Decline of anthropogenic lead in South Atlantic Ocean surface waters from 1990 to 2011 : new constraints from concentration and isotope data

• Published in: Marine Pollution Bulletin
• Main Authors: Olivelli, Arianna, Murphy, Katy, Bridgestock, Luke, Wilson, David J., Rijkenberg, Micha, Middag, Rob, Weiss, Dominik J., van de Flierdt, Tina, Rehkämper, Mark
• Other Authors: University of St Andrews.School of Earth & Environmental Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Lead; Isotopic composition; Seawater; Pollution; GEOTRACES; GE Environmental Sciences; NDAS; SDG 14 - Life Below Water; MCC; GE; South Atlantic Ocean
• Online Access: https://hdl.handle.net/10023/27185; https://doi.org/10.1016/j.marpolbul.2023.114798

Funding: Arianna Olivelli was supported by the Natural Environment Research Council (NE/S007415/1). Katy Murphy was supported by the Natural Environment Research Council (NE/J021636/1). Dominik Weiss, Tina van de Flierdt, and Mark Rehkämper were supported by the Natural Environment Research Council (NE/H006095/1). David Wilson was supported by the Leverhulme Trust (RPG-398) and a Natural Environment Research Council independent research fellowship (NE/T011440/1). The GEOTRACES GA02 section cruises were financed by the Netherlands Organization for Scientific Research (NWO) project grant 839.08.410. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising. Anthropogenic emissions have severely perturbed the marine biogeochemical cycle of lead (Pb). Here, we present new Pb concentration and isotope data for surface seawater from GEOTRACES section GA02, sampled in the western South Atlantic in 2011. The South Atlantic is divided into three hydrographic zones: equatorial (0–20°S), subtropical (20–40°S), and subantarctic (40–60°S). The equatorial zone is dominated by previously deposited Pb transported by surface currents. The subtropical zone largely reflects anthropogenic Pb emissions from South America, whilst the subantarctic zone presents a mixture of South American anthropogenic Pb and natural Pb from Patagonian dust. The mean Pb concentration of 16.7 ± 3.8 pmol/kg is 34 % lower than in the 1990s, mostly driven by changes in the subtropical zone, with the fraction of natural Pb increasing from 24 % to 36 % between 1996 and 2011. Although anthropogenic Pb remains predominant, these findings demonstrate the effectiveness of policies that banned leaded gasoline. Peer reviewed