Acute Toxicity of Fire Control Chemicals to Daphnia magna (Straus) and Selenastrum capricornutum (Printz)

Table 4

Table 4. Summary of the Ammonia Characteristics of Five Fire-Fighting Chemicals Used in Tests with Neonate D. magna Exposed in ASTM Soft and Hard Waters

Chemical	Water type	Regression equation	EC₅₀ (mg/liter)	Total ammonia (NH₃-N,^b mg/liter) EC₅₀	Un-ionized^a ammonia (mg/liter)
Fire-Trol GTS-R	Soft	NH₃-N = -0.736 + 0.250× EC₅₀ Adj R² = 0.9996	257	51.95	0.73-2.70
Fire-Trol GTS-R	Hard	NH₃-N = -0.249 + 0.240× EC₅₀ Adj R² = 0.9999	339	81.11	1.96-4.86
Fire-Trol LCG-R	Soft	NH₃-N = -1.541 + 0.109 × EC₅₀ Adj R² = 0.9996	848	90.89	0.56-2.37
Fire-Trol LCG-R	Hard	NH₃-N = -2.822 + 0.119 × EC₅₀ Adj R² = 0.9993	813	94.74	0.57-2.15
Phos-Chek D75-F	Soft	NH₃-N = -0.244 + 0.175 × EC₅₀ Adj R² = 0.9998	140	24.26	0.15-0.32
Phos-Chek D75-F	Hard	NH₃-N = 2.032 + 0.179 × EC₅₀ Adj R² = 0.9998	280	52.15	0.48-0.89
Phos-Chek WD-881	Soft	NH₃-N = 0.0799 + 0.000234 × EC₅₀ Adj R² = -0.4525	11	0.08	0.00
Phos-Chek WD-881	Hard	NH₃-N = 0.0509 + -0.000207 × EC₅₀ Adj R² = 0.9782	4	0.05	0.00
Silv-Ex	Soft	NH₃-N = 0.0705 + 0.00748 × EC₅₀ Adj R² = 0.9995	7	0.12	0.00-0.01
Silv-Ex	Hard	NH₃-N = 0.0521 + 0.00768 × EC₅₀ Adj R² = 0.9994	7	0.11	0.01-0.02

Note. A regression equation 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/liter) at the 48-hr ED₅₀.
^a Un-ionized ammonia, total ammonia adjusted for temperature and pH.
^b NH₃-N, total ammonia as nitrogen (mg/liter) used as dependent variable in regression model; EC₅₀ =48-hr EC₅₀ (mg/liter) used as independent variable in regression model; adjusted R², 1 - (1 - R²) (n - 1/df error).

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