2.3. Calculation methods
The statistical analysis and the graphic representation of the obtained results were carried out using Microsoft Excel 2007. Results were of a non-parametric nature, so the Kruskal–Wallis test was used to determine the significance of differences (p < 0.05). The dependences were determined using the Spearmann's correlation coefficient (r), adopting a confidence interval of 95%.
The bioconcentration factor (BCF) was determined according to the formulas presented by Hu et al. (2005).