Water Quality Problem: Ammonia in Warmwater Fish

The ability of ammonia to enter cells increases with pH and temperature in zero-salinity surface water. As levels concentrate in cells, they become toxified. To proceed at this point, you must know the pH, NH3 concentration, and temperature of your water resource.

The table indicates the ammonia levels that are acceptible for the given pH and temperature. If the ammonia concentration is below the given limit, you have no problem. If the concentration in your water resource is higher than that given below, then you have a problem.

Select the answer that most clearly describes your water resource

Also see the State of Missouri criteria for warmwater fish below which is an example of criteria more precise than the EPA values.

Table 2. Chronic Criteria for Total Ammonia (mg/l): Salmonids and Other Sensitive Coldwater Fish Absent*

Temp                            pH
 C   6.5  6.75  7.0  7.25  7.5   7.75  8.0  8.25  8.5  8.75   9.0

 0   2.5  2.5   2.5  2.5   2.5   2.3   1.5  0.9   0.5  0.3  0.2   
 5   2.4  2.4   2.4  2.4   2.4   2.2   1.4  0.8   0.5  0.3  0.2       
10   2.2  2.2   2.2  2.4   2.2   2.1   1.4  0.8   0.4  0.3  0.2   
15   2.2  2.2   2.2  2.4   2.2   2.0   1.3  0.8   0.4  0.3  0.2    
20   2.1  2.1   2.1  2.1   2.1   2.0   1.3  0.8   0.5  0.3  0.2  
25   1.5  1.5   1.5  1.5   1.5   1.4   0.9  0.5   0.3  0.2  0.1    
30   1.0  1.0   1.0  1.0   1.1   1.0   0.7  0.4   0.3  0.2  0.1

(Adapted from EPA, 1986 (to 2 signif. digits))

*The criteria recommendation made by the EPA has a high degree of uncertainty except at 20 degrees C; EPA states that below and above 20 degrees C, limited data are available yet small changes may have a significant impact on the level of treatment required.

Table 4. Acute Criteria for Total Ammonia (mg/l): Salmonids and Other Sensitive Coldwater Fish Absent

Temp                                pH

 C   6.5  6.75  7.0  7.25  7.5   7.75  8.0  8.25  8.5  8.75   9.0

 0   35   32    28   23    17    12    8.0   4.5   2.6  1.5  0.9   
 5   33   30    26   22    16    11    7.5   4.2   2.4  1.4  0.8       
10   31   28    25   20    16    11    7.1   4.1   2.3  1.4  0.8   
15   30   27    24   20    15    11    6.9   4.0   2.3  1.4  0.9    
20   29   27    23   19    15    10    6.8   3.9   2.3  1.4  0.9  
25   29   26    23   19    15    10    6.8   4.0   2.4  1.5  1.0    
30   20   19    17   14    10   7.3    4.9   2.9   1.8  1.2  0.8

(Adapted from EPA, 1986)

Table 5. Chronic Criteria for Total Ammonia (mg/l): Warmwater Fish

Temp                                pH

 C    6.6   6.8   7.0   7.2   7.4   7.6   7.8   8.0   8.2   8.4   8.6   8.8   9.0

 4    2.5   2.5   2.5   2.5   2.5   2.5   2.1   1.5   0.9   0.6   0.4   0.3   0.2
 6    2.4   2.4   2.4   2.4   2.4   2.4   2.1   1.5   0.9   0.6   0.4   0.2   0.2
 8    2.3   2.3   2.3   2.3   2.3   2.4   2.0   1.4   0.9   0.6   0.4   0.2   0.2
10    2.3   2.3   2.3   2.3   2.3   2.3   2.0   1.4   0.9   0.6   0.4   0.2   0.2
12    2.3   2.3   2.3   2.3   2.3   2.3   2.0   1.4   0.9   0.6   0.4   0.2   0.2
14    2.2   2.2   2.2   2.2   2.2   2.2   2.0   1.4   0.9   0.6   0.4   0.2   0.2
16    2.2   2.2   2.2   2.2   2.2   2.2   1.9   1.4   0.9   0.6   0.4   0.2   0.2
18    2.2   2.2   2.2   2.2   2.2   2.2   1.9   1.3   0.9   0.6   0.4   0.3   0.2
20    2.1   2.2   2.2   2.2   2.2   2.2   1.9   1.3   0.9   0.6   0.4   0.3   0.2
22    1.9   1.9   1.9   1.9   1.9   1.9   1.6   1.2   0.8   0.5   0.3   0.2   0.2
24    1.6   1.6   1.6   1.6   1.6   1.6   1.4   1.0   0.7   0.4   0.3   0.2   0.1
26    1.4   1.4   1.4   1.4   1.4   1.4   1.2   0.9   0.6   0.4   0.3   0.2   0.1
28    1.2   1.2   1.2   1.2   1.2   1.2   1.1   0.8   0.5   0.3   0.2   0.2   0.1
30    1.1   1.1   1.1   1.1   1.1   1.1   0.9   0.7   0.5   0.3   0.2   0.2   0.1

(Adapted from Missouri State Regulations, 1994)

Table 6. Acute Criteria for Total Ammonia (mg/l): Warmwater Fish

Temp                                pH
 C     6.6   6.8   7.0   7.2   7.4   7.6   7.8   8.0   8.2   8.4   8.6   8.8   9.0

 4    50.6  46.9  42.0  36.0  29.4  22.8  16.8  11.9  7.6   4.8   3.1   2.0   1.3
 6    49.4  45.8  41.0  35.2  28.7  22.3  16.4  11.6  7.4   4.7   3.0   2.0   1.3
 8    48.3  44.8  40.1  34.4  28.1  21.8  16.1  11.4  7.3   4.7   3.0   2.0   1.3
10    47.4  44.0  39.3  33.7  27.6  21.4  15.8  11.2  7.2   4.6   3.0   2.0   1.3
12    46.6  43.2  38.7  33.2  27.1  26.0  15.6  11.1  7.1   4.6   3.0   2.0   1.3
14    45.9  42.5  38.1  32.7  26.7  20.8  15.4  10.9  7.0   4.5   3.0   2.0   1.3
16    45.3  42.0  37.6  32.3  26.4  20.5  15.2  10.8  7.0   4.5   3.0   2.0   1.4
18    44.8  41.5  37.2  32.0  26.1  20.3  15.1  10.8  7.0   4.5   3.0   2.0   1.4
20    44.4  41.2  36.9  31.7  25.9  20.2  15.0  10.7  6.9   4.5   3.0   2.0   1.4
22    44.1  40.9  36.6  31.5  25.8  20.1  14.9  10.7  6.9   4.6   3.0   2.1   1.5
24    43.9  40.7  36.5  31.4  25.7  20.0  14.9  10.7  7.0   4.6   3.1   2.2   1.6
26    40.8  37.9  34.0  29.0  24.0  18.7  14.0  10.0  6.6   4.4   3.0   2.1   1.5
28    35.5  33.0  29.6  25.5  20.9  16.3  12.2  8.8   5.8   3.9   2.7   1.9   1.4
30    31.0  28.7  25.8  22.2  18.3  14.3  10.7  7.8   5.1   3.4   2.4   1.7   1.3

(Adapted from Missouri State Regulations, 1994)

? Information on Ammonia

NCSU Water Quality Group

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