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Individual effects 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), nitroglycerin (NG), and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) on litter decomposition, an essential biologically-mediated soil process, were assessed using Orchard grass (Dactylis glomerata) straw in Sassafras sandy loam (SSL) soil, which has physicochemical characteristics that support “very high” qualitative relative bioavailability for organic chemicals. Batches of SSL soil were separately amended with individual EMs or acetone carrier control. To quantify the decomposition rates, one straw cluster was harvested from a set of randomly selected replicate containers from within each treatment, after 1, 2, 3, 4, 6, and 8 months of exposure. Results showed that soil amended with 2,4-DNT or NG inhibited litter decomposition rates based on the median effective concentration (EC50) values of 1122 mg/kg and 860 mg/kg, respectively. Exposure to 2-ADNT, 4-ADNT or CL-20 amended soil did not significantly affect litter decomposition in SSL soil at ≥ 10,000 mg/kg. These ecotoxicological data will be helpful in identifying concentrations of EMs in soil that present an acceptable ecological risk for biologically-mediated soil processes.

We investigated the toxicity of selenium (Se) to the soil invertebrates Folsomia candida (Collembola) and Enchytraeus crypticus (potworm). Studies were designed to generate ecotoxicological benchmarks for developing ecological soil screening levels (Eco-SSLs) for risk assessments of contaminated soils. For the present studies, we selected Sassafras sandy loam, an aerobic upland soil with soil characteristics (low levels of clay and organic matter, soil pH adjusted from 5.2 to 7.1) that support high relative bioavailability of the anionic Se species that is typically found in aerobic soil. The Se was amended into soil as sodium selenate, subjected to weathering and aging using 21 d of alternating cycles of air-drying/rehydration to 60% of the water-holding capacity of the Sassafras sandy loam soil, under ambient greenhouse conditions. Effective concentrations at 20 and 50% (EC20 and EC50) levels for production of juveniles (reproduction) were 4.7 and 10.9 mg of Se/kg of soil (dry mass basis), respectively, for Collembola, and 4.4 and 6.2 mg/kg, respectively, for the potworms. The data enabled the derivation of toxicity benchmarks, contributing to the development of a soil invertebrate-based Eco-SSL of 4.1 mg/kg for Se. Environ Toxicol Chem 2018;37:846-853. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

We investigated the bioconcentration potential of nitrogen-based compounds 4-nitroanisole (4-NAN), 3,5-dinitro-o-toluamide (3,5-DNoTAME), and 2-methoxy-5 nitropyridine (2-M-5-NPYNE) using earthworm Eisenia andrei exposures in aqueous exposure media in sand. Separate toxicity studies were conducted prior to bioconcentration studies using a range of chemical concentrations to establish the sublethal exposure conditions for the earthworms. The objectives of the present studies were to: (1) develop an experimental test system for estimating bioconcentration potentials of new and emerging munition compounds that partition into earthworms, using aqueous exposure media; and (2) apply this experimental model to establish original bioconcentration data for 4-NAN, 3,5-DNoTAME, and 2-M-5-NPYNE. Experimental design includes earthworm exposures to chemicals for up to 14 days in aqueous media (Römbke medium; 0.08 mM KCl, 2 mM CaCl₂, 0.5 mM MgSO₄, and 0.8 mM NaHCO₃) in the presence of water-washed coarse sand (0.5–1.0 mm) substrate. Concentrations of test chemicals in respective exposure media remained relatively stable during these independent studies. Tissue analyses revealed a rapid uptake of each chemical by the earthworms; a steady state was attained within 24 h from commencement of these exposures. Estimated steady-state bioconcentration factors (BCFss; mL/g dry tissue) were 47, 6, and 11 for 4-NAN, 3,5-DNoTAME, and 2-M-5-NPYNE, respectively. These results will contribute to the BCF database being developed for use in models aimed at predicting environmentally significant parameters for new munition compounds in soil., The 10th International Symposium on Earthworm Ecology (ISEE-10), June 22-27, 2014, Athens, Georgia, USA

We investigated the toxicity of selenium (Se) to the soil invertebrates Folsomia candida (Collembola) and Enchytraeus crypticus (potworm). Studies were designed to generate ecotoxicological benchmarks for developing ecological soil screening levels (Eco-SSLs) for risk assessments of contaminated soils. For the present studies, we selected Sassafras sandy loam, an aerobic upland soil with soil characteristics (low levels of clay and organic matter, soil pH adjusted from 5.2 to 7.1) that support high relative bioavailability of the anionic Se species that is typically found in aerobic soil. The Se was amended into soil as sodium selenate, subjected to weathering and aging using 21 d of alternating cycles of air-drying/rehydration to 60% of the water-holding capacity of the Sassafras sandy loam soil, under ambient greenhouse conditions. Effective concentrations at 20 and 50% (EC20 and EC50) levels for production of juveniles (reproduction) were 4.7 and 10.9 mg of Se/kg of soil (dry mass basis), respectively, for Collembola, and 4.4 and 6.2 mg/kg, respectively, for the potworms. The data enabled the derivation of toxicity benchmarks, contributing to the development of a soil invertebrate-based Eco-SSL of 4.1 mg/kg for Se. Environ Toxicol Chem 2018;37:846-853. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

We investigated individual toxicities of the 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 CO

We investigated the effects of nitramine explosive CL-20 (China Lake compound 20) on the indigenous soil invertebrate community in Sassafras sandy loam (SSL) soil using a 12-week soil microcosm assay. Freshly collected SSL soil was amended with CL-20 to prepare multiple treatment concentrations ranging from 0 (acetone control) to 10,300 mg kg−1. The selected concentration range of CL-20 adequately assessed the concentration–response relationships for total microarthropods, and for individual microarthropod groups. The overall composition of microarthropod community in SSL soil was not affected by exposure to CL-20, based on the number of taxonomic groups present in the individual treatments after 12 weeks. However, community structure analysis revealed greater sensitivity to CL-20 by predatory mesostigmatid mites. Microarthropod and nematode communities showed contrasting sensitivities to CL-20 in SSL soil. Total numbers of nematodes were either unaffected or significantly (p

