Consumption of the Clam, Galatea paradoxa (Born 1778) in Ghana: Human Health Implications with Reference to Heavy Metals

  • K. A. Obirikorang
  • D. Adjei-BoatengEmail author
  • S. Amisah


This study was carried out over a 7-month period at two active clam fishing locations, Ada and Aveglo at the Volta estuary in Ghana, to assess the levels of some heavy metals: Mn, Zn, Fe and Hg in whole soft tissue of Galatea paradoxa and their suitability for human consumption. The clam, Galatea paradoxa (Born 1778) is a commercially important bivalve species exploited mainly for its flesh. In Ghana, it constitutes an important and affordable protein source and is consumed by the riparian communities and beyond the Volta estuary. For each sampling location 30 clams were obtained and grouped into three size classes of 10 individuals, each based on shell lengths. The categorization was as follows: small (25–40 mm), medium (41–55 mm), and large (above 55 mm). The groupings were chosen based on the three dominant size groups in the natural population to give a broad and representative range of metal concentrations in the clams. The concentrations of zinc, iron and manganese were determined using a flame Atomic Absorption Spectrophotometer (AAS) and mercury concentrations were determined using an Atomic Mercury Analyzer. The results were expressed as total concentrations (μg/g dry weight (dw)). There were no significant differences (p>0.05) in Mn, Fe and Zn concentrations among the different size classes except for Hg concentration in clams from Ada, indicating a similar bioavailability of Mn, Fe, Zn at both locations and, possibly, an efficient metabolism to keep the concentrations of Mn, Fe and Zn relatively similar in the tissues of the different clam sizes. Spatial variations in metal concentrations (i.e., Ada small vs. Aveglo small, Ada medium vs. Aveglo medium, and Ada large vs. Aveglo large) were not significant for Mn, Zn and Hg for all the size classes. However, variations in Fe concentration in the large-sized clams was significant (p<0.05).

Heavy metal concentrations in the tissues of the clams were found to be suitable for human consumption based on the WHO Safety Reference Standards for Bivalves and a human health risk assessment methodology.

Freshwater clam Galatea paradoxa Heavy metal Human health implications Consumption Volta estuary 


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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • K. A. Obirikorang
    • 1
  • D. Adjei-Boateng
    • 1
    Email author
  • S. Amisah
    • 1
  1. 1.Department of Fisheries and Watershed Management, Faculty of Renewable Natural ResourcesKwame Nkrumah University of Science and TechnologyKumasiGhana

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