Total Mercury Distribution in Different Fish Species Representing Different Trophic levels from the Atlantic Coast of Ghana

Abstract

Concentrations of total mercury (Hg) were measured in the edible muscle tissues of different fish species representing different trophic levels from the Atlantic Coast of Ghana using Cold Vapour Atomic Absorption Spectrophotometry (CVAAS). Mercury concentrations were gener-ally found to increase with trophic levels. The concentrations of the metal (Hg) were highest (mean=0.093 μg g-1) in high trophic level predatory fish, followed by middle trophic level preda-tory fish (mean=0.063 μg g-1) and low trophic level fish (mean=0.047 μg g-1). However the differ-ences were not significant at the 0.05 level according to ANOVA. All fish species analysed in this study had total mercury concentrations (range: 0.001-0.278 μg g-1) less than the FAO/WHO limit of 0.5 μg g-1 wet weight. The low concentrations of mercury in the fish species obtained in this study do not appear to contribute any significant mercury exposure to the general popula-tion; and suggest a relatively clean marine environment that has not yet been significantly im-pacted by mercury contamination probably due to minimal industrial activity in the region.