Water Quality
Water
Quality Criteria for Nitrogen (Nitrate, Nitrite, and Ammonia)
Overview
Report
Prepared
pursuant to Section 2(e) of the
Environment Management Act, 1981
R.
N. Nordin Ph.D.
L. W. Pommen M.Sc. P.Eng.
Resource Quality Section
Water Management Branch
Ministry of Environment and Parks (now called
Ministry of Water, Land and Air Protection)
Original
signed by Ben Marr
Deputy Minister
November 12, 1986
Updated:
August 7, 2001
Table
of Contents
Tables
Preface
Recommended
Guidelines
Application
of the Guidelines
NOTE:
The marine ammonia criteria found in this document have been
replaced by newer values found in the document Ambient
Water Quality Guidelines for Ammonia to Protect Marine Aquatic
Life.
Tables
Table
1. Summary of Water Quality Criteria for Nitrogen
Water
Use
|
Nitrate
mg/L as Nitrogen
|
Nitrite
mg/L as Nitrogen
|
Ammonia
(total)
mg/L as Nitrogen
|
Drinking
Water
|
10
mg/L (maximum)
|
1
mg/L (maximum)
|
None proposed
|
Fresh
Water Aquatic Life - maximum
|
200
mg/L (maximum)
|
0.06
mg/L (maximum)
|
|
Fresh
Water Aquatic Life - average
|
less
than or equal to 40 mg/L (average)
|
0.02
mg/L (average) when the chloride is less than or equal
to 2 mg/L - also see
Table 2
|
|
Marine
Aquatic Life - maximum
|
None
proposed
|
None
proposed
|
2.5 mg/L (maximum)
|
Marine
Aquatic Life - average
|
None
proposed
|
None
proposed
|
less than or
equal to 1.0 mg/L (average)
|
Livestock
Watering
|
100
mg/L (maximum)
|
10
mg/L (maximum)
|
None proposed
|
Wildlife
|
100
mg/L (maximum)
|
10
mg/L (maximum)
|
None proposed
|
Recreation
and Aesthetics
|
10
mg/L (maximum)
|
1
mg/L (maximum)
|
None proposed
|
1.
The average value is calculated from at least 5 weekly
samples taken in a period of 30 days.
2.
Where nitrate and nitrite are present, the total
nitrate-nitrite nitrogen should not exceed these
values.
|
Return
to the Table of Contents
Table
2. Criteria for Nitrite for Protection of Freshwater Aquatic
Life
Chloride
in mg/L
|
Nitrite
(maximum) mg/L as Nitrogen
|
Nitrite
(average)
mg/L as Nitrogen
|
less
than 2 mg/L
|
0.06
mg/L
|
0.02
mg/L
|
2
to 4 mg/L
|
0.12
mg/L
|
0.04
mg/L
|
4
to 6 mg/L
|
0.18
mg/L
|
0.06
mg/L
|
6
to 8 mg/L
|
0.24
mg/L
|
0.08
mg/L
|
8
to 10 mg/L
|
0.30
mg/L
|
0.10
mg/L
|
greater
than 10 mg/L
|
0.60
mg/L
|
0.20
mg/L
|
The
30-day average chloride concentration should be used
to determine the appropriate 30-day average nitrite
criterion.
|
Return
to the Table of Contents
Table
3. Maximum Concentration of Total Ammonia Nitrogen for Protection
of
Aquatic Life (mg/L of Nitrogen)
Temperature
(T) in degrees Celcius
pH
|
T
= 0.0
|
T
= 1.0
|
T
= 2.0
|
T
= 3.0
|
T
= 4.0
|
T
= 5.0
|
T
= 6.0
|
6.5
|
27.7
|
28.3
|
27.9
