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Toxicity of Fire Retardant Chemicals to Aquatic Organisms: Progress Report

Table 11

Table 11. Summary of the ammonia characteristics of five fire retardant chemicals used in tests with adult Hyalella azteca 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 96-hour LC50.

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 = 0.386 + 0.197 x EC50 Adj R² = 1.0000
127
24.63
7.49-7.58
0.13-0.79
Hard
NH3 - N = 1.834 + 0.215 x EC50 Adj R² = 0.9999
363
76.21
7.72-8.00
0.53-2.40
Fire-Trol LCG-R
Soft
NH3 - N = 0.366 + 0.107 x EC50 Adj R² = 0.9999
73
7.44
6.78-7.04
0.02-0.08
Hard
NH3 - N = 1.291 + 0.108 x EC50 Adj R² = 0.9996
535
56.49
6.99-7.03
0.24-1.09
Phos-Chek D-75-F
Soft
NH3 - N = 0.382 + 0.197 x EC50 Adj R² = 1.0000
53
10.06
6.98-7.43
0.09-0.25
Hard
NH3 - N = 5.257 + 0.192 x EC50 Adj R² = 0.9971
394
80.90
7.29-7.84
0.38-1.01
Phos-Chek WD-881
Soft
NH3 - N = 0.0597 + 0.000151 x EC50 Adj R² = 0.2944
10
0.06
7.44-7.45
0.00
Hard
NH3 - N = 0.0418 + 0.000141 x EC50 Adj R² = 0.2072
22
0.04
8.14-8.19
0.00
Silv-Ex
Soft
NH3 - N = 0.0230 + 0.00784 x EC50 Adj R² = 0.9995
24
0.21
7.47-7.47
0.00-0.01
Hard
NH3 - N = 0.0270 + 0.00719 x EC50 Adj R² = 1.0000
27
0.22
8.09-8.10
0.00-0.02
1NH3-N = total ammonia as nitrogen (mg/L) used as dependent variable in regression model;
EC50 = 96-hour LC50 (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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