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Environmental fate & pathways


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Description of key information

According to structural properties, hydrolysis is not expected/probable.

Key value for chemical safety assessment

Additional information

Hydrolysis of ammonium sulfate does not occur. In aqueous solution, ammonium sulfate is completely dissociated into the ammonium ion (NH4+) and the sulfate anion (SO42-). Depending on pH, ammonia (NH3) exists in equilibrium with the ammonium ion (NH4+), according to the following relationship:


           NH4+ + H2O <-> NH3 + H3O+


In general, as pH increases, the fraction of the total ammonia which is un-ionized increases. For example, at 5 °C and pH 6.5, 0.0395% of the total ammonia is present as NH3. Increasing the pH from 6.5 to 8.5 will increase the un-ionized ammonium by a factor of approximately 100 (Rice and Bailey 1980). Increasing the temperature will also increase the percentage of unionized ammonium. For example, in seawater at 25 °C and pH of approximately 8.1, approximately 7% of the total ammonia is present as NH3.


Holt GJ, Arnold CR (1983). Effects of Ammonia and Nitrite on Growth and Survival of Red Drum Eggs and Larvae. Transactions of the American Fisheries society 112: 314-318.

OECD (2007). SIDS Initial Assessment Report. Ammonium Sulfate, CAS Number: 7783-20-2.

Riceand Bailey JE (1980). Survival, size, and emergence|of pink salmon, Oncorhynchus gorbuscha, alevins after short- and long-term exposures to ammonia. Fishery Bulletin. 78: 641-648.