Determination of mercury in fish by cold vapour atomic absorption spectrometry using an automatic mercury analyzer

The concentration of mercury in fish samples from the Atlantic coast of Ghana was determined using a simple, rapid and accurate method. A mixture of HNO3, HClO4 and H2SO4 was used for complete oxidation of organic tissue. Mercury is detected by the cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer developed at the National Institute for Minamata Disease (NIMD). In total, 56 samples covering 13 species of fish were analysed for total mercury. The concentration of mercury in the edible muscle tissue of these fish ranged from 0.004 to 0.122 μg g−1 wet weight. All fish species sampled had concentrations less than the WHO limit of 0.5 μg g−1 wet weight. The low concentrations of mercury detected in the samples do not constitute any significant mercury exposure to the general population through fish consumption.