A survey for the presence of microcystins in aquaculture ponds in Zaria, Northern-Nigeria: Possible public health implication

Aquaculture ponds in Zaria, Nigeria, were screened for the occurrence of the hepatotoxic microcystins using an ELISA method. Four genera of cyanobacteria (Microcystis, Nostoc, Planktothrix and Anabaena) were recorded from 11 aquaculture ponds screened. These cyanobacteria are generally known to produce microcystins and other bioactive substances. Six of the 11 aquaculture ponds had detectable concentrations of microcystins (ranging from 0.6 to 5.89 ìg/L). This means that there is the possibility of bioaccumulation of microcystins in fish. The implication of this is that people that feed on contaminated fish from these ponds stand the risk of microcystins poisoning.