Organic mercury compounds: human exposure and its relevance to public health

Abstract

Humans may be exposed to organic forms of mercury by either inhalation, oral, or dermal routes, and the effects of such exposure depend upon both the type of mercury to which exposed and the magnitude of the exposure. In general, the effects of exposure to organic mercury are primarily neurologic, while a host of other organ systems may also be involved, including gastrointestinal, respiratory, hepatic, immune, dermal, and renal. While the primary source of exposure to organic mercury for most populations is the consumption of methylmercury-contaminated fish and shellfish, there are a number of other organomercurials to which humans might be exposed. The antibacterial and antifungal properties of organomercurials have resulted in their long use as topical disinfectants (thimerosal and merbromin) and preservatives in medical preparations (thimerosal) and grain products (both methyl and ethyl mercurials). Phenylmercury has been used in the past in paints, and dialkyl mercurials are still used in some industrial processes and in the calibration of certain analytical laboratory equipment. The effects of exposure to different organic mercurials by different routes of exposure are summarized in this article.

Toxicity of organic and inorganic mercury species in differentiated human neurons and human astrocytes

“…Organic mercury (Hg) compounds are important neurotoxicants capable of damaging the developing and adult nervous system [1]. Due to its accumulation in the aquatic food chain, chronic exposure to methylmercury (MeHg) via seafood intake still poses a risk to human health [2].…”

Trophodynamics of inorganic pollutants in a wide-range feeder: The relevance of dietary inputs and biomagnification in the Yellow-legged gull (Larus michahellis)

“…Aquatic organisms, and those exploiting aquatic resources, are particularly exposed to increasing levels of pollutants as aquatic systems are usually the ultimate pollutant sink, either due to diffuse sources, or direct discharges from the terrestrial and atmospheric compartments. In addition, the increasing fish consumption by most human populations (FAO, 2005) raises the need of understanding the trophodynamics of these contaminants, particularly in those marine and freshwater foodwebs (Dewailly and Knap, 2006;Risher et al, 2002;Simmonds et al, 2002;Tchounwou et al, 2003). In this sense, top predators are often suggested as ideal biomonitoring candidates as they integrate pollutant levels along food chains (Becker, 2003;Burger and Gochfeld, 2004;Cabana and Rasmussen, 1994;McIntyre and Beauchamp, 2007).…”

Mercury in Traditional Medicines: Is Cinnabar Toxicologically Similar to Common Mercurials?

“…Until the 1970s, methyl mercury and ethyl mercury compounds were used to protect grain seeds from fungal infection. This use was banned after consumption of organomercury-treated grains in Iraq and China in 1970s leading to mass poisonings with hundreds of deaths (12,13). No methyl mercury is used in any of traditional medicines.…”

“…Mercury can form a number of stable organic metallic compounds by attaching to one or two carbon atoms. Methyl mercury (CH 3 Hg + ) is the toxicologically most important organic form (11), but dimethyl mercury [(CH 3 ) 2 Hg] is the most toxic mercurial (12). Ethyl mercury (C 2 H 5 Hg + ) is the major component of thimerosal, used as preservative in many vaccine preparations routinely administered to infants (13).…”