Although small arms ranges are known to be contaminated with lead, the full extent of metal contamination has not been described, nor has the oral bioavailability of lead in these soils. In this work, soil samples from ranges with diverse geochemical backgrounds were sieved to <250 microm and analyzed for total metal content. Soils had consistently high levels of lead and copper, ranging from 4549 to 24 484 microg/g and 223 to 2936 microg/g, respectively, while arsenic, antimony, nickel, and zinc concentrations were 100-fold lower. For lead bioavailability measurements, two widely accepted methods were used: an in vivo juvenile swine relative bioavailability method measuring lead absorption from ingested soils relative to equivalent lead acetate concentrations and an in vitro bioaccessibility procedure which measured acid-extractable lead as a percent of total lead in the soil. For eight samples, the mean relative bioavailability and bioaccessibility of lead for the eight soils was about 100% (108 +/- 18% and 95 +/- 6%, respectively) showing good agreement between both methods. Risk assessment and/or remediation of small arms ranges should therefore assume high bioavailability of lead.
Environmental toxicity testing and chemical analyses of soil were performed as part of an ecological risk assessment at the Joliet Army Ammunition Plant (JAAP), Joliet, Illinois Soils were collected from an area where munitions were loaded, assembled, and packed (area L7, group I), 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 lu minescence 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-amino-2,6 DNT, 1,3,5 trinitro 1,3,5 triazine (RDX), and octahydro-1,3,5,7 tetranitro-1,3,5,7-tetrazocine (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 con taining TNT, RDX, and other contaminants related to munitions production Keywords -Ecological risk assessment ExplosivesTNT RDX
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
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been widely used as an explosive in U.S. army munitions formulations since World War II. Two-year carcinogenicity studies revealed RDX to be noncarcinogenic in two strains of rats, but a 2-year carcinogenicity study in B6C3F1 mice revealed an increased incidence of hepatocellular neoplasms in females. Based on results of the study in B6C3F1 mice, RDX has been classified as a possible carcinogen. The authors reevaluated the archived histological sections from the B6C3F1 mouse study, using current histopathologic diagnostic criteria and interpretations. The earlier evaluation showed a statistically significant increase in the incidence of hepatocellular adenoma/carcinoma in female mice from the three highest dose groups (7, 35, and 175/100 mg/kg/day). The revaluation yielded a slightly lower incidence at each of the dose levels in female mice. The reduced number of hepatocellular neoplasms was largely due to reclassification of hepatocellular adenomas as foci of cytoplasmic alteration, in compliance with current diagnostic criteria. The reevaluation was reviewed by a pathology working group (PWG), which arrived at a consensus classification of each lesion. Based on the consensus diagnoses of the PWG, only one female group (35 mg/kg/day) showed a significant increase when compared to controls. The incidence of hepatocellular neoplasms for all groups, including the 35 mg/kg/day group, was within the reported incidence range for spontaneous hepatocellular neoplasms in female B6C3F1 mice. The increased incidence of hepatocellular neoplasms in female mice given RDX at 35 mg/kg/day was interpreted as equivocal evidence of a carcinogenic effect.
The biosynthetic pathway ofn‐alkanes was investigated in the cockroachesPeriplaneta americana andPeriplaneta fuliginosa. Both sodium [1‐14C] acetate and randomly tritiated long chain fatty acids were incorporated into the cuticular hydrocarbons of both species. The relative incorporation of acetate into each component of the hydrocarbon fraction was about the same as the relative amount of each component in the fraction. In contrast, [R‐3H] hexacosanoic acid was preferentially incorporated inton‐pentacosane inP. americana and [R‐3H] tetracosanoic acid inton‐tricosane inP. fuliginosa. Long chain ketones and secondary alcohols, likely intermediates in the proposed condensation‐reduction pathway forn‐alkane biosynthesis, were not incorporated into hydrocarbon. Results from experiments with dual labeled lauric aicd were also not consistent with the condensation‐reduction pathway. The demonstration of the direct decarboxylation of long chain fatty acids ton‐alkanes one carbon unit shorter and the lack of incorporation of proposed intermediates of a condensation‐reduction pathway constitute the strongest evidence to date that insects utilize an elongation‐decarboxylation pathway forn‐alkane biosynthesis.
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