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Mean EFs (and standard deviation) of the elements assessed in the exposed lichens. The red line represents the threshold of 10, the accepted minimum for the enrichment from a non-crustal source. Regarding the box plot, the square represents the mean, upper and lower times sign (×) shows the maximum and minimum values, the box provides the 25 percentile, the median and the 75% percentile, and the lower and upper minus sign (−) shows the 5 and 95 percentiles, respectively.
