Advantages and disadvantages of the use of immunodetection techniques for the enumeration of micro-organisms and toxins in water

Abstract

The applications of immunological techniques to the analytical challenges presented by water pollution and its tremendous expansion during recent decades are reviewed. Examples of the immunodetection methods evaluated for their advantages and disadvantages in the water field include the use of enzyme-linked immunosorbent assays (ELISA) and radio-immuno-assays (RIA) for the direct detection of viruses from water concentrates; cyto-immuno-labelling and immunofluorescence techniques specific for rota and hepatitis A viruses; and the use of ELISA and immunofluorescence for the detection of bacteria (Legionella, faecal coliforms) and protozoan parasites (Giardia, Cryptosporidium). The production and use of monoclonal antibodies against algal toxins are also evaluated. The advantages to be gained by utilizing these techniques in the water field are numerous. In general, they simplify the detection method, shorten detection time and are less labour intensive than other conventional methods. They also provide a tool for the detection of pollutants that otherwise could not be identified. However, many disadvantages are associated with utilising immunological techniques. False positives are often reported due to reactions with non-specific matter in the water sample or cross-reactivity with a wide range of organisms. These methods are also unable to indicate the viability of organisms. The successful use of immunodetection techniques in the water field often depends on their combination with conventional culturing methods and/or microscopic observation.