The Shapiro–Wilk's test for normality was applied, and non-normal
distributed elements were not found so log-transformation was not
necessary. Heteroscedasticity was found in almost all cases, so it was
included in the model using Infostat/E coupled to R to perform an
Analysis of Variance (ANOVA) to determine Pb soil effects on the Pb
concentration in plant. Whenever the ANOVA indicated significant
effects (p b 0.05), a pairwise comparison of means was undertaken
using the Tukey test.