Investigation into organic phosphorus species in sediments of Baiyangdian Lake in China measured by fractionation and ~(31P NMR)

摘要

Organic phosphorus (OP) species in sediments of the Baiyangdian Lake in China was investigated via fractionation and phosphorus-31 nuclear magnetic resonance (~)(31)P NMR) spectroscopy. Results of chemical fractionation showed that different OP fractions ranked in the order: humic acid-P>HCl-OP>ful-vic acid-P≈NaHC0_(3-)OP>residual OP. Labile OP and moderately labile OP, which can be degraded for phy-toplankton uptake, contributed to 58.7-68.5% of total extracted OP, indicative of the potential P release from sediments in the lake. ~(31)P NMR spectroscopy results suggested the rank order of P species present in the NaOH-EDTA extractant of the sediments: orthophos-phate>monoester-P>DNA-P>pyrophosphate-P. Phytate, polyphosphates, and phosphonates, which appeared in sediments of some deeper lakes, were not detected in the shallow lake. Significant correlations were identified between total P (TP) in water column and sediment TP, monoester-P and DNA-P, positively indicating that sediment P species, especially OP components, should probably contribute to the contents of P in water column and further to the lake eutrophication.