revised final - Agency for Toxic Substances and Disease Registry ...

MERCURY 263
2. HEALTH EFFECTS
exposure to only a few drops of dimethylmercury is striking example of the danger of these forms of organic
mercury (Blayney et al. 1997; Nierenberg et al. 1998). At least 5 other deaths have been reported due to alkyl
mercury exposure since its first synthesis in the mid-19th century (Toribara et al. 1997). These accidental
poisoning cases also reveal a latency period of some months between the exposure and the onset of
symptoms. In such cases, irreversible brain damage has already occurred by the time the first symptoms
appeared.
No information was located regarding specific concentrations of elemental mercury vapor that may be lethal;
however, lethal exposures have generally occurred as a result of exposure under conditions in which exposure
levels are likely to be quite high (e.g., heating metallic mercury in a closed space). Death in these cases has
generally been attributed to respiratory failure (Campbell 1948; Kanluen and Gottlieb 1991; Matthes et al.
1958; Rowens et al. 1991; Soni et al. 1992; Taueg et al. 1992; Teng and Brennan 1959; Tennant et al. 1961).
Deaths resulting from inhalation exposure to organic mercury compounds have also been reported (Brown
1954; Hill 1943; Hook et al. 1954; Lundgren and Swensson 1949). Although the cause of death following
inhalation of organic mercury was not reported, severe neurological dysfunction was observed prior to death.
Lethal doses for acute oral exposure to inorganic mercury have been estimated to be 29–50 mg Hg/kg (Troen
et al. 1951). Deaths resulting from oral exposure to inorganic mercury have been attributed to renal failure,
cardiovascular collapse, and severe gastrointestinal damage (Gleason et al. 1957; Kang-Yum and Oransky
1992; Troen et al. 1951).
Deaths from consumption of methylmercury-contaminated foods are well documented in outbreaks in Japan
and Iraq, and lethal doses of 10–60 mg Hg/kg have been estimated from tissue concentrations (Bakir et al.
1973; Tsubaki and Takahashi 1986). Fatalities were attributed to central nervous system toxicity (Bakir et al.
1973; Tamashiro et al. 1984). Pneumonia and nonischemic heart disease were prominent secondary causes of
death in the Japan epidemic (Tamashiro et al. 1984). Case reports of deaths associated solely with dermal
mercury exposure to inorganic mercury are limited to a woman who died after inserting a mercuric chloride
tablet into her vagina (Millar 1916) and a man who died after a 2-month treatment with a topical medicine
containing mercurous chloride (Kang-Yum and Oransky 1992). Death was attributed to renal failure in one
of these cases (Kang-Yum and Oransky 1992), and severe renal damage was noted at the autopsy in the other
(Millar 1916).