Mercury isotope signatures in sediments and marine organisms as tracers of historical industrial pollution. (November 2020)

• Record Type: Journal Article
• Authors: Bonsignore, Maria; Manta, Daniela Salvagio; Barsanti, Mattia; Conte, Fabio; Delbono, Ivana; Horvat, Milena; Quinci, Enza Maria; Schirone, Antonio; Shlyapnikov, Yaroslav; Sprovieri, Mario
• Is Part Of: Chemosphere. Volume 258(2020)
• Publication Date: 2020-11
• Subjects: Marine pollution -- Mercury isotope ratios -- Dating -- Sources -- Historical trends; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127435
• Languages: English
• ISSNs: 0045-6535

Abstract

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 δ 202 Hg 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 210 Pb dating method, validated through 137 Cs. 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 Δ 199 Hg/Δ 201 Hg ratio recorded in organisms are reasonably consistent with limited processes of MMHg demethylation in the water column. Graphical abstract: Image 1 Highlights: The Hg isotope composition in marine organisms and core sediments was explored. Sediments chronology was determined by 210 Pb dating method. Historical trend in Hg contaminated sediments was reconstructed. Benthic organisms and surface sediments have similar isotopic composition.