Intoxicação por mercúrio - factos, dúvidas e ficção

O mercúrio é um metal pesado, tóxico para a saúde. Nem sempre é fácil, contudo, distinguir a realidade do desvario; esta área tem sido, como muitas outras, terreno fértil para especulação pouco assente em factos.

Assim, e como estou com o tempo limitado, fica aqui este fragmento de uma revisão sobre o tema. O resto do artigo, de Novembro de 2005, extenso e bem suportado, encontra-se aqui.

• One major risk factor is industrial contamination.

• Workers, particularly those employed in the manufacturing of mirrors, thermometers, incandescent lights, and x-ray machines, are at risk for inorganic mercury toxicity.

• Organic mercury poisoning can occur among exposed workers in the paper and pulp industries.

• In the United States, exposure to organic mercury is primarily through ingestion of contaminated fish. Those who consume large amounts of seafood from contaminated waters have an increased risk of toxicity. Surveys indicate that public awareness of the risks of mercury-contaminated fish is limited.

• Exposure to contaminated grains, on which mercury was used as a fungicide, has resulted in mercury toxicity in the third world.

• More unusual sources of exposure have included numerous pools of standing and vaporizing liquid mercury in a renovated building in New Jersey. Several residents of this building exhibited urinary mercury levels in the neurotoxic range.

• Also, the Centers for Disease Control and Prevention (CDC) identified at least 3 residents of the southwestern United States who developed toxic effects from a Mexican beauty cream that contained 6-8% mercurous chloride.

• Traditional religious and healing practices are risk factors for mercury exposure. Mercury has been identified as a contaminant of Chinese herbal balls, and it has been used deliberately for its putative supernatural attributes in amulets in the Santeria religion.

• Even the mercury vapors from dental amalgam have been implicated as a possible, though controversial, source of exposure among dental workers and the general population. A recent study of 1663 veterans utilized a wide battery of noncognitive tests and found no clinically evident deficits associated with amalgam exposure. However, a subclinical decrement in vibration as measured by an automated device correlated with amalgam exposure and accounted for 15% of the variance in a multiple regression model.

• Finally, recent concerns about the mercury content of childhood vaccines that utilized mercury derivatives for their antimicrobial and preservative qualities have led to the increased availability of mercury-free vaccines.