Assessment of heavy metals concentration in water, soil sediment and biological tissues of the lesser flamingos in four eastern rift valley lakes
The term heavy metal refers to any metallic chemical element that has a relatively high density and is toxic at low concentrations. This study was conducted in four eastern Rift Valley lakes which included Lakes Oloidien, Crater, Elementaita and Nakuru, to determine the presence and levels of lead, arsenic, cadmium and chromium concentration in water, soil sediments and biological tissues of the Lesser Flamingos (Phoeniconaias minor) and compare with the set standards. As these lakes catchments fall directly within a combination of agricultural and industrial regions, the run-offs and the resulting effluents will make the waters highly prone to chemical contamination. The methodology involved collection of water samples (n=40), sediments samples (n=51) and the Lesser Flamingos (live n= 6; dead n=2) for qualitative and quantitative toxicological analysis. The analysis was done using Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS) model-Specter AA-10 Varian. Lead and arsenic were found to be in high concentration in soil sediments in all four lakes while chromium and cadmium were in low concentration. Soil sediments analysed from the inflow of the Nakuru sewerage drain (1754±22.81 ppb) and rivers to Lake Nakuru (1129±107 ppb) had the highest mean ± SD lead concentration. Arsenic, cadmium, chromium and lead were also observed in bird tissues. Metals in the Lesser Flamingo tissues were below the toxicological levels that are reported in literature to be harmful, except lead which was above the level recommended by the US Environmental Protection Agency.
Keywords: Heavy metals, lesser flamingo, environment