Isotopic composition of mercury (Hg) in marine organisms and sediment cores was used to identify sources and reconstruct historical trends of contamination in the coastal-marine area of Rosignano Solvay (Italy), affected by Hg pollution from a chlor-alkali plant on the near land. Sediments show a wide range of Hg concentration and Hg isotope signatures. Particularly, coupled Hg concentration and δ202Hg values trace inputs from different sources. The two depth-profiles clearly indicate three distinct periods: “pre-industrial” (before 1941), “industrial” (between 1941 and 2007) and “post-industrial” (after 2007) ages. This is also corroborated by sediment chronology, using 210Pb dating method, validated through 137Cs. Marine organisms are characterized by Hg isotope signatures comparable to “post-industrial” surface sediments. Notably, specimens of Mullus spp. evidence isotope composition comparable to the “industrial” sediments, thus suggesting a still active role of those sediments as source of Hg for the benthic fish compartment. The small amount of MIF and the Δ199Hg/Δ201Hg ratio recorded in organisms are reasonably consistent with limited processes of MMHg demethylation in the water column.

Mercury isotope signatures in sediments and marine organisms as tracers of historical industrial pollution

Barsanti M.;Conte F.;Delbono I.;Schirone A.;
2020

Abstract

Isotopic composition of mercury (Hg) in marine organisms and sediment cores was used to identify sources and reconstruct historical trends of contamination in the coastal-marine area of Rosignano Solvay (Italy), affected by Hg pollution from a chlor-alkali plant on the near land. Sediments show a wide range of Hg concentration and Hg isotope signatures. Particularly, coupled Hg concentration and δ202Hg values trace inputs from different sources. The two depth-profiles clearly indicate three distinct periods: “pre-industrial” (before 1941), “industrial” (between 1941 and 2007) and “post-industrial” (after 2007) ages. This is also corroborated by sediment chronology, using 210Pb dating method, validated through 137Cs. Marine organisms are characterized by Hg isotope signatures comparable to “post-industrial” surface sediments. Notably, specimens of Mullus spp. evidence isotope composition comparable to the “industrial” sediments, thus suggesting a still active role of those sediments as source of Hg for the benthic fish compartment. The small amount of MIF and the Δ199Hg/Δ201Hg ratio recorded in organisms are reasonably consistent with limited processes of MMHg demethylation in the water column.
Dating
Historical trends
Marine pollution
Mercury isotope ratios
Sources
Animals
Aquatic Organisms
Environmental Monitoring
Environmental Pollution
Fishes
Geologic Sediments
Industry
Isotopes
Italy
Mercury
Mercury Isotopes
Water Pollutants, Chemical
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12079/56747
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