HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Christophoridis, C. Articles by Fytianos, K. Search for Related Content PubMed PubMed Citation Articles by Christophoridis, C. Articles by Fytianos, K. GeoRef GeoRef Citation Agricola Articles by Christophoridis, C. Articles by Fytianos, K. Related Collections Laboratory Column Studies Nutrients Sorption/Exchange Other Environmental Contamination Phosphorus

TECHNICAL REPORTS

Wetlands and Aquatic Processes

Conditions Affecting the Release of Phosphorus from Surface Lake Sediments

Environmental Pollution Control Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece

^* Corresponding author (fyti{at}chem.auth.gr)

Received for publication May 25, 2005. Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho-phosphates in lake sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH–P fraction, indicating participation of both fractions in the overall release of sediment-bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P-bearing metal oxides and the competitive exchange of phosphate anions with OH^– at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading.

Abbreviations: DOC, dissolved organic carbon • LOI, loss of ignition • TOC, total organic content • TP, total phosphorus