Detection of phycotoxins along the South African coast: a comparison of three different biological assay systems and instrumental analysis by high performance liquid chromatography
In recent years, harmful algal blooms have been of growing concern in many parts of the world. These blooms often result in deterioration in water quality, large-scale mortalities in marine life, and shellfish poisonings which can adversely affect local mariculture industries, coastal tourism and fisheries. Because of problems related to some of the methods that are currently used to detect phycotoxins (e.g. false positives), it has become necessary to explore new approaches, especially for routine monitoring. In this study, High Performnance Liquid Chromatography was used as an instrumental method for detecting Paralytic Shellfish Poisoning in mussel samples. Three bioassays were also examined, viz. the luminescent bacteria assay (LUMIStox kit), the Artemia larvae assay (Artox kit), and the sea urchin gamete test. The bioassays were assessed as to their suitability, reliability and practicality in detecting phycotoxins in water and mussel samples. HPLC was used to establish toxin profiles of mussel samples from South Africa, where Alemndrium catenella was present in the water. The three bioassays were found to be unsuitable for detection of toxins in mussel samples. However, based on the results obtained in this study, the Artox kit seems to be the most suitable, sensitive and practical bioassay for the detection of PSP toxins in water samples.