Toxicity Profile for Phosphoric acid and common inorganic phosphates (1993)

Abstract

Phosphorus is an essential body constituent. The phosphate anion is a normal body metabolite and is present naturally in the diet. Phosphoric acid was irritant or corrosive to the skin, eyes and other mucous membranes of man and laboratory animals; its salts, in general, exhibited a lower irritant potential. Ingestion of phosphoric acid has apparently caused a human fatality due to its caustic properties. The acid and its salts have generally shown a low acute oral and dermal toxicity in laboratory animals, whilst in a Soviet experiment phosphoric acid exhibited a moderate acute inhalation toxicity in mice. Ingestion of phosphates by man may result in electrolyte imbalances in the body which, if excessive, can disrupt the function of a variety of organ systems. In particular, high phosphate intakes can affect calcium distribution in the body and may in some cases produce soft tissue calcification and affect bone formation. Kidney damage, soft tissue calcification and bone effects were the main findings in laboratory animals fed phosphates repeatedly. No conclusive evidence of reproductive effects have been demonstrated in feeding studies with phosphoric acid or phosphate salts in various species of laboratory animal although limited studies have suggested testicular effects and reduced fertility in rats. No carcinogenic potential was demonstrated in limited feeding studies in rats treated with phosphoric acid or several of its salts, however, in rodents treated orally, several phosphates have been shown to promote the effects of known carcinogens. A wide range of genotoxicity assays (including the Ames bacterial test) have yielded essentially negative results with the acid or its salts. There are few reports of sensitization reactions arising from this class of compound, however, one phosphate (diammonium hydrogen phosphate) does seem to have induced sensitization responses in a few subjects.