Concentrations of mercury and cadmium in Silver Cyprinid (Dagaa) fish from Lake Victoria, Kenya.

Abstract

The toxicity of heavy metals is in part because they bioaccumulate in biological tissues. The objective of this study was to assess the concentrations of lead (Pb) and cadmium (Cd) in dagaa from open and gulf waters and compare the concentrations to their maximum permissible limits under Kenya Bureau of Standards (KEBS), European Commission (EC) and World Health Organization (WHO) regulations. The study was undertaken in December 2020 (dry season) and samples (dry and wet) were collected from six dominant dagaa landing sites along Lake Victoria, Kenya (Marenga, Uhanya, Litare, Sori, Asat, and Bao) for heavy metal analyses. The study indicated that Rastrineobola argentea from different sources had different concentrations of heavy metals (Table 1). Mercury and cadmium were detected in all dagaa samples analyzed; however, their concentrations were within the permissible limits of 0.5ppm as recommended by World Health Organization (WHO, 2010; EC, 2001; SDF&BE, 2018). We recommend continued surveillance measures necessary in containing industrial and sewerage effluents discharge and agricultural inputs run-off impacts towards heavy metal deposition in the lake and bioaccumulation in fish.