Responses in sediment phosphorus and lanthanum concentrations and composition across 10 lakes following applications of lanthanum modified bentonite

Dithmer, Line; Nielsen, Ulla Gro; Lurling, Miquel; Spears, Bryan M. ORCID: https://orcid.org/0000-0002-0876-0405; Yasseri, Said; Lundberg, Daniel; Moore, Alanna; Jensen, Nicholai D.; Reitzel, Kasper. 2016 Responses in sediment phosphorus and lanthanum concentrations and composition across 10 lakes following applications of lanthanum modified bentonite [in special issue: Geo-engineering to manage eutrophication in lakes] Water Research, 97. 101-110. https://doi.org/10.1016/j.watres.2016.02.011

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Official URL: http://dx.doi.org/10.1016/j.watres.2016.02.011

Abstract/Summary

A combined field and laboratory scale study of 10 European lakes treated between 2006 and 2013 with a lanthanum (La) modified bentonite (LMB) to control sediment phosphorus (P) release was conducted. The study followed the responses in sediment characteristics including La and P fractions and binding forms, P adsorption capacity of discrete sediment layers, and pore water P concentrations. Lanthanum phosphate mineral phases were confirmed by solid state 31P MAS NMR and LIII EXAFS spectroscopy. Rhabdophane (LaPO4 · nH2O) was the major phase although indications of monazite (LaPO4) formation were also reported, in the earliest treated lake. Molar ratios between La and P in the sediments were generally above 1, demonstrating excess La relative to P. Lanthanum was vertically mixed in the sediment down to a depth of 10 cm for eight of the ten lakes, and recovery of La in excess of 100% of the theoretical aerial load indicated translocation of the LMB towards the deepest areas of the lakes. Lanthanum was generally recovered from bed sediment samples following sequential chemical extraction from the HCl fraction. Soluble reactive P (SRP) release experiments on intact sediment cores indicated conditions of P retention (with the exception of two lakes) by sediments, indicating effective control of sediment P release, i.e. between two and nine years after treatment.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.watres.2016.02.011
UKCEH and CEH Sections/Science Areas:	Watt
ISSN:	0043-1354
Additional Keywords:	lake restoration, dissolved organic carbon (DOC), 31P NMR, lanthanum, P sequestration, EXAFS, full scale, lanthanum modified bentonite
NORA Subject Terms:	Ecology and Environment
Date made live:	28 Feb 2017 11:50 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/516403

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.watres.2016.02.011

UKCEH and CEH Sections/Science Areas:

Watt

ISSN:

0043-1354

Additional Keywords:

lake restoration, dissolved organic carbon (DOC), 31P NMR, lanthanum, P sequestration, EXAFS, full scale, lanthanum modified bentonite

NORA Subject Terms:

Ecology and Environment