Water Quality Problem: Ammonia

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.

Table 1. Chronic (four-hour) Criteria for Total Ammonia (mg/l): Salmonids or Other Sensitive Coldwater Fish Present 
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  2.2   2.2   2.1   1.4  0.8   0.5  0.3  0.2   
15   2.2  2.2   2.2  2.2   2.2   2.0   1.3  0.8   0.4  0.3  0.2    
20   1.5  1.5   1.5  1.5   1.5   1.4   0.9  0.5   0.3  0.2  0.1    
25   1.0  1.0   1.0  1.0   1.1   1.0   0.7  0.4   0.2  0.2  0.1  
30   0.7  0.7   0.7  0.7   0.7   0.7   0.5  0.3   0.2  0.1  0.1
(Adapted from EPA, 1986 (to 2 signif. digits))

Table 2. Acute (One-hour) Criteria for Total Ammonia (mg/l): Salmonids or Other Sensitive Coldwater Fish Present 
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   20   19    17   13   10    7.2   4.8  2.8   1.7  1.1  0.7 
30   14   13    12   9.5  7.3   5.2   3.5  2.1   1.3  0.8  0.6
(Adapted from EPA, 1986)

Temperature is in degrees C.


? Information on Ammonia