[Acute toxicity of ammonia to Artemia sp]

The acute toxicity of total ammonia-N, (NH3 + NH4+), and un-ionized ammonia-N, NH3-N, on newly hatched Artemia nauplii and Artemia adults was measured in 24, 48, 72, and 96-h semi-static bioassays system. There was a significant difference (P < 0.05) in medial lethal concentrations (LC50) obtained during the tests. The LC50 values on nauplii ranged from 650 mg/l, in 24-h, to 399.1 mg/l total ammonia-N, in 96-h, while the LC50 values on adults ranged from 1290.4 mg/l to 600.5 mg/l total ammonia-N, in the same period. Two methods for calculations of un-ionized ammonia toxicity are analyzed and discussed.