simultaneous accumulation/removal of several metals from multi-metal concoctions are rare despite its ecological and toxicological relevance.

Therefore, the present study aims at (i) performing the phytoremediation trials on various concentrations of a multi-metal pulp and paper-mill effluent with C. asiatica to assess its metal accumulation and stress responses, (ii) assessing the effluent quality before and after phytoremediation trials, and (iii) performing bioassays with fish, C. batrachus to validate the success of phytoremediation.

Write the main points

Answer 1

1. Phytoremediation is a valuable method for cleaning up contaminants in soil and water.
2. Validation of phytoremediation through bioassays with indicator species is crucial.
3. Catfish species like Clarias batrachus can be used as indicator species in India for testing the effectiveness of phytoremediation efforts.
4. Centella asiatica, a medicinal herb, has been reported to take up various metals from soil and water.
5. The study aims to conduct phytoremediation trials using C. asiatica on a multi-metal pulp and paper-mill effluent.
6. The study will assess metal accumulation and stress responses in C. asiatica, as well as the quality of the effluent before and after phytoremediation.
7. Bioassays will be performed using Clarias batrachus to validate the success of the phytoremediation process.
8. The study is important for understanding the potential of C. asiatica in removing multiple metals from contaminated water bodies and its environmental implications.