Spatio-temporal assessment of the polychlorinated biphenyl (PCB) sediment contamination in four major French river corridors (1945–2018)

Abstract

Abstract. Environmental pollution by polychlorinated biphenyls (PCBs) is a key cause for concern about river quality because of their low degradation rates leading to their accumulation in sediments and living organisms. An original interdisciplinary work was conducted 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 (sediment cores, bed and flood deposits, suspended particulate matter and dredged sediments). This dataset focused on the seven indicator PCBs and their sum (ΣPCBi) from 1945 to 2018 (nΣPCBi =1416). Special effort was put into 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 in ΣPCBi (up to 4 mg kg−1 dry weight, dw) and a sharp decrease in the 1980s on the Seine and Loire rivers and (2) increasing but moderate ΣPCBi 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, PCB emissions from urban and industrial areas or accidental events were significant in each river. Finally, when calculating specific flux, the Rhône exhibited the uppermost ΣPCBi load (up to 12 µgm-2yr-1 in 1977–1987), at least 25 % higher than those of the Seine and Loire rivers, while the Garonne showed a very low flux. In western Europe, we confirmed that the Rhône, Seine and Loire rivers contribute significantly to the PCB contamination of the seas, while French specific ΣPCBi fluxes are 2 orders of magnitude lower than those found in American or Asian rivers. The dataset is available at https://doi.org/10.1594/PANGAEA.904277 (Dendievel et al., 2019).

Sediment archives reveal irreversible shifts in plankton communities after World War II and agricultural pollution

“…PCB contamination profiles sustain the hypothesis of contaminations of agricultural origin from the 1950s onward. These profiles in sediment are similar to those of other French human-impacted sites 33,34 or other agriculturally exploited sites. 35,36 A palynological study (pollen grains and dinoflagellate cysts) carried out on a twin core of the DE allowed direct comparison between the evolution of landscape, surface water, and human practices in Bay of Brest watersheds and corroborate the hypothesis of post-war agricultural contamination.…”

Foraminiferal Distribution in Two Estuarine Intertidal Mudflats of the French Atlantic Coast: Testing the Marine Influence Index

“…The EF is obtained by dividing the Th-normalised concentration by the concentration found in an unpolluted reference sediment, representative of the regional geochemical background [53]. Several studies have demonstrated that the regional geochemical backgrounds can be defined via the bottom/base of sediment cores in French continental systems, especially when the age model suggests that those deeper layers have been deposited before the onset of regional contamination sources (e.g., [54][55][56][57]). To this end, values from the basis of a long sediment core sampled in the western part of the Morbihan Gulf [58] have been used.…”

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

“…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.…”