Organoleptic Assessment and Median Lethal Dose Determination of Oral Aniline in Rats

Aniline, an aromatic amine, is used as a reagent or precursor in many chemical and industrial processes, including pesticide and pharmaceutical creation. A three-phase approach was used to comprehensively assess aniline as an oral-ingestion hazard. First, the solubility of aniline in popular consumer beverages (bottled water, apple juice, and 2 milk) was assessed, but aniline proved to be poorly soluble and typically formed a suspension at projected lethal concentrations. Lethality was then assessed by administering aniline via gavage in bottled water across varying concentrations. A probit model was fit to 24-hour survival data and predicted a median lethal dose of 762.15 mg/kg (95 CI: 550.30 983.97 mg/kg; slope: 7.05). Intoxication was rapid, with lethargy and ataxia typically occurring within 5 minutes. Tremor and rapid breathing were observed within 30 minutes post-exposure at moderate doses. High doses of aniline produced cyanosis that was often followed by death. Finally, the organoleptic properties (i.e., taste, smell, texture, etc.) were assessed by allowing rats to voluntarily consume 3.0 mL of the above beverages adulterated with aniline at various concentrations. This organoleptic assessment determined that aniline was readily detected at toxic concentrations and rats failed to consume significant amounts of the adulterated beverages except at concentrations equivalent to and lower than the LD01. These results suggest that aniline is not likely to be consumed in toxic or lethal concentrations by humans and primarily remains an occupational hazard and environmental pollutant.