ABSTRACT
The element mercury has been known as a speci c chemical from at least as far back as 1500 BC. The physician Paracelsus (AD 1493-1541) attempted to cure syphilis by administering metallic mercury to sufferers of the disease. His treatment was probably based on intuitive or empirical knowledge that at an appropriate dosage, mercury was more toxic to the cause of the disease than to the patient. The true etiology of syphilis was, however, unknown to him. The extent of mercury toxicity for human beings and other animals became very apparent only in recent times as a consequence of environmental pollution by mercury compounds. The toxicity manifests itself in major physical impairments and death from the intake of the compounds in food and water. Incidents of mercury poisoning in Japan (Minimata disease), Iraq, Pakistan, Guatemala, and the United States drew special attention to the problem. In some cases, food was consumed, which had been made from seed grain treated with mercury compounds to inhibit fungal damage before planting. The seed grain had not been intended for food use. In other cases, food such as meat had become tainted because the animals yielding the meat drank water that had become polluted by mercury compounds or they had eaten mercury-tainted feed. Tracing the fate of mercury introduced into the environment has revealed an intimate role of microbes in the interconversion of some mercury compounds.
