FN Archimer Export Format PT J TI Mercury transformations and exchanges in a high turbidity estuary: The role of organic matter and amorphous oxyhydroxides BT AF LAURIER, Fabien COSSA, Daniel GONZALEZ, Jean-Louis BREVIERE, Emily SARAZIN, G AS 1:;2:;3:;4:;5:; FF 1:PDG-DEL-PC;2:PDG-DEL-PC;3:PDG-DEL-PC;4:PDG-DEL-PC;5:; C1 IFREMER, F-44311 Nantes 3, France. IFREMER, F-83507 La Seyne Sur Mer, France. Univ Paris 07, Lab Geochim Eaux, F-75005 Paris, France. C2 IFREMER, FRANCE IFREMER, FRANCE UNIV PARIS 07, FRANCE SI NANTES TOULON SE PDG-DEL-PC IN WOS Ifremer jusqu'en 2018 copubli-univ-france IF 3.465 TC 72 UR https://archimer.ifremer.fr/doc/2003/publication-425.pdf LA English DT Article CR MERCAUX 1 MERCAUX 2 BO Thalia DE ;Sediments;Biogenic thiols;Fluorescence detection;Seine estuary;Mercury AB The speciation and partition of mercury in a macrotidal estuary (Seine estuary, France) was studied in order to explore the role of the high turbidity zone (HTZ) in mercury transfer to the adjacent coastal waters. Water and particles were analyzed to determine the concentrations of various mercury species, including monomethylmercury and the inorganic fraction. The exchangeable particulate mercury, which varies with salinity, and the mercury fraction associated with the amorphous oxyhydroxides were evaluated. The distribution of dissolved mercury species during early mixing suggests non-conservative behavior of organically bound mercury at the head of the estuary. Mercury in the particles covaried positively with suspended particulate matter concentrations up to a threshold, which constitutes the typical mercury load of particles and deposited sediments of the HTZ. This distribution pattern is well explained by a dilution model: a slowly settling, low metal population of particle, characterized by relatively invariant turbidity, becomes admixed with a variable amount of higher metal content particles derived from the resuspension in the HTZ. In addition, in the HTZ, which acts as a degradation reactor for particulate organic matter, particulate mercury concentrations increase with increasing C:N ratios and amorphous oxyhydroxides particles. Mercury reaches the estuarine HTZ mainly associated with the riverine and marine particles, including organic matter and oxyhydroxides, which are temporarily trapped in the HTZ and mixed with autochthonous HTZ particles. The largest particles periodically settle and undergo diagenetic reactions and resuspensions, which lead to their mercury enrichment. Depending upon hydrodynamic conditions, mercury escapes seaward as fine particulate within the plume, partially associated with the oxyhydroxides. A surface complexation model reproduces most of the partitioning observed. In the dissolved phase the model simulation suggests that a very strong ligand must be present to explain the field observations. PY 2003 PD SEP SO Geochimica et Cosmochimica Acta SN 0016-7037 PU Elsevier VL 67 IS 18 UT 000185441300003 BP 3329 EP 3345 DI 10.1016/S0016-7037(03)00081-4 ID 425 ER EF