Copper is one of the most toxic metals to aquatic organism and ecosystem and it does not break down in the environment because it can accumulate in to plant and animals via food web. Acute toxicity test is the studies about effects of toxic agents on aquatic organisms are short-term tests designed to measure the effects of toxic agents on aquatic species during a short period of their life span. Acute toxicity test evaluate effect on survival over a 24- to 96- hour period. Focus on the need to identify suitable freshwater organism to assess the toxicity of copper in tropical reigns, but there is limited toxicity data for tropical freshwater organism, and there have been a call for further research and development in the care of tropical freshwater ecotoxicology. The LC50 results expressed as 95% confidence limit obtained at 48 hour in tap water using the tropical test species Moina (Moina macrocopa), Chironomid (Chironomus javanus), Grass Carp (Ctenopharyngodon idella) and Nile tilapia (Oreochromis niloticus) were 12μg/L, 16,399μg/L, 118μg/L and 1,383 μg/L, respectively. This gave the following order of toxicity of copper in tap water: Moina > Grass Carp > Nile tilapia > Chironomid. Exposure of the test species to this series of laboratory experiments has provided useful data for determine the risk of copper in Mekong river water compared with dosed distilled and tap water.
Keywords: Acute toxicity, Copper, Tropical freshwater biota