ASSESSMENT OF MICROCYSTIS BLOOM TOXICITY ASSOCIATED WITH WILDLIFE MORTALITY IN THE KRUGER NATIONAL PARK, SOUTH AFRICA

Based on previous necropsy results, Microcystis blooms in constructed water impoundments in the Kruger National Park (KNP) have been identified as a cause of woldlife mortality. In response to wildlife mortality during 2007, water samples, containng algal bloom material, were collected during February 2007 and July 2007 from four dams (Nhlanganzwani, Mpanamana, Makhohlola, and Sunset) in the southeastern part of the KNP as a part of the follow-up investigation. The toxicity of the Microcystis blooms was determined using the enzyme-linked immunosorbent assay (ELISA), protein phosphatease inhibition (PPI) assay, mouse bioassay, and African sharptooth catfish (clarias gariepinus) primary hepatocytes. Both the ELISA and PPI assays indicated that the water sample collected during February 2007 from the Nhlgangzwani Dam, and samples collected from the Nhlanganzwani and Sunset dams in the 2007, were toxic. These, dams exhibiting the toxic Microcystis blooms, were also associated with the wildlife mortality. Mice injected intraperitoneally with water samples from Nhlanganzwani Dam (February 2007) induced hepatotoxicity and mortality within 1 hr. Primary hepatocytes from the sharptooth catfish exposed to samples from these dams gave similar results. This laboratory investiation and results strongly incriminate the toxic Microcystis blooms as the cause of the the high numbers of hippopotami (Hipopopotamus amphibius) in specific dams