ISO/DIS 24295

This document specifies a method for the determination of the dioxin‑like activity of water and wastewater by means of an AhR‑mediated reporter gene assay utilizing stably transfected mammalian cell line. This reporter gene assay is based on the activation of the mammalian AhR signalling pathway. This method is applicable to: —       drinking water; —       fresh water; —       groundwater; —       river water; —       wastewater. The limit of quantification (LOQ) at CV 20 % or less of this method is 0,5 pg and 1,0 pg 2,3,7,8‑tetrachlorodibenzo‑p‑dioxin (2,3,7,8-TCDD) equivalents (TCDD-EQ)/l based on the results of laboratory trials using appropriately extracted and cleaned up water samples for dioxins and dioxin‑like compounds in rat and mouse cell lines, respectively. The LOQ depends on the sample volume. For determination of TCDD-EQ derived from dioxins and dioxin‑like compounds in water and wastewater, suitable extraction and clean‑up are necessary for water samples, since AhR ligands/agonists are composed of a wide variety of structurally diverse compounds including natural, and anthropology-natural substances. NOTE          In this document, TCDD-EQ is used instead of TEQ which represents toxicity equivalent quantity.