Influence of particle surfaces ton the bioavailability to different species of 2,4-dichlorophenol and pentachlorophenol

Studies on the bioavailability of contaminants that accumulate in sediments have been complicated by the chemical and structural variability of substr ates and by the different biological properties of test organisms that are used by regulators. The purpose of this work was to overcome some of these difficulties by devising a test system that used artificial particles with known chemical surfaces. These were coated with 2,4-dichlorophenol or penta chlorophenol and fed to oligochete worms (Lumbriculus variegatus) and midge larvae (Chironimus riparius). The adsorption coefficient (Kd) Of the parti cle surface was compared with the concentration of contaminant accumulated by the test organisms. There were major differences in bioaccumulation betw een the two species used despite identical particles and pollutants. This c learly reflects differences in the uptake and detoxification pathways betwe en species. The particle surface and its interaction with the chlorophenols was a major factor in the accumulation of the contaminants in an organism. The techniques that are described provide a way of standardizing results b etween different natural sediments and different test organisms and provide some insights into the processes involved in bioaccumulation from particle surfaces.