Ammonium sulfate

CAS RN: 7783-20-2

Toxicity Summary

IDENTIFICATION AND USE: Ammonium sulfate is a white solid. Ammonium sulfate is used primarily as a nitrogen source in commercial fertilizer mixtures or as a direct application fertilizer, which accounts for > 90 % of the total amount. It is further used in a variety of industrial applications and is also approved as a direct food additive in the EU. It is registered for use in the USA but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses. Non-agricultural products containing ammonium sulfate which are intended for use by the general public (e.g. cleaning products, paints); contain ammonium sulfate levels up to 50%. Ammonium sulfate has been identified as being used in hydraulic fracturing as a breaker. HUMAN EXPOSURE AND TOXICITY: In humans, inhalation exposure to 0.1 to 0.5 mg ammonium sulfate/cu m aerosol for two to four hours produced no pulmonary effects. At 1 mg ammonium sulfate/cu m very slight pulmonary effects in the form of a decrease in expiratory flow, in pulmonary flow resistance and dynamic lung compliance were found in healthy volunteers after acute exposure. 18 people who drank water polluted with ammonium sulfate fertilizer (1500 - 2000 mg/L) suffered gastrointestinal pain similar to acute enteritis. All symptoms passed after 24 hr. It did not induce chromosomal aberrations in mammalian or human cell cultures. Ammonium is also an endogenous substance that serves a major role in the maintenance of the acid-base balance. Minor amounts of ammonium nitrogen are incorporated in the physiological N-pool. Sulfate is a normal intermediate in the metabolism of endogenous sulfur compounds, and is excreted unchanged or in conjugated form in urine. ANIMAL STUDIES: Ammonium sulfate is of relatively low acute toxicity (LD50, oral, rat: 2000 - 4250 mg/kg bw; LD50 dermal, rat/mouse > 2000 mg/kg bw; 8-hr LC50, inhalation, rat > 1000 mg/cu m). Clinical signs after oral exposure included staggering, prostration, apathy, and labored and irregular breathing immediately after dosing at doses near to or exceeding the LD50 value. Neat ammonium sulfate was not irritating to the skin and eyes of rabbits. A 14-day inhalation study on rats exposed to 300 mg/cu m, the only tested dose, did not report histopathological changes in the lower respiratory tract. After feeding diets containing ammonium sulfate for 13 weeks to rats the only toxicity sign found was diarrhea in male animals of the high-dose group. The total dose of 1500 mg/kg of ammonium sulfate was administered to three rabbits, all of which showed similar symptoms such as mydriasis, irregular respiratory rhythms, local and general convulsions, until they fell into respiratory failure with cardiac arrest. EEG showed slow, suppressive waves and high-amplitude slowing wave pattern, which is generally observed clinically in hyperammonemia in man and animal. There was a remarkable increase in the concentration of ammonium ion and inorganic sulfate ion in serum, and blood gas analysis showed severe metabolic acidosis. These results, mainly findings by EEG, have shown that a rapid increase in ammonium ions in blood can cause damaging the central nervous system without microscopic change. Ammonium sulfate was not mutagenic in bacteria (Ames test) and yeasts with and without metabolic activation systems. It did not induce chromosomal aberrations in mammalian or human cell cultures. Similarly to other salts, high doses of ammonium sulfate may have the capability of tumor promotion in the rat stomach; it is, however, much less potent than sodium chloride when tested under identical conditions. In the 13-week feeding study of ammonium sulfate with rats, no histological changes of testes were observed up to 1792 mg/kg bw. The ovaries were not examined. ECOTOXICITY STUDIES: The most sensitive amphibians were 6 week-old Pseudacris regilla tadpoles. Marine acute data are available for fish, invertebrates and for phytoplankton, the latter being most sensitive. For Gymnodinium splendens and Gonyaulax polyedra, growth reduction was found at concentrations of 0.7 mg/L and above. For seawater invertebrates the lowest effect value was obtained for green mussel Perna viridis (96h-LC50 = 47.7 mg/L). For marine fish the lowest effect value was found for larvae of Sciaenops ocellatus with a LC50 (10 d) of 27 mg/L.
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