In separate, replicated experiments, we experimentally established wash-off coefficients (kw) for the chemical agent VX on grass, utilizing 1 and 3 L VX droplets at 0.017 (1 min), 1, and 4 h after dissemination. A 10 mm (0.39 in.) rain event at 0.017 h after dissemination washed off 95 and 83% of the 1 and 3 L VX droplets, respectively. At 1 h after dissemination, a 10 mm rain event washed off 0.03 and 0.5% of the 1 and 3 L VX droplets, respectively. At 0.017 h after dissemination, the kw values for 1 and 3 L droplets were 0.095 and 0.083 mm1, respectively. At 1 and 4 h after dissemination, the kw values for VX were approximately 3 orders of magnitude less than those at 0.017 h. Grass contaminated with 3 L VX droplets was exposed to multiple (10) 100 L light rain events, followed by multiple (10) surface wipes at 0.017, 0.5, 1, 4, and 24 h after dissemination. The cumulative proportions of 3 L VX droplets washed off by the rain events at 0.017 and 1 h after dissemination were 75.3 and 0.99%, respectively, and the cumulative proportions of VX wiped off after those rain events were 0.8 and 0.3%, respectively. Results from these investigations of agentplant interactions provide input for predictive models and functional information for Go/No-Go decisions that can affect soldiers on agent-contaminated battlefields.

A method was developed for maintaining healthy plants in a chemical surety hood and for disseminating, observing, and evaluating VX [O-ethyl-S-(2-diisopropylaminoethyl) methyl phosphonothioate] droplet spread, absorption, and appearance on leaves. In separate experiments, 1 or 3 microL droplets were dispensed onto plant leaves using a high-precision syringe. Digital photographs of the droplets were taken at intervals, saved, and analyzed. Each image was electronically traced and converted to surface area (SA) using Image-Pro Insight software (Media Cybernetics; Rockville, MD). Droplets on foliage initially appeared as transparent areas and spread with time. After 1 h, the 1 and 3 microL droplets ceased to spread, the VX appeared fully absorbed into leaf tissue, and the leaf tissue within the spread area appeared dry and darkened. After 24 h, the affected leaf tissue appeared light tan and necrotic. Mean SAs of the affected tissues for 1 microL droplets were 132, 192, 163, 135, and 142 mm2 at 0.017, 0.05, 1, 4, and 24 h, respectively, and those for 3 microL droplets were 166, 301, 303, 278, and 274 mm2 at 0.05, 1, 4, 24, and 48 h, respectively. Using these results can accelerate field identification and characterization of VX to more effectively protect Warfighters.

The presence of energetic materials (used as explosives and propellants) at contaminated sites is a growing international issue, particularly with respect to military base closures and demilitarization policies. Improved understanding of the ecotoxicological effects of these materials is needed in order to accurately assess the potential exposure risks and impacts on the environment and its ecosystems. We studied the toxicity of the nitroaromatic energetic material 2,4-dinitrotoluene (2,4-DNT) on alfalfa (Medicago sativa L.), barnyard grass (Echinochloa crusgalli L. Beauv.), and perennial ryegrass (Lolium perenne L.) using four natural soils varying in properties (organic matter, clay content, and pH) that were hypothesized to affect chemical bioavailability and toxicity. Amended soils were subjected to natural light conditions, and wetting and drying cycles in a greenhouse for 13 weeks prior to toxicity testing to approximate field exposure conditions in terms of bioavailability, transformation, and degradation of 2,4-DNT. Definitive toxicity tests were performed according to standard protocols. The median effective concentration (EC50) values for shoot dry mass ranged from 8 to 229 mg kg- 1, depending on the plant species and soil type. Data indicated that 2,4-DNT was most toxic in the Sassafras (SSL) and Teller (TSL) sandy loam soils, with EC50 values for shoot dry mass ranging between 8 to 44 mg kg- 1, and least toxic in the Webster clay loam soil, with EC50 values for shoot dry mass ranging between 40 to 229 mg kg- 1. The toxicity of 2,4-DNT for each of the plant species was significantly (p ? 0.05) and inversely correlated with the soil organic matter content. Toxicity benchmark values determined in the present studies for 2,4-DNT weathered-and-aged in SSL or TSL soils will contribute to development of an Ecological Soil Screening Level for terrestrial plants that can be used for ecological risk assessment at contaminated sites. Crown Copyright © 2010.

Summary A microcosm technique was used to determine the ecotoxicity of the chemical warfare agent HD (mustard) to the indigenous soil microinvertebrate communities. HD was thoroughly incorporated into Sassafras sandy loam (SSL) soil (4.9% OM) and an oak-beech forest silt loam soil (FS, 16% OM) at nominal HD concentrations ranging from 6 to 1076 mg kg−1. After a 7-day incubation period, microarthropods were extracted from soils using a high-gradient extractor and sorted to Acari suborders Prostigmata, Mesostigmata, and Oribatida, and the insect order Collembola. Nematodes were extracted using Baermann funnels and were sorted into bacterivore, herbivore, fungivore and omnivore/predator trophic groups. Microarthropods were more sensitive to HD in both soil types compared with nematodes. The EC50 values for total numbers of microarthropods in SSL and FS were similar (65 and 71 mg kg−1, respectively). The EC50 values for total numbers of nematodes were 130 and 235 mg kg−1, respectively. Toxicity of HD to nematodes was significantly greater in SSL soil compared to FS, based on 95% confidence intervals. Results show that community-level assessment of chemical toxicity in soil using a microcosm assay is sufficiently robust and can provide the means for validating the ecotoxicity data from standardized laboratory single-species toxicity tests.

Assessments of chemical toxicity to soil invertebrates have been traditionally performed in formulated Standard Artificial Soil, or in standard LUFA 2.2 natural soil. Physical and chemical properties of these standard soils often do not represent the diversity of properties of natural soils and can be inadequate surrogates of exposure conditions of soil biota in the field. We investigated performance of three species of the genus Enchytraeus (E. albidus, E. crypticus, E. luxuriosus) using soil types covering a wide range of European and North American soil properties. Results showed that adult survival and juvenile production by E. albidus and E. luxuriosus were inhibited in acidic soils with pH ≤ 5, while less acidic soils having properties within following ranges: 2.5-8.0% OM, 6-26% clay, and 4-80% sand, could sustain survival and reproduction at or near validity criteria levels of enchytraeid toxicity test ISO/16387. Performance of E. crypticus in North American soils having properties within following ranges: 1.2-42% OM, 1-29% clay, and 4.4-8.2 pH, met or exceeded all validity criteria. Data established in our studies can be used for amending the validity criteria of current ISO/16387 when used with E. crypticus and OECD soil. Published by Elsevier Masson SAS.

The U.S. Environmental Protection Agency is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites. Eco-SSLs are developed from published values whenever sufficient quantity and quality of data exist. Because insufficient information was available to generate an Eco-SSL for Mn, standardized toxicity testing was undertaken to fill the data gaps. Tests included the earthworm (Eisenia fetida) cocoon production test, the enchytraeid (Enchytraeus crypticus) reproduction test, and the collembolan (Folsomia candida) reproduction test, all conducted in Sassafras sandy loam soil that supports a relatively high bioavailability of metals. Weathering and aging of manganese-amended soil were carried out to more closely simulate exposure effects at Superfund sites on soil invertebrates. Data were analyzed by nonlinear regression to determine EC20 and EC50 values based on concentration-response relationships. The toxicity order for manganese in Sassafras sandy loam was E. crypticus>E. fetida>F. candida, with EC20 values of 116, 629, and 1209 mg kg(-1), respectively. The Eco-SSL requirement for the testing of multiple representative species is well justified. All study results will be submitted to the Eco-SSL Task Group for quality control review prior to inclusion in the Eco-SSL database.

Summary Proteins are known to respond rapidly when an organism is exposed to a toxicant and this response is consistent and unique to the xenobiotics. Induced and repressed proteins together create a specific signature that can be used to identify a toxic agent and its concentration in the environmental matrix. The resulting protein expression signature for each agent will include a small number of the most potent proteins, which can be used to detect the presence and determine the concentration of a toxicant. We exposed the earthworm Eisenia fetida to a range of concentrations of chemical warfare agents (CWA) HD (mustard) and VX (nerve agent) in a natural sandy loam soil. Results demonstrated specificity of protein signatures in response to HD and VX exposure in soil. This study also showed that protein patterns were specific for different concentrations of HD or VX in otherwise clean agent-amended soil. Several proteins were induced in all HD or VX concentrations tested suggesting the potential of identifying the key proteins for use in detection of HD or VX presence in soil regardless of their concentrations. The robustness of the proteome-based response to chemical exposure by soil biota needs to be further investigated by including determinations of protein patterns for chemicals in different soil types and in the presence of additional chemical stressors using variety of soil invertebrate models.

Munitions manufacturing, disposal, testing, training and other operations at military sites have produced elevated levels of explosives and related materials in soil. Insufficient data were available on the toxicity of the explosives, RDX and HMX to soil invertebrates, necessitating toxicity testing. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a sandy loam soil that supports relatively high bioavailability of test compounds. Earthworm (Eisenia fetida) toxicity was assessed using a standardized earthworm reproduction test in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival. Cocoon production EC20 values for RDX were 1.2 and 19 mg kg-1 in freshly amended and weathered/aged soils, respectively. Juvenile production EC20 values were 1.6 and 4.8 mg kg-1 in freshly amended and weathered/aged soils, respectively. Cocoon production and juvenile production EC20 values for HMX were 2.7 and 0.4 mg kg-1 in freshly amended soil. Both cocoon production and juvenile production in weathered/aged HMX treated soils were not significantly different (p > 0.05) from control soils. Results of these toxicity studies will be submitted to the Eco-SSL Task Group and will be included in the Eco-SSL database for Eco-SSL derivation.Munitions manufacturing, disposal, testing, training and other operations at military sites have produced elevated levels of explosives and related materials in soil. Insufficient data were available on the toxicity of the explosives, RDX and HMX to soil invertebrates, necessitating toxicity testing. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a sandy loam soil that supports relatively high bioavailability of test compounds. Earthworm (Eisenia fetida) toxicity was assessed using a standardized earthworm reproduction test in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival. Cocoon production EC20 values for RDX were 1.2 and 19 mg kg-1 in freshly amended and weathered/aged soils, respectively. Juvenile production EC20 values were 1.6 and 4.8 mg kg-1 in freshly amended and weathered/aged soils, respectively. Cocoon production and juvenile production EC20 values for HMX were 2.7 and 0.4 mg kg-1 in freshly amended soil. Both cocoon production and juvenile production in weathered/aged HMX treated soils were not significantly different (p > 0.05) from control soils. Results of these toxicity studies will be submitted to the Eco-SSL Task Group and will be included in the Eco-SSL database for Eco-SSL derivation.

Summary Munition manufacturing, disposal, testing, training and other operations at military sites produced elevated levels of explosives and related materials in soil. The effects of these persistent and highly mobile in the environment energetic materials on soil biota have not been sufficiently investigated. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a Baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Insufficient data were available on the toxicity of energetic compounds, RDX and HMX, to soil invertebrates, necessitating toxicity testing. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a Sassafras sandy loam soil that supports relatively high bioavailability of test compounds. Toxicity testing was performed using enchytraeid reproduction test (ISO/16387 2001) measuring adult survival and juvenile production by the potworm Enchytraeus crypticus in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival in the definitive tests in all treatment concentrations. Juvenile production EC 20 values were 3,715 and 8,797 mg kg –1 RDX in freshly amended and weathered/aged amended soils, respectively. Juvenile E. crypticus production was not adversely affected by exposure to HMX in freshly amended and weathered/aged amended soils. Juvenile production was stimulated in freshly amended soil up to 21,750 mg kg –1 HMX. Results of these toxicity studies will be submitted to the Eco-SSL Task Group for quality control review, and pending approval will be included in the Eco-SSL database for Eco-SSL derivation.

