Screening of grasses and legumes for phytoremediation of nitroglycerin in soil
Six plant species were screened to determine potential suitability for phytoremediation of nitroglycerin (NG), a component in smokeless powders (SP). Seeds of Zea mays (corn), Triticum aestivum (wheat), Medicago sativa (alfalfa), Poa pratensis (Kentucky bluegrass), Trifolium pratense (red clover), and Phaseolus vulgaris (common bean) were sown into greenhouse mesocosms containing commercially prepared soil spiked with 0, 1, and 5% SP (w/w). Soil samples were collected 7, 60, and 90 days after seeding, extracted with ethanol, and analyzed for NG using a gas chromatograph with an electron capture detector. Plant growth observations were recorded using a simple scoring metric at 7, 14, 30, and 60 days after seeding. Soil nitrate and ammonium, potential by-products of NG decomposition, were quantified 90 days after seeding. NG disappearance in plant treatments was markedly, although not significantly (p > 0.05), higher than control at 1% SP, with legumes being the most successful treatment. Nitrate concentrations were significantly (p < 0.05) higher in legume than grass treatments. Soil ammonium was not correlated to any plant or SP treatment. Plant uptake of NG was minimal, suggesting a soil microbial effect in NG disappearance. More extensive screening studies are needed to determine which plants are the most successful remediators of NG.