Spatio-temporal assessment of the PCB sediment contamination in the four main French River Basins (1945–2018)

Abstract

Abstract. Environmental pollution by Polychlorinated Biphenyls (PCBs) is a key concern about river quality because of their low degradation rates leading to their accumulation in sediments or living organisms. This original interdisciplinary work was conducted at a large scale along the four main French rivers (Seine, Rhône, Loire and Garonne Rivers), which flow into major European seas. We completed a dataset based on sediment analyses provided by monitoring agencies, port authorities and research teams on different solid matrices (cores, bed and flood sediments, suspended particulate matters, dredged sediments). This dataset (n=1416) focused on the seven indicator PCBs and their sum (∑PCBi) from 1945 to 2018. Special effort was put on the quality control to provide robust spatio-temporal information. Taking into account hydrological and human drivers, we outlined two main pollution trends: (1) from 1945 to 1975, a quick increase of ∑PCBi (up to 4 mg.kg−1 dry weight, dw) and a sharp decrease in the 1980s on the Seine and Loire Rivers; (2) increasing but moderate ∑PCBi levels (50 to 150 µg.kg−1 dw) followed by a decline after the 1990s on the Rhône and Garonne Rivers. In addition to these patterns, PCBs emissions from urban and industrial areas or accidental events were significant on each river. Finally, when calculating specific fluxes, the Rhône River exhibited the biggest ∑PCBi load (up to 12 µg.m−2.year−1 in 1977–1987), at least 25 % higher than those of the Seine and Loire Rivers, while the Garonne River showed very low fluxes. French specific ∑PCBi fluxes are two orders of magnitude lower than those found in American or Asian Rivers. In Europe, we confirmed that the Rhone and Seine Rivers provide a major supply of PCBi to the Western Mediterranean and the English Channel, respectively. The dataset is available at https://doi.pangaea.de/10.1594/PANGAEA.904277.

Legacy‐micropollutant contamination levels in major river basins based on findings from the Rhône Sediment Observatory

“…‑9% per year; Figure 3). This trend is in line with the general pattern of decreasing PCB contamination of the Rhône River waters that began in the 1990s (Desmet et al, 2012; Mourier et al, 2014; Babut et al, 2016; Liber et al, 2019; Dendievel, Mourier, Coynel, et al, 2020; Figure 2a). Nonetheless, the trend showed a change‐point in October 2013, with a slight increase in PCB concentrations of about +1.6 μg kg −1 per year (i.e.…”

“…More specifically, PAH data from bed and flood sediments over the period 1994–1997 were available from the Rhône–Mediterranean–Corsica water agency (data source: http://www.naiades.eaufrance.fr; Table 2), whereas PAH data for SPM come from the OSR data set over the period 2011–2016 (Delile et al, 2020; Thollet et al, 2021). The TME and ∑ 7 PCB analyses are available since the 1980s (Table 2) based on data for sediment cores and bed and flood deposits (see Dendievel, Mourier, Coynel, et al, 2020 for details on the data, stations and methods used). Over the periods 2011–2018 for TME and 2008–2017 for PCBi, we only used SPM data from the OSR data set (Delile et al, 2020; Thollet et al, 2021).…”

“…Data sources (Data S1) include data and scientific papers (e.g. Dendievel, Mourier, Coynel, et al, 2020), academic studies (e.g. Masson, 2007), databases of river monitoring surveys (e.g.…”

Temporal trends, sources, and relationships between sediment characteristics and polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment cores from the major Seine estuary tributary, France

“…The general temporal trend of PCB contents was similar to previously reported trends in France (Seine River watershed: Lorgeoux et al, 2016;Rhône River watershed: Desmet et al, 2012), Europe (UK: Sanders et al, 1992;Germany: Bruckmeier et al, 1997;Italy: Combi et al, 2020), and the US (Christensen and Lo, 1986;Van Metre et al, 1997), and were similar to temporal trends in global PCB production and consumption (Breivik et al, 2002). The maxima obtained during the 1950s-1970s (~1.6 mg kg -1 for the two ponds) were higher than those historically recorded in several French watersheds, such as the Loire (1.2 mg kg -1 , Dendievel et al, 2019), Garonne (0.145 mg kg -1 , Dendievel et al, 2019) and Rhône rivers watersheds (0.28 mg kg -1 , Desmet et al, 2012;0.42 mg kg -1 , Mourier et al, 2014); European watersheds such as the Brno Reservoir, Czech Republic (0.08 mg kg -1 , Franců et al, 2010);…”

“…It should be noted that total PCB J o u r n a l P r e -p r o o f concentrations were calculated from 7 congeners in the cited studies and up to 22 for Sanders et al (1992), compared with the 6 congeners studied herein. Nevertheless, the maximum concentrations recorded in the Eure River watershed remain lower than those recorded in recent flood deposits in the Rhône River (Dendievel et al, 2019), the Seine River (2.31 mg kg -1 , Lorgeoux et al, 2016), or the Seine estuary, France (5 mg kg -1 ; Dendievel et al, 2019), the Lippe River, Germany (2.63 mg kg -1 , Heim et al, 2004), or Milwaukee Harbour, US (13.4 mg kg -1 , Christensen and Lo, 1986). plasticizers, carbonless copy paper, lubricants, inks, laminating and impregnating agents, paints, adhesives, waxes, cement and plaster additives, casting and dedusting agents, sealing liquids, fire retardants, immersion oils, and pesticides (de Voogt and Brinkman, 1989;Bigus et al, 2014)), which may explain why it was after this date that the levels started to show a substantial decrease, especially in Martot Pond.…”