Date Published: February 24, 2012
Publisher: BioMed Central
Author(s): Anniina Suutari, Anja Hallikainen, Päivi Ruokojärvi, Hannu Kiviranta, Mauri Nieminen, Sauli Laaksonen.
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) are environmentally stable and toxic compounds, listed in Stockholm Convention  created to restrict and ultimately eliminate the production, use, release and storage of Persistent Organic Pollutants (POPs), and observed to exist globally in terrestrial and aquatic biota [2-4]. PCDD/Fs enter the environment solely as unintentional by-products from industrial and thermal processes, while DL-PCBs are merely intentionally produced chemicals that are released due to inappropriate disposal practices, accidents and leakages from industrial facilities [2,5].
The sampling area of reindeer and moose located in the sub-arctic northern Finland (Figure 1) and covered the reindeer herding region. The region was divided into three different sampling zones; the northern, the middle and the southern zone. The method of sampling was standardized hence allowing a comparison of the results between the different zones. The samples were built up in a ratio of carcass meat consumption. Concentrations of 17 toxic PCDD/F and 12 DL-PCB (dioxin-like PCBs; 4 non-ortho and 8 mono-ortho congeners) were measured from each sample (Table 1).
WHO-PCDD/F-TEQs were generally higher in reindeer calf muscle than in adult reindeer. PCDD/Fs showed partly similar profiles in reindeer and moose muscle, reindeer liver and milk samples-indicating equal mode of bioaccumulation. Among the most abundant congeners were 23478-PeCDF, 123478-HxCDF, 123678-HxCDF, 234678-HxCDF, 1234678-HpCDD and OCDD. However, stillborn calves‘ brown adipose was somewhat exception showing both accumulation and absence of congeners compared to muscle. In addition, more infrequent PCDD/F congeners existed in moose muscle samples; OCDD being the most visible. OCDD also showed interesting appearance to the reindeer milk PCDD/F set not until in the autumn. With DL-PCBs, a strong contribution of non-ortho-PCBs (PCB-77, -81, -126 and -169) to total TEQ was detected in all studied samples, although there were some differences in the frequent of particular congeners in the different species. Differences found in this study may indicate species-, individual- and tissue-specific accumulation of PCDD/Fs and DL-PCBs. In addition to metabolic potential, which concerns mainly liver, an extent and quality of exposure may explain the congener-specific accumulation.
HRGC/HRMS: High resolution gas chromatography/high resolution mass spectrometer; WHO-TEQ: Toxic equivalent defined by WHO; WHO-PCDD/F-TEQ: Toxic equivalent for 17 PCDD/Fs; WHO-PCB-TEQ: Toxic equivalent for 12 DL-PCBs; TEF-value: Toxic Equivalence Factor; LOQ: Limit of quantification.
The authors declare that they have no competing interests.
Study design: SL. Data collection: SL, MN. Analysis of samples: PR. Data analysis: AS, SL. Statistical analysis: AS. Manuscript writing: AS. Critical review and approval of the final manuscript: AS, AH, PR, HK, MN, SL.