TY - JOUR
T1 - Uptake, bioaccumulation, and biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its reduced metabolites (MNX and TNX) by the earthworm (Eisenia fetida)
AU - Zhang, Baohong
AU - Pan, Xiaoping
AU - Cobb, George P.
AU - Anderson, Todd A.
N1 - Funding Information:
This research was supported in part by the US Department of Defense Contract CU1141, through the Strategic Environmental Research and Development Program (SERDP) under a Cooperative Agreement IERA-99-001 with the USAF, Institute of Environment, Safety, and Occupational Health, Brooks AFB, TX. Sandy loam soil was kindly provided by Scott McMurry.
PY - 2009/6
Y1 - 2009/6
N2 - Uptake and accumulation kinetics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its two major N-nitroso metabolites, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), in earthworms was investigated. Results indicated that RDX and its N-nitroso metabolites were rapidly absorbed into earthworms (Eisenia fetida), reaching the highest concentrations within a few days. Accumulation of RDX was greater than its N-nitroso metabolites, as evidenced by a higher bioconcentration factor (BCF); BCFs were 1.86, 0.39, and 0.05 for RDX, MNX, and TNX, respectively. RDX and its N-nitroso metabolites were also rapidly eliminated from the earthworm and/or transformed to other metabolites, as evidenced by the rapid decrease of test compounds in earthworms after reaching their highest concentrations. The uptake of MNX and TNX increased as exposure concentration increased. Although these earthworms might (anaerobically) degrade RDX to MNX and MNX to TNX, it is hypothesized that this process would be slow. Other biotransformation pathways may be involved in biodegradation of RDX and its N-nitroso metabolites due to the fact that concentrations of tested compounds decreased in both soil and earthworms. It is hoped that these data can be used to refine environmental management strategies for RDX and for performing specific risk assessments of RDX and its N-nitroso metabolites.
AB - Uptake and accumulation kinetics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its two major N-nitroso metabolites, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), in earthworms was investigated. Results indicated that RDX and its N-nitroso metabolites were rapidly absorbed into earthworms (Eisenia fetida), reaching the highest concentrations within a few days. Accumulation of RDX was greater than its N-nitroso metabolites, as evidenced by a higher bioconcentration factor (BCF); BCFs were 1.86, 0.39, and 0.05 for RDX, MNX, and TNX, respectively. RDX and its N-nitroso metabolites were also rapidly eliminated from the earthworm and/or transformed to other metabolites, as evidenced by the rapid decrease of test compounds in earthworms after reaching their highest concentrations. The uptake of MNX and TNX increased as exposure concentration increased. Although these earthworms might (anaerobically) degrade RDX to MNX and MNX to TNX, it is hypothesized that this process would be slow. Other biotransformation pathways may be involved in biodegradation of RDX and its N-nitroso metabolites due to the fact that concentrations of tested compounds decreased in both soil and earthworms. It is hoped that these data can be used to refine environmental management strategies for RDX and for performing specific risk assessments of RDX and its N-nitroso metabolites.
KW - Bioconcentration
KW - Biotransformation
KW - Earthworm
KW - MNX
KW - RDX
KW - TNX
UR - http://www.scopus.com/inward/record.url?scp=67349101307&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2009.02.021
DO - 10.1016/j.chemosphere.2009.02.021
M3 - Article
C2 - 19278715
AN - SCOPUS:67349101307
VL - 76
SP - 76
EP - 82
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
IS - 1
ER -