Bioaccumulation tests applied in whole effluent assessment: A review

Abstract

Until recently, the emphasis within whole effluent assessment has been on the application of bioassays for acute and chronic toxicity. Although the need for additional parameters to assess the ecotoxicological hazard and risk of effluents for receiving water systems has been repeatedly advocated, other parameters such as bioaccumulation, genotoxicity, sediment toxicity, and nutrient impacts are seldom addressed. This paper discusses the potential additional value of including bioaccumulation parameters in whole effluent assessment and methods that can be used for routine assessment. It is concluded that screening on the presence of potentially bioaccumulating compounds leads to a more comprehensive hazard assessment and should therefore be included in whole effluent assessment. A chemical method to assess potentially bioaccumulating substances (PBSs) is preferred above methods using organisms or classical group parameters such as extractable organic halogens (EOX). In situ studies with organisms are not feasible for routine assessment for a number of reasons, including cost efficiency and matrix problems. Classical group parameters such as EOX do not relate to bioaccumulation or toxicity. Chemical methods for assessing bioaccumulation are usually presented as integrated methods composed of different procedure steps such as pretreatment, extraction, separation, and detection. However, an optimal method may be constructed by combining procedure steps from different reported methods. Solid phase microextraction combined with high performance liquid chromatography or gas chromatography combined with mass spectrometry is regarded as the preferable method for the assessment of PBSs. Before implementation in whole effluent assessment, however, the method must be carefully validated. Hazard assessment based on bioaccumulation seems feasible. For risk assessment, however, additional information is a prerequisite. Quantitative causal relationships between test assay results and relevant effects on the population and ecosystem level are absent, hampering the desired upgrading from hazard to risk assessment.