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. 2014 May 7;48(11):6291–6299. doi: 10.1021/es5000534

Figure 2.

Figure 2

PCA on 4th root transformed PAH profiles using the first two principal components, PC1 and PC2, which together account for 55.4% of data set variation. The PCA scores plot for sample profiles (A) is provided with numbers indicating sampling location and colored triangles differentiating freely dissolved (▼) and crayfish (▲) samples. Red circles enclose samples collected within the Superfund Mega-site. The PCA loadings plot (B) shows directions of increasing weight for each indicated PAH variable in terms of PC1 and PC2. The length of the vectors corresponds to the percentage of that PAH’s variation explained jointly by PC1 and PC2, with the perimeter of the reference circle indicating 100%. FLO and BAP were not included in the analysis.