Evaluation of the use of CALUX results for dioxins and dioxin-like PCBs analysis for quantitative human exposure assessments

Abstract

The objective of this study was to evaluate if the analysis results of dioxins and dioxin-like PCBs in food matrices obtained using the screening CALUX (Chemically Activated LUciferase gene eXpression) method, could be used for quantitative risk assessment.Contamination data of dioxins and dioxin-like PCBs in food matrices (dairy product, eggs, fish, animal fat and vegetable oil) obtained by the CALUX screening method and by the reference method (GC-HRMS) have been compared. Significant differences between the two methods were observed. Median concentrations of dioxins with the CALUX methods for the food matrices are about twice the median concentration of dioxins with the GC-HRMS. These discrepancies indicate that the data obtained using the CALUX method within the framework of the Belgian official control program cannot be used in risk assessment, specifically for an accurate estimation of the dietary intake of dioxins and dioxin-like PCBs. This can be explained, on one hand, by the promiscuous nature of the Aryl hydrocarbon Receptor (AhR) (whose ligand activation is responsible of the response measured in the CALUX assay) as it effectively binds to a large number of diversely shaped compounds not belonging to the 17 dioxins/furans and the 12 dioxin-like PCBs congeners. On the other hand, the assay is implemented as a screening tool for compliance monitoring where emphasis on method performance is required around the maximum levels, leading to a lack of accuracy for lower or higher concentrations.