|
27.5
|
27.2
|
26.8
|
26.5
|
6.6
|
27.9
|
27.5
|
27.2
|
26.8
|
26.4
|
26.1
|
25.8
|
6.7
|
26.9
|
26.5
|
26.2
|
25.9
|
25.5
|
25.2
|
24.9
|
6.8
|
25.8
|
25.5
|
25.1
|
24.8
|
24.5
|
24.2
|
23.9
|
6.9
|
24.6
|
24.2
|
23.9
|
23.6
|
23.3
|
23.0
|
22.7
|
7.0
|
23.2
|
22.8
|
22.5
|
22.2
|
21.9
|
21.6
|
21.4
|
7.1
|
21.6
|
21.3
|
20.9
|
20.7
|
20.4
|
20.2
|
19.9
|
7.2
|
19.9
|
19.6
|
19.3
|
19.0
|
18.8
|
18.6
|
18.3
|
7.3
|
18.1
|
17.8
|
17.5
|
17.3
|
17.1
|
16.9
|
16.7
|
7.4
|
16.2
|
16.0
|
15.7
|
15.5
|
15.3
|
15.2
|
15.0
|
7.5
|
14.4
|
14.1
|
14.0
|
13.8
|
13.6
|
13.4
|
13.3
|
7.6
|
12.6
|
12.4
|
12.0
|
11.9
|
11.9
|
11.7
|
11.6
|
7.7
|
10.8
|
10.7
|
10.5
|
10.4
|
10.3
|
10.1
|
10.0
|
7.8
|
9.26
|
9.12
|
8.98
|
8.88
|
8.77
|
8.67
|
8.57
|
7.9
|
7.82
|
7.71
|
7.60
|
7.51
|
7.42
|
7.33
|
7.25
|
8.0
|
6.55
|
6.46
|
6.37
|
6.29
|
6.22
|
6.14
|
6.08
|
8.1
|
5.21
|
5.14
|
5.07
|
5.01
|
4.95
|
4.90
|
4.84
|
8.2
|
4.15
|
4.09
|
4.04
|
3.99
|
3.95
|
3.90
|
3.86
|
8.3
|
3.31
|
3.27
|
3.22
|
3.19
|
3.15
|
3.12
|
3.09
|
8.4
|
2.64
|
2.61
|
2.57
|
2.54
|
2.52
|
2.49
|
2.47
|
8.5
|
2.11
|
2.08
|
2.06
|
2.03
|
2.01
|
1.99
|
1.98
|
8.6
|
1.69
|
1.67
|
1.65
|
1.63
|
1.61
|
1.60
|
1.59
|
8.7
|
1.35
|
1.33
|
1.32
|
1.31
|
1.30
|
1.29
|
1.28
|
8.8
|
1.08
|
1.07
|
1.06
|
1.05
|
1.04
|
1.04
|
1.03
|
8.9
|
0.871
|
0.863
|
0.856
|
0.849
|
0.844
|
0.839
|
0.836
|
9.0
|
0.703
|
0.697
|
0.692
|
0.688
|
0.685
|
0.682
|
0.681
|
Temperature
(T) in degrees Celcius
pH
|
T
= 7.0
|
T
= 8.0
|
T
= 9.0
|
T
= 10.0
|
T
= 11.0
|
T
= 12.0
|
T
= 13.0
|
6.5
|
26.2
|
26.0
|
25.7
|
25.5
|
25.2
|
25.0
|
24.8
|
6.6
|
25.5
|
25.2
|
25.0
|
24.7
|
24.5
|
24.3
|
24.1
|
6.7
|
24.6
|
24.4
|
24.1
|
23.9
|
23.7
|
23.5
|
23.3
|
6.8
|
23.6
|
23.4
|
23.1
|
22.9
|
22.7
|
22.5
|
22.3
|
6.9
|
22.5
|
22.2
|
22.0
|
21.8
|
21.6
|
21.4
|
21.3
|
7.0
|
21.1
|
20.9
|
20.7
|
20.5
|
20.3
|
20.2
|
20.0
|
7.1
|
19.7
|
19.5
|
19.3
|
19.1
|
18.9
|
18.8
|
18.7
|
7.2
|
18.1
|
17.9
|
17.8
|
17.6
|
17.4
|
17.3
|
17.2
|
7.3
|
16.5
|
16.3
|
16.2
|
16.0
|
15.9
|
15.7
|
15.6
|
7.4
|
14.8
|
14.7
|
14.5
|
14.4
|
14.2
|
14.1
|
14.0
|
7.5
|
13.1
|
13.0
|
12.9
|
12.7
|
12.6
|
12.5
|
12.4
|
7.6
|
11.5
|
11.4
|
11.3
|
11.2
|
11.1
|
11.0
|
10.9
|
7.7
|
9.92
|
9.83
|
9.73
|
9.65
|
9.57
|
9.50
|
9.43
|
7.8
|
8.48
|
8.40
|
8.32
|
8.25
|
8.18
|
8.12
|
8.07
|
7.9
|
7.17
|
7.10
|
7.04
|
6.98
|
6.92
|
6.88
|
6.83
|
8.0
|
6.02
|
5.96
|
5.91
|
5.86
|
5.81
|
5.78
|
5.74
|
8.1
|
4.80
|
4.75
|
4.71
|
4.67
|
4.64
|
4.61
|
4.59
|
8.2
|
3.83
|
3.80
|
3.76
|
3.74
|
3.71
|
3.69
|
3.67
|
8.3
|
3.06
|
3.03
|
3.01
|
2.99
|
2.97
|
2.96
|
2.94
|
8.4
|
2.45
|
2.43
|
2.41
|
2.40
|
2.38
|
2.37
|
2.36
|
8.5
|
1.96
|
1.95
|
1.94
|
1.93
|
