Geochemical behavior of metals-sulfide-phosphorus at SWI (sediment/water interface) assessed by DGT (Diffusive gradients in thin films) probes

Element profiles/images in sediment porewater at five sites of Dianchi Lake (China) were measured by AgI/Chelex-100, ferrihydrite and Chelex-100 DGT (Diffusive gradients in thin films) probes for labile sulfide, metals and P. Based on DGT profiles, remobilization character and geochemical behavior of multi-elements at fine scale were assessed. Fe remobilization characters at five sites indicated the distinct Fe-reduction process. The correspondence of Fe and Cu/AI/Zn, and good linear correlation in profiles verified the co-release of them by Fe-redox process in some sites. The reduction of Fe (III) hydroxyoxide caused P-release from Ferbound Pin anoxic sediment and internal P loading character, which has been verified by the linear correlation (R = 0.77) in the whole DGT-profiles of Fe/P and the co-existence of Fe/P peaks at same depths. The peak flux (1.13 x 10(-6)-1.10 x 10(-5) mu g cm(-2) s(-1)), niche area (3.6 x 10(-5)-6.0 x 10(-2) cm(2)), circularity (0.204-1.0) and R-JM (4.02-6.62%) derived by CID (computer image densitometry) have revealed the existence of sulfide microniche in sediments. (C) 2015 Elsevier B.V. All rights reserved.