Spatial variations in the surface water chemistry of subtropical peatlands (central China) linked to anthropogenic pressures

Compared with the extensively surveyed temperate and boreal peatlands, subtropical peatlands have received rather little scientific attention. In this study, spatial variations in water chemistry were investigated in 57 samples collected from three subtropical peatlands (central China). Generally, water pH and major cation concentrations of these samples approached the characteristics of poor fens along the bog-rich fen gradient. Four distinct groups were identified by cluster analysis and principal component analysis. High concentrations of trace elements in Group I were probably linked to airborne dust pollutants from a nearby road under construction. Low pH values and low major cation concentrations in Group II may be attributed to the great cation exchange capacity of Sphagnum. In contrast, samples in Group III, mainly collected from sites suffering from Sphagnum harvest, showed high pH levels and major cation concentrations. Relatively low concentrations of trace elements (except boron) in Group IV can be regarded as reference conditions for restoration efforts in these peatlands. Taken together, spatial variations in the water chemistry of the three peatlands were closely linked to natural processes (e.g., cation exchange of Sphagnum) and anthropogenic pressures (e.g., Sphagnum harvest). Overall, the mean health risk values of the six trace elements were low, indicating good water quality in these peatlands. This study provided baseline water chemistry information for the sustainable management of these subtropical peatlands, as well as other similar ecosystems.