**Appendix A**

Distance from sampling positions to the industry are detailed in Table A1. Experimental conditions and validation data of PTEs analysis procedure are included in Tables A2–A5 of this Appendix.


**Table A1.** Distance from farm to industry.

N: Near; F: Far.


**Table A2.** Temperature gradient program used in the acid digestion of soil, forage, and milk.

For each element analyzed by ICP-MS, the LOD and LOQ were calculated as 3 and 10 times the standard deviation (SD) of ten blank samples, respectively.


**Table A3.** Instrumental limit of detection (LOD), limit of quantification (LOQ), and calibration range for inorganic elements quantification by using inductively coupled plasma mass spectrometry.

Repeatability of extraction procedure from replicates of certified European reference materials was calculated according to the following expression:

$$RSD\_r = \frac{\sqrt{\frac{\sum (x\_1 - x\_2)^2}{n - 1}}}{\bar{\chi}} \cdot 100$$

where x1 and x2 are the measured values for duplicates, n is the number of total measures, and <sup>−</sup> x is the average concentration of the element in all the samples.


**Table A4.** Relative standard deviation (RSD) values of soil, ryegrass, and milk powder.

In Table A5, validation statistics are included. Note that for Na, Mg, K, and Ca (ERM CD-281 "Rye-grass") there was no availability of uncertainty values because these inorganic elements were included as additional material information in the ERM CD-281 report. As detailed in this report, the results were obtained from "*semi-quantitative screening analysis using ICP-SFMS (* ... *). The elements were determined using 18 scans over the mass range, resulting in a total measurement time of 300 s. The results are an average of triplicate measurements*".

**Table A5.** Method validation statistics for ERM-CC141 (loam soil), ERM-CD 281 (rye grass), and ERM BD-151 (skimmed milk powder) analysis by ICP-MS.


<sup>1</sup> Selenium was added to rye grass ERM before acid digestion. <sup>2</sup> Chromium was added to skimmed milk powder ERM before acid digestion. <sup>3</sup> Data between brackets indicate approximate values.

PAH quantification was carried out by using GC-MS. A representative chromatogram of a soil sample was included in Figure A1.

**Figure A1.** Merged-SIM chromatogram of PAHs found in a representative sample of soil collected in the vicinity of the industrial areas. Concentrations found in <sup>μ</sup>g·kg−<sup>1</sup> (main peaks): naphthalene (1.04), acenaphthylene (0.71), acenaphtene (0.64), Fluorene (0.61), phenanthrene (9.73), anthracene (0.89), fluoroanthene (10.23), pyrene (7.98), benzo(a)anthracene (5.06), chrysene (7.06), benzo(k)fluoroanthene (14.68), benzo(b)fluoroanthene (3.43), benzo(a)pyrene (5.62), and benzo(g,h,i)perylene (5.44).
