Bismuth: health and environmental effects-Metalpedia

Scientific literature concurs that bismuth and most of its compounds are less toxic compared to other heavy metals ( lead, antimony, etc.) and that it is not bioaccumulative. They have low solubilities in the blood, are easily removed with urine, and showed no carcinogenic, mutagenic or teratogenic effects in long-term tests on animals (up to 2 years). Its biological half-life for whole-body retention is 5 days but it can remain in the kidney for years in patients treated with bismuth compounds.
Bismuth poisoning exists and mostly affects the kidney, liver, and bladder, although the degree of such damage is usually mild. Skin and respiratory irritation can also follow exposure to respective organs. Serious and sometimes fatal poisoning may occur from the injection of large doses into closed cavities and from extensive application to burns (in the form of soluble bismuth compounds). It is stated that the administration of bismuth should be stopped when gingivitis appears, for otherwise serious ulceration stomatitis is likely to result. Other toxic results may develop, such as a vague feeling of bodily discomfort, the presence of albumin or other protein substances in the urine, diarrhea, skin reactions and sometimes serious exodermatitis.

Bismuth metal is not considered toxic and poses minimum threat to the environment. Bismuth compounds generally have very low solubility but they should be handled with care, as there is only limited information on their effects and fate in the environment.