Historical trends of metals and metalloids into lake and coastal sediments of Halong Bay (Vietnam)

Sandrine Chifflet; Thomas Zambardi; Pieter van Beek; Marc Souhaut; Van Vuong Bui; Lars-Eric Heimbürger-Boavida; Bernard Angeletti; Sylvain Ouillon; Thuoc Chu Van; Xavier Mari

doi:10.1016/j.marpolbul.2024.117490

Historical trends of metals and metalloids into lake and coastal sediments of Halong Bay (Vietnam)

Mar Pollut Bull. 2024 Dec 21:211:117490. doi: 10.1016/j.marpolbul.2024.117490. Online ahead of print.

Affiliations

¹ Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France. Electronic address: sandrine.chifflet@mio.osupytheas.fr.
² UMR5566 LEGOS, University of Toulouse, IRD, CNES, CNRS, UPS, 14 Avenue Edouard Belin, 31400 Toulouse, France.
³ Institute of Marine Environment and Resources (IMER), Vietnam Academy of Science and Technology (VAST), 246 Danang, Haiphong 04000, Viet Nam.
⁴ Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France.
⁵ Aix Marseille University, CNRS, IRD, Collège de France, INRAE, CEREGE, 13545 Cedex 4 Aix-en-Provence, France.
⁶ UMR5566 LEGOS, University of Toulouse, IRD, CNES, CNRS, UPS, 14 Avenue Edouard Belin, 31400 Toulouse, France; Department Water-Environment-Oceanography, University of Science and Technology of Hanoi (USTH), Vietnamese Academy of Science and Technology (VAST), 18 Hoang Quoc Viet, Hanoi 100000, Viet Nam.
⁷ Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France; Department Water-Environment-Oceanography, University of Science and Technology of Hanoi (USTH), Vietnamese Academy of Science and Technology (VAST), 18 Hoang Quoc Viet, Hanoi 100000, Viet Nam; IRD, Chulalongkorn University, 254 Henri Dunant Road, Pathumwan, 10330 Bangkok, Thailand.

PMID: 39709780
DOI: 10.1016/j.marpolbul.2024.117490

Abstract

Halong Bay (northern Vietnam) is heavily affected by human activities. Metals and metalloids (e.g., Al, Cu, Hg, Ni, Sb, Pb, V; MM) were used as proxies to assess the origin and transport of anthropogenic inputs. The chronology of inputs was examined according to different particle transport pathways using two sediment cores, one from coastal waters (HL) exposed to both atmospheric deposition and the Red River drainage, and the other from a small isolated lake on an islet (HT) receiving only atmospheric deposition. Higher accumulation rates were observed in HL (0.449 g cm^-2 year^-1) than in HT (0.069 g cm^-2 year^-1). In both cores, all anthropogenic MM fluxes are controlled by sedimentation processes regardless of their origin and transport pathways. Results show that coastal waters are strongly influenced by Red River drainage with specific events recorded in 1947 (Indochina War), 1960 (first five-year plan), 1974 and 1985 (flash flooding) and 2002 (Tuyen Quang Dam landslides). In HL core, the highest variabilities were observed for Cr, Hg, Ni, Pb and V with surface maxima of 67.7, 0.107, 26.0, 31.4, 82.2 μg g^-1, respectively. Geochemical ratios (Pb/Hg and V/Ni) showed specific signatures related to fossil fuel combustion. Estimated Pb deposition fluxes follow the increase in CO₂ emissions in the region.

Keywords: Anthropogenic fluxes; Atmospheric and fluvial inputs; Historical change.