Joint action of ammonia and nitrite on Artemia nauplii

Abstract

Newly hatched Artemia nauplii were exposed to ammonia, nitrite, and different ratios of ammonia and nitrite, employing the static renewal method. The 24-h LC50 concentrations were 839.5 mg/l for TAN (total ammonia nitrogen), 14.17 mg/l for FAN (free ammonia nitrogen) and 1609.7 mg/l for nitrite-N. The corresponding 48 h LC50 concentrations were 334.7 mg/l for TAN, 5.65 mg/l for FAN and 1141.0 mg/l for nitrite-N. When the toxicity ratio of the ammonia-nitrite mixture was 1:1, equivalent 24-h LC50 concentrations were 252.3 mg/l for TAN, 4.26 mg/l for FAN and 928.4 mg/l for nitrite-N, while the 48-h LC50 concentrations were 106.3 mg/l for TAN, 1.80 mg/l for FAN and 362.3 for nitrite-N. At a toxicity ratio of 2:1 for ammonia-nitrite mixtures, the 24-h and 48-h LC50 concentrations were 305.2 and 162.3 mg/l for TAN, 5.15 and 2.74 mg/l for FAN and 500.8 and 266.2 mg/l for nitrite-N, respectively. In mixtures, ammonia and nitrite exhibited a synergistic effect on the Artemia nauplii after 48-h exposure.