Acetic Acid (alias of Vinegar acid)

CAS RN: 64-19-7

Toxicity Summary

IDENTIFICATION AND USE: Acetic acid is a colorless liquid or solid, having a pungent characteristic odor, and when diluted in water an acidic taste. Glacial acetic acid is a 99% active chemical. It is used as an acidifier, flavoring agent, for the prevention of rope in baking, and as a solvent. Acetic acid is used as a laboratory reagent in chemical and biochemical analysis, in field testing of lead fumes, vinyl chloride determination, uric acid in urine, aniline vapors, and separation of gases. In addition, acetic acid is used in pesticide formulations as a herbicide to controls weeds on fruits, vegetables, ornamentals and turf. It is also a component of the hydraulic fracturing fluids preventing precipitation of metal oxides (iron control). Registered for use in the U.S., but approved pesticide uses may change periodically, so federal, state and local authorities must be consulted for currently approved uses. Three to 5% acetic acid is commonly used in the field of gynecology for colposcopic examinations of the cervix. It gives an 'acetowhite' effect that may assist clinicians in identifying neoplastic areas. HUMAN EXPOSURE AND TOXICITY: Acetic acid is absorbed from the gastrointestinal tract and through the lungs and almost completely oxidized by tissues. The metabolic pathways are reasonably well known and involve the formation of ketone bodies. As little as 1.0 mL of glacial acetic acid has resulted in perforation of the esophagus. During acetic acid dialysis, patients showed a frequent onset of sudden hypotension and arrhythmia with concomitant symptoms of the so-called disequilibrium syndrome. Extreme eye and nasal irritation has occurred at concentrations in excess of 25 ppm and conjunctivitis from concentrations below 10 ppm has been reported. Glacial acetic acid has caused permanent corneal opacification. Ingestion of 200 mL of an 80% solution of acetic acid caused repeated shock due to myocardial infarction and massive intestinal bleeding led to an organic brain psychosyndrome. The patient survived the intoxication by use of hemodialysis and intensive care therapy. An excess of prostate cancer was observed among former chemical plant workers, some of whom had been exposed to both acetic acid and acetic anhydride. ANIMAL STUDIES: Toxic effects of acetic acid are due to irritant properties as well as its effect on the central nervous system and kidneys. Large oral doses cause CNS depression and death in rats and mice. Inhalation of 16,000 ppm killed 1 of 6 exposed rats. Groups of 3-6 rats were given acetic acid in drinking water for periods from 9-15 weeks. Fluid uptake was the same in all treatment groups, at the high dose group there was a progressive reduction in body weight gain, loss of appetite and fall in food consumption. Four groups of two young pigs were fed daily diets for successive 30 day periods for a total of 150 days. There were differences in growth rate, weight gain, early morning urinary ammonia and terminal blood pH between controls and test groups. Acetic acid had no effects on implantation or on maternal or fetal survival in rats, mice or rabbits dosed via gavage during gestation days 6-19 at doses up to 1600 mg/kg/day. The number of abnormalities seen in either soft or skeletal tissues of the test groups did not differ from the number occurring in the controls. Acetic acid has shown no evidence of mutagenic activity with or without metabolic activation using several strains of Salmonella typhimurium. Acetic acid did not show clastogenicity on cultured Chinese hamster ovary K1 cells at neutral pH, but it was clastogenic at pH 5.2 to 6.0 with or without metabolic activation. ECOTOXITY STUDIES: Acetic acid was harmful to aquatic life. High concentrations produced pH levels toxic to oxidizing bacteria, inhibiting oxygen demand. It was lethal to Mosquito fish: at 320 ppm and higher all fish were dead at 24 hours.
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