抄録
Surface peat pore waters were collected from Sarobetsu peatland, Kiritappu peatland, Bekanbeushi peatland and Tokachi coastal peatland in Hokkaido, Japan. The concentrations of dissolved organic matter (DOM) and dissolved iron in peat pore waters, and their relation to the several physical and chemical properties, and the indices for the decomposition degree of peat samples, were investigated. The concentrations of dissolved organic carbon (DOC) and chemical oxygen demand (COD) were higher in the peat waters of Sarobetsu peatland and Bekanbeushi peatland, which cover relatively wide areas. In contrast, they were lower in those of Tokachi coastal peatland, where the effect of an incorporation of inorganic materials was distinct. In general, DOC had a signitificant correlation with the decomposition degree and organic matter content of peat samples. The concentrations of dissolved iron were also higher in peat waters of Sarobetsu peatland, followed by those of Kiritappu peatland and Bekanbeushi peatland, and lower in those of Tokachi coastal peatland. When the peat waters were passed through the reverse-phase cartridge column to remove hydrophobic fractions of DOM, the percolated waters, which were almost transparent and colorless, still had strong absorption at 260 nm and were rich in dissolved iron. It was suggested that dissolved iron in peat waters had a significant relationship with colorless and hydrophilic organic fractions in DOM. The multiple-regression analysis showed that the concentrations of dissolved iron increased with the increase in the concentrations of DOM as the peat decomposed, which concentrations were abundant in carboxylic autd phenolic-hydroxyl groups. It was also revealed that dissolved iron in peat waters increased with the increase in contents of both organic matter and iron in peat samples, and with the decrease in the fiber contents. The concentrations of dissolved iron in peat waters were mutually affected by organic matter and iron contents of peat soils, being dependent on an incorporation of mineral materials and the degree of decomposition of peat soils.
