title: Phytotoxicity of 2,4,6-trinitrotoluene (TNT) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in spiked artificial and natural forest soils.
abstract: Toxicity of 2,4,6-trinitrotoluene (TNT) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) using two terrestrial plant species, lettuce (Lactuca sativa) and barley (Hordeum vugare), was assessed in artificial soil (silica) and forest soil. Lettuce emergence was significantly decreased after 5 days of exposure to TNT nominal spiked concentrations >/= 1,040 mg/kg dry soil in silica. Barley emergence was significantly reduced after 14 days of exposure at initial (t = 0) TNT concentrations >/= 55.9 +/- 4.5 mg/kg dry soil in silica and at >/= 291.9 +/- 42.8 mg/kg dry forest soil. Biomasses of shoot and roots of barley seeds were significantly reduced after 14 days of exposure at TNT initial exposure concentrations >/= 55.9 +/- 4.5 (LOEC) mg/kg dry soil in silica. Results were similar with the forest soil (LOEC = 91.4 +/- 7.9 mg TNT/kg dry soil) using the root growth parameter, but the shoot biomass was reduced only at concentrations >/= 291.9 +/- 42.8 mg TNT/kg dry soil. Plants were not affected by an HMX exposure up to 3,320 +/- 1,019 mg/kg dry soil using silica or 1,866 +/- 438 mg/kg dry soil using a forest soil. During the 14-day experiments, TNT was partially transformed in the spiked soil samples, as indicated by the presence of its amino metabolites (2-ADNT and 4-ADNT). Higher quantities of metabolites were detected in forest soils having higher initial TNT concentrations (</= 1,849.4 +/- 228.2 mg/kg) compared to silica (</= 239.3 +/- 88.0 mg TNT/kg). After 14 days, TNT concentrations in spiked silica and forest soil were reduced up to 80.5% at 55.9 +/- 4.5 mg/kg initial concentration and 94.4% at 91.4 +/- 7.9 mg/kg initial concentration, respectively. Data indicate that TNT is the probable phytotoxicant because it decreased plant emergence and growth in the presence and absence of the ADNT metabolites.
authors.affiliation: Applied Ecotoxicology Group, Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec, H4P 2R2 Canada. Pierre-Yves.Robidoux@nrc.ca
authors.forename: P Y
authors.initials: PY
authors.lastname: Robidoux
authors.forename: G
authors.initials: G
authors.lastname: Bardai
authors.forename: L
authors.initials: L
authors.lastname: Paquet
authors.forename: G
authors.initials: G
authors.lastname: Ampleman
authors.forename: S
authors.initials: S
authors.lastname: Thiboutot
authors.forename: J
authors.initials: J
authors.lastname: Hawari
authors.forename: G I
authors.initials: GI
authors.lastname: Sunahara
mesh_terms: D001392:Azocines / Q000633:toxicity*; D018533:Biomass; D006573:Heterocyclic Compounds, 1-Ring / Q000633:toxicity*; D001467:Hordeum / Q000254:growth & development; D018545:Lactuca / Q000254:growth & development; D018515:Plant Leaves / Q000254:growth & development; D018517:Plant Roots / Q000254:growth & development; D012822:Silicon Dioxide; D012989:Soil Pollutants / Q000633:toxicity*; D014197:Trees; D014303:Trinitrotoluene / Q000633:toxicity*
chemical_list: D001392:Azocines; D006573:Heterocyclic Compounds, 1-Ring; D012989:Soil Pollutants; D014303:Trinitrotoluene; D012822:Silicon Dioxide; C007950:octogen