Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Popoola Samuel Olatunde ekanpopesam@gmail.com Nigerian Institute for Oceanography and Marine Research http://www.niomr.gov.ng/ https://ror.org/01exgks31 Yao Marcel Konan yaomarcelkonan@gmail.com Université Félix Houphouët-Boigny http://www.univ-fhb.edu.ci/ https://ror.org/03haqmz43 Akpetou Lazare Kouame lazakpetou@gmail.com Université Jean Lorougnon Guédé UJLog http://www.ujlog.ci/ https://ror.org/03q1wc761 Yao N'goran‪ Jean-Paul dryao_ngoran@yahoo.fr Université Félix Houphouët-Boigny http://www.univ-fhb.edu.ci/ https://ror.org/03haqmz43 Edmond Sossoukpe esossoukpe@yahoo.fr Université d'Abomey-Calavi UAC https://ror.org/03gzr6j88 Sossou Ehoumi Paul esossou6@gmail.com Université d'Abomey-Calavi UAC https://ror.org/03gzr6j88 Nkwoji Joseph josephunilag@gmail.com University of Lagos http://www.unilag.edu.ng/ https://ror.org/05rk03822 Botwe Benjamin Osei boseibotwe@yahoo.co.uk University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Agyekumhene Andrews aagyekumhene@gmail.com University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Nunoo Francis Kofi Ewusie fkenunoo@hotmail.com University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Nyarko Elvis University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Gnakabi Edgar Michael edgardgnakabi@gmail.com Université Félix Houphouët-Boigny http://www.univ-fhb.edu.ci/ https://ror.org/03haqmz43 Biney Charles Ecosystems Environmental Solutions Limited Akoetey Charlotte Mawoussi Yawa akoetey.c9@gmail.com University of Lomé UL http://www.univ-lome.tg/ https://ror.org/00wc07928 Gnimassoun Jean Baptiste Gbêssi gnimassoung@gmail.com University of Lomé UL http://www.univ-lome.tg/ https://ror.org/00wc07928 Ayoola Nubi Olubunmi oanubi@yahoo.com Nigerian Institute for Oceanography and Marine Research http://www.niomr.gov.ng/ https://ror.org/01exgks31 Laudien Jürgen juergen.laudien@awi.de https://www.awi.de/en/about-us/organisation/staff/single-view/juergen-laudien.html 0000-0003-2663-4821 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven AWI https://www.awi.de/ https://ror.org/032e6b942 Asamoah Eunice Konadu ekonadutwum@gmail.com University of Ghana http://www.ug.edu.gh/ https://ror.org/01r22mr83 Emeka Chimezie chimezie.n.emka@gmail.com University of Calabar UNICAL http://www.unical.edu.ng/ https://ror.org/05qderh61 Seeyave Sophie ssve@pml.ac.uk Plymouth Marine Laboratory PML http://www.pml.ac.uk/pml https://ror.org/05av9mn02 2026 Spatial Variability of Total Mercury and Methyl Mercury Concentrations in Coastal Sediments from Five African Countries in the Gulf of Guinea Region dataset https://doi.org/10.1594/PANGAEA.996125 2026-08-18T12:18:21 Anthropogenic activities, such as untreated sewage disposal and mining, contribute to metal pollution in coastal marine environments. Toxic metals (e.g., mercury) are detrimental, even in small amounts,tal and can be transferred through the aquatic food chain via bioaccumulation and biomagnification. Mercury is a naturally abundant element and a potentially toxic industrial metal, mostly released into the environment via drinking water, dietary intake, and industrial activities (Charkiewicz et al., 2025; Genchi et al., 2017; Li et al., 2024). Therefore, there is a need to investigate the status of mercury contamination in the coastal marine environment. Mercury occurs in different forms, including inorganic elemental mercury, monovalent mercury, divalent mercury, and organic forms such as methylmercury (MeHg)(Tian et al., 2023). There are mainly three forms: elemental mercury (Hg0), inorganic mercury (IHg: Hg+ and Hg2+), and organic mercury(methyl—MeHg; ethyl—EtHg; and phenyl—PhHg), with the MeHg form being the most dangerous and harmful to human health or even life (Genchi et al., 2017; Hu et al., 2021)'. The study assessed spatial distribution of total mercury (THg) and methyl mercury (meHg) in coastal sediments from five African countries covering five coastal water bodies, mainly, Ebrié Lagoon (E.L., Côte d'Ivoire), Volta Estuary (V.E., Ghana), Lake Togo (L.T., Togo), Lake Nokoué (L.N., Benin), and Lagos Lagoon (L.L., Nigeria) within the Gulf of Guinea region to understand the spatial dynamics and transboundary mercury pollution for protection of life below water (SDG14), promote good health and well-being (SDG3), promote clean water and sanitation (SDG6), and building partnerships to advocate for reforms in mercury pollution policies in the sub Saharan Africa region. Sediment is a source of environmental contamination and a permanent component of aquatic ecosystems. Forty-eight surficial coastal sediment samples (0–10 cm) were collected from the five selected coastal systems based on their ecological significance and human impacts in the dry season (November 2022, February, and March 2023) using bottom sampling gear ( Eckman and Van Veen grabs) based on the depth of the waterbodies. Wet coastal sediment (the uppermost oxidised portion, 0 –2 cm) was air-dried immediately after collection for preservation. Before the analytical procedures, all sediments were oven-dried at 60°C and sieved to obtain particle-size fractions. The Direct Mercury Analyser (Model DMA-80, Milestone) was used to determine total mercury (THg) and methyl mercury (MeHg) in the <63 μm size fraction of sediment according to the standard methods (e.,g US-EPA 1998). The analyses were carried out at the Department of Marine and Fisheries Sciences at the University of Ghana. The use of thermal release to obtain mercury speciation information has been used for a long time (Valsecchi et al., 2021). The DMA uses thermal energy and atomic absorption spectrometry Valsecchi et al., 2021). The direct mercury analyser (DMA) enabled i) no sample digestion; ii) quantitative analysis, including the detection of total mercury (THg) and methyl mercury (meHg) at mg kg⁻¹ levels; and iii) the analysis of very small sample quantities, allowing a greater variety of studies on the redoxx transformations of the metal in environmental matrices (Barst et al., 2013; Charkiewicz et al., 2025; Li et al., 2024; Valsecchi et al., 2021; Windmöller et al., 2017). Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X et al. submitted Spatial Distribution, Contamination Levels, and Ecological Risk of Total Mercury and Methyl Mercury in the Gulf of Guinea Sediments journal article Water Air and Soil Pollution Barst Benjamin D Hammerschmidt Chad R Chumchal Matthew M Muir Derek C G 0000-0001-6631-9776 Smith JD Roberts Aaron P Rainwater Thomas R Drevnick Paul E 2013 Determination of mercury speciation in fish tissue with a direct mercury analyzer journal article Environmental Toxicology and Chemistry 32(6) https://doi.org/10.1002/etc.2184 1237-1241 Charkiewicz Angelika Edyta 0000-0003-2657-454X Omeljaniuk Wioleta Justyna 0000-0001-8412-3937 Garley Marzena 0000-0002-6727-3850 Nikliński Jacek 0000-0002-8437-1401 2025 Mercury Exposure and Health Effects: What Do We Really Know? journal article International Journal of Molecular Sciences 26(5) https://doi.org/10.3390/ijms26052326 2326 Genchi Giuseppe 0000-0003-0538-4907 Sinicropi Maria 0000-0003-2435-8931 Carocci Alessia Lauria Graziantonio Catalano Alessia 0000-0002-7420-4706 2017 Mercury Exposure and Heart Diseases journal article International Journal of Environmental Research and Public Health 14(1) https://doi.org/10.3390/ijerph14010074 74 Hu Xue Feng Lowe Mackenzie 0000-0001-9889-1558 Chan Hing Man 2021 Mercury exposure, cardiovascular disease, and mortality: A systematic review and dose-response meta-analysis journal article Environmental Research 193 https://doi.org/10.1016/j.envres.2020.110538 110538 Li Kai likai@zjnu.edu.cn Sun Ranhao Guo Guanghui 2024 Spatial and temporal variations in environmental impacts of heavy metal emissions from China's non-ferrous industry: An enterprise-specific assessment journal article Science of the Total Environment 929 https://doi.org/10.1016/j.scitotenv.2024.172770 172770 Tian Xue Lin Xiaoying Zhao Jiating Cui Liwei Gao Yuxi Yu Yong-Liang Li Bai Li Yu-Feng 2023 Gut as the target tissue of mercury and the extraintestinal effects journal article Toxicology 484 https://doi.org/10.1016/j.tox.2022.153396 153396 United States Environmental Protection Agency 1998 Method 7473 (SW-846): Mercury in Solids and Solutions by Thermal Decomposition, Amalgamation, and Atomic Absorption Spectrophotometry, Revision 0 other Washington, DC Valsecchi Lucia 0000-0002-6506-8079 Roscioli Claudio 0000-0002-0857-4143 Schiavon Alfredo 0000-0002-4386-4912 Marziali Laura 0000-0003-4321-0721 2021 Methylmercury determination in freshwater biota and sediments: Static headspace GC-MS compared to direct mercury analyzer journal article MethodsX 8 https://doi.org/10.1016/j.mex.2021.101581 101581 Windmöller Cláudia Carvalhinho 0000-0001-8517-8104 Silva Nayara Carolinne Morais Andrade Pedro Henrique Mendes Louise Aparecida Magalhães do Valle Cláudia 2017 Use of a direct mercury analyzer® for mercury speciation in different matrices without sample preparation journal article Analytical Methods 9(14) https://doi.org/10.1039/C6AY03041F 2159-2167 -4.306111 3.578 5.258056 6.602 0.32965151742798326 5.95445059355967 2022-11-18T00:00:00 2023-03-28T00:00:00 Ebrié_Lagoon 5.272778 -4.240556 Ivory Coast 2022-11-18T00:00:00 Lagos_Lagoon 6.525 3.401 Nigeria 2023-01-15T00:00:00 Lake_Nokoué 6.36916 2.38666 Benin 2023-03-22T00:00:00 Lake_Togo 6.230256 1.514903 Togo 2023-03-10T00:00:00 Volta_Estuary 5.774694 0.662111 Volta River estuary, Ghana, Africa 2023-03-28T00:00:00 426 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Event label Event Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Event Sample code/label Sample label Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Sample label Water Body Water Body water body http://purl.obolibrary.org/obo/ENVO_00000063 Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Water Body Name Name Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Name Description Description description Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Description Location Location location Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Location LONGITUDE Longitude http://en.wikipedia.org/wiki/ISO_6709 Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Longitude LATITUDE Latitude http://en.wikipedia.org/wiki/ISO_6709 Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Latitude Sample method Sample method Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Sample method Plate Plate Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X number Plate Sample, dry mass Samp dm g dry mass https://en.wikipedia.org/wiki/Dry_matter Mass M http://dbpedia.org/resource/Mass Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Samp dm [g] Mercury Hg mg/kg mercury Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X Hg [mg/kg] Methylmercury MeHG µg/kg Akita Lailah Gifty lailah.lailah@gmail.com 0000-0002-1074-296X 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