Use of Quick Lime (CaO) as a Means to Reduce Cadmium Toxicity in Common Carp, Cyprinus carpio

Abstract

Static bioassays were made in the laboratory and in outdoor vats with two groups of common carp, Cyprinus carpio, one pre-exposed to 100 mg/L quick lime (CaO) for 4 days and another without pre-exposure. Exposure of fish to 2.5-mg/L cadmium (Cd) for 96 hours resulted in a decrease in the feeding rate and weight gain of the fish not pre-exposed to CaO. In contrast, these parameters and respiratory rate were increased in fish pre-exposed to CaO with subsequent Cd exposure. Fish pre-exposed to CaO and then subjected to chronic exposure to Cd (2.5 mg/L) for 90 days also showed an increase in activity and growth compared to fish not pre-exposed to quick lime. Pre-expo-sure to CaO also significantly reduced tissue concentrations of Cd.

Key Words:

• Cadmium
• toxicity
• fish
• calcium