Metal Status of Nairobi River Waters and Their Bioaccumulation in Labeo Cylindricus

Abstract

This study focused on the analysis of metals in water and fish from Nairobi River. Water from Kikuyu, Kawangware, Chiromo, Eastleigh, Njiru and Fourteen Falls along the Nairobi River was analyzed for the presence of metals. Most of the metal levels in water were below the critical limit of World Health Organization and Kenya Bureau of Standards except for lead, chromium, iron and manganese. Isolated cases of mercury and aluminium pollution were recorded. Except for iron, sodium and potassium, there was no significant difference in the concentration of metals at different sites. This study also analyzed metal levels in fish organs and tissues of fish caught from downstream (Fourteen Falls). The highest zinc concentration (360 µg/g) was in the scales, copper recorded the highest concentration in the kidney (45 µg/g), while cadmium recorded high values (167 µg/g) in the heart. Lead recorded high values (178 µg/g) in the heart and mercury recorded high values also in the heart (1000 ng/g). Most of these organs, are however, not eaten by man as food. Although metal levels were within normal levels in the water at Fourteen Falls, mercury, copper, lead and iron recorded higher than accepted levels in some fish organs. This calls for caution in the consumption of fish from Fourteen Falls.

A comparative biological study on Oreochromis niloticus from two Nilotic Canals in the Delta of Egypt

“…Fish are usually considered as organisms of choice for assessing the effects of environmental changes and they are used as bio-indicators in monitoring the water pollution of the aquatic ecosystem