- Ottawa, Ontario, Canada
Sabine Dodard
Concordia University (Canada), Science, Graduate Student
... Jalal Hawari, Vimal Balakrishnan, Ghalib Bardai, Bharat Bhushan, Sabine Dodard, Diane Fournier, Carl Groom, Annamaria Halasz, Fanny Monteil-Rivera, Pierre Yves Robidoux, Sylvie Rocheleau, Manon Sarrazin, Kathleen Savard, Geoffrey... more
... Jalal Hawari, Vimal Balakrishnan, Ghalib Bardai, Bharat Bhushan, Sabine Dodard, Diane Fournier, Carl Groom, Annamaria Halasz, Fanny Monteil-Rivera, Pierre Yves Robidoux, Sylvie Rocheleau, Manon Sarrazin, Kathleen Savard, Geoffrey Sunahara, Ph.D. Chemistry, PI ...
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Research Interests:
The high explosive nitroaromatic 2,4-dinitroanisole (DNAN) is less shock sensitive than 2,4,6-trinitrotoluene (TNT), and is proposed as a TNT replacement for melt-cast formulations. Before using DNAN in munitions and potentially leading... more
The high explosive nitroaromatic 2,4-dinitroanisole (DNAN) is less shock sensitive than 2,4,6-trinitrotoluene (TNT), and is proposed as a TNT replacement for melt-cast formulations. Before using DNAN in munitions and potentially leading to environmental impact, the present study examines the ecotoxicity of DNAN using selected organisms. In water, DNAN decreased green algae Pseudokirchneriella subcapitata growth (EC50 = 4.0mg/L), and bacteria Vibrio fischeri bioluminescence (Microtox, EC50 = 60.3mg/L). In soil, DNAN decreased perennial ryegrass Lolium perenne growth (EC50 =7 mg/kg), and is lethal to earthworms Eisenia andrei (LC50 = 47 mg/kg). At sub-lethal concentrations, DNAN caused an avoidance response (EC50 = 31 mg/kg) by earthworms. The presence of DNAN and 2-amino-4-nitroanisole in earthworms and plants suggested a role of these compounds in DNAN toxicity. Toxicity of DNAN was compared to TNT, tested under the same experimental conditions. These analyses showed that DNAN was equally, or even less deleterious to organism health than TNT, depending on the species and toxicity test. The present studies provide baseline toxicity data to increase the understanding of the environmental impact of DNAN, and assist science-based decision makers for improved management of potential DNAN contaminated sites.
Research Interests: Engineering, Ecotoxicology, Risk assessment, Toxicity, Animals, and 14 moreBioluminescence, Hazardous Materials, Ecotoxicity, Oligochaeta, Bioavailability, Environmental Impact, Dose Response Relationship, Oxidative phosphorylation, Biotransformation, Risk Assessment, Environmental Pollutants, Explosives, Fluid Balance, and Toxicity Test
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Research Interests:
We investigated individual toxicities of nitrogen-based energetic materials (EMs) 2,4-dinitrotoluene (2,4-DNT); 2-amino-4,6-dinitrotoluene (2-ADNT); 4-amino-2,6-dinitrotoluene (4-ADNT); and nitroglycerin (NG) on microbial activity in... more
We investigated individual toxicities of nitrogen-based energetic materials (EMs) 2,4-dinitrotoluene (2,4-DNT); 2-amino-4,6-dinitrotoluene (2-ADNT); 4-amino-2,6-dinitrotoluene (4-ADNT); and nitroglycerin (NG) on microbial activity in Sassafras sandy loam (SSL) soil, which has physicochemical characteristics that support "very high" qualitative relative bioavailability for organic chemicals. Batches of SSL soil for basal respiration (BR) and substrate-induced respiration (SIR) assays were separately amended with individual EMs or acetone carrier control. Total microbial biomass carbon (Biomass C) was determined from CO2 production increases after addition of 2500 mg/kg of glucose-water slurry to the soil. Exposure concentrations of each EM in soil were determined using U.S. EPA Method 8330A. BR was the most sensitive endpoint for assessing the effects of nitroaromatic EMs on microbial activity in SSL, whereas SIR and Biomass C were more sensitive endpoints for assessing the...
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AbstractMonocyclic nitramine explosives such as 1 3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic... more
AbstractMonocyclic nitramine explosives such as 1 3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (˜0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).
