title: Phytotoxicity of nitroaromatic energetic compounds freshly amended or weathered and aged in sandy loam soil.
abstract: The toxicities of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), and 2,6-dinitrotoluene (2,6-DNT) to terrestrial plants alfalfa (Medicago sativa L.), Japanese millet (Echinochloa crusgalli L.), and perennial ryegrass (Lolium perenne L.) were determined in Sassafras sandy loam soil using seedling emergence, fresh shoot, and dry mass measurement endpoints. A 13-week weathering and aging of energetic materials in soils, which included wetting and drying cycles, and exposure to sunlight of individual soil treatments, was incorporated into the study design to better reflect the soil exposure conditions in the field than toxicity determinations in freshly amended soils. Definitive toxicity tests showed that dinitrotoluenes were more phytotoxic for all plant species in freshly amended treatments based on EC20 values for dry shoot ranging from 3 to 24mgkg(-1) compared with values for TNB or TNT ranging from 43 to 62mgkg(-1). Weathering and aging of energetic materials (EMs) in soil significantly decreased the toxicity of TNT, TNB or 2,6-DNT to Japanese millet or ryegrass based on seedling emergence, but significantly increased the toxicity of all four EMs to all three plant species based on shoot growth. Exposure of the three plant species to relatively low concentrations of the four compounds initially stimulated plant growth before the onset of inhibition at greater concentrations (hormesis).
authors.affiliation: Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Que., Canada H4P 2R2.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rocheleau
authors.forename: Roman G
authors.initials: RG
authors.lastname: Kuperman
authors.forename: Majorie
authors.initials: M
authors.lastname: Martel
authors.forename: Louise
authors.initials: L
authors.lastname: Paquet
authors.forename: Ghalib
authors.initials: G
authors.lastname: Bardai
authors.forename: Stephen
authors.initials: S
authors.lastname: Wong
authors.forename: Manon
authors.initials: M
authors.lastname: Sarrazin
authors.forename: Sabine
authors.initials: S
authors.lastname: Dodard
authors.forename: Ping
authors.initials: P
authors.lastname: Gong
authors.forename: Jalal
authors.initials: J
authors.lastname: Hawari
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Checkai
authors.forename: Geoffrey I
authors.initials: GI
authors.lastname: Sunahara
mesh_terms: D001555:Benzene Derivatives / Q000032:analysis / Q000633:toxicity*; D031747:Echinochloa / Q000187:drug effects* / Q000254:growth & development; D008129:Lolium / Q000187:drug effects* / Q000254:growth & development; D000455:Medicago sativa / Q000187:drug effects* / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D012822:Silicon Dioxide; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013997:Time Factors; D014887:Weather
chemical_list: D001555:Benzene Derivatives; D012987:Soil; D012989:Soil Pollutants; D012822:Silicon Dioxide