1.92
|
1.91
|
1.91
|
8.6
|
1.58
|
1.57
|
1.56
|
1.55
|
1.55
|
1.54
|
1.54
|
8.7
|
1.27
|
1.26
|
1.26
|
1.25
|
1.25
|
1.25
|
1.25
|
8.8
|
1.03
|
1.02
|
1.02
|
1.02
|
1.02
|
1.02
|
1.02
|
8.9
|
0.833
|
0.832
|
0.831
|
0.831
|
0.832
|
0.834
|
0.838
|
9.0
|
0.681
|
0.681
|
0.681
|
0.682
|
0.684
|
0.688
|
0.692
|
Temperature
(T) in degrees Celcius
pH
|
T
= 14.0
|
T
= 15.0
|
T
= 16.0
|
T
= 17.0
|
T
= 18.0
|
T
= 19.0
|
T
= 20.0
|
6.5
|
24.6
|
24.5
|
24.3
|
24.2
|
24.0
|
23.9
|
23.8
|
6.6
|
23.9
|
23.8
|
23.6
|
23.5
|
23.3
|
23.3
|
23.2
|
6.7
|
23.1
|
23.0
|
22.8
|
22.7
|
22.6
|
22.5
|
22.4
|
6.8
|
22.2
|
22.0
|
21.9
|
21.8
|
21.7
|
21.6
|
21.5
|
6.9
|
21.1
|
21.0
|
20.8
|
20.7
|
20.6
|
20.5
|
20.4
|
7.0
|
19.9
|
19.7
|
19.6
|
19.5
|
19.4
|
19.3
|
19.2
|
7.1
|
18.5
|
18.4
|
18.3
|
18.2
|
18.1
|
18.0
|
17.9
|
7.2
|
17.1
|
16.9
|
16.8
|
16.8
|
16.7
|
16.6
|
16.5
|
7.3
|
15.5
|
15.4
|
15.3
|
15.2
|
15.2
|
15.1
|
15.1
|
7.4
|
13.9
|
13.9
|
13.8
|
13.7
|
13.6
|
13.6
|
13.5
|
7.5
|
12.4
|
12.3
|
12.2
|
12.2
|
12.1
|
12.1
|
12.0
|
7.6
|
10.8
|
10.8
|
10.7
|
10.7
|
10.6
|
10.6
|
10.5
|
7.7
|
9.37
|
9.31
|
9.26
|
9.22
|
9.18
|
9.15
|
9.12
|
7.8
|
8.02
|
7.97
|
7.93
|
7.90
|
7.87
|
7.84
|
7.82
|
7.9
|
6.79
|
6.75
|
6.72
|
6.69
|
6.67
|
6.65
|
6.64
|
8.0
|
5.71
|
5.68
|
5.66
|
5.62
|
5.61
|
5.60
|
5.74
|
8.1
|
4.56
|
4.54
|
4.53
|
4.51
|
4.50
|
4.49
|
4.49
|
8.2
|
3.65
|
3.64
|
3.63
|
3.62
|
3.61
|
3.61
|
3.61
|
8.3
|
2.93
|
2.92
|
2.92
|
2.91
|
2.91
|
2.91
|
2.91
|
8.4
|
2.36
|
2.35
|
2.35
|
2.35
|
2.35
|
2.35
|
2.36
|
8.5
|
1.90
|
1.90
|
1.90
|
1.90
|
1.90
|
1.91
|
1.92
|
8.6
|
1.54
|
1.54
|
1.54
|
1.55
|
1.56
|
1.56
|
1.57
|
8.7
|
1.25
|
1.25
|
1.26
|
1.26
|
1.27
|
1.28
|
1.29
|
8.8
|
1.02
|
1.03
|
1.03
|
1.04
|
1.05
|
1.06
|
1.07
|
8.9
|
0.842
|
0.847
|
0.853
|
0.861
|
0.870
|
0.880
|
0.891
|
9.0
|
0.698
|
0.704
|
0.711
|
0.720
|
0.729
|
0.740
|
0.752
|
Return
to the Table of Contents
Table
4. Average 30-Day Concentration of Total Ammonia Nitrogen
for Protection of Aquatic Life (mg/L of Nitrogen)
Temperature
(T) in degrees Celcius
pH
|
T
= 0.0
|
T
= 1.0
|
T
= 2.0
|
T
= 3.0
|
T
= 4.0
|
T
= 5.0
|
T
= 6.0
|
6.5
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
6.6
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
6.7
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
6.8
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
6.9
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
7.0
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
7.1
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
7.2
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
7.3
|
2.08
|
2.05
|
2.02
|
1.99
|
1.97
|
1.94
|
1.92
|
7.4
|
2.08
|
2.05
|
2.02
|