Proteins are known to respond rapidly when an organism is exposed to a toxicant and this response is consistent and unique to the xenobiotics. Induced and repressed proteins together create a specific signature that can be used to identify a toxic agent and its concentration in the environmental matrix. The resulting protein expression signature for each agent will include a small number of the most potent proteins, which can be used to detect the presence and determine the concentration of a toxicant.We exposed the earthworm Eisenia fetida to a range of concentrations of chemical warfare agents (CWA) HD (mustard) and VX (nerve agent) in a natural sandy loam soil. Results demonstrated specificity of protein signatures in response to HD and VX exposure in soil. This study also showed that protein patterns were specific for different concentrations of HD or VX in otherwise clean agent-amended soil. Several proteins were induced in all HD or VX concentrations tested suggesting the potential of identifying the key proteins for use in detection of HD orVX presence in soil regardless of their concentrations. The robustness of the proteome-based response to chemical exposure by soil biota needs to be further investigated by including determinations of protein patterns for chemicals in different soil types and in the presence of additional chemical stressors using variety of soil invertebrate models.

Summary Munitions manufacturing, disposal, testing, training and other operations at military sites have produced elevated levels of explosives and related materials in soil. Insufficient data were available on the toxicity of the explosives, RDX and HMX to soil invertebrates, necessitating toxicity testing. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a sandy loam soil that supports relatively high bioavailability of test compounds. Earthworm (Eisenia fetida) toxicity was assessed using a standardized earthworm reproduction test in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival. Cocoon production EC20 values for RDX were 1.2 and 19 mg kg–1 in freshly amended and weathered/aged soils, respectively. Juvenile production EC20 values were 1.6 and 4.8 mg kg–1 in freshly amended and weathered/aged soils, respectively. Cocoon production and juvenile production EC20 values for HMX were 2.7 and 0.4 mg kg–1 in freshly amended soil. Both cocoon production and juvenile production in weathered/aged HMX treated soils were not significantly different (p > 0.05) from control soils. Results of these toxicity studies will be submitted to the Eco-SSL Task Group and will be included in the Eco-SSL database for Eco-SSL derivation.

We investigated the ecotoxicity of the chemical-warfare agent (CWA) HD (Mustard) using Collembola reproduction test with numbers of adults and juveniles as measurement endpoints. Toxicity tests were conducted using soils with contrasting parameters to investigate the effects of soil properties on chemical toxicity. These included standard artificial soil (SAS; 10% OM; 6 pH), O’Neill-Hall sandy loam (OHSL; natural soil with 4.3% OM; 5.1 pH), and Sassafras sandy loam (SSL; natural soil with 2% OM; 4.9 pH). Soils were individually spiked with HD concentrations ranging from 1 to 125 mg kg –1 . Lowest observed effect concentrations (LOECs) for adult mortality were 25, 50, and 6.97 mg kg –1 for SAS, OHSL, and SSL, respectively. The LOECs for reproduction were 6.97, 6.25, and 1.9 mg kg –1 for SAS, OHSL, and SSL, respectively. HD toxicity to both adults and juveniles was greater in SSL. These results show that soil toxicity testing should not rely solely on the adult acute endpoints using artificial soils, but should include assays with reproductive endpoints using natural soils with varying physical and chemical parameters to adequately assess toxicity to test species.

We investigated the effects of individual 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), nitroglycerin (NG), and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) on decomposition, an essential soil process, utilizing Orchard grass (Dactylis glomerata) straw in Sassafras sandy loam (SSL) soil. Three pieces of 5-cm long internodular sections of straw were used to form a straw cluster. Pre-weighed straw clusters were placed in the soil in each 900 mL volume test container containing approximately 200 g of loosely packed EM-amended soil or carrier (acetone) control soil. After 1, 2, 3, 4, 6, and 8 months of exposure, one straw cluster was harvested from a set of randomly selected replicate containers from within each treatment to quantify the decomposition rates. The exposure concentrations of each EM in soil were analytically determined soils using the U.S. Environmental Protection Agency Method 8330A. The results showed that soil contamination with 2,4-DNT or NG can inhibit litter decomposition rates based on the EC50 values of 1122 mg/kg and 860 mg/kg, respectively. Exposure to 2-ADNT, 4-ADNT or CL-20 did not significantly affect litter decomposition in SSL soil at 10000 mg/kg. These ecotoxicological benchmarks can help identify concentrations of contaminant EM in soil that present an acceptable ecological risk for biologically-mediated processes in soil.

The authors used a refined microcosm technique to investigate the toxicity of copper, cadmium, malathion, and the polychlorinated biphenyl, to trophic groups of soil nematodes and to the microarthropod community. Comparisons of changes in nematode abundance in control soils through time indicated that day 7 was the most appropriate time to sample the microcosms after chemical application. Nematode abundance was reduced after exposure to copper at 100 {micro}g/g, with fungivore, bacterivore, and omnivore-predator nematodes being the most sensitive groups. Cadmium did not affect the nematode or microarthropod communities. Microarthropods were far more sensitive to malathion than were nematodes, and total microarthropod abundance was lower than controls at 400 {micro}g/g. Prostigmatid mites and other arthropods were the most affected groups. PCB also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g/g, with prostigmatid and oribatid mites exhibiting the highest susceptibility. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups should be examined to fully evaluate the biological impact of chemicals on soils. The authors conclude that microcosms with field-collected soil microfaunal communities offer high resolution of the ecotoxicologic effects of chemicals in complex soil systems.

The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific.

This study was designed to produce scientifically defensible benchmark data for the development of ecological-based soil screening levels for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) for terrestrial plants. The physical and chemical properties of different soils may alter the bioavailability and toxicity of TNT and RDX to plant species. We investigated individual ecotoxicities of TNT and RDX to alfalfa (Medicago sativa L.), Japanese millet (J. millet; Echinochloa crus-galli L. [Beauv.]), and perennial ryegrass (Lolium perenne L.) in five natural soils that varied in pH, organic matter, and clay contents. On the basis of EC50 values (the TNT or RDX concentrations that produce 50% reductions in selected measurement endpoints) and 95% confidence intervals for shoot fresh and dry masses (SDM), TNT weathered-and-aged (W-A) in soils significantly reduced (p 0.05) growth of alfalfa, J. millet, and perennial ryegrass. RDX W-A in soil was moderately inhibitory to growth of J. millet and perennial ryegrass in all five soils but did not affect growth of alfalfa. No statistically significant correlations between TNT toxicity and these soil properties were identified; however, statistically significant (p 0.05) inverse relationships were identified between the RDX EC50 values for perennial ryegrass SDM and soil clay content and pH.

Studies were designed to characterize soil physicochemical parameters that can affect the toxicities of 2,4,6- trinitrotoluene (TNT) or hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to Eisenia fetida earthworms and also to generate ecotoxicological benchmarks for development of ecological soil screening levels (Eco-SSLs) for ecological risk assessments of contaminated soils. Soils with varied physicochemical properties were tested, including Teller sandy loam (TSL), Sassafras sandy loam (SSL), Richfield clay loam (RCL), Kirkland clay loam (KCL), and Webster clay loam (WCL). Reproduction toxicity of TNT to E. fetida in freshly amended soils was in the order (greatest to least) of TSL SSL = KCL = RCL WCL. Weathering-and-aging of TNT in SSL, KCL, RCL, and WCL soils increased the toxicity to E. fetida compared with corresponding freshly amended treatments. Reproduction toxicity of RDX weathered-and-aged (W-A) in soil was comparable with that of TNT W-A in TSL, SSL, RCL, and WCL soils. No clear relationships were identified between TNT or RDX toxicities and the soil organic matter or clay contents or the pH levels. Toxicity benchmarks established utilizing TSL and SSL will be submitted to the U.S. Environmental Protection Agency Eco-SSL Workgroup for developing soil invertebrate-based Eco-SSLs for TNT and RDX.

The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific.

Environmental toxicity testing and chemical analyses of soil were performed as part of an ecological risk assessment at the Joliet Army Ammunition Plant (JAAP), Johet, Illinois Soils were collected from an area where munitions were loaded, assembled, and packed (area L7, group 1), and from an area where waste explosives were burned on unprotected soil (area L2) Control samples were collected from an adjacent field Soil toxicity was determined using early seedling growth and vigor tests, earthworm survival and growth tests, and Microtox® assays Relative toxicity of soils was determined within each area based on statistical significance (p = 0 05) of plant and earthworm growth and survival, and the effective concentration at which luminescence of the bacterium Photobacterium phosphoreum was reduced by 50% (EC50) in the Microtox assay Samples were designated as having high, moderate, or no significant toxicity Soil that had significant toxicity according to at least one test, and representative samples showing no toxicity, were analyzed for munitions via HPLC Chemical residues found in soils were 2,4,6 trinitrotoluene (TNT), 1,3,5 trinitrobenzene (TNB), 2,4 dinitrotoluene (2,4-DNT), 2,6 dinitrotoluene, 2 amino-4,6-DNT, 4-ammo-2,6 DNT, 1,3,5 trinitro 1,3,5 triazine (RDX), and octahydro-1,3,5,7 tetramtro-l,3,5,7-tetrazocme (HMX) All soils with no significant toxicity were void of these chemicals However, some soils void of munitions still showed toxicity that may have been caused by elevated levels of heavy metals Linear regressions of toxicity test results vs chemical concentrations showed that TNT and TNB accounted for most of the soil toxicity Lowest observable-effect concentrations (LOEC) of TNT were de termined from these data This study presents a simple, relatively inexpensive methodology for assessing toxicity of soils containing TNT, RDX, and other contaminants related to munitions production

We investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the Enchytraeid Reproduction Test (ISO 16387:2004). Studies were designed to identify and characterize the predominant soil physicochemical parameters that affect the acute (mortality) and chronic (reproduction) toxicities of TNT or RDX to E. crypticus, and to generate ecotoxicological benchmarks for developing the ecological soil screening levels (Eco-SSLs) for risk assessments of contaminated soils. Soils with a wide range of physicochemical parameters included: Teller sandy loam (TSL), Sassafras sandy loam (SSL), Richfield clay loam (RCL), Kirkland clay loam (KCL), and Webster clay loam (WCL). Reproduction toxicity of TNT weathered-and-aged in soil, based on EC50 values, correlated strongly with soil organic matter and clay contents. The order of soil toxicity (from greatest to least) was: TSL SSL KCL = RCL WCL. RDX was less toxic to E. crypticus compared with TNT in the same soil types. RDX toxicity for E. crypticus was greater in sandy loam soils compared with clay loam soils. Toxicity benchmarks established in TSL and SSL will be submitted to the U.S. Environmental Protection Agency Eco-SSL Workgroup for use in developing soil invertebrate-based Eco-SSLs for TNT and RDX.

The ecotoxicological benchmarks developed for terrestrial plants and soil invertebrates were compiled, reviewed, and used in this report to develop scientifically defensible terrestrial plant-based and soil invertebrate-based draft ecological soil screening levels (Eco-SSLs) for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The draft Eco-SSL values were derived using the EC20 (the 20% negative) level toxicity benchmarks for the effects of each explosive compound as a contaminant in soil and on plant growth or soil invertebrate reproduction endpoints, which were determined in standardized toxicity tests. Ecotoxicological testing was specifically designed and reviewed for these studies to meet the U.S. Environmental Protection Agency (USEPA) criteria for Eco-SSL derivation. Following acceptance by the USEPA, these draft Eco-SSL values will be used to screen site-soil data to identify the contaminants that are not of potential ecological concern and do not need to be considered in the baseline ecological risk assessment, which will result in significant cost-savings during site assessments. These Eco-SSLs will also provide an indispensable tool for installation managers to gauge the ecotoxicological impacts of military operations that involve the use of explosives, thus ultimately promoting the sustainable use of testing and training ranges.

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 percent 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.

This report summarizes the health effects of inhaling aerosolized corn oil and its oxidation products. Literature reports that inhalation of aerosolized oils, including vegetable oils, can elicit lipoid pneumonia, promote proliferative fibrosis in the lungs, and result in the development of respiratory insufficiency that may lead to corpulmonale or educe carcinomas; however, none of these were specifically attributed to the inhalation of corn oil. Investigation of inhalation toxicity to mice of refined corn oil aerosol, at rates 300 to 600 times greater than those used in the representative testing in the exposure chamber operated by the U.S. Army Edgewood Chemical Biological Center, revealed that oil droplets were immediately phagocytosed by macrophages, resulting in nearly complete clearing of the lungs of corn oil droplets within 48 h with no inflammatory effects. The National Institute for Occupational Safety and Health reports that corn oil has been proven effective as an inward leakage test agent for personal protective equipment because it does not put the test subject at risk and does not have inherent dangers with storage or handling. Autooxidation of corn oil at room temperature is inconsequential in short-term (months) storage but can produce potentially harmful compounds during long-term (years) storage.

A microcosm technique is presented that uses community and trophic-level analysis of soil nematodes and microarthropods to determine the effects of chemicals on soil systems. Forest soil was treated with either copper (0, 100, 200, 400, and 600 mg g−1), p-nitrophenol (0, 20, 40, 80, and 160 mg g−1), or trinitrotoluene (0, 25, 50, 100, and 200 mg g−1). Nematodes were sorted into bacterivore, fungivore, herbivore, and omnivore-predator trophic groups, and a hatchling category. Microarthropods were sorted to the acarine suborders Prostigmata, Mesostigmata, and Oribatida; the insectan order Collembola; and a miscellaneous group. Omnivore-predator nematodes and mesostigmatid and oribatid mites were the groups most sensitive to copper and were significantly reduced at levels as low as 100 mg g−1 copper. Total nematode and microarthropod numbers declined above 200 mg g−1 copper. Trophic structure analysis suggested that high sensitivity of nematode predators to intermediate levels of copper reduced predation on herbivore nematodes and resulted in greater numbers of nematodes compared to controls. p-Nitrophenol was very toxic to the nematode community, and all trophic groups were significantly reduced above 20 mg g−1. However, there was no effect of p-nitrophenol on microarthropods. Trinitrotoluene had no significant negative effect on total abundance of either group of soil fauna, but oribatids were significantly reduced at 200 mg g−1. Our results demonstrated that soil nematodes and microarthropods were sensitive indicators of environmental contaminants and that trophic-structure and community analysis has the potential to detect more subtle indirect effects of chemicals on soil food-web structure. We conclude that microcosms with field communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

Open-top chambers were used to determine the relationships between a hexachloroethane (HC) obscurant, zinc deposition, and foliar injury of tree species indigenous to military training facilities. Eight eastern U.S. tree species were exposed four times to three exposure regimens (0x, 1x, 2x) of the obscurant, measured as Zn, during the 1990 growing season. Plots received ambient or charcoal-filtered air for comparison purposes. Black locust (Robinia pseudoacacia L.) and black cherry (Prunus serotina Ehrh.) were the most sensitive species, exhibiting significant (p < 0.05) necrotic leaf spot, chlorotic mottle, and marginal necrosis of leaves at the 2x levels throughout the season. Defoliation was also greater (p < 0.05) in exposed vs. unexposed plots. Sugar maple (Acer saccharum Marsh.) injury was different among exposure regimens (p < 0.05) only near the end of the season. Sweet gum (Liquidambar styraciflua L.), eastern white pine (Pinus strobus L.), loblolly pine (Pinus taeda L.), and Virginia pine (Pinus virginiana Mill.) were asymptomatic. Charcoal filtration did not affect severity of symptoms. Zinc deposition was positively correlated (p < 0.05) with most of the symptoms on black locust and black cherry. The HC obscurant in the concentrations used in this study adversely affected these species.

The controlled environment soil‐core microcosm unit (CESMU) methods embody a collection of techniques that began with soil sampling in the field and continued throughout the laboratory investigation of chemical fate, migration, and transformation in site‐specific soils; it was a cost‐effective investigative methodology that could be used to screen chemical materials before initiating high‐cost environmental field studies. Intact soil cores were collected in the field using a hydraulically controlled probe, delivering intact soil‐cores with minimal disturbance directly into high‐density polyethylene pipe (10.3‐cm ID). The inert polyethylene pipe was an effective hydrophobic barrier that remained an integral part of the soil‐core column, obviating subsequent transfers of soil. In the laboratory, each soil column was fitted with a porous ceramic plate and a polyethylene endcap containing fittings for teflon tubing, so that a tension could be applied at the bottom of each soil column (30–35 kPa) to m...

3-Nitro-l,2,4-triazol-5-onc (NTO) is an explosive developed at the Los Alamos National Laboratory in 1984. The thermal decomposition characteristics of NTO, including calculated detonation velocity and pressure, are similar to those of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX); however, NTO is less sensitive and more stable. Little or no open literature is available about the environmental toxicity of NTO and understanding of potential ecological impacts of its accidental release into aquatic ecosystems is necessary prior to its large-scale production. We conducted aquatic toxicity testing of NTO using the freshwater organism Ceriodaphnia dubia in a 7 day survival and reproduction assay and the unicellular green algae Selenastrum capricornutum in a 96 hr growth inhibition assay. The studies were conducted under pH-adjusted conditions due to a concentration-dependent increase in acidification of aqueous media by the addition of NTO. The resulting inhibitory concentration (IC) IC2 and IC50 values for reproduction of C. dubia were 51 and 57 mg/L, respectively. The estimated IC2o and IC50 values for S. capricornutum growth inhibition were 2195 and 3465 mg/L. Applying these results to the Chemical Scoring System for Hazard and Exposure Identification, NTO was ranked as practically nontoxic.

Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands. Durante as últimas duas décadas, ecotoxicologistas de solo têm feito progressos ao utilizar conceitos básicos e avanços da zoologia e ecologia do solo. Os métodos existentes têm sido aplicados, e têm-se desenvolvido novas ferramentas para avaliar de que modo a contaminação química pode afetar o ecossistema terrestre, inclusive pela degradação ou destruição da qualidade do solo e dos habitats ou pela redução da biodiversidade edáfica. Os ecotoxicologistas de solo utilizam um conjunto de protocolos padronizados, originalmente desenvolvidos como testes de laboratório com compostos químicos simples como os pesticidas e, posteriormente, adaptados em termos de abordagens e métodos, para a avaliação de áreas contaminadas. No entanto, a relevância ecológica de algumas abordagens permanece questionável. Neste artigo, os autores discutem os recentes desafios para uma avaliação ecotoxicológica coerente do ecossistema solo em áreas contaminadas e apresentam recomendações de como integrar os efeitos das propriedades físicoquímicas do solo, as variações na diversidade de invertebrados do solo e, as interações entre organismos dos vários níveis tróficos. São analisadas novas abordagens e métodos de avaliação, usando-se exemplos de três continentes (particularmente o trabalho desenvolvido no Brasil), e são dadas recomendações de como aumentar a relevância ecológica na avaliação ecotoxicológica de áreas contaminadas.

This paper discusses U.S. Army guidance procedures for ecological risk assessments (ERA) for risk assessors under contract to the U.S. Army. Using this approach provides the Army with cost-effective, tiered procedures with which to direct and coordinate the scientific and technical efforts of contractors involved in ERA. Employing a common framework across sites can assure the Army that requirements of state and federal regulators are satisfied. The process described in this report follows the EPA "Framework" paradigm put forward in 1992. This document is a technical "road map", with examples and discussion of the thought process to lead environmental scientists through this effort. A tiered or phased approach has been put forward as a rational procedure by several scientists. The purpose of a tiered approach is to do the necessary and sufficient amount of work to characterize the risk to an ecological system with an acceptable degree of uncertainty. The assessment should proceed if risk is possible, but complete characterization of risk cannot be determined due to significant data gaps. The assessment should not proceed if no significant risk is apparent, or if the risk is so great that action (e.g., remediation, containment, etc.) is immediately warranted.

The Assembled Chemical Weapons Alternatives (ACWA) Program has been tasked to demonstrate alternative technologies to incineration that will safely dispose of assembled chemical munitions. The ACWA program is currently investigating GB-hydrolysate as a secondary waste that can be transported offsite to a commercial Treatment Storage and Disposal Facility (TSDF). The Microtox assay with bioluminescent marine bacterium Vibrio fischeri and the survival and reproduction of freshwater organism Ceriodaphnia dubia were used to investigate the aquatic toxicities of ACWA GB-hydrolysate or the neutralized (pH adjusted) ACWA GB-hydrolysate. The Microtox assay was also used to assess the aquatic toxicity of Bluegrass Depot GB-hydrolysate. The 5-min EC50 values for V. fischeri exposed to either ACWA GB-hydrolysate or neutralized ACWA GB-hydrolysate were 0.24 and 28% vol/vol, respectively. The 5-min EC50 values for V. fischeri exposed to Bluegrass GB-hydrolysate or neutralized ACWA GB-hydrolysate were 0.05 and 4.7% vol/vol, respectively. The 24-hr EC50 values for C. dubia exposed to either ACWA GB-hydrolysate or neutralized ACWA GB-hydrolysate were 0.8 and 1.3% vol/vol, respectively.

Energetic materials are employed in a wide range of commercial and military activities and often are released into the environment. Scientifically based ecological soil-screening levels (Eco-SSLs) are needed to identify contaminant explosive levels in soil that present an acceptable ecological risk. Insufficient information for 2,4,6-trinitrotoluene (TNT) to generate Eco-SSLs for soil invertebrates necessitated toxicity testing. We adapted the standardized Enchytraeid Reproduction Test and selected Enchytraeus crypticus for these studies. Tests were conducted in Sassafras sandy loam soil, which supports relatively high bioavailability of TNT. Weathering and aging procedures for TNT amended to test soil were incorporated into the study design to produce toxicity data that better reflect the soil exposure conditions in the field compared with toxicity in freshly amended soils. This included exposing hydrated TNT-amended soils in open glass containers in the greenhouse to alternating wetting and drying cycles. Definitive tests showed that toxicity for E. crypticus adult survival and juvenile production was increased significantly in weathered and aged soil treatments compared with toxicity in freshly amended soil based on 95% confidence intervals. The median effect concentration and 20% effective concentration for reproduction were 98 and 77 mg/kg, respectively, for TNT freshly amended into soil and 48 and 37 mg/kg, respectively, for weathered and aged TNT soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged TNT soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of energetic contaminants in soil.

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).

Red-backed salamanders (Plethodon cinereus) were exposed to four different concentrations of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in soil under controlled laboratory conditions for 28 days. Wild-caught P. cinereus (N = 20/treatment) were exposed to target concentrations of 5,000, 1000, 100, 10, and 0 mg RDX/kg soil (dry wt) using a microcosm design. Animals were fed 5 to 10 uncontaminated mutant Drosophila flies every 3 days and monitored daily. Animals were weighed 1 day before being placed in treatment and weekly thereafter. RDX concentrations in soil were analytically determined after the compound was added and mixed at the beginning, the midpoint, and the end of exposure. RDX soil concentrations were relatively stable throughout the exposure period. Signs of overt toxicity were observed primarily in the highest exposure group. Salamanders exposed to 5,000 mg RDX/kg soil exhibited signs of neuromuscular effects (lethargy, gaping, hypersensitivity, tremors) and exhibited significant weight loss. A single moribund animal from this group lost >20% of its original body weight and was killed. Animals in this exposure group also lost weight relative to animals in other treatments. Histopathologic evaluations, including an evaluation of melanomacrophage parameters, indicated no strong treatment-related findings. This study provided information regarding the effects from subchronic dermal exposure of a terrestrial amphibian species to RDX in soil and provides a microcosm approach to the evaluation of toxicity of contaminants in soil to a terrestrial vertebrate.

