Fig 1. Decrease in PCB congeners caused by planting nettles in the contaminated soil from Lhenice.

Standard errors are expressed as a standard deviation depending on the square root of the number of replicas [56]. The decrease in individual congeners was determined as the variance between the congener amount in the planted soil and non-planted soil (expressed in %, relative to 1 g of nettles). The data were analyzed using Fisher's Least Significant Difference (LSD) test at 5% probability level.