Copper, lead and cadmium concentrations in surface water, sediment and fish, C. Carpio, samples from Lake Naivasha: effect of recent anthropogenic activities

摘要

Following recent concerns of chemical pollution around Lake Naivasha, especially originating from recent agricultural activities in the catchment, samples of water, sediments, and fish Common carp (Cyprinus carpio) were collected from the Hippo Point, Kasarani, Mouth of Malewa River, Mouth of Karati River, Crescent Island, Sher Karuturi Discharge outlet and Oserian Bay for analysis of Cu, Cd and Pb by FAAS. The mean heavy metal levels ranged from 5.12–58.11 (Pb), 1.06–1.73 (Cd), and 0.03–2.29 (Cu) mg/kg wet weight in C. carpio muscle, 100–179.83 (Pb), 10.00–10.06 (Cd) and 30.00–32.33 (Cu) μg/L in surface water, and 17.11–53.07 (Pb), 1.18–5.58 (Cd) and 3.00–8.48 (Cu) mg/kg dry weight in sediment and showed a wide variation within and between samples with relatively high concentrations in sediments and fish muscle tissues. The results indicate that Lake Naivasha, in some parts, is polluted with these heavy metals of which relatively higher concentrations are found at the discharge outlets near Sher Karuturi and Oserian Bay. This indicates possible contribution from surrounding horticultural/floricultural activities and the Mouths of the Rivers Malewa and Karati which flow from it’s upper catchment.