Determination of lipid content in fish samples from bioaccumulation studies: contributions to the revision of guideline OECD 305

An overview and appraisal of a broad range of lipid extraction methods is presented. Extraction procedures applied in bioaccumulation studies described in the literature and procedures currently used for such studies by governmental, academic, and industrial labs are surveyed. Possible impacts of unsuitable extraction techniques on lipid normalized BCF results were assessed. Default values for BCF normalization commonly used in bioaccumulation studies are described. The effect of differences in residue distribution over different organs and/or lipids on the normalization of BCF values is discussed.A broad range of procedures for lipid extraction are available. However, only the use of suitable extraction techniques guarantees the complete extraction of total lipids from fish samples in bioaccumulation studies which is required to ensure the correct lipid normalization of BCF values. Preferred methods for inclusion in the updated OECD 305 test guideline as well as a standard schedule for lipid measurements are suggested.Bioaccumulation of chemical substances can be caused by bioconcentration, mainly via respiratory membranes, or by biomagnifications via dietary uptake. As partitioning between water or food and outer membranes of organisms represents the most important process of bioaccumulation, it is of particular interest when dealing with substances with certain physicochemical properties, e.g., lipophilicity and persistence. In aquatic systems, sediments, and soils, these substances tend to concentrate mainly in the lipid fraction of organisms and may lead to substantial physiological burdens. The accumulation of such residues in the food chain can reach levels toxic to predators and represents a risk for human health. Assessing the bioconcentration as well as the biomagnification potential is therefore an important issue for the environmental and human risk assessment of chemicals and one of the main features in environmental monitoring.The Organization for Econ