Assessment of Water Mimosa (Neptunia oleracea Lour.) Morphological, Physiological, and Removal Efficiency for Phytoremediation of Arsenic-Polluted Water.

Narges Atabaki,Rosimah Nulit,Rambod Abiri,Siti Aqlima Ahmad,Noor Azmi Shaharuddin

doi:10.3390/plants9111500

Abstract

Arsenic is considered to be a toxic and heavy metal that exists in drinking water and can lead to acute biotoxicity. Water mimosa (Neptunia oleracea) has been widely identified as a feasible phytoremediator to clean up aquatic systems. In the current study, the phytoremediation potential of water mimosa exposed to different concentrations of sodium heptahydrate arsenate (Na2HAsO4·7H2O) was tested. A number of plant physiological and growth responses such as height of frond, existence of green leaves, relative growth rate, relative water content, tolerance index, decrease in ratio of biomass and ratio of dry weight, chlorophyll content, photosynthesis rate, intercellular CO2 concentrations, stomatal conductance, air pressure deficit, transpiration rate, proline and lipid peroxidation, as well as arsenic accumulation and removal efficacy were analyzed. The micromorphological analysis results confirmed water mimosa’s tolerance of up to 30 ppm of arsenic treatment. The results obtained from the chlorophyll and gas exchange content also showed severe damage by arsenic at doses higher than 30 ppm. In addition, the highest arsenic accumulation and arsenic removal efficacy were observed at the range of 30–60 ppm. An analysis of proline and lipid peroxidation content confirmed water mimosa’s tolerance of up to 30 ppm of arsenic. The scanning electron microscopy (SEM) and X-ray spectroscopy (EDX) and analysis also confirmed the accumulation of arsenic as shown by the deformation of water mimosa tissues. The results showed that water mimosa is a reliable bioremediator for removing arsenic from aquatic systems.

Highlights

Environmental pollution is a phenomenon where air, water, and land become unsuitable or unsafe due to the existence of materials harmful towards living organisms [1,2]
The results indicated that plants treated with different concentrations of arsenic suffered a significant decline in transpiration rate as compared with the controls
A significant toxicity effect was obtained in the form of a 60% chlorophyll content loss after five days, even for initial arsenic concentrations. These results demonstrate the inactivation of the photosystem electron transport and a chloroplast membrane disorder due to arsenic treatments [68]

Summary

Introduction

Environmental pollution is a phenomenon where air, water, and land become unsuitable or unsafe due to the existence of materials harmful towards living organisms [1,2]. A toxic environment happens as a consequence of the release of heavy metal ions (even in small amounts) from mining, metallurgy, chemical manufacturing, and nuclear energy activities, bringing extreme threats to the Earth’s crust [5]. Arsenic is an extremely toxic metalloid that is carcinogenic predominantly to humans’ liver, lungs, kidney, and bladder. It can cause nerve damage and skin diseases [6]. This heavy metal is ubiquitous in the Earth’s crust with the potential effect of dietetic intake on human health in developed countries

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Results

Conclusion