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Toxicity of Fire Retardant Chemicals to Aquatic Organisms: Progress Report

Table 10

Table 10. Summary of the ammonia characteristics of five fire retardant chemicals used in tests with neonate Daphnia magna exposed in ASTM soft and hard waters. A regression equation (in parenthesis) was fitted for each chemical tested using the total ammonia as nitrogen (NH3-N) concentrations determined at test initiation (N=4). Each regression model was used to predict NH3-N (mg/L) at the 48-hour EC50.

Chemical
Water type
Regression equation
EC50 (mg/L)
Total ammonia1 (NH3-N, mg/L) EC50
pH² range
Un-ionized³ ammonia (mg/L)
Fire-Trol GTS-R
Soft
NH3 - N = 0.736 + 0.205 x EC50 Adj R² = 0.9996
257
51.95
7.55-7.68
0.73-2.70
Hard
NH3 - N = 0.249 + 0.240 x EC50 Adj R² = 0.9999
339
81.11
7.74-8.03
1.96-4.86
Fire-Trol LCG-R
Soft
NH3 - N = 1.541 + 0.109 x EC50 Adj R² = 0.9996
848
90.89
7.10-7.17
0.56-2.37
Hard
NH3 - N = 2.822 + 0.119 x EC50 Adj R² = 0.9993
813
94.74
7.05-7.15
0.57-2.15
Phos-Chek D-75-F
Soft
NH3 - N = 0.244 + 0.175 x EC50 Adj R² = 0.9998
140
24.26
6.91-7.27
0.15-0.32
Hard
NH3 - N = 2.032 + 0.179 x EC50 Adj R² = 0.9998
280
52.15
7.10-7.75
0.48-0.89
Phos-Chek WD-881
Soft
NH3 - N = 0.0799 + 0.000234 x EC50 Adj R² = -0.4525
11
0.08
7.90-7.90
0.00
Hard
NH3 - N = 0.0509 + 0.000207 x EC50 Adj R² = 0.9782
4
0.05
8.28-8.29
0.00
Silv-Ex
Soft
NH3 - N = 0.0705 + 0.00748 x EC50 Adj R² = 0.9995
7
0.12
7.97-7.97
0.00-0.01
Hard
NH3 - N = 0.0521 + 0.00768 x EC50 Adj R² = 0.9994
7
0.11
8.29-8.29
0.01-0.02
1NH3-N = total ammonia as nitrogen (mg/L) used as dependent variable in regression model;
EC50 = 48-hour EC50 (mg/L) used as independent variable in regression model;
adjusted R2 = 1-(1-R2)(n-1/df error);
2pH range = lowest and highest pH measurements for each test at test initiation;
3Un-ionized ammonia = total ammonia adjusted for temperature and pH.

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