Characteristics, distribution and ecological risk assessment of phosphorus in surface sediments from different ecosystems in Eastern China: A P-31-nuclear magnetic resonance study

摘要

Surface sediments in different ecosystems (lake, river, reservoir, estuary and wetland) in Eastern China were extracted with NaOH-EDTA, and the extracts were analyzed by P-31-NMR to reveal the phosphorus (P) species distribution. The P release risk was also assessed by sorption experiments. The river sediments accumulated significant amounts of P compared with other sediments. The organic phosphorus (Po) concentration in the estuarine sediment was lower than that in other sediments. Two P compounds classes (phon-P and mono-P) and five P compounds were detected in the sediments. Ortho-P (83.3-97.6%) was the dominant P compounds and mono-P (1.1-18.0%) were the dominant Po compounds classes, while smaller amounts of DNA-P (0-4.1%), pyro-P (0-4.0%) and lipid-P (0-0.8%) were found in the surface sediment. Poly-P and phon-P were detected only in site 11 (wetland), site 10 (wetland) and 11, respectively. The ERI values, as a measure of eutrophication risk, were different in the various sediments, being greater than 25% in sites 1 (river), 3 (estuary) and 4 (estuary), and with values of 26, 59 and 83%, respectively. The Xm and ERI values fitted a power function (RXm-ERI = 0.89, p0.01) and a positive correlation between Xm and OM in the sediment (RXm-OM = 0.84, p0.01) indicated that the chemical-physical conditions play a vital role in controlling P sorption and desorption. (C) 2014 Elsevier B.V. All rights reserved.