Tracing basin-scale circulation of Hg from multiple sources using paleolimnological, approaches, sediment long-term monitoring data and isotopic fingerprinting: a case study from Lake Maggiore (Italy/Switzerland)
Abstract
The ubiquitous nature of mercury contamination complicates the understanding of its behavior in aquatic ecosystems suffering from legacy pollution. By combining paleolimnological approaches, long-term monitoring and isotopic fingerprinting, we reconstructed the chronology of total Hg contamination (i.e., all inorganic and organic species) from multiple sources in sediment cores of Lake Maggiore (Italy/Switzerland). Anthropogenic Hg contamination spanned at least 400 years, from the early 17th century until the end of the 20th century, with inputs from artisanal and industrial gold mining, hat making and chlor-alkali production. Mercury used as a catalyst in chlor-alkali production had a distinctly heavier 202Hg signature compared with natural Hg and could be traced as far as the southernmost part of the lake, outside of the zone of of concern delimited in 2000 by the Italian Ministry of the environment. Sediments impacted by gold mining or hat making did not have a specific 202Hg signature, but paleolimnological and monitoring information allowed to identify the contribution of these sources to Hg contamination. Mercury contamination has decreased steadily since the early 2000s, but total Hg concentrations remain above background values, especially in the southern part of the lake. According to model calculations, Hg in sediments should return to background concentrations between 2040 and 2100, but the agreement between these estimates and recent observations varies across sampling sites. The proposed methodological approach exemplifies complementary lines of evidence can help in better understanding how mercury moves in aquatic ecosystems. This information can improve monitoring programs and, where needed, management and remediation strategies for legacy Hg contamination.
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BibTeX
@misc{vignati2026tracing,
title = {{Tracing basin-scale circulation of Hg from multiple sources using paleolimnological, approaches, sediment long-term monitoring data and isotopic fingerprinting: a case study from Lake Maggiore (Italy/Switzerland)}},
author = {Davide A.L. Vignati and Aldo Marchetto and Andrea Lami and Benedetta Ponti and Marina Camusso and Lucia Valsecchi and Angela Boggero and Simona Musazzi and Holger Hintelmann and Roberta Bettinetti and Laura Marziali},
howpublished = {HAL},
year = {2026},
month = oct,
url = {https://hal.univ-lorraine.fr/hal-05360582v2},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Tracing basin-scale circulation of Hg from multiple sources using paleolimnological, approaches, sediment long-term monitoring data and isotopic fingerprinting: a case study from Lake Maggiore (Italy/Switzerland)
AU - Davide A.L. Vignati
AU - Aldo Marchetto
AU - Andrea Lami
AU - Benedetta Ponti
AU - Marina Camusso
AU - Lucia Valsecchi
AU - Angela Boggero
AU - Simona Musazzi
AU - Holger Hintelmann
AU - Roberta Bettinetti
AU - Laura Marziali
PY - 2026
DA - 2026/10/11
PB - HAL
UR - https://hal.univ-lorraine.fr/hal-05360582v2
AB - The ubiquitous nature of mercury contamination complicates the understanding of its behavior in aquatic ecosystems suffering from legacy pollution. By combining paleolimnological approaches, long-term monitoring and isotopic fingerprinting, we reconstructed the chronology of total Hg contamination (i.e., all inorganic and organic species) from multiple sources in sediment cores of Lake Maggiore (Italy/Switzerland). Anthropogenic Hg contamination spanned at least 400 years, from the early 17th century until the end of the 20th century, with inputs from artisanal and industrial gold mining, hat making and chlor-alkali production. Mercury used as a catalyst in chlor-alkali production had a distinctly heavier 202Hg signature compared with natural Hg and could be traced as far as the southernmost part of the lake, outside of the zone of of concern delimited in 2000 by the Italian Ministry of the environment. Sediments impacted by gold mining or hat making did not have a specific 202Hg signature, but paleolimnological and monitoring information allowed to identify the contribution of these sources to Hg contamination. Mercury contamination has decreased steadily since the early 2000s, but total Hg concentrations remain above background values, especially in the southern part of the lake. According to model calculations, Hg in sediments should return to background concentrations between 2040 and 2100, but the agreement between these estimates and recent observations varies across sampling sites. The proposed methodological approach exemplifies complementary lines of evidence can help in better understanding how mercury moves in aquatic ecosystems. This information can improve monitoring programs and, where needed, management and remediation strategies for legacy Hg contamination.
ER -