Cobalt: An Update Review from Biokinetic and Toxicological Data to Treatment after Internal Exposure

Cobalt is an essential element with a wide range of applications. It is made up of one stable isotope ( 59 Co) and 36 radioactive isotopes, including 60 Co, the only one with a half-life of more than one year. It is an activation product, and irradiation is the main mode of exposure to 60 Co. Nevertheless, the risk of internal contamination should not be overlooked, particularly for workers who may be involved in maintenance tasks in nuclear power plants or on dismantling sites. The general population may also be affected in the event of a reactor accident where 60 Co would be released with other radionuclides. The health effects of exposure to stable cobalt are mainly respiratory and cutaneous. However, the recently revealed carcinogenic nature of certain cobalt compounds calls for vigilance. Otherwise, the radiotoxicity of cobalt has not yet been explored. In view of the many uses of cobalt and the potential exposures identified, effective means of protection for humans and their environment are of paramount importance. To date, in the event of incorporation by inhalation, ingestion, or cutaneous injury, the current pharmacological treatments offer perfectible efficacy. This review article outlines an updated state of knowledge on cobalt, with a special focus on its biokinetic and toxicological data, the recommended medical countermeasures, and the research in progress in this field. Finally, this review suggests new research perspectives, particularly in the field of medical countermeasures, an area of utmost importance in terms of radiation protection and occupational health.