title: Toxicity of the explosive metabolites hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) and hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) to the earthworm Eisenia fetida.
abstract: Toxicity of hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) to earthworm was evaluated. Both MNX and TNX had lethal and sublethal effects on earthworms. Exposure to MNX- or TNX-contaminated soil caused a significant concentration-dependent decrease in earthworm survival and growth. The lowest observed lethal concentration (LOLC) for both MNX and TNX was 100 and 200 mgkg(-1) soil dry weight in the sandy loam soil and in the silt loam soil, respectively. No earthworms survived for 14 days in MNX- or TNX-spiked soil at 500 mgkg(-1) soil dry weight. After 7 days exposure, the lowest observed effect concentration (LOEC) for earthworm growth was 50 mgkg(-1) soil dry weight for TNX and 100 mgkg(-1) soil dry weight for MNX in both soil types. The LC20 and LC50 for MNX in sandy loam soil were 114 and 262 mgkg(-1) and for TNX, they were 114 and 254 mgkg(-1) soil dry weight, respectively. The corresponding values for MNX and TNX in silt loam soil were 234 and 390 mgkg(-1) soil dry weight, respectively, and 200 and 362 mgkg(-1) soil dry weight, respectively. After 35 days exposure, earthworm growth was reduced 8-39% by TNX in sandy loam soil, whereas TNX only inhibited earthworm growth 5-18% at the same concentration range in silt loam soil. LC20 and LC50 for TNX were slightly lower than for MNX; this indicates that TNX was more toxic than MNX. No significant morphological or developmental abnormalities were observed in earthworms surviving exposure.
authors.affiliation: The Institute of Environmental and Human Health (TIEHH), Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409-1163, USA. baohong.zhang@tiehh.ttu.edu
authors.forename: Baohong
authors.initials: B
authors.lastname: Zhang
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Kendall
authors.forename: Todd A
authors.initials: TA
authors.lastname: Anderson
mesh_terms: D000818:Animals; D007928:Lethal Dose 50; D009602:Nitrosamines / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D009835:Oligochaeta / Q000187:drug effects* / Q000254:growth & development; D012989:Soil Pollutants / Q000633:toxicity; D014227:Triazines / Q000378:metabolism / Q000633:toxicity*
chemical_list: D009602:Nitrosamines; D012989:Soil Pollutants; D014227:Triazines; C508167:hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine; C014233:trinitrosotrimethylenetriamine; C009160:cyclonite