Phytoremediation of soil co-contaminated with heavy metals and TNT using four plant species

Abstract

We investigated the germination, growth rates and uptake of contaminants of four plant species, barnyard grass (Echinochloa crusgalli), sunflower (Helianthus annuus), Indian mallow (Abutilon avicennae) and Indian jointvetch (Aeschynomene indica), grown in soil contaminated with cadmium (Cd), lead (Pb) and 2,4,6-trinitrotoluene (TNT). These contaminants are typically found at shooting ranges. Experiments were carried out over 180 days using both single plant cultures and cultures containing an equal mix of the 4 plant species. Germination rates differed among the species in single culture (92% for H. annuus, 84% for E. crusgalli, 48% for A. avicennae and 38% Ae. indica). In the 4-plant mix culture, < 20% of seeds germinated for all 4 species. E. crusgalli and H. annuus grew slightly faster in the four-plant mix culture than in single culture, whereas A. avicennae and Ae. indica grew much slower in the 4-plant mix culture. In both single and 4-plant mix cultures, Cd concentrations in the roots of A. avicennae and E. crusgalliwere high, and Pb concentrations were high in A. avicennae and H. annuus. Cd and Pb concentrations in shoots were low to negligible in both treatment cultures for all species, except E. crusgalli in the 4-plant mix culture. The concentrations of TNT and its metabolites, 2-amino-4,6-dinitrotoluene (2ADNT) and 4-amino-2,6-dinitrotoluene (4ADNT) were high in H. annuus, Ae. indica and A. avicennae. Total Cd removal from soil differed among species, with E. crusgalliremoving the most (50.1%) followed by H. annuus(41.3%), Ae. indica(41.1%) and A. avicennae(33.3%). The four-plant mix removed more Cd (25.8%) than a no-plant control (12.9%). Pb removal was negligible for all plant species. All plant species rapidly removed TNT and its metabolites, regardless of whether the culture was single or mixed. From in these results, we conclude that a phytoremediation for the removal of heavy metals and TNT from contaminated soils should use a single plant species rather than a mixture of several plants.

Remediation of inorganic and organic contaminants in military ranges

“…Vetiver grass completely removed TNT from contaminated soil in the presence of urea (Das et al 2010). Similarly, four plant species (barnyard grass (Echinochloa crusgalli), sunflower (Helianthus annuus), Indian mallow (Abutilon avicennae) and Indian jointvetch (Aeschynomene indica)) effectively removed TNT and its reduction metabolites from soil irrespective of whether planted in single-or mixedspecies cultures (Lee et al 2007).…”

Phytoremediation as an Effective Remedy for Removing Trace Elements from Ecosystems

“…Their sources can be divided into natural and anthropogenic [2,18]. TEs can come from two sources-natural (products of bedrock weathering, volcanic eruptions, ocean evaporation, forest fires) and anthropogenic (mining, metallurgy, municipal and household waste, sewage discharges, industrial and commercial activities, oil industry, warfare, nuclear power plants, use of agrochemicals, active and inactive military zones-weapons testing, bomb disposal, shooting exercises) [9,11,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Effect of cadmium supply levels to cadmium accumulation by Salix

“…Traditional remediation technologies of soils contaminated with toxic metals are generally too costly, and often result in decoration of soil properties (Meers et al, 2004). The potential use of trees as a suitable vegetation cover for heavy metalcontaminated land, with their lower cost and environmental friendly nature, has attracted increasing attentions (Lee et al, 2007;Perez-Sirvent et al, 2008). Most of studies on phytoremediation have mainly focused on metal hyperaccumulating plants (Blaylock and Huang, 2000;Nouri et al, 2009).…”