Reproduction and survival of Eisenia fetida in a sandy loam soil amended with the nitro-heterocyclic explosives RDX and HMX

Abstract

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.NRC publication: Ye