CONCENTRATIONS OF PCDDs, PCDFs AND PCBs IN SAMPLES OF BUTTER FROM 24 COUNTRIES

Introduction Residues of PCDD/Fs and PCBs present in butter may indicate the occurrence of these contaminants in pastureland on which cattle graze, and thus provide a useful environmental indicator of fluxes to pastures. These would have principally an atmospheric component although there are also other possible sources of contamination to pastures such as a water-based contribution from irrigation or periodic flooding for cattle grazing on flood plains, and animal feed. Caution must therefore be observed when using this data as an indicator of local environmental contamination. Nevertheless, as previously noted for chlorinated pesticide residues and PCBs, the potential for the use of butter as a convenient, widely available and relatively uniform matrix for the determination of spatial trends in distributions of persistent organic pollutants warrants further research. This is especially the case in many countries where research and monitoring programmes are lacking and for which few or no data are therefore available. This study examines the levels of dioxins and PCBs in butter samples taken from 24 different countries around the world (Table 1).