Nutrient, heavy metal and organic pollutant composition of suspended and bed sediments in the Rhone River

Despite increasingly strict control of polychlorinated biphenyl (PCB) releases in France since the mid-1970s, PCB contamination of fish recently has emerged as a major concern in the lower Rhône River basin. We measured PCB concentrations in Rhône sediment to evaluate the effects of PCB releases from major urban and industrial areas, sediment redistribution by large floods, and regulatory controls on PCB trends from 1970 to present. Profiles of PCBs (the sum of seven indicator PCB congeners) were reconstructed from sediment cores collected from an off-river rural reference site and from three depositional areas along the Rhône upstream and downstream from the city of Lyon, France. Core chronology was determined from radionuclide profiles and flood deposits. PCB concentrations increased progressively in the downstream direction, and reached a maximum concentration in 1991 of 281 g/kg at the most downstream site. At the rural reference site and at the upstream Rhône site, PCB concentrations peaked in the 1970s (maximum concentration of 13 and 78 g/kg, respectively) and have decreased exponentially since then. PCB concentrations in the middle and downstream cores were elevated into the early 1990s, decreased very rapidly until 2000, and since then have remained relatively stable. Congener profiles for three time windows (1965-80, 1986-93, and 2000-08) were similar in the three sediment cores from the Rhône and different from those at the rural reference site. The results indicate that permitted discharges from a hazardous-waste treatment facility upstream from Lyon might have contributed to high concentrations into the 1980-90s, but that industrial discharges from the greater Lyon area and tributaries to the Rhône near Lyon have had a greater contribution since the 1990s. There is little indication that PCB concentration in sediments downstream from Lyon will decrease over at least the short term.

Section: Environmental Protectionmentioning

confidence: 95%

Spatial and temporal trends in PCBs in sediment along the lower Rhône River, France

Desmet

Mourier

Mahler

et al. 2012

“…This site is likely to be influenced by industrial effluents south of Lyon (Santiago et al, 1994). The site also showed increased concentrations of DOC, conductivity, and dissolved solids.…”

Section: Trace Metal Spatial Distribution and Partitioningmentioning

confidence: 98%

“…The Rhône River is particularly suitable as a test site because of two main features: (i) its longitudinal contrast with a more human activity -impacted lower part downstream of the city of Lyon (Olivier et al, 2009a;Santiago et al, 1994) and (ii) the persistence of numerous floodplain sectors with an array of water bodies differing in lateral connectivity (Amoros et al, 1987;Riquier et al, 2015). We selected sites from the two extremes of the lateral connectivity gradient (permanent connection upstream and downstream vs. disconnected at base flow) in floodplain sectors upstream and downstream of Lyon.…”

Section: Introductionmentioning

confidence: 99%

Lateral and longitudinal patterns of water physico-chemistry and trace metal distribution and partitioning in a large river floodplain

Peter

Castella

2017

• Distribution of trace metals in different floodplain water bodies is not well known.• Water, sediment, SPM and invertebrates from different types of water bodies were analyzed.• Trace metal partitioning varied between connected and disconnected sites.• Lateral gradient was more important than the longitudinal gradient.• Observed differences need to be considered in floodplain management. Floodplain water bodies provide habitat to diversified ecological communities. Floodplains are also among the most impacted aquatic ecosystems. While the link between the lateral connectivity of floodplain sites to the main channel and their plant, fish and invertebrate communities has been well established, detailed information on chemical characteristics and particularly on trace metal spatial distribution and partitioning is scarce. The aim of this study was to examine the link between the lateral connectivity and physico-chemical variables, their trace metal concentrations and partitioning as well as the upstream-downstream gradient of these parameters. In connected and disconnected water bodies of the Rhône River upstream and downstream of the city of Lyon, we measured major ions, dissolved organic carbon, trace metal concentrations (Al, Cr, Ni, Cu, Zn, Cd, Pb and U) in water, suspended particulate matter (SPM) and sediment. The results revealed a clear difference between connected and disconnected water bodies. pH, SPM, Na + , and NO 3 − concentrations were lower in disconnected sites while conductivity, DOC, Ca 2+ and Mg 2+ were higher. Conductivity and a part of the major ion concentrations increased in the downstream sections. Trace metal concentrations and partitioning varied between connected and disconnected sites. In the dissolved fraction, trace metal concentrations were higher in connected sites. In the surface sediment, concentrations were higher in disconnected sites for the majority of metals. The upstream-downstream gradient was less important than the connected-disconnected gradient. Only three metals in the dissolved fraction (Cu, Cd and Pb) showed a clear increase in downstream sections. Overall, the study shows that the functioning of floodplains produces strong spatial patterns concerning the concentrations and partitioning of trace metals. These findings improve our understanding of trace metal biogeochemistry in floodplains and have important applications for floodplain restoration projects. © 2017 Elsevier B.V. All rights reserved. G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o

“…Although Santiago et al (1994) showed that the occurrence of pollutants increased dramatically downstream from Lyon, new analyses were performed by using sedimentary archives: PCB concentrations were linked to an upstream-downstream pattern because of different drivers (floods, flushing events, tributary contaminations, populations, and the small amounts released by PCB treatment facilities) (Mourier et al, 2014). Desmet et al (2012) noted that PCB concentrations decreased in the mid-nineties but remained relatively stable afterwards.…”

Section: Spatial and Temporal Contextmentioning

confidence: 99%

How chemical pollution becomes a social problem. Risk communication and assessment through regional newspapers during the management of PCB pollutions of the Rhône River (France)

Comby

Lay

Piégay

2014

The case study of the polychlorinated biphenyl (PCB) pollutions of the Rhône River (France) offers the possibility of studying criteria for the construction of social problems that result from chemical pollution (2005)(2006)(2007)(2008)(2009)(2010). We investigated the dynamics of competition that create and define pollution as a social problem and entail its decline. News outlets are crucial for determining how an environmental issue emerges locally or nationally; this study used stakeholders. In terms of management, we described the temporal dynamics of the social problem based on the case study and considered an explanation of the selections. We considered the organization of particular stakeholders who define the social problem from its beginning to end by focusing on their discourses, relationships, decision-making and political choices, and scientific studies. Despite some biases, newspapers are useful for retrospectively evaluating the emergence of a social problem in the public arena by describing it through 2 discourse and then understanding the temporal patterns of information. Despite uncertainties and information flow, decisions are made and science is translated to the public.