*2.6. Data Treatment and Statistical Analyses*

Univariate statistical descriptors (mean, median, coefficient of variation, minimum, and maximum) were calculated for the concentrations of PTEs and PAHs in each type of sample. The variation (%) in the mean concentration for each metal or PAH between the close and far groups of farms was calculated using the following expression:

$$Variation(\%) = \frac{mean\_{close}}{mean\_{far}} \cdot 100\tag{1}$$

Principal component analysis was performed for soil data to identify anthropogenic or natural factors associated with the concentrations of contaminants. Factors were extracted using the Kaiser/Gutmann criterion and varimax rotation, reflecting recommendations and our own experience [27–29].

The soil–forage transfer factor (TFsf) and forage–milk transfer factor (TFfm) for the inorganic elements were calculated as follows:

$$TF\_{sf} = \mathbb{C}\_{\wedge}/\mathbb{C}\_{\ast} \tag{2}$$

$$TF\_{f\!m} = \mathbb{C}\_{\!m} / \mathbb{C}\_{\!f} \tag{3}$$

where Cf, Cs, and Cm are the median concentrations in the forage, soil and milk, respectively. SPSS 24 (IBM, Armonk, NY, USA) was used for all statistical analyses.
