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
Fire-Trol GTS-R	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
Fire-Trol LCG-R	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
Phos-Chek D-75-F	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
Phos-Chek WD-881	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
Silv-Ex	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.