Accumulation of 2,4‐dinitroanisole in the earthwormEisenia fetidafrom chemically spiked and aged natural soils

Abstract

An initiative within the US military is targeting the replacement of traditional munitions constituents with insensitive munitions to reduce the risk of accidental detonation. The bioavailability and bioaccumulative potential of the insensitive munitions compound 2,4-dinitroanisole (DNAN) to Eisenia fetida was assessed in soils with different geochemical characteristics. Prior to exposure, soils were chemically spiked with DNAN and aged for 1 wk or 29 wk. Transformation products 2- and 4-amino-nitroanisole (2A-4NAN and 4A-2NAN) occurred in aged soils and their porewater but never at concentrations higher than the residual DNAN. The sum of DNAN, 2A-4NAN, and 4A-2NAN (sumDNAN) in soil decreased with aging, likely by irreversible binding. Both clay and organic matter contents of the soil appeared to affect the bioavailability of DNAN. The sumDNAN body residues of earthworms approached apparent steady state after 1 d and remained relatively constant through to day 7. Higher concentrations of 2A-4NAN and 4A-2NAN measured in worm tissues relative to those in soil suggest reductive transformation of DNAN in the tissues. Mean bioaccumulation factors (ratio of tissue to soil concentrations) varied from 1.2 to 4.3, whereas mean bioconcentration factors (ratio of tissue to porewater concentrations) ranged from 1.4 to 3.2. Porewater seems to play a significant role in the accumulation of DNAN in earthworms, consistent with equilibrium partitioning theory. The concentration of DNAN in soil porewater could serve as an indicator of bioavailability as well as a predictor of the concentration of that compound in earthworms. Environ Toxicol Chem 2016;35:1835-1842. Publlished 2015 SETAC. This article is a US Government work, and as such, is in the public domain in the United States of America.

Accumulation of Insensitive Munition Compounds in the Earthworm Eisenia andrei from Amended Soil: Methodological Considerations for Determination of Bioaccumulation Factors

“…Reductive transformation of DNAN and soil concentration decrease over time are consistent with previous investigations with DNAN (Dodard et al 2013;Richard and Weidhass 2014;Lotufo et al 2016;Temple et al 2018) and also with TNT, a related nitroaromatic compound (see Simini et al 2013). The DNAN strongly adsorbs to soil and is (bio)transformed via reduction of nitro groups to amino groups to form a variety of products, including 2-ANAN, 4-ANAN, and 2,4-diaminoanisole (DAAN; Dontsova et al 2014;Hawari et al 2015;Lotufo et al 2016;Olivares et al 2016;Indest et al 2017;Temple et al 2018). The preferential reduction to 2-ANAN we observed further corroborates previous evidence for regioselective reduction of the ortho-nitro group (Hawari et al 2015;Lotufo et al 2016;Olivares et al 2016;Arthur et al 2017;Temple et al 2018).…”

“…Lotufo et al (2016) reported E. fetida BAF values for 4 different soils that, when converted to dry weight basis (Supplemental Data, Table S4), were overall in the same range as the BAF values derived for SSL soil in the present study (Tables 1 and 2). Following amendment with DNAN, the soils also equilibrated for 7 d in Lotufo et al (2016). The SumDNAN BAF values determined in the present study were also similar to the BAF values reported for TNT (5.0 kg/kg dry wt), 2-aminodinitrotoluene (5.1 kg/kg dry wt), and 4-aminodinitrotoluene (6.4 kg/kg dry wt; Lachance et al 2004).…”

“…It is toxic to a wide variety of aquatic species (Dodard et al 2013; Kennedy et al 2015; Stanley et al 2015; Gust et al 2018; Lotufo et al 2018) and to soil invertebrates (Dodard et al 2013; Gong et al 2018). Lotufo et al (2016) conducted bioaccumulation studies involving the uptake of DNAN by earthworms in amended soil and showed that the DNAN concentration in tissue exceeded the concentration of DNAN in soil. No published information was found on the elimination kinetics of DNAN.…”

Adsorption and oxidation of 3-nitro-1,2,4-triazole-5-one (NTO) and its transformation product (3-amino-1,2,4-triazole-5-one, ATO) at ferrihydrite and birnessite surfaces

“…As a nitroaromatic compound, DNAN is effectively adsorbed to phyllosilicate clay surfaces by nitro group complexation with exchangeable cations (Linker et al, 2015) and it also exhibits an affinity for binding to natural organic matter (NOM) (Lotufo et al, 2016). In contrast, the high aqueous solubility, low NOM affinity (Mark et al, 2016), and anion exclusion from phyllosilicate clay surfaces observed for NTO (Linker et al, 2015) raises particular concern about potential ground water contamination (Le Campion et al, 1999;Pizzigallo et al, 1998;Smith and Cliff, 1999;Spear et al, 1989).…”

Preparation of sediment amended with Insensitive Munitions (IM) compounds for use in toxicity tests with freshwater invertebrates; Scientific Operating Procedure series : characterization of IMX ecotoxicological effects

“…Sufficient contact time between IM compounds and the sediment prior to conducting toxicity testing should be provided. Increased contact time, or aging, affects the chemical composition, bioavailability, and toxicity of organic compounds in soils and sediments, including munitions constituents (Northcott and Jones 2000;Conder et al 2004;Kuperman et al 2013;Lotufo et al 2016). This SOP provides a method for spiking IM compounds with sediments that is solvent-free, and provides adequate equilibration time prior to use in toxicity testing.…”