NBN ISO 23196:2022

This document specifies the derivation of biological equivalence (BEQ) concentrations for results of in
vitro bioassays which are based on measuring effects on a biological process such as enzyme induction
or cellular growth. The concept described here can be used for any biological assay after the proof of its
applicability.
To derive BEQ concentrations, the effect on a biological process caused by a sample – i.e. the activity
of the sample – is expressed in terms of a concentration of a reference compound which results in an
equivalent effect on the process. The term "sample" used in this document addresses environmental
samples as well as defined mixtures and pure compounds used as test item in a bioassay. BEQ
concentrations can be derived for environmental water samples, extracts of environmental water
samples including tap water or solutions of pure chemicals or mixtures of chemicals.