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Research Interests:
This study investigated the possibility that titanium dioxide nanoparticles (nano-TiO2) toxicity in Pseudokirchneriella subcapitata involves reactive oxygen species (ROS) production, using the dichlorodihydrofluorescein (DCF) assay. Algae... more
This study investigated the possibility that titanium dioxide nanoparticles (nano-TiO2) toxicity in Pseudokirchneriella subcapitata involves reactive oxygen species (ROS) production, using the dichlorodihydrofluorescein (DCF) assay. Algae were exposed to nano-TiO2 under laboratory fluorescent lamps supplemented with UV irradiation for 3h, with or without a UV filter. Results showed that nano-TiO2 increased ROS production in UV-exposed cells, with or without a UV filter (LOEC values were 250 and 10mg/L, respectively). Sublethal effects of nano-TiO2 on UV pre-exposed algae were also examined. Toxicity studies indicated that exposure to nano-TiO2 agglomerates decreased algal growth following 3h pre-exposure to UV, with or without a UV filter (EC50s were 8.7 and 6.3mg/L, respectively). The present study suggests that the growth inhibitory effects of nano-TiO2 in algae occurred at concentrations lower than those that can elevate DCF fluorescence, and that ROS generation is not directly in...
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CL-20 is an emerging munition compound that may replace RDX and HMX, but little information is available on its environmental fate and ecological impact. Therefore the present report first describes the development and validation of an... more
CL-20 is an emerging munition compound that may replace RDX and HMX, but little information is available on its environmental fate and ecological impact. Therefore the present report first describes the development and validation of an analytical method to analyze CL-20 in soil and water and the determination of key physicochemical parameters such as Kow (82.6), solubility (3.87 mg/L) and sorption/desorption parameters (Kd, Koc) of the chemical under various conditions of aging, T, and pH. CL-20 is found to sorb strongly onto the organic fraction of soils, and that sorption is reversible and governed by the type of organic matter. Degradation of CL-20 was determined in different soil/water systems and degradation products, reaction kinetics and stoichiometry were determined using LC/MS and [15N]-CL-20. We found that initial denitration caused by either Fe(0), light, hydrolysis, bacteria, fungi and enzymes lead to the decomposition of CL-20 to give nitrite, ammonia, nitrous oxide, gl...
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US Environmental Protection Agency is developing Ecological Soil Screening Level (Eco-SSL) values for ecological risk assessment of contaminants at Superfind sites. Insufficient information for RDX, HMX, 2,4-DNT, 2,6-DNT, and TNB to... more
US Environmental Protection Agency is developing Ecological Soil Screening Level (Eco-SSL) values for ecological risk assessment of contaminants at Superfind sites. Insufficient information for RDX, HMX, 2,4-DNT, 2,6-DNT, and TNB to generate Eco-SSLs ...
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Research Interests: Polymorphism, Ecotoxicology, Seed germination, Multidisciplinary, Toxicity, and 30 moreNitrification, Oxidoreductases, Bacteria, Statistical Significance, Bioluminescence, Nitrogen, Luminescence, Green Algae, Marine Bacteria, Soil Microbiology, Environmental Impact, Vibrio, Analysis of Variance, Gramineae, Water soluble polymers, Toxicity Tests, Growth Inhibition, Triazines, Soil Microorganism, Vibrio Fischeri, Acute Toxicity, Chlorophyta, Lolium Perenne L., Heterocyclic compounds, Toxicity Test, Soil Pollutants, Microbial community, Thallophyta, Medicago sativa, and Adverse effect
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Research Interests:
Research Interests:
Research Interests: Management, Decision Making, Natural Resources, Toxicology, Decomposition, and 26 moreRisk, Ecology, Strategy, Soil Pollution, Risk Analysis, Electromagnetic Radiation, Ecosystems, Ecological Risk Assessment, Knowledge Based Systems, Nitrogen, Soils, Environmental Assessment, Contamination, Habitats, Knowledge base, Microorganisms, Waste Treatment, Microbial Activity, Natural Resource, Litter Decomposition, Decontamination, Enzymatic Activity, Explosives, Hazardous Wastes, Environments, and Ecological Risk
Research Interests: Ecotoxicology, Carbon, Enzyme Inhibitors, Embryo, Biological Sciences, and 18 moreEnvironmental Sciences, In Vitro, Liver, Animals, Degradation, Japanese Quail, Enzyme, CHEMICAL SCIENCES, Time Factors, Biotransformation, Molecular Conformation, Glutathione Transferase, Rabbits, Amino Acid Sequence, Environmental Toxicology and Chemistry, Explosives, Heterocyclic compounds, and Molecular Sequence Data
