Pistia Stratiotes based heavy metals phytoremediation of a Himalayan river impacted by hydroelectric plant in an Indo Burma hotspot region

ABSTRACT

Present study attempts to study the impact of Serlui-B hydroelectric dam on water quality (‘water-energy nexus’) of a Himalayan river and to devise possible phytotechnology for heavy metals remediation. Physico-chemical characteristics of water were analyzed using ‘American Public Health Association (APHA)’ methods while Atomic Absorption Spectrophotometer (AAS) was used for estimation of heavy metals. To this end, concentrations of Fe and Ni were recorded above permissible limit which can impose public health risks. Therefore, phytoremediation experiments were performed by using Pistia stratiotes L. (water lettuce) and effects of Fe and Ni concentrations (1.0, 2.0, and 5.0 mg/L) on photosynthetic pigments were observed. Phytoremediation investigations using 24 aquaria (of 40.5 L) revealed that P. stratiotes was an effective hyperaccumulator of Fe and Ni with maximum removal efficiency of 96.2% and 92%, respectively. In relation to bioaccumulation indices, the bioconcentration factor (BCF) values decreased with increase in Fe and Ni concentrations, whereas the translocation factor (TF) was noted higher at low concentrations and vice versa. Furthermore, the total chlorophyll content and carotenoid levels in P. stratiotes demonstrated negative significant correlation with the rise in Fe/Ni concentrations that may be considered as an adaptive biochemical strategy to mitigate metals induced oxidative stress. The present study can further be extrapolated to field phytoremediation for ameliorating both physico-chemical and metallic contaminants. Last, the role of microbial biodiversity associated with P. stratiotes should be elucidated in future to help achieve SDG 6 and environmental sustainability.

KEYWORDS:

• Pistia stratiotes
• phytoremediation
• heavy metals
• bioaccumulation indices
• health risks
• oxidative stress

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Authors are grateful to the Department of Science and Technology (DST)-Nexus project WTI: [Grant Number DST/TMD/EWO/WTI/2K19/EWFH/2019(C)] for financial assistance.

Notes on contributors

Prabhat Kumar Rai

Prabhat Kumar Rai is a professor in the department of environmental science, Mizoram University, Aizawl, North East India. He attempted to address heavy metals and particulate matter (PM) contamination in the environment. The Quest of eco-sustainable phyto-technologies (mediated through wetland plants, macrophytes and roadside plants of marginal/riparian land) for detoxifying environmental contamination was conducted by Prof. Rai in the Singrauli Industrial region and Loktak Lake in Manipur, NE India. Bio-magnetic monitoring of PM pollution was done in Aizawl (Mizoram, N.E. India) and Rourkela Steel plant (of Odisha) to assess their effects on biochemical parameters; thereby screening the tolerant plants for urban greenbelt development. Dr. Rai is a widely cited (ca 9,000 Google scholar citations with h-index 45) travelled (UK, USA, Belgium and China) researcher and continuously figuring (2020-23) in the list of top 2% global researchers of Scopus/Stanford. He is an elected fellow of the International Society of Environmental Botanists (FISEB) and a member of prestigious Indian Science Academies such as NASI (MNASc) and INSA (INYAS).

Emacaree S. Nongtri

Emacaree S. Nongtri worked as a research project scholar under the DST Nexus Research Project of Prof. P.K. Rai in the department of environmental science, Mizoram University.

Lalawmpuii

Lalwampuii worked as a research project scholar under the DST Nexus Research Project of Prof. P.K. Rai in the department of environmental science, Mizoram University.

Roger Bruce Syngkli

Roger Bruce Syngkli worked as a research project scholar under the DST Nexus Research Project of Prof. P.K. Rai in the department of environmental science, Mizoram University.