Abstract
INTRODUCTION: Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and polychlorinated biphenyls (PCBs) are a group of undesirable chemical substances classified as persistent organic pollutants (POPs). They enter the bodies of humans and animals mainly through the digestive tract. Therefore, the safety of the food chain with specific regard to keeping out these POPs depends heavily upon their elimination from animal feed. The aim of this study was to determine trends in PCDD/PCDF/PCB concentrations in three feed matrices over a six-year period. MATERIAL AND METHODS: Altogether, 360 feed samples were analysed using the isotope-dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry. Analysis of the variability of PCDD/PCDF, dioxin-like-PCB and non-dioxin-like-PCB concentrations by Mann-Kendall test and regression analysis for mean and median values was performed for the three most common feed categories (plant materials, fishmeal and feed mixtures). RESULTS: For two of the three types of feed materials analysed, changes in trends in the concentrations of the tested compounds over time were observed. CONCLUSION: Considering the very limited amount of feed material analysis data on which to assess trends in dioxin concentrations, it is necessary to continue research on a wider group of feed types.