Additional notes from Canadian government: CANADA Total Kjeldahl Nitrogen (TKN) – refers to a method used in the determination of nitrogen in its trinegative state including organic nitrogen plus ammonia nitrogen.

 

Limits:

Maine Maximum Exposure Guideline limit:

USA Primary Drinking Water Standard limit:

USA Secondary Drinking Water Standard limit:

Canada Health standard limit:

Canada Aesthetic standard limit:

USA daily recommended allowance:

Other standard:

 

Additional Resources: