Work

Legacy and modern trace metals contamination in Aiguillon Bay: A 150-Year record of human influence

Year: 2026

Type: article

Abstract: This study presents a multi-proxy, diachronic reconstruction of the historical trajectory of anthropogenic contamination in direct connection with the land-use transformations of the Aiguillon Bay (south-west France). By integrating geomatic analysis of land-use change with high-resolution geochemistry and radionuclide dating ( 210 Pb xs and 137 Cs) of four sediment cores, we have reconstructed the historical imprint of human activities over the past ~150 years. Land-use analysis reveals a significant homogenization of agricultural systems since 1990, notably an increase of 4.74 percentage points in non-irrigated arable land concurrent with accelerated urban artificialization since the 1950s. The studied cores record a distinct geochemical signature of anthropogenic pressures, characterized by significant enrichment of lead (Pb) and zinc (Zn) across the bay. The most critical contamination signals include extreme Cd peaks (CF up to 6.09), an early 20th-century Pb and pulsed Hg enrichments. Conversely, Cd concentrations exhibit a pronounced increase beginning in the 1970s. Principal Component Analysis (PCA) may reflect a robust association between trace Metals, organic matter, and fine-grained sediments, underscoring synchronized transport and sequestration mechanisms. By aligning the sedimentary geochemical record with land-use history, these findings establish the Aiguillon Bay cores not merely as pollution archives but as integrative sentinels of a century of socio-environmental transformation across the Marais Poitevin watershed.

Source: Regional Studies in Marine Science

DOI: 10.1016/j.rsma.2026.105370