All dependent data were log-transformed to improve normality of the residuals. Comparisons of least square means (within-group means adjusted for the other effects in Ceritinib research buy the model, i.e. season) were calculated by t-tests. p-Values less than 0.05 were considered significant. Adjustment for correcting for Type I errors (rejection of a null hypothesis that is actually true) was not applied, as any indication of effects of the variables was considered

interesting and there was no reason to be overly cautious. Half the LOD value was used in calculations for samples with concentrations < LOD. The number of such samples was none for PFUnDA, and for the other PFAAs only one sample per chemical. Samples for which the analysis did not meet analytical performance criteria were treated as missing values. A principle

component analysis (PCA) was performed using the SIMCA P + software (Umetrics, Umeå, Sweden, version 12.0.1). In total one hundred observations (mink samples) and twenty x-variables; the variable area, season and age and body condition and the log-transformed concentrations of contaminants were included in the model. All data were centered and scaled selleck chemical prior to modeling. The value of explained variation (R2) was calculated and the estimate of the predictive ability of the model (Q2) was performed by cross validation. In this study, the concentrations of PFCAs in mink from subarctic areas (Table 1) were Buspirone HCl generally higher than those reported in mink from the Canadian arctic, where PFNA was the major contaminant found (mean 16 ng/g), followed by PFOS (8.7 ng/g), PFUnDA (4.3 ng/g), PFDA (3.7 ng/g), PFDoDA and PFTrA (both < 0.5 ng/g) (Martin et al., 2004a). The concentrations of PFOS in our study were similar to concentrations previously reported for mink livers from various locations in the USA; on average 2630 ng/g liver (Giesy and Kannan, 2001) and 74–2370 ng/g (Kannan et al., 2002b).

However, in our study, some mink had extremely high concentrations of PFOS: four mink from the highly anthropogenic inland area (M) with concentrations ranging from 9640 to 21,800 ng/g ww and five mink with concentrations between 2070 and 3740 ng/g ww. Also, in the Skagerrak coast area (K), two mink contained PFOS concentrations of 2580 ng/g and 4490 ng/g. These high concentrations in Swedish mink are among the highest ever reported for this species in the literature. Higher levels of PFOS were only found in mink from Michigan, USA (Kannan et al., 2005) with concentrations of 1280–59,500 ng/g. Other mammals in which high liver PFOS concentrations have been found are wood mice in Belgium with a range of 470–178,550 ng/g (Hoff et al., 2004), otters in Sweden with a range of 19–16,000 ng/g (Roos, 2013), polar bears in East Greenland with a range of 83–3868 ng/g (Dietz et al., 2008), and harbor seals in the German Bight with concentrations up to 3676 ng/g (Ahrens et al., 2009).