Toxic effects of oral hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine in the western fence lizard (Sceloporus occidentalis)

Abstract

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been widely used as an explosive in munition formulations, resulting in contamination of wildlife habitat on military installations. To estimate health effects for reptilian species, acute, subacute, and subchronic oral toxicity studies were conducted using the Western fence lizard (Sceloporus occidentalis). Estimated oral median lethal doses were 72 (95% confidence interval [CI], 49-106) mg/kg body weight (slope, 3.754) for males and 88 (95% CI, 65-119) mg/kg (slope, 4.525) for females. Toxicity from RDX suggested the neurological system as the critical target tissue. A 14-d subacute study followed with males dosed orally with RDX (corn oil) at 0, 10, 20, 25, 30, 45, and 60 mg/kg/d. Signs of toxicity frequently included a characteristic body posture. A significant dose-survival relationship was seen over the range of doses, with a significant decrease in survival at 20 mg/kg/d. Males in the 60-d subchronic study were dosed at 0, 1, 2.5, 5, 8, and 11 mg/kg/d, and signs of toxicity included lethargy, cachexia, and anorexia. Survival was decreased at 8 and 11 mg/kg/d. Reduced growth rate and food consumption occurred at 5 mg/kg/d. Brain tissue was assayed for RDX when seizures were observed at a residue concentration of at least 18 microg/g. No abnormalities were observed in the hematologic indices, whereas plasma proteins were reduced. Hepatic enlargement and decreased testes mass occurred at 8 and 11 mg/kg/d. Plasma testosterone concentrations, sperm counts, and motility measures were variable for all treatment levels. Based on survival, growth rate, food intake, and testes to brain weight ratios, these data suggest a lowest-observed-adverse effect level of 5 mg/kg/d and a no-observed-adverse effect level of 2.5 mg/kg/d.

Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans

“…These findings are in accordance with our results. Similar findings such as seminiferous tubular degeneration, abnormal spermatogenesis and sloughing were observed in S. occidentalis (McFarland et al 2009). Oedema and haemorrhage were also reported in the interstitial tissue of the testes of rats exposed to (Afifi et al 1991), cadmium (Shimada et al 2009) like in O. elegans exposed to carbaryl.…”

“…Effects of methyl thiophanate on liver (Buono et al 2007), on adrenal gland (De Falco et al 2007), on thyroid (Sciarrillo et al 2008) were examined in a lizard, Podarcis sicula. Toxic effects of oral hexahydro-1,3,5-triazine and 2-amino-4,6-dinitrotoluene were also studied in terms of histopathologic changes in S. occidentalis (McFarland et al 2009(McFarland et al , 2011.…”

Stereoselective metabolism, distribution, and bioaccumulation brof triadimefon and triadimenol in lizards

“…Dosing was prepared according to those described previously with modifications (Di Renzo et al, 2009;McFarland et al, 2011McFarland et al, , 2009Suski et al, 2008). TF was first dissolved in the ethanol (analytical grade, Beijing Chemical Reagent Co. Ltd, China) then dispersed in corn oil (ethanol:corn oil was 1:9, v/v).…”

Multiple environmental stressors elicit complex interactive effects in the western fence lizard (Sceloporus occidentalis)

“…Similarly, MCs affect reproductive organs in the WFL. Earlier studies (McFarland et al 2008(McFarland et al , 2009) have demonstrated a negative influence on testes mass and abnormal histopathology in lizards exposed to 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazine (RDX).…”