Evidence for Phytoremediation and Phytoexcretion of NTO from Industrial Wastewater by Vetiver Grass

Abstract

The use of insensitive munitions such as 3-nitro-1,2,4-triazol-5-one (NTO) is rapidly increasing and is expected to replace conventional munitions in the near future. Various NTO treatment technologies are being developed for the treatment of wastewater from industrial munition facilities. This is the first study to explore the potential phytoremediation of industrial NTO-wastewater using vetiver grass (Chrysopogon zizanioides L.). Here, we present evidence that vetiver can effectively remove NTO from wastewater, and also translocated NTO from root to shoot. NTO was phytotoxic and resulted in a loss of plant biomass and chlorophyll. The metabolomic analysis showed significant differences between treated and control samples, with the upregulation of specific pathways such as glycerophosphate metabolism and amino acid metabolism, providing a glimpse into the stress alleviation strategy of vetiver. One of the mechanisms of NTO stress reduction was the excretion of solid crystals. Scanning electron microscopy (SEM), electrospray ionization mass spectrometry (ESI-MS), and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of NTO crystals in the plant exudates. Further characterization of the exudates is in progress to ascertain the purity of these crystals, and if vetiver could be used for phytomining NTO from industrial wastewater.

Vetiver Grass (Chrysopogon zizanoides L.): A Hyper-Accumulator Crop for Bioremediation of Unconventional Water

“…It is reported that vetiver grass can effectively treat contaminants, such as organic matter, nutrients, heavy metals, as well as aromatic mixtures that are highly tolerant against extreme weather conditions (cold, hot, flood, and water shortage). According to the reports, vetiver has the capability of remediating toxic heavy-metal-polluted soil and water [92], herbicides [93], petroleum hydrocarbons (PHCs) [94], nuclear waste [95], acid mine drainage [96], textile dyes [97], ciprofloxacin (CIP), and tetracycline (TTC) [98], as well as 3-nitro-1,2,4-triazol-5-one (NTO) [99]. According to the unique characteristics reported for vetiver grass in the previous sections, several recent studies used this plant species to remove or decrease pollutants in unconventional water.…”

Evaluation of Phytoremediation Potential of Vetiver Grass (Chrysopogon zizanioides (L.) Roberty) for Wastewater Treatment

“…is is the first study to discover the potential plant treatment of industrial NTO wastewater using Vetiver grass (Chrysopogon zizanioides L.). e results showed that vetiver can effectively remove NTO from wastewater and also transfer NTO from the root to the stem [32,33].…”