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Research Interests:
Research Interests: Polymorphism, Ecotoxicology, Seed germination, Multidisciplinary, Toxicity, and 29 moreNitrification, Oxidoreductases, Bacteria, Statistical Significance, Bioluminescence, Nitrogen, Luminescence, Green Algae, Marine Bacteria, Soil Microbiology, Environmental Impact, Vibrio, Analysis of Variance, Gramineae, Water soluble polymers, Toxicity Tests, Growth Inhibition, Triazines, Soil Microorganism, Vibrio Fischeri, Acute Toxicity, Chlorophyta, Lolium Perenne L., Heterocyclic compounds, Toxicity Test, Soil Pollutants, Microbial community, Thallophyta, and Medicago sativa
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The acetonitrile-sonication extraction method (US EPA Method 8330) associated with aquatic-based toxicity tests was examined to study the ecotoxicity of energetic substances in soil. Three studies were carried out: (1) toxicological... more
The acetonitrile-sonication extraction method (US EPA Method 8330) associated with aquatic-based toxicity tests was examined to study the ecotoxicity of energetic substances in soil. Three studies were carried out: (1) toxicological characterization of different energetic substances to select a representative toxicant and to validate the choice of bioassays; (2) choice of an appropriate solvent to transfer acetonitrile extracts to the bioassay incubation media; and (3) optimization of Method 8330 using soil samples spiked with the toxicant. Initial studies indicated that pure 2,4,6-trinitrotoluene (TNT) was toxic to Vibrio fischeri [Microtox; IC50 (15 min) of 4.2 microM], whereas RDX was less toxic (IC20 = 181 microM) and HMX was not toxic up to its limit of water solubility (< 22 microM). Selected pure TNT metabolites were less toxic than TNT. Similar results were found using the 96-h Selenastrum capricornutum growth inhibition test. The toxicity of pure TNT in different solvents (acetonitrile, acetone, and DMSO) and that from Method 8330-extracted TNT-spiked soil samples were compared to TNT dissolved in water. Data indicated that DMSO was the most appropriate solvent to transfer the acetonitrile extracts. A modified Method 8330 may be used in conjunction with bioassays and chemical analyses to examine the ecotoxicity of soils contaminated with energetic substances.
Research Interests: Ecotoxicology, Environmental Monitoring, Environmental Sciences, Soil contamination, High Pressure Liquid Chromatography, and 12 moreCHEMICAL SCIENCES, Vibrio, Rodenticides, Water soluble polymers, Toxicity Tests, Extraction Method, Triazines, Acetone, Chlorophyta, Soil Pollutants, Toxicity Testing, and Solvents
Research Interests: Bioaccumulation, Environmental Monitoring, Biological Sciences, Environmental Sciences, Animals, and 10 moreOligochaeta, CHEMICAL SCIENCES, Time Factors, Toxicity Tests, Triazines, Environmental Toxicology and Chemistry, Explosives, Forensic Chemistry and Toxicology, Soil Pollutants, and Channel catfish
Nitroglycerin (NG) is widely used for the production of explosives and solid propellants, and is a soil contaminant of concern at some military training ranges. NG phytotoxicity data reported in the literature cannot be applied directly... more
Nitroglycerin (NG) is widely used for the production of explosives and solid propellants, and is a soil contaminant of concern at some military training ranges. NG phytotoxicity data reported in the literature cannot be applied directly to development of ecotoxicological benchmarks for plant exposures in soil because they were determined in studies using hydroponic media, cell cultures, and transgenic plants. Toxicities of NG in the present studies were evaluated for alfalfa (Medicago sativa), barnyard grass (Echinochloa crusgalli), and ryegrass (Lolium perenne) exposed to NG in Sassafras sandy loam soil. Uptake and degradation of NG were also evaluated in ryegrass. The median effective concentration values for shoot growth ranged from 40 to 231 mg kg(-1) in studies with NG freshly amended in soil, and from 23 to 185 mg kg(-1) in studies with NG weathered-and-aged in soil. Weathering-and-aging NG in soil did not significantly affect the toxicity based on 95% confidence intervals for either seedling emergence or plant growth endpoints. Uptake studies revealed that NG was not accumulated in ryegrass but was transformed into dinitroglycerin in the soil and roots, and was subsequently translocated into the ryegrass shoots. The highest bioconcentration factors for dinitroglycerin of 685 and 40 were determined for roots and shoots, respectively. Results of these studies will improve our understanding of toxicity and bioconcentration of NG in terrestrial plants and will contribute to ecological risk assessment of NG-contaminated sites.
