Levels of PCBs, PCDDs and PCDFs in commercial butter samples in Spain.

Feasibility of three different extraction methods for the simultaneous dete rmination of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-di oxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in butter is discus sed. The method based on liquid-liquid extraction with water of the non fat ty solids from butter dissolved in hexane was found to be the most efficien t for the determination of the lipid content and the levels of the investig ated pollutants. This method was used to evaluate the background levels of PCBs, PCDDs and PCDFs in butters commercially available in Spain. Broad ran ges of PCB, specifically, PCDD and PCDF concentrations were found in the di fferent brands analysed. Levels, profiles and patterns of these pollutants in butter were compared with those previously reported for different Spanis h dairy products. The toxic tetra-equivalents of 2,3,7,8-TCDD (I-TEQ) avera ges for PCDDs and PCDFs in the 21 butter samples analysed were 0.41 and 0.7 0 pg/g fat basis, respectively. These values were similar or lower than tho se cited in the literature for other countries. (C) 1999 Elsevier Science L td. All rights reserved.