Munition manufacturing, disposal, testing, training and other operations at military sites produced elevated levels of explosives and related materials in soil. The effects of these persistent and highly mobile in the environment energetic materials on soil biota have not been sufficiently investigated. The U.S. Environmental Protection Agency (USEPA) in conjunction with stakeholders, is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites to identify those contaminants in soil that warrant additional evaluation in a Baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Insufficient data were available on the toxicity of energetic compounds, RDX and HMX, to soil invertebrates, necessitating toxicity testing. Tests were conducted under conditions preferred for Eco-SSL benchmarks, using a Sassafras sandy loam soil that supports relatively high bioavailability of test compounds. Toxicity testing was performed using enchytraeid reproduction test (ISO/16387 2001) measuring adult survival and juvenile production by the potworm Enchytraeus crypticus in freshly amended soil and weathered/aged amended soil. RDX or HMX had no effect on adult survival in the definitive tests in all treatment concentrations. Juvenile production EC 2 0 values were 3,715 and 8,797 mg kg - 1 RDX in freshly amended and weathered/aged amended soils, respectively. Juvenile E. crypticus production was not adversely affected by exposure to HMX in freshly amended and weathered/aged amended soils. Juvenile production was stimulated in freshly amended soil up to 21,750 mg kg - 1 HMX. Results of these toxicity studies will be submitted to the Eco-SSL Task Group for quality control review, and pending approval will be included in the Eco-SSL database for Eco-SSL derivation.

This handbook is written for the person that manages the Ecological Risk Assessment (ERA) process to ensure that it stays on schedule and meets budget and regulatory requirements. The objectives* of this handbook are to give the Remedial Project Manager (RPM) of a hazardous waste site at Department of Defense (DoD) facilities: (1) An overview of the ERA process that complies with current regulations and laws, (2) Listings of when and where to seek technical assistance, (3) A list of Key Terms cross-referenced for use in ERAs, (4) Some "Rules of Thumb" for overseeing ERAs, (5) Internet sites with useful information for performing and managing ERAs. This handbook, written in easy to read format, is an updated summary of the Tri-Service Procedural Guidelines for Ecological Risk Assessments and is designed to help the RPM understand the ERA process, This handbook does not, per se, show the reader how to manage the ERA. However, it can be used by the RPM as a management tool. This handbook distinguishes between the ERA approach used by the Army and Air Force and the approach used by the Navy. Both approaches incorporate procedures from the U.S. Environmental Protection Agency ERA Guidance for Superfund.

The purpose of this report is to assess and predict the potential for ecological risk due to the use of brass infrared (IR) wavelength obscurant in the field. Although not an ERA tutorial, explanatory information is included to explain concepts involved in predictive ERA. The USEPA ERA guidelines have been applied. This study is a tier-1 screening level, ERA; it uses available environmental toxicity data, material fate and effects data, appropriate environmental fate modeling data and proposed field scenarios to predict the possibility of impact to the envirnoment under study. These field use scenarios for brass flake obscurant materials are evaluated to predict the environmental impact on terrestrial ecosystems. Ecotoxicological information on brass, existing data gaps, and field scenarios are presented in a fair manner to best assess the potential for ecological risk and help program/risk managers make educated decisions regarding brass usage. This report addresses neither materials other than brass nor the smoke testing and training program in general. A comparable report has been published on the predictive ecological risk assessment for the usage of graphite flake obscurant materials in the terrestrial environment.

The U.S. Environmental Protection Agency is developing ecological soil screening levels (Eco-SSLs) for the ecological risk assessment of contaminants at Superfund sites. The Eco-SSLs for several soil contaminants have been developed from toxicity benchmarks for soil invertebrates in the existing literature. Insufficient information to generate Eco-SSLs for Sb, Ba, and Be necessitated toxicity testing to fill the data gaps. We used standardized toxicity tests with the earthworm Eisenia fetida, enchytraeid Enchytraeus crypticus, and collembolan Folsomia candida in the present study. These tests were selected on the basis of their ability to measure chemical toxicity to ecologically relevant test species during chronic assays and their inclusion of at least one reproduction component among the measurement endpoints. Tests were conducted in Sassafras Sandy Loam soil, which supports relatively high bioavailability of metals. Weathering and aging procedures for metals in amended soil were incorporated into these studies to better reflect exposure conditions in the field. The relative toxicity of metals to the soil invertebrates tested was Be > Sb > Ba based on the median effective concentration values for reproduction. These studies produced toxicological data that can contribute to the development of Eco-SSLs for Sb, Ba, and Be for soil invertebrates.

Scientifically based ecological soil-screening levels are needed to identify concentrations of contaminant energetic materials (EMs) in soil that present an acceptable ecological risk at a wide range of military installations. Insufficient information regarding the toxicity of 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), and 1,3,5-trinitrobenzene (TNB) to soil invertebrates necessitated toxicity testing. We adapted the standardized Enchytraeid Reproduction Test (International Standardization Organization 16387:2003) and selected Enchytraeus crypticus for these studies. Tests were conducted in Sassafras sandy loam soil, which supports relatively high bioavailability of nitroaromatic EMs. Weathering and aging procedures for EMs amended to test soil were incorporated into the study design to produce toxicity data that better reflect the soil exposure conditions in the field compared with toxicity in freshly amended soils. This included exposing hydrated, EM-amended soils in open glass containers in the greenhouse to alternating wetting and drying cycles. Definitive tests established that the order of EM toxicity to E. crypticus based on the median effect concentration values for juvenile production in either freshly amended or weathered and aged treatments was (from the greatest to least toxicity) TNB > 2,4-DNT > 2,6-DNT. Toxicity to E. crypticus juvenile production was significantly increased in 2,6-DNT weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. This result shows that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information regarding ecotoxicological effects of energetic contaminants in soil.