The researchers studied metal pollution in Sphagnum mosses in the Sudety mountains from 1986 to 2011. They found that concentrations of certain metals like Cd, Cr, Cu, Fe, Pb, and Zn were much higher in 1986 compared to 2011, indicating a decrease in pollution over time. Different Sphagnum species showed varying abilities to accumulate metals, with hollow species being better indicators of Co pollution and hummock species being better indicators of Mn pollution. Overall, improvements in pollution control in the region have led to lower metal levels in the mosses.