title: Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.
abstract: Monocyclic nitramine explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (approximately 0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).
authors.affiliation: Applied Ecotoxicology Group, Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada. pierre-yves.robidoux@cnrc-nrc.gc.ca
authors.forename: Pierre Yves
authors.initials: PY
authors.lastname: Robidoux
authors.forename: Geoffrey I
authors.initials: GI
authors.lastname: Sunahara
authors.forename: Kathleen
authors.initials: K
authors.lastname: Savard
authors.forename: Yann
authors.initials: Y
authors.lastname: Berthelot
authors.forename: Sabine
authors.initials: S
authors.lastname: Dodard
authors.forename: Majorie
authors.initials: M
authors.lastname: Martel
authors.forename: Ping
authors.initials: P
authors.lastname: Gong
authors.forename: Jalal
authors.initials: J
authors.lastname: Hawari
mesh_terms: D000327:Adsorption; D000818:Animals; D001372:Aza Compounds / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005298:Fertility / Q000187:drug effects; D006571:Heterocyclic Compounds / Q000633:toxicity*; D007928:Lethal Dose 50; D009835:Oligochaeta; D011157:Population Dynamics; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: C482139:2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane; D001372:Aza Compounds; D006571:Heterocyclic Compounds; D012989:Soil Pollutants