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The effects of 2,4,6-trinitrotoluene (TNT) exposure in spiked artificial soil on the survival and reproduction rate of the white potworm Enchytraeus albidus were studied. Based on the initial concentrations, TNT in freshly spiked soil... more
The effects of 2,4,6-trinitrotoluene (TNT) exposure in spiked artificial soil on the survival and reproduction rate of the white potworm Enchytraeus albidus were studied. Based on the initial concentrations, TNT in freshly spiked soil decreased enchytraeid survival (21-day LC(50)=422+/-63 (SD)mg/kg, N=3) and fecundity (42-day EC(50)=111+/-34, N=4). Data also indicated that TNT was 5-10 times more lethal to juveniles than adults, and lethality was less pronounced in TNT-spiked soils aged for 21 days. A time-dependent decrease in the TNT concentrations, as well as a concomitant increase in the levels of 2- and 4-aminodinitrotoluene, was observed during the 42-day toxicity test. Taken together, TNT (or one of its metabolites) is more lethal to juvenile than adult enchytraeids. This effect may explain, at least in part, the ability of TNT to decrease fecundity as determined using the enchytraeid mortality-reproduction test.
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The acetonitrile-sonication extraction method (US EPA SW-846 Method 8330) and aquatic-based toxicity tests were used on laboratory and field samples, to characterize the ecotoxicity of soils contaminated with energetic substances. Spiked... more
The acetonitrile-sonication extraction method (US EPA SW-846 Method 8330) and aquatic-based toxicity tests were used on laboratory and field samples, to characterize the ecotoxicity of soils contaminated with energetic substances. Spiked soil studies indicated that 2,4, 6-trinitrotoluene (TNT)-dependent soil toxicity could be measured in organic extracts and aqueous leachates using the 15-min Microtox (Vibrio fischeri, IC50=0.27 to 0.94 mg TNT/liter incubation medium) and 96-h Selenastrum capricornutum growth inhibition (IC50=0.62 to 1. 14 mg/liter) toxicity tests. Analyses of leachates of composite soil samples [containing TNT and some TNT metabolites, 1,3,5-trinitro-1,3, 5-triazacyclohexane (RDX), and 1,3,5,7-tetranitro-1,3,5, 7-tetrazacyclooctane (HMX)] from an explosives manufacturing facility, indicated toxicities similar to those found in the TNT-spiked soil studies and pure TNT in solution, and suggested that TNT was the major toxicant. Using TNT as a model toxicant in soils having different moisture contents (20% vs dry) and textures (sandy vs clayey-sandy) but similar organic matter content (3-4%), multi-factorial analyses of Microtox test data revealed that these soil factors significantly influenced the TNT extractability from soil and subsequent toxicity measurements. Taken together, data indicate that the modified Method 8330 may be used in conjunction with ecotoxicity tests to reflect the toxic potential of soils contaminated with energetic substances.
Research Interests: Soil, Methodology, Ecotoxicology, Environmental Monitoring, Daphnia, and 28 moreSoil Pollution, Environmental Sciences, Toxicity, Soil contamination, Substance Use, Animals, Bacteria, Bioassay, Soils, Sol, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Ecosystem, Vibrio, Moisture Content, Leachate, Industrial Waste, Pollutant, Toxicity Tests, Extraction Method, Growth Inhibition, Cell Proliferation, Vibrio Fischeri, Organic Matter, Explosives, Soil Pollutants, Toxicity Testing, and Thallophyta
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The uptake of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from soil by the earthworm Eisenia andrei was examined by using the equilibrium partitioning (EqP) theory and a three-compartment model including soil (S), interstitial water... more
The uptake of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from soil by the earthworm Eisenia andrei was examined by using the equilibrium partitioning (EqP) theory and a three-compartment model including soil (S), interstitial water (IW), and earthworms (E). The RDX concentrations were measured using U.S. Environmental Protection Agency (U.S. EPA) Method 8330A and high-performance liquid chromatography (HPLC). The S-IW studies were conducted using four natural soils with contrasting physicochemical properties that were hypothesized to affect the bioavailability of RDX. Each soil was amended with nominal RDX concentrations ranging from 1 to 10,000 mg/kg. The HPLC analysis showed that the IW extracted from soil was saturated with RDX at 80 mg/kg or greater soil concentrations. The calculated S-IW coefficient (Kp) values for RDX ranged from 0.4 to 1.8 ml/g soil, depending on the soil type, and were influenced by the organic matter content. In the IW-E studies, earthworms were exposed to nonlethal RDX concentrations in aqueous media. The uptake of RDX by the earthworms correlated well (r2 = 0.99) with the dissolved RDX concentrations. For the E-S studies, earthworms were exposed to RDX-amended soils used in the S-IW studies. The bioconcentration factors (BCF; ratios of E-to-IW RDX concentrations) were relatively constant (∼5) up to 80 mg/kg soil RDX concentrations, which encompass the RDX saturation limit in the interstitial water of the tested soils. At this concentration range, the RDX uptake from interstitial water was likely dominated by passive diffusion and could be used as an indicator of bioavailability. Other mechanisms may be involved at greater RDX soil concentrations. Environ. Toxicol. Chem. 2010;29:998–1005. © 2009 SETAC