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

MERCURY 343
2. HEALTH EFFECTS
Inhalation exposure to metallic mercury vapors for an intermediate duration has resulted in renal and/or
neurological effects in rabbits (Ashe et al. 1953) and rats (Fukuda 1971; Kishi et al. 1978). No studies
were located regarding effects in animals after intermediate-duration inhalation exposure to organic
mercury. An intermediate inhalation MRL was not derived for metallic mercury because studies were
considered inadequate. Following intermediate-duration oral exposure to inorganic mercury, adverse
cardiovascular, hepatic, and renal health effects have were observed in rats and mice exposed to mercuric
chloride (Andres 1984; Carmignani et al. 1992; Dieter et al. 1992; Hultman and Enestrom 1992; Jonker et
al. 1993a; NTP 1993; Rana and Boora 1992). Immunological and neurological health effects were also
observed (Chang and Hartmann 1972a; Dieter et al. 1983; Hultman and Enestrom 1992). An intermediate
oral MRL was derived for inorganic mercury based on increased kidney weight in rats (NTP 1993).
Intermediate-duration oral exposure to organic mercury has resulted in adverse cardiovascular, renal,
immunological, neurological, and developmental health effects in rats, mice, cats, and monkeys (Berthoud
et al. 1976; Burbacher et al. 1988; Chang and Hartmann 1972a; Chang et al. 1974; Concas et al. 1983;
Elsner 1991; Evans et al. 1977; Fowler 1972; Fowler and Woods 1977; Ganser and Kirschner 1985;
Hirano et al. 1986; Ilback 1991; Khera and Tabacova 1973; Leyshon and Morgan 1991; Lindstrom et al.
1991; MacDonald and Harbison 1977; Magos and Butler 1972; Mitsumori et al. 1981; Olson and Boush
1975; Sharma et al. 1982; Tsuzuki 1981; Wakita 1987; Yip and Chang 1981). The data were insufficient
to derive an intermediate-duration MRL for oral exposure to organic mercury because serious adverse
health effects (e.g., neurological degeneration, behavioral changes) were observed at the lowest doses
(Burbacher et al. 1988; Chang et al. 1974; Chang and Hartmann 1972a). No studies were located
regarding intermediate-duration dermal exposure in animals. Because populations surrounding hazardous
waste sites might be exposed to higher-than-normal levels of mercury for an intermediate duration, more
quantitative information on metallic and organic mercury toxicity, specifically neurotoxicity, following
inhalation and oral exposure in humans and animals is needed. The potential for latent or delayed
expression of toxicity after an exposure of intermediate duration needs to be addressed.
Chronic-Duration Exposure and Cancer. Occupational exposure to metallic mercury vapors has
been reported to result in adverse cardiovascular, gastrointestinal, renal, ocular, immunological, and
reproductive health effects (Barregard et al. 1988, 1990; Bencko et al. 1990; Bidstrup et al. 1951; Buchet
et al. 1980; Cardenas et al. 1993; Cordier et al. 1991; Danziger and Possick 1973; Ehrenberg et al. 1991;
Kazantzis et al. 1962; Langworth et al. 1992b; Lille et al. 1988; Moszczynski et al. 1990b; Piikivi 1989;
Piikivi and Hanninen 1989; Roels et al. 1982; Schuckmann 1979; Siblerud 1990; Smith et al. 1970;
Stewart et al. 1977; Tubbs et al. 1982; Vroom and Greer 1972). Substantial evidence indicates that