toxicological profile for malathion - Agency for Toxic Substances and ...

MALATHION 69
3. HEALTH EFFECTS
peroxidase activity in the liver of female Swiss albino mice treated with 30 mg/kg/day malathion
(98% pure) for 14 days (Chhabra et al. 1993). The same result was obtained following 21 days of
treatment, with the added finding of a significant decrease in liver glutathione reductase activity (Chhabra
et al. 1993).
No significant effects on liver weight were reported in rats following a single gavage dose of 500 mg/kg
of malathion (unspecified purity) (Bulusu and Chakravarty 1984) or following administration of
approximately 11.5 mg/kg/day malathion (>99% pure) in the food to Wistar rats for 8–22 weeks
(Banerjee et al. 1998) or 75 mg/kg/day malathion (95% pure) to CFY rats in the food for 90 days (Desi et
al. 1976). However, mice given approximately 21 mg/kg/day malathion (>99% pure) in the diet for 3–
12-weeks had increased relative liver weight (Banerjee et al. 1998). Increased absolute and relative liver
weight was reported in male and female Fischer-344 rats administered 359 or 415 mg/kg/day of
malathion (97.1% pure), respectively, in the diet for 2 years (Daly 1996a), no significant effects were seen
at 29 mg/kg/day in males or 35 mg/kg/day in females.
The data in animals suggest that the nonneoplastic liver changes may represent adaptive responses unless
very high bolus doses are administered, which may cause more serious histopathologic damage.
Renal Effects. Renal abnormalities in humans have been observed in several case reports. Five
poisoning cases (Crowley and Johns 1966; Dive et al. 1994; Healy 1959; Namba et al. 1970; Zivot et al.
1993) reported a variety of urinary/renal changes following malathion ingestion. It should be kept in
mind, however, that many of these cases resulted in death or near death, such that the true toxicological
significance of the findings is unclear. In a subject who ingested approximately 514 mg/kg of malathion,
protein was found in the urine, and mild renal insufficiency (measured by creatinine clearance) was
observed (Dive et al. 1994). In another case, after ingestion of approximately 600 mg/kg of malathion,
protein, sugar, and white blood cells were found in the urine (Crowley and Johns 1966). At a dose of
approximately 1,045 mg/kg, protein and glucose again were also seen (Namba et al. 1970). Decreased
urine production and a urinary tract infection (with Escherichia coli) were observed prior to death in an
80-year-old woman who ingested an undetermined amount of malathion (Zivot et al. 1993). Healy (1959)
found increased secretion of ketone bodies and glucose in the urine in an 18-month-old boy who ingested
malathion.
No remarkable alterations in urynalises were observed in a study in which male volunteers were
administered daily capsules containing malathion (purity not reported) in corn oil that provided an