Influence of Sediment Dredging on Chemical Forms and Release of Phosphorus

A laboratory experiment was carried out through a six-month incubation of undredged (control) and dredged cores to study the effect of sediment dredging on phosphorus (P) release from the sediment in the Taihu Lake. During the experiment, dredging the upper 30 cm layer could efficiently reduce the interstitial PO34 -P concentration and different P forms in the sediment. The P fluxes of the undredged and dredged cores ranged from −5.1 to 3047.6 and −60.7 to 14.4 μg m−2 d−1, respectively. The fluxes of the dredged cores were generally lower than those of the control. Differences in the fluxes between the dredged and undredged cores were statistically significant (P < 0.05) from March to June 2006. The sediment P in the dredged cores had a lower release potential than that in the control. Dredging can be considered as a useful measure for rehabilitating the aquatic ecosystem after the external P loading in the Taihu Lake catchment was efficiently reduced.