Arsenical

An arsenical is a term used for any compound that contains arsenic. In chemistry, arsenicals include inorganic species such as arsenites (As III) and arsenates (As V), as well as a wide range of organoarsenicals with carbon–arsenic bonds. Many arsenicals are toxic to humans and animals, and their use is tightly regulated depending on the context and country.

In medicine, arsenicals have had a significant historical role and continue to be used in limited, controlled ways. Salvarsan (arsphenamine) and related arsenic-containing drugs were among the first antimicrobial agents for syphilis. Arsenic trioxide is used today to treat acute promyelocytic leukemia, often alongside retinoic acid. Some organoarsenicals have served as antiparasitics, such as melarsoprol for treating certain forms of sleeping sickness.

In agriculture and industry, arsenicals have been employed as pesticides, wood preservatives, and feed additives. Their use has declined due to safety concerns, since inorganic arsenic is a persistent toxin that can accumulate in soil, water, crops, and animal products. Environmental and public health concerns—together with regulatory actions—have led to restrictions, bans, or tighter controls on many arsenic-containing products.

Safety and regulation focus on limiting exposure and contamination. Because arsenic compounds can cause acute toxicity and long-term health effects, including cancer, occupational exposure limits are enforced, and monitoring of arsenic levels in air, water, food, and clinical samples is common in affected contexts.