FN Archimer Export Format
PT J
TI Mercury in the Lot-Garonne River system (France): Sources, fluxes and anthropogenic component
BT 
AF SCHAFER, Jörg
   BLANC, Gerard
   AUDRY, S
   COSSA, Daniel
   BOSSY, C
AS 1:1;2:1;3:1;4:2;5:1;
FF 1:;2:;3:;4:PDG-DOP-DCN-BE-LBCM;5:;
C1 Univ Bordeaux 1, TGM, CNRS, UMR 5805,EPOC, F-33405 Talence, France.
   IFREMER, Biogeochim Contaminants Met, F-44311 Nantes 03, France.
C2 UNIV BORDEAUX, FRANCE
   IFREMER, FRANCE
SI NANTES
SE PDG-DOP-DCN-BE-LBCM
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 1.866
TC 61
UR https://archimer.ifremer.fr/doc/2006/publication-1343.pdf
LA English
DT Article
DE ;Lot;Garonne;SPM;River;Organic matter;Mercury
AB Dissolved and particulate Hg fluxes in the Lot-Garonne-Gironde fluvial-estuarine system were obtained from observation of daily discharge and suspended particulate matter (SPM) concentrations. In addition to the measurements of the total dissolved (< 0.45 gm) and particulate Hg (> 0.45 gm), called HgTD and HgTp respectively, the dissolved inorganic Hg species (HgRD) were determined monthly. Geochemical background values for HgTp in sediments and SPM were similar to crustal values and to typical concentrations in SPM of non-contaminated river systems, respectively. The Riou Mort watershed already known as the origin of important historical polymetallic (e.g., Cd, Zn) pollution was identified as an important Hg point source. In the downstream Lot River, Hg concentrations were clearly higher than those in other moderately contaminated systems. The mean relative contribution of HgRD to HgTD in the Lot River and in the Garonne River was close to 25% and 50%, respectively, and showed no correlation with water discharge or SPM concentration. Depending on the origin and nature of SPM, HgTp concentrations were correlated or not with particulate organic C (POC). Maximum HgTp concentrations were measured in samples containing low POC concentrations and were attributed to sediment resuspension. In contrast, high POC concentrations (6-17%) during algal blooms were associated with low/moderate HgTp concentrations (< 0.5 mg kg(-1)) at different sites, suggesting that Hg concentrations in fluvial phytoplankton may be limited by bioavailability of dissolved Hg and/or physiologically controlled Hg accumulation. Mercury was mostly (up to 98%) transported in the particulate phase with estimated annual Hg fluxes at the outlet of the Lot River system ranging from 35 to 530 kg a(-1) for the past decade. The minimum anthropogenic component (58-84% of total Hg fluxes) could not be explained by present Riou Mort point source contributions, suggesting important Hg release from contaminated sediment as a major source and from downstream point sources (e.g., coal-fired power plants and/or metal processing industries). HgTp concentrations and fluxes were strongly related to hydrologic variations and were clearly increased by riverbed dredging during lock construction. Therefore, the estimated Hg stocks in the Lot River sediment (5-13 tons) represent an important potential Hg source for the downstream fluvial-estuarine system. 
PY 2006
PD MAR
SO Applied Geochemistry
SN 0883-2927
PU Elsevier
VL 21
IS 3
UT 000236507900008
BP 515
EP 527
DI 10.1016/j.apgeochem.2005.12.004
ID 1343
ER

EF