Solid-phase microextraction for bioconcentration studies according to OECD TG 305

The European Community Regulation on chemicals and their safe use dealing with Registration, Evaluation, Authorisation and Restriction of Chemicals [REACh] [1] defines specific registration requirements for substances that are (very) persistent, (very) bioaccumulative, and toxic [PBT/vPvB substances]. As part of other regulatory chemical safety assessments such as for pharmaceuticals, biocides, and pesticides, the identification of PBT/vPvB substances is of increasing importance. With regard to the bioaccumulative properties of substances, bioconcentration factors [BCFs], which are defined as the concentration of a test substance in fish divided by the concentration of the chemical in the surrounding medium exceeding 2,000 and 5,000, are limiting criteria for B and vB substances, respectively. As a consequence, numerous BCF tests for hydrophobic organic compounds [HOCs] must be performed according to REACh requirements, and thus, efficient and reliable analytical methods for water and tissue samples are needed to guarantee accurate BCF estimates from flow-through fish tests carried out according to Organisation for Economic Co-operation and Development Technical Guideline [OECD TG] 305 [2].OECD TG 305 describes a procedure for characterizing the bioconcentration potential of substances in fish. The test consists of two phases: the exposure (uptake) and post-exposure (depuration) phases. During the uptake phase, separate groups of fish of one species are exposed to at least two concentrations of the test substance. They are then transferred to a medium free of the test substance for the depuration phase. The concentration of the test substance in the fish is followed through both phases of the test. Where possible, the BCF is calculated preferably both as the ratio of the concentration in the fish and in the water at apparent steady state (BCFss) and as the kinetic bioconcentration factor BCFK, which is the ratio of the rate constants of uptake (k1) and depuration (k