A Continuous Flow System (CFS) for chronic exposure of aquatic organisms

Effect studies on marine life are changing focus from acute lethal effects to long term sublethal effects. There is a need for laboratory test systems that can facilitate continuous supplies of test substances at sublethal concentrations. Stability and reproducibility of the test solutions and application of test substances in mixtures are required. With the Continuous Flow System (CFS) described, the aim has been to make a flexible tool adjustable to a wide range of studies. Thus, test solutions and dispersions of substances poorly miscible in water can be made in various ways, using different methods and devices for substance injection, mixing and further conditioning. More than one species of organisms can be tested simultaneously. The system can be run both with freshwater and seawater. Presently the system is used for bioaccumulation and biomarker studies related to impacts of oil industry discharges of produced water off shore. This paper presents the main features and functional parts of the system and some result examples.