Fifty-year sedimentary record of heavy metal pollution (Cd, Zn, Cu, Pb) in the Lot River reservoirs (France).

The Lot-Garonne fluvial system is known for its historic heavy metal pollution resulting from mining and smelting activities since the late 19th century. Here, we report 137Cs activities and heavy metal (Cd, Zn, Cu, Pb and V) concentration-depth profiles from sediment cores retrieved in 2001 from three reservoirs in the Lot River. High mean sedimentation rates of 2.4-2.8 cm a(-1) are indicated by 137Cs dating. The reservoir sediments have recorded the heavy metal deposition and thus allow establishing a connection between the temporal evolution of the heavy metal pollution and historical changes in smelting and waste-treatment proceedings. Based on heavy metal concentrations in sediments upstream of the anthropogenic inputs and bottom-sediments of the furthest downstream core (interpreted as old soil or riverbed), concentrations of approximately 17, approximately 82, approximately 0.33 and approximately 28 mg kg(-1) for Cu, Zn, Cd and Pb, respectively, are proposed as natural background values for the Lot fluvial system. The geoaccumulation index (Igeo [Müller, G., 1979. Schwermetalle in den Sedimenten des Rheins-Veränderungen seit. Umschav 79, 133-149.]) revealed that the Lot River sediments must be considered as "severely polluted" in Cd and Zn. Moreover, despite remediation efforts undertaken in the former smelting site, the Lot River is still "severely" (Igeo approximately 4) and "moderately to severely" (Igeo>2) impacted by Cd and Zn inputs, respectively.

[1]  A. Wörman,et al.  Desorption and diffusion of episodic pollutants in sediments: a 3-phase model applied to Chernobyl 137Cs , 1996 .

[2]  T. Johnson.  Sedimentation in Large Lakes , 1984 .

[3]  M. Sevilla,et al.  Study of fractionation and potential mobility of metal in sludge from pyrite mining and affected river sediments: changes in mobility over time and use of artificial ageing as a tool in environmental impact assessment. , 2003, Environmental pollution.

[4]  G. Blanc,et al.  Relationship between ore deposits in river catchments and geochemistry of suspended particulate matter from six rivers in southwest France. , 2002, The Science of the total environment.

[5]  H. Beck,et al.  Radiation exposures in Utah from Nevada Nuclear Tests. , 1983, Science.

[6]  J. Arnason,et al.  A 40+ year record of Cd, Hg, Pb, and U deposition in sediments of Patroon Reservoir, Albany County, NY, USA. , 2003, Environmental pollution.

[7]  S. Audry,et al.  Cadmium transport in the Lot-Garonne River system (France) - temporal variability and a model for flux estimation. , 2004, The Science of the total environment.

[8]  James M. Ross,et al.  Stable lead isotopes, contaminant metals and radionuclides in upper Hudson River sediment cores: implications for improved time stratigraphy and transport processes , 2003 .

[9]  M. Sturm,et al.  200-Year Record of Metals in Lake Sediments and Natural Background Concentrations , 1997 .

[10]  A. Putnis,et al.  A TEM study of samples from acid mine drainage systems: metal-mineral association with implications for transport , 1999 .

[11]  J. Morillo,et al.  Partitioning of metals in sediments from the Odiel River (Spain). , 2002, Environment international.

[12]  Stuart L. Simpson,et al.  Effect of Short-Term Resuspension Events on the Oxidation of Cadmium, Lead, and Zinc Sulfide Phases in Anoxic Estuarine Sediments , 2000 .

[13]  H. Etcheber,et al.  Ten-year observation of the Gironde tributary fluvial system: fluxes of suspended matter, particulate organic carbon and cadmium , 2002 .

[14]  P. Krey,et al.  Radioactive fallout reconstruction from contemporary measurements of reservoir sediments. , 1990, Health physics.

[15]  J. Zwolsman,et al.  Mobilisation of Heavy Metals in Contaminated Sediments in the River Meuse, The Netherlands , 1999 .

[16]  W. C. Camplin,et al.  Pollution: Chernobyl's legacy in food and water , 2000, Nature.

[17]  R. Glud,et al.  In situ study of bromide tracer and oxygen flux in coastal sediments , 1999 .

