Dose-related Effects Following Oral Exposure of 2,4-Dinitrotoluene on the Western Fence Lizard, Sceloporus occidentalis

Abstract

2,4-dintitrotoluene (2, is an explosive frequently found in the soil of military installations. Because reptiles can be common on these sites, ecological risk assessments for compounds such as 2,4-DNT could be improved with toxicity data specific to reptiles. Western fence lizards, Sceloporus occidentalis, were used to develop a laboratory toxicity model for reptiles. A hierarchical approach was used; acute to subchronic studies were conducted to provide toxicity data relevant to short-and longterm exposures. First, a modified median lethal dose (LD50) study was conducted on male and female lizards using a stage-wise probit model. The LD50 was 577 mg/kg for female and 380 mg/kg for male lizards. Subsequently, a subacute experiment was conducted to further assess 2,4-DNT toxicity to male lizards and to define exposure levels for a longer term, subchronic study. The subchronic study was conducted for 60 consecutive days; male lizards were exposed to 0, 9, 15, 25, 42, 70 mg/kg/d. Dosedependent mortality was observed in the three highest dose groups (25, 42, and 70 mg/kg/d); all other animals survived the study duration. Benchmark dose model calculations based on mortality indicated a 5% effect level of 15.8 mg/kg/d. At study termination, a gross necropsy was performed, organ weights were taken, and blood was collected for clinical and hematological analysis. Body weight, kidney weight, food consumption, postdose observations, and blood chemistries all were found to be significantly different from controls at doses above 9 mg/kg/d. Also, preliminary results suggest behavioral observations, and reduced food consumption may be a sensitive indicator of toxicity. The present study indicates Sceloporus occidentalis is suitable for evaluating toxicity of compounds to reptilian species.

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).…”

Tissue distribution, metabolism and hepatic tissue injury in Chinese lizards (Eremias argus) after a single oral administration of lambda-cyhalothrin

“…To ensure that the corn oil was homogenously mixed with LCT, the dosing method was set up in steps (Suski et al, 2008;McFarland et al, 2012). LCT was first dissolved in methanol and then dispersed into the corn oil (methanol/oil ¼ 1/9, v/v, total volume 20 mL).…”

Biodegradation of 2,4-dinitrotoluene by different plant species

“…Both 2,4-and 2,6-DNT are highly toxic to different organisms including rats , carp (Zheng and Xu, 2012;Shen et al, 2010), reptile (Suski et al, 2008), amphibian (Paden et al,2011) and invertebrates (Karnjanapiboonwong et al, 2009),. There is, however, little information about the toxicity of 2,4-and 2,6-DNT to higher plants, especially to the crop plants.…”