A comparative study on acute toxicity of methylarsonic acid, dimethylarsinic acid and trimethylarsine oxide in mice

The acute toxicity of methylarsonic acid, CH 3 AsO(OH) 2 (MAA), dimethylarsininc acid, (CH 3 ) 2 AsO(OH) (DMAA), and trimethylarsine oxide, (CH 3 ) 3 AsO (TMAO), were examined in mice with oral administration. The LD 50 values of MAA, DMAA and TMAO were 1.8, 1.2 and 10.6 g kg −1 respectively. The toxicity of MAA and DMAA was very much lower than that for inorganic arsenic compounds. It was shown that TMAO has a similar acute toxicity to arsenobetaine. On the other hand, when the mice were administered 14.4 g kg −1 of TMAO once only orally, a garlic‐like odor (trimethylarsine, (CH 3 ) 3 As) was definitely detectable in the exhalation of the animals by the human olfactory sense within about a few minutes.