Inorganic phosphate in exposed sediments of the River Garonne

Abstract

Fractionation of inorganic phosphates in sediments of the River Garonne was carried out during a period of low water discharge. Sediments were collected under 5 cm of water (LS), in the dried river bank (MS) and in the riparian forest (RS). Sediments were sampled at two dates, during a period in which the water level fell gradually, causing sediment LS to be air exposed.Sediments were analysed for total phosphate, iron bound phosphate (Fe(OOH)-P) using Ca-NTA and Ca bound phosphate (CaCO 3 P) using Na-EDTA.Total-P varies from 552 (RS at date 1) to 2072 pg g-' (LS at date 2). There are significant differences between sediments and a significant increase from date 1 to date 2 in sediment LS only (1825 to 2072 pg g 1). Fe(OOH)-P varies from 186 (RS at date 1) to 874 pgg -' (LS at date 2). The highest values correspond to sediment LS. Moreover, Fe(OOH)-P increased significantly between date 1 and 2 in LS (560 to 874 g g-') as well as in sediment MS (248 to 432 pg g-'). Ca bound P concentrations differed significantly between sediments (75, 112, 235 g g-for sediments RS, MS and LS respectively) but not between sampling dates.These differences are attributed to the conditions of deposition of the sediments (such as morphology and hydrology of the river) and to the changes in chemical composition during the drying out of the sediments.

Effects of pretreatment on the sequential phosphorus fractionation of anaerobic sediment

“…In the present study, however, P HCl was not influenced by pretreatment. Fabre (1992) and Kerr et al, (2010) also found the consistent result. However, less P HCl was extracted when anaerobic sediment was preserved in air for 89 days compared with that extracted from fresh sediment (Lukkari et al, 2007b Reduced sediment Long-term aerobic storage Increasing P BD strongly and decreasing P HCl Lukkari et al, 2007b Aerobic sediment Long-term anaerobic storage Decreasing P BD and P Org Lukkari et al, 2007b Aerobic sediment Long-term aerobic storage Decreasing P BD Lukkari et al, 2007b Surficial 2 cm sediment Nature and laboratory Increasing labile P and decreasing P Org ; Kerr et al, 2010 drying (desiccation) changes of P BD and P NaOH depending on the sediment characteristics; laboratory drying has no influence on P HCl and P Res N o n -c o m m e r c i a l u s e o n l y days, laboratory drying was finished in a short time, which might prevent changes in the P HCl content in the sediment.…”

“…o n l y Lukkari et al, 2007b). Drying has also been verified to increase P BD (Fabre, 1992;Kerr et al, 2010) (Tab. 5).…”

“…Drying and desiccation have been found to increase or decrease P bound to ferric J. Limnol., 2014;73(2): 274-281 ORIGINAL ARTICLE DOI: 10.4081/jlimnol.2014.871 Effects of pretreatment on the sequential phosphorus fractionation of anaerobic sediment Lei (Fabre, 1992;De Groot and Fabre, 1993;Kerr et al, 2010). In addition, drying decreases or has no influence on calcium bound P (De Groot and Fabre, 1993;Kerr et al, 2010).…”

Effects of pretreatment on the sequential phosphorus fractionation of anaerobic sediment

“…The storage of anaerobic sediment in aerobic condition has been verified to change P fractionation results, so does the storage of aerobic sediment in anaerobic condition Lukkari et al, 2007b). Golterman (1996) oxyhydroxides (Fabre, 1992;De Groot and Fabre, 1993;Kerr et al, 2010). In addition, drying decreases or has no influence on calcium bound P (De Groot and Fabre, 1993;Kerr et al, 2010).…”

The Chemistry of Phosphate and Nitrogen Compounds in Sediments

“…Fabre (1992) found important differences in Tot-P concentrations and in fractional composition in sediment of the river Garonne (France). Fabre (1992) found important differences in Tot-P concentrations and in fractional composition in sediment of the river Garonne (France).…”