Levels of Total Mercury in Different Fish Species and Sediments from the Upper Volta Basin at Yeji in Ghana

• Published in: Bulletin of environmental contamination and toxicology 2011-04, Vol.86 (4), p.406-409
• Main Authors: Kwaansa-Ansah, E. E, Agorku, S. E, Nriagu, J. O
• Format: Article
• Language: English
• Subjects: Animals; Aquatic Pollution; Bagrus docmac; Basins; Bioaccumulation; Chrysichthys nigrodigitatus; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental Monitoring; Fish; Fishes - metabolism; Food and Agriculture Organization; Fresh Water - chemistry; Geologic Sediments - chemistry; Ghana; Gnathonemus senegalensis; Gold; guidelines; Mercury; Mercury - analysis; Mercury - metabolism; Mining; Muscles - metabolism; Pollution; River basins; Rivers; Sediments; Soil Science & Conservation; Synodontis; Synodontis membranaceus; Waste Water Technology; Water Management; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Pollution Control; Water Pollution, Chemical - statistics & numerical data; World Health Organization
• ISSN: 0007-4861; 1432-0800
• DOI: 10.1007/s00128-011-0214-2

In this study, total mercury concentrations were determined in sediments and seven different fish species from the Upper Volta Basin area of Yeji in Ghana. Mercury concentrations found ranged from 44.17 to 85.88 ng/g wet weight for Synodontis gambiesis, from 11.25 to 79.73 ng/g wet weight for Synodontis membranaceus, from 13.11 to 38.64 ng/g wet weight for Synodontis ocellifer, from 16.39 to 25.82 ng/g wet weight for Distishodus rotratus, from 40.80 to 90.30 ng/g wet weight for Bagrus docmac, from 10.48 to 61.90 ng/g wet weight for Chrysichthys nigrodigitatus and from 12.33 to 24.18 ng/g wet weight for Gnathoneus senegalensis. These values are below the 500 ng/g guideline recommended by the WHO/FAO, implying that fish from the Upper Volta Basin area of Yeji are safe for human consumption. Good correlation was observed between mercury concentration and fresh weight (R² = 0.6067) and total length (R² = 0.8754) for Gnathonemus senegalensis. However, poor correlations were observed between mercury concentration and fresh weight and total length for the other six species. Mercury in sediments ranged from 11.87 to 70.25 ng/g dry weights with a mean of 41.60 ng/g dry weight being below the IAEA threshold of 810 ng/g.. These values show that sections of the Upper Volta River remain relatively clean in spite of substantial loadings of mercury into the river's basin from gold mining activities.