Toxicity of the explosives 2,4,6‐trinitrotoluene, hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine, and octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine in sediments toChironomus tentansandHyalella azteca: Low‐dose hormesis and high‐dose mortality

Abstract

The toxicity of the explosives 2,4,6-trinitrotoluene (TNT); hexahydro-1,3,5-trinitro-1,3,5-triazine (royal demolition explosive [RDX]); and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (high-melting explosive [HMX]), was evaluated in spiked sediment with two freshwater invertebrates. The midge Chironomus tentans and the amphipod Hyalella azteca demonstrated significant toxic effects after exposure to TNT and its degradation products, 1,3,5-trinitrobenzene (TNB) and 2,4-diamino-6-nitrotoluene (2,4-DANT). Significant reductions in survival of C. tentans exposed to TNT, TNB, and 2,4-DANT were observed at nominal sediment concentrations as low as 200 mg/kg. Hyalella azteca was more sensitive to TNT, TNB, and 2,4-DANT than the midge, where significant reductions in survival were observed at nominal concentrations of 50, 100, and 200 mg/kg, respectively. Survival of the midge and the amphipod was unaffected after exposure to RDX or HMX at the highest concentrations of 1,000 and 400 mg/kg, respectively. Growth of the midge, measured as total weight, was significantly reduced by 2,4-DANT. However, significantly increased growth was observed after exposure to sublethal concentrations of RDX and HMX. Although significant reductions in amphipod survival were observed at high concentrations of TNB, growth was significantly increased at sublethal concentrations. The results of the current investigation suggest that organisms exposed to explosives at contaminated sites may be affected at concentrations less than 25 mg/kg through hormetic growth enhancement and at higher concentrations through increased mortality.

Nondestructive, Minimal-Disturbance, Direct-Burial Solid-Phase Microextraction Fiber Technique for Measuring TNT in Sediment

“…Neat crystals of TNT and TNT degradation compounds 2-amino-4,6-dinitrotoluene (2ADNT), 4-amino-2,6-dinitrotoluene (4ADNT), and 2,4-diamino-6-nitrotoluene (2,4DANT) (>98% purity, purchased from R. Spanggord, SRI International, Menlo Park, CA) were dissolved in pure HPLC-grade acetonitrile and spiked into ultrapure water. In addition to 2,6-diamino-4-nitrotoluene (2,6DANT), which could not be obtained, these compounds are the predominant compounds found in TNT-contaminated sediments and soils (16,(25)(26)(27)(28). Since solvent concentrations above 1 vol % can affect Kfs (1), spiking levels for these experiments were such that solvent concentrations were 1%.…”

“…TNT degrades rapidly (on the order of hours to days) in spiked sediment, soils, and natural waters (Conder,unpublished data;16,25); therefore, several experiments were performed with compounds added to ultrapure water to investigate the amount of exposure time needed to achieve steady-state equilibrium and to calculate Kfs. In this matrix, deviation (greater than 5%) of measured NA concentrations from nominal levels was not observed (0-96 h at 23°C).…”

“…The main objective of our study was to develop and demonstrate a technique for using raw SPME fiber to measure organic contaminants directly within whole sediment. We chose to investigate the explosive 2,4,6-trinitrotoluene (TNT) and its nitroaromatic (NA) degradation products, contaminants present in sediments at concentrations up to percentage levels at many military sites (16)(17)(18). As bioavailability of these compounds in soil has been found to differ by soil composition (19), the biomimetic SPME technique may be a powerful tool for use in ecological risk assessment.…”

Assessment of 4-nitro-1,8-naphthalic anhydride reductase activity in homogenates of bakers’ yeast by reversed-phase high-performance liquid chromatography

“…Nitroarenes, arylhydroxylamines and arylamines are important intermediates in the industrial manufacturing of dyes, pesticides and plastics, and are significant environmental pollutants. In recent years, increasing concern of ecological and health threats posed by nitroaromatics has attracted much attention and encouraged the development of sensitive methods for their detection followed by microorganismmediated biodegradation/bioremediation [19][20][21][22][23][24][25]. Recent investigations have demonstrated the usefulness of bakers' yeast for the reduction of nitroarene compounds to their corresponding amines in chemoselective bioorganic synthesis [26][27][28][29].…”

Investigation of the ionisation and fragmentation behaviour of different nitroaromatic compounds occurring as polar metabolites of explosives using electrospray ionisation tandem mass spectrometry

“…In many studies, the toxicological effects have been ascertained for explosives and their metabolites. [5][6][7][8] There is still a considerable interest in the determination of highly water-soluble acidic compounds, because a number of new polar substances have been found at explosivescontaminated sites. 9,10 However, the analysis of environmental samples from contaminated areas of former ammunition plants is still challenging.…”