Toxic substances list: ammonia dissolved in water

Ammonia exists in two forms simultaneously, with the equilibrium between the two forms governed in large part by pH and temperature. The forms are NH3 (un-ionized ammonia) and NH4+ (ionized ammonia or ammonium). Together they are called total ammonia. It is the NH3 form that is particularly harmful to aquatic organisms. The primary human use of ammonia is as a nitrogen source in fertilizers, especially anhydrous ammonia and urea. Ammonia is released into the environment by many industries and other human activities. The major quantifiable sources of ammonia released to aquatic ecosystems across Canada are wastewater treatment plants. Ammonia is also a naturally occurring compound required by most organisms for protein synthesis and a waste product of animal, fish and microbial metabolism.

CAS (Chemical Abstract Service) registry number: 7664-41-7

Risk Assessment

Risk Management Strategy

Click on the following link to view strategies and actions recommended to manage risks associated with the substance:

Risk Management Tool(s)

Tool(s) developed to manage risks associated with the substance:


Consultation (past and present) on the substance:

Other Information


Substances Management Information Line
Chemicals Management Plan
Gatineau, QC K1A 0H3
Telephone: 1-800-567-1999 (in Canada) or 819-938-3232
Fax: 819-938-3231

Return to Substance List

Page details

Date modified: