DETERMINATION OF DIOXINS IN ENVIRONMENTAL -SAMPLES - COMPARISON OF BIOLOGICAL AND CHEMICAL-ANALYTICAL RESULTS

Toxic equivalents (TE) of dioxins, furans and related compounds can be determined directly by measuring the aryl hydrocarbon hydroxylase act ivity (AHH-assay) in rat hepatoma cells. This method has major advanta ges over the classical chemical-analytical approach, if TEs in complex environmental samples are to be determined with little expense in ter ms of work and time. The specific bioassay covers all compounds with d ioxin-like effects. These include over 5000 possible mixed halogenated dioxins and furans (PXDD/F) and in addition mixed halogenated bipheny ls (PXB). Statutory regulations stipulate that only 17 selected chlori nated dioxins and furans (PCDD/F) have to be determined by chemical-an alytical means [3]. Previous results show [1, 2], that the biologicall y determined TEs are higher than TEs calculated from chemical-analytic al data. Exact reasons for this are unknown. The AHH-assay allows inex pensive screening for TEs in environmental samples. Our results indica te that there are compounds with dioxin-like effects, which are unknow n or have not yet been recorded by chemical analysis.