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

MERCURY 113
Renal Effects
2. HEALTH EFFECTS
Inorganic Mercury. The kidney appears to be the critical organ of toxicity for the ingestion of mercuric
salts. Renal effects in humans have been observed following acute oral exposure to inorganic mercury.
Acute renal failure has been observed in a number of case studies of mercuric chloride ingestion (Afonso
and deAlvarez 1960; Murphy et al. 1979; Samuels et al. 1982). An autopsy of a 35-year-old man who
ingested a lethal dose of mercuric chloride and exhibited acute renal failure showed pale and swollen
kidneys (Murphy et al. 1979). A case study reported acute renal failure characterized by oliguria,
proteinuria, hematuria, and granular casts in a woman who ingested 30 mg Hg/kg as mercuric chloride
(Afonso and deAlvarez 1960). Another case study reported a dramatic increase in urinary protein secretion
by a patient who ingested a single dose of 15.8 mg Hg/kg as mercuric chloride (assuming a body weight of
70 kg) (Pesce et al. 1977). The authors of the report surmised that the increased excretion of both albumin
and β2-microglobulin was indicative of mercury-induced tubular and glomerular pathology. Acute renal
failure that persisted for 10 days was also observed in a 19-month-old child who ingested an unknown
amount of powdered mercuric chloride (Samuels et al. 1982). Decreased urine was observed in a
22-year-old who attempted suicide by ingesting approximately 20 mg Hg/kg (Chugh et al. 1978).
Myoglobin and pigmented casts were observed in the urine, and the authors suggested that these
observations, in combination with a highly elevated level of serum creatine phosphokinase, indicated that
rhabdomyolysis may have contributed to the renal failure.
Ingestion of mercurous chloride has also resulted in renal toxicity in humans. Decreased urinary output and
edema were observed in a 60-year-old woman who ingested an unspecified amount of mercurous chloride
in a Chinese medicine (Kang-Yum and Oransky 1992). Renal failure was a contributing factor in the death
of this woman. Renal failure also developed in two female patients who chronically ingested a mercurous
chloride-containing laxative (Davis et al. 1974).
Renal toxicity has been observed in Fischer 344 rats and B6C3F 1 mice following acute-, intermediate-, and
chronic-duration exposures to mercuric chloride (Dieter et al. 1992; NTP 1993). In the 14-day study,
male and female rats were exposed by gavage to 0.93–14.8 mg Hg/kg/day as mercuric chloride for 5
days a week. There was a significant increase in the absolute and relative kidney weights of males beginning
at the 1.9-mg/kg/day dose level. An increased incidence of tubular necrosis was observed in rats exposed to
at least 3.7 mg/kg/day; severity progressed with increasing dose levels. Increases in urinary levels of
alkaline phosphatase, AST, and LDH were also observed at 3.7 mg Hg/kg/day; at 7.4 mg Hg/kg/day,