[18]  R. Battarbee,et al.  Distribution of some trace metals in Lochnagar, a Scottish mountain lake ecosystem and its catchment. , 2002, The Science of the total environment.

[19]  A. Schmidt,et al.  Contaminants in sediments: remobilisation and demobilisation. , 2001, The Science of the total environment.

[20]  Stéphane Audry,et al.  Anthropogenic components of heavy metal (Cd, Zn, Cu, Pb) budgets in the Lot-Garonne fluvial system (France) , 2004 .

[21]  Sáenz,et al.  Heavy metal fluxes at the sediment-water interface of three coastal ecosystems from south-west of the Iberian Peninsula , 2000, The Science of the total environment.

[22]  J. C. Fernández-Caliani,et al.  Heavy metal partitioning in river sediments severely polluted by acid mine drainage in the Iberian Pyrite Belt , 2003 .

[23]  F. Grousset,et al.  A 70 year Record of Contamination from Industrial Activity Along the Garonne River and its Tributaries (SW France) , 1999 .

[24]  K. H. Wedepohl.  The Composition of the Continental Crust , 1995 .

[25]  J. Robbins,et al.  TRANSPORT AND ACCUMULATION OF RADIONUCLIDES AND STABLE ELEMENTS IN A MISSOURI RIVER RESERVOIR , 1993 .

[26]  Jerry C. Ritchie,et al.  Application of Radioactive Fallout Cesium-137 for Measuring Soil Erosion and Sediment Accumulation Rates and Patterns: A Review , 1990 .

[27]  J. Abril.  Constraints on the use of 137Cs as a time-marker to support CRS and SIT chronologies. , 2004, Environmental pollution.

[28]  M. Bradbury,et al.  Experimental and modelling studies of caesium sorption on illite , 1999 .

[29]  E. Callender.  Geochemical effects of rapid sedimentation in aquatic systems: minimal diagenesis and the preservation of historical metal signatures , 2000 .

[30]  R. Comans,et al.  Modelling the diffusive transport and remobilisation of 137Cs in sediments: The effects of sorption kinetics and reversibility , 1996 .

[31]  M. Salkinoja-Salonen,et al.  100 Years of Sediment Accumulation History of Organic Halogens and Heavy Metals in Recipient and Nonrecipient Lakes of Pulping Industry in Finland , 1998 .

[32]  Jing Zhang.  Geochemistry of Trace Metals from Chinese River/Estuary Systems: An Overview , 1995 .

[33]  K. H. Wedepohl.  Handbook of Geochemistry , 1969 .

[34]  J. Zwolsman,et al.  Dredging-related mobilisation of trace metals: a case study in The Netherlands. , 2001, Water research.

[35]  Geochronology of Pb and Hg pollution in a coastal marine environment using global fallout 137Cs. , 2003, Journal of environmental radioactivity.

[36]  D. Stanley,et al.  Manzala lagoon, Nile delta, Egypt: modern sediment accumulation based on radioactive tracers , 1998 .

[37]  W. Shotyk,et al.  Geochemistry, mineralogy, and geochemical mass balance on major elements in two peat bog profiles (Jura Mountains, Switzerland) , 1997 .

[38]  Wim Salomons,et al.  Environmental impact of metals derived from mining activities: Processes, predictions, prevention , 1995 .

[39]  C. W. Francis,et al.  Preferential adsorption of 137Cs to micaceous minerals in contaminated freshwater sediment , 1976, Nature.

[40]  J. Lancelot,et al.  Taux de sédimentation dans l'étang de Thau à partir des données géochronologiques, géochimiques et des repères stratigraphiques , 1997 .

[41]  R. Comans,et al.  Experimental and in situ study of radiocaesium transfer across the sediment-water interface and mobility in lake sediments , 2000 .

[42]  Y. Muramatsu,et al.  Reservoir sediments – a witness of mining and industrial development (Malter Reservoir, eastern Erzgebirge, Germany) , 2000 .

[43]  C. Latouche,et al.  Pollution en Cadmium Dans Les Sédiments du Lot (France) et Calcul du Stock de Polluant Cadmium Pollution in Sediments of the Lot River (France). Estimate of the Mass of Cadmium , 1995 .