Behavioral effects of mercury and methylmercury.

Intoxication by elemental mercury or by methylmercury is revealed primarily by changes in behavior and by neurological signs. Disorders of movement and posture have been most widely reported, both in animal experiments and in cases of human exposure. Specific sensory symptoms are also prominent in human methylmercury poisoning. Recent data indicate similar symptoms in monkeys during long-term exposure to methylmercury. Similar sensory impairment has not been described in experiments with subprimates. Variations in the profile of behavioral and neurological effects are discussed in terms of differences in species and differences between acute and long-term exposure. The latter condition poses the most difficult questions for human health, yet has been less frequently studied. Procedures are suggested that may help to revolve these problems. In particular, tests of learned behavior hold great promise toward identifying specific symptoms and toward understanding how mercury compounds affect behavior.