Assessment of acute and chronic toxicity of unweathered and weathered diluted bitumen to freshwater fish and invertebrates.

This paper presents the results of two different studies investigating the acute and chronic toxicity of two blends of diluted bitumens ("dilbit") and weathered dilbit on freshwater fish and invertebrates after exposure to different concentrations of physically-dispersed (water accommodated fraction; WAF) and chemically-dispersed (chemically-enhanced WAF; CEWAF). The first study evaluated the acute and chronic toxicity of weathered, unweathered and dispersed Access Western Blend (AWB) dilbit on Fathead minnow (Pimephales promelas). In the second study, acute and chronic toxicity of weathered and unweathered Cold Lake Blend (CLB) dilbit was assessed on Rainbow trout (Oncorhynchus mykiss), and two invertebrate species, Daphnia (Daphnia magna) and Ceriodaphnia (Ceriodaphnia dubia).

Immunotoxicity and genotoxicity of single-walled carbon nanotubes co-exposed with cadmium in the freshwater mussel, Elliptio complanata.

Potential immunotoxicity and genotoxicity of as-produced and purified single walled carbon nanotubes (SWCNT, 500 μg L-¹) with or without cadmium (20 μg L-¹) was investigated in hemocytes of the freshwater mussel, Elliptio complanata. Our results showed a decrease in hemocyte viability after 3, and 8 days of exposure and an increase of hemocyte phagocytic efficiency for organisms exposed to Cd. No modification of the cyclo-oxygenase (COX) activity was measured.

Bioavailability and chronic toxicity of bismuth citrate to earthworm Eisenia andrei exposed to natural sandy soil.

The present study describes bioavailability and chronic effects of bismuth to earthworms Eisenia andrei using OECD reproduction test. Adult earthworms were exposed to natural sandy soil contaminated artificially by bismuth citrate. Average total concentrations of bismuth in soil recovered by HNO digestion ranged from 75 to 289mg/kg.

Single-Walled Carbon Nanotubes Toxicity to the Freshwater Amphipod : Influence of to the Freshwater Amphipod Sediment and Exposure Duration.

Carbon nanomaterials are present in various industrial applications and therefore their release into the environment including freshwater ecosystem is expected to increase. The aim of the present study was to investigate the influence of several parameters on the toxicity of single-walled carbon nanotubes (SWCNT) to the freshwater amphipod, . The effect of period of exposure, sediment presence and possible impurities released during SWCNT preparation on survival and/or growth of such organism was evaluated.

Estimation of the bioaccumulation potential of a nonchlorinated bisphenol and an ionogenic xanthene dye to Eisenia andrei in field-collected soils, in conjunction with predictive in silico profiling.

In silico-based model predictions, originating from structural and mechanistic (e.g., transport, bioavailability, reactivity, and binding potential) profiling, were compared against laboratory-derived data to estimate the bioaccumulation potential in earthworms of 2 organic substances (1 neutral, 1 ionogenic) known to primarily partition to soil.

Ecotoxicity of xanthene dyes and a non-chlorinated bisphenol in soil.

Soil eco-toxicity testing was conducted in support of Canada's Chemical Management Plan (CMP) to fill data gaps for organic chemicals known to primarily partition to soil, and of which the persistence and inherent toxicity are uncertain. Two compounds representative of specific classes of chemicals: non-chlorinated bisphenols containing an -OH group (4,4'-methylenebis(2,6-di-tert-butylphenol (Binox)) and xanthene dyes (2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3',6'-dihydroxy-, disodium salt (Phloxine B), 2',4',5',7'-tetrabromofluorescein (TBF), 4',5'-dibromofluorescein (DBF), and 4,5,6,7-tetrachlorofluorescein (TCF)) were evaluated. The effect of these substances on plant growth (Elymus lanceolatus and Trifolium pratense) and soil invertebrate survival and reproduction (Folsomia candida and Eisenia andrei) were assessed using a field-collected sandy soil.

Integration of toxicological and chemical tools to assess the bioavailability of metals and energetic compounds in contaminated soils.

Bioavailability is critical for understanding effects that might result from exposure of biota to contaminated soils. Soils from military range and training areas (RTAs) are contaminated principally by energetic materials (EM) and metals. Their chemical characteristics are relatively well known and toxicity assessment of soils from RTAs are in some cases available.

Assessment of soil quality using bioaccessibility-based models and a biomarker index.

Bioavailability in heterogeneous media such as soils is a multi-factorial concept which ranges from soil chemistry to toxicity. The complexity of this factor has been tackled by various studies pinpointing its relevancy for laboratory to field extrapolation of toxicity data. As contaminant bioavailability on these sites is virtually unknown, a global assessment of this issue has been conducted on soils impacted by antitank firing from a Canadian Range and Training Area (RTA) and contaminated by energetic materials (EM) and metals.

Effects of HMX-lead mixtures on reproduction of the earthworm Eisenia andrei.

High metal (e.g., Pb) concentrations are typically found in explosive-contaminated soil, and their presence may increase, decrease, or not influence toxicity predicted on the basis of one explosive alone (e.

Photosynthetic parameters as indicators of trinitrotoluene (TNT) inhibitory effect: change in chlorophyll a fluorescence induction upon exposure of lactuca sativa to TNT.

Trinitrotoluene, as a compound of conventional explosive, may cause inhibitory effect on terrestrial plants. When Lactuca sativa was exposed to different concentrations of trinitrotoluene (32-1000 mg/kg), photosynthetic process was investigated by using rapid chlorophyll fluorescence kinetic and pulse modulated fluorometry. The decrease of chlorophyll a variable fluorescence was seen to be caused by the deactivation of photosystem II reaction centers.

Assessment of soil toxicity from an antitank firing range using Lumbricus terrestris and Eisenia andrei in mesocosms and laboratory studies.

Earthworm mesocosms studies were carried out on a explosives-contaminated site at an antitank firing range. Survival of earthworms and the lysosomal neutral red retention time (NRRT), a biomarker of lysosomal membrane stability, were used in these studies to assess the effect of explosives-contaminated soils on the earthworms Lumbricus terrestris and Eisenia andrei under field conditions. Toxicity of the soils samples for E.

Preliminary ecotoxicological characterization of a new energetic substance, CL-20.

A new energetic substance hexanitrohexaazaisowurtzitane (or CL-20) was tested for its toxicities to various ecological receptors. CL-20 (epsilon-polymorph) was amended to soil or deionized water to construct concentration gradients. Results of Microtox (15-min contact) and 96-h algae growth inhibition tests indicate that CL-20 showed no adverse effects on the bioluminescence of marine bacteria Vibrio fischeri and the cell density of freshwater green algae Selenastrum capricornutum respectively, up to its water solubility (ca.

Toxicity assessment of contaminated soils from an antitank firing range.

Explosives are released into the environment at production and processing facilities, as well as through field use. These compounds may be toxic at relatively low concentrations to a number of ecological receptors. A toxicity assessment was carried out on soils from an explosive-contaminated site at a Canadian Forces Area Training Center.

Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.

Monocyclic 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.

Phytotoxicity and bioaccumulation of copper and chromium using barley (Hordeum vulgare L.) in spiked artificial and natural forest soils.

The toxicities of two heavy metals, copper (Cu2+) and chromium (Cr6+), to barley (Hordeum vulgare L.) were evaluated using two types of substrates: artificial and natural forest soils. Phytotoxicity was assessed using a standardized toxicity test.

Immune response of earthworms (Lumbricus terrestris, Eisenia andrei and Aporrectodea tuberculata) following in situ soil exposure to atmospheric deposition from a cement factory.

In order to reduce their energy costs, many cement plants use fuel product substitutes (old tyres and used oil). The combustion of these products generates a metal increase (e.g.

Evaluation of tissue and cellular biomarkers to assess 2,4,6-trinitrotoluene (TNT) exposure in earthworms: effects-based assessment in laboratory studies using Eisenia andrei.

The lysosomal neutral red retention time (NRRT) assay, a biomarker for lysosomal membrane stability, and the total immune activity (TIA) assay, a measure of non-specific immune system activity, were used in laboratory studies to assess the toxic effects of 2,4,6-trinitrotoluene (TNT) on earthworms (Eisenia andrei) in vivo. The results were compared with the concentration of TNT and its metabolites in earthworm tissue, as well as standard sublethal toxicity endpoints including growth (i.e.