Determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in Brazilian cow milk

The determination of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in raw cow milks have never been reported in Brazil. Since the consumption of food of animal origin, including milk and dairy products, is the major source of human exposure to these compounds, this study aimed to establish the levels and profile of seven PCDDs and ten PCDFs in raw cow milk samples collected in eight Brazilian states which among the major milk producer states. Raw milk samples were collected in 34 different dairy cattle farms during the summer of 2013. All PCDD/Fs congeners were found at least in some of the 34 samples studied. The octa-chlorinated congeners (OCDD and OCDF) were ubiquitous and also present in high concentrations. The mean values of WHO-TEQ_1998;2005 were respectively 1.66 and 1.36pgTEQg^-1 fat and samples taken in São Paulo showed the highest WHO-TEQ values (2.46 TEQ₁₉₉₈g^-1 fat and 2.10pgTEQ₂₀₀₅g^-1 fat). Although all samples showed some contamination level, all values were below the limit established by European Union for total PCDD/Fs in cow milk (3pgWHO-TEQ₁₉₉₈g^-1 fat). Principal Component Analysis (PCA) showed that OCDD and OCDF were responsible for 73% and 20% of the total data variance, respectively and they presented an independent behavior, probably as a result of distinct origins. The use of TEQ as weights in the PCA, revealed the importance of the penta-chloro congeners and it was possible to identify sample distribution patterns probably associated with the main PeCDD and PeCDF. The importance of local sources to PCDD/Fs concentrations is still to be evaluated and determined.