title: Trajectories of river chemical quality issues over the Longue Durée: the Seine River (1900S-2010).
abstract: River quality trajectories are presented for (i) organic pollution, (ii) eutrophication, (iii) nitrate pollution, and (iv) metal contamination over the Longue Durée (130 to 70 years). They are defined by a quantified state indicator (S) specific to each issue, compared to drivers (D) or pressures (P) and to social responses (R) that reflect the complex interactions between society and river quality. The Lower Seine River, naturally sensitive to anthropogenic pressures, greatly impacted by Paris urban growth, industrialization, and intensive agriculture, and well documented by the PIREN-Seine 25-year research program, was chosen to illustrate these trajectories. State indicators, dissolved oxygen, algal pigments, nitrate, and heavy metals (Cd, Cr, Hg, Pb, Zn) in sediments have only been monitored by river basin authorities since 1971. Therefore, their past changes have been reconstructed using three approaches: (i) reassessment of historical sources, (ii) pressure-state models that reconstruct past water quality, and (iii) sedimentary archives of past persistent contamination from dated floodplain cores. The indicators were then transformed into river quality status using contemporary water quality criteria throughout these records. Each environmental issue shows specific trajectories because each has its own relationship between the issue evidence and the social response, but all are characterized by very poor quality in the past, largely ignored: the long-term summer hypoxia (<1880-1995), the summer eutrophication peak (1965-2005), the growing nitrate level since the 1950s, recently stabilized but still high, and the extreme metal contamination (>1935-2000) that peaked in the 1960s. The efficiency of social responses has been highly variable but more efficient in the last 15-25 years.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Meybeck
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005, Paris, France. laurence.lestel@upmc.fr.
authors.forename: L
authors.initials: L
authors.lastname: Lestel
authors.affiliation: Université Paris1 Panthéon-Sorbonne, Laboratoire LADYSS-Laboratoire Dynamique Sociales et Recomposition des Espaces (UMR 7533), 2 rue Valette, 75005, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Carré
authors.affiliation: IRSTEA Bordeaux, Unité environnement, territoires, infrastructures, 50 Avenue de Verdun, 33612, Cestas, France.
authors.forename: G
authors.initials: G
authors.lastname: Bouleau
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Garnier
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005, Paris, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Mouchel
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D005068:Eutrophication; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D010297:Paris; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
chemical_list: D019216:Metals, Heavy; D009566:Nitrates; D014874:Water Pollutants, Chemical
keywords: Eutrophication; Nitrate; Organic pollution; River quality trajectory; Seine River; metals