Survival and reproduction of enchytraeid worms, Oligochaeta, in different soil types amended with energetic cyclic nitramines.
Hexanitrohexaazaisowurtzitane (CL-20), a new polycyclic polynitramine, has the same functional nitramine groups (N-NO2) as the widely used energetic chemicals hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (royal demolition explosive [RDX]) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (high-melting explosive [HMX]). Potential impacts of CL-20 as an emerging contaminant must be assessed before its use. The effects of CL-20, RDX, or HMX on adult survival and juvenile production by potworms Enchytraeus albidus and Enchytraeus crypticus were studied in three soil types, including Sassafras sandy loam (1.2% organic matter [OM], 11% clay, pH 5.5), an agricultural soil (42% OM, 1% clay, pH 8.2), and a composite agricultural-forest soil (23% OM, 2% clay, pH 7.9) by using ISO method 16387 (International Standard Organization, Geneva, Switzerland). Results showed that CL-20 was toxic to E. crypticus with median lethal concentration values for adult survival ranging from 0.1 to 0.7 mg/kg dry mass (DM) when using the three tested soils. In addition, CL-20 adversely affected juvenile production by both species in all soils tested, with median effective concentration (EC50) values ranging from 0.08 to 0.62 mg/kg DM. Enchytraeus crypticus and E. albidus were similarly sensitive to CL-20 exposure in the composite agricultural-forest soil, which supported reproduction by both species and enabled comparisons. Correlation analysis showed weak or no relationship overall among the soil properties and reproduction toxicity endpoints. Neither RDX nor HMX affected (p > 0.05) adult survival of either species below 658 and 918 mg/kg DM, respectively, indicating that CL-20 is more toxic to enchytraeids than RDX or HMX. Examination of data shows that CL-20 should be considered as a potential reproductive toxicant to soil invertebrates, and that safeguards should be considered to minimize the potential for release of CL-20 into the environment.
Dodard
Sabine G
SG
Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada.
Sunahara
Geoffrey I
GI
Kuperman
Roman G
RG
Sarrazin
Manon
M
Gong
Ping
P
Ampleman
Guy
G
Thiboutot
Sonia
S
Hawari
Jalal
J
D000383:Agriculture; D000818:Animals; D001372:Aza Compounds / Q000633:toxicity*; D001392:Azocines / Q000633:toxicity*; D006571:Heterocyclic Compounds / Q000633:toxicity*; D006573:Heterocyclic Compounds, 1-Ring / Q000633:toxicity*; D009835:Oligochaeta / Q000254:growth & development* / Q000502:physiology; D012098:Reproduction / Q000187:drug effects; D012989:Soil Pollutants / Q000633:toxicity*; D013534:Survival; D014197:Trees; D014227:Triazines / Q000633:toxicity*
C482139:2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane; D001372:Aza Compounds; D001392:Azocines; D006571:Heterocyclic Compounds; D006573:Heterocyclic Compounds, 1-Ring; D012989:Soil Pollutants; D014227:Triazines; C007950:octogen; C009160:cyclonite