SUB-LETHAL BIOMARKER RESPONSES TO Cu IN OREOCHROMIS MOSSAMBICUS

Contamination of aquatic ecosystems with heavy metals has become a global problem and the impact of them on aquatic environments is severe due to the inability of water to disperse contaminants. To meet this threat, ecotoxicologists face a difficult challenge on how to assess the long-term impacts of metals which have already been released into the environment. Biomarkers indicate molecular and biochemical responses in exposed individuals as a tool to assess the status of an impacted environment and they can also serve as a basis for a Rapid Risk Assessment of Fish Health. In this context, this study evaluated three biomarkers (metallothionein (MT), Na+K+ ATPase and heat shock/stress protein 70 (HSP 70)) to determine the integrated physiological responses in Oreochromis mossambicus to one metal (copper (Cu)) at a sub lethal level over the short term. The information gained from these tests was valuable in suggesting what the baseline levels of biomarkers in O. mossambicus would be. The demand for sensitive, specific and rapid biological assays was also addressed by the development of an HSP 70 ELISA.