Bismuth isn’t as innocent as expected either, often used in medicine it can be absorbed, build up and migrate around the body with excessive exposure. Some 1st nation subsistence hunters have already suffered from bismuth poisoning. This same article states that bismuth is rare, one of the least understood elements and is usually only produced as a by product of mining other heavy metals. This is an exert from an article that was written before bismuth became common as a lead shot replacement.
Side Effects of Bismuth
“Although bismuth is considered to be nontoxic as stated previously, the long-term use of bismuth may result in certain degree of side effects on human subjects. Besides the few cases caused by occupational exposure to bismuth in the manufacturing industry, most of the poisoning incidents occur in the form of accidental or deliberate over-dosage of bismuth drugs. The extent of bismuth toxicity depends on individual cases, i.e., the types of bismuth compounds and the amounts absorbed. It is still not clear why only selected individuals develop bismuth toxicity.
Patients suffer toxicity at different bismuth levels in blood but the syndrome is rare when bismuth levels are below 50 μg/L. Among the bismuth-based regimens, the use of insoluble bismuth compounds such as bismuth oxychloride and bismuth subcarbonate are related to low toxicity, whereas the use of soluble bismuth organic compounds such as bismuth sodium tartrate and tripotassium dicitratobismuthate, or the combined use of bismuth with thiolate-containing ligands, are associated with high toxicity, such as neurotoxicity and nephrotoxicity. This is probably due to the enhanced uptake of soluble bismuth salts in human bodies. It has also been suggested that the oral bismuth drugs need to undergo methylation by intestinal microbes to enable them to be absorbed. Absorbed bismuth will accumulate in the kidneys, lungs, spleen, liver, brain, and muscles, and will be eliminated in urine and feces via bile and intestinal secretions. In the clinic, depending on the administration time of bismuth, its toxicity can be roughly divided into acute and chronic exposures. Both exposure doses can cause neurotoxicity, gastrointestinal toxicity, nephrotoxicity, hepatotoxicity, and increased bismuth concentration in blood. In spite of the toxicity, most of these side effects can be alleviated after the discontinuation of bismuth therapies. Bismuth iodoform paraffin paste (BIPP), which reduces the risk of bacterial infection, renders a deep necrotic wound cavity clean and promotes the development of granulation tissue, and is widely used in oral, maxillofacial, and ENT surgery (ear, nose, and throat surgery) as an antiseptic dressing. However, a few examples of serious adverse effects of BIPP were observed in the clinic when some patients were treated with BIPP. In one case, the patient became acutely confused and the gait became unsteady, indicative of an encephalopathy caused by over-dosage of bismuth. This was confirmed by the observation of a toxic level of bismuth in the patient’s serum. Another case involved using BIPP to cover the dura mater in a wound after removal of a large basal cell carcinoma. The patient became confused and then comatose. An encephalopathy was confirmed by the observation of diffuse cerebral edema in a tomographic scan. However, upon removal of the BIPP, the patient recovered, and deteriorated if the pack was applied again. The mechanism of intoxication has not been well understood till now. It was probably caused by the interference of bismuth with the oxidative metabolism of the central nervous system by binding to essential enzymes and reducing cerebral blood flow”