Influence of oral 2,4-dinitrotoluene exposure to the northern bobwhite (Colinus virginianus).

Military activities associated with training, munitions manufacturing, and demilitarization has resulted in soil residues of munition compounds and their breakdown products. Two isomers of dinitrotoluene (2,4- and 2,6-) are often found in soil associated with those activities at considerable concentrations. Consequently, issues regarding the effects of exposure to birds that visit these habitats require evaluation. To provide data useful to a risk assessment approach, we followed a controlled dosing regime (gavage) using 2,4-dinitrotoluene (2,4-DNT) in the Northern Bobwhite (Colinus virginianus) for 60 days following a 14-day range-finding study and the determination of a LD50 using the up/down method. The LD50 was determined to be 55 mg/kg using corn oil as a vehicle. Individuals dosed exceeding this level were moribund or died within 60 h of exposure. Morbidity and death occurred during the 14-day range-finding study at dosing regimens of 35 and 55, but not at 15, 5, and 0.5 mg/kg-day. Compound-related morbidity/mortality occurred in the 60-day study during the first week of exposure at 25 and 15, but not at 5, 1, and 0 mg/kg-day. Overt signs of toxicity occurred with both sexes at the onset of exposure. Signs included weight loss, diarrhea, and lethargy. Dose-related changes in egg production, ovary, kidney, and brain mass, and body weight, but not feed consumption, were found. Changes in kidney mass and histological observations suggest accumulation of nitrogenous waste may be the cause of morbidity. These data suggest that oral 2,4-DNT exposures are more acutely toxic and has a different etiology than 2,4,6-trinitrotoluene in birds.