Reconstruction of anthropogenic activities in legacy sediments from the Eure River, a major tributary of the Seine Estuary (France)

Most rivers worldwide are contaminated by various trace metals from different origins, which may be stored for considerable periods of time in depositional areas. Most of these studies are focused on the main river of a watershed and the tributaries are often neglected which can be important sources of contamination. The aim of this study was to reconstruct the anthropogenic activities that occurred in the Eure River, tributary of the Seine Estuary, since the 1940s using "legacy sediments". The results showed that the temporal trends of trace metals were not related to detrital inputs and TOC variations but with the industrial history of the Eure River watershed. The high levels of Zn, Cu, and Ni during the 1950s and the 1960s, and the decrease with the decline of the probable main source of release showed the watershed reactivity to anthropogenic activities. The high levels of Pb during the 1990s and the 2000s showed that the watershed reacted immediately to anthropogenic pressures. The Pb levels remained important after the cease of industrial activity, showing that a resilience period is necessary for the system, and that interactions between human activities and the environment go beyond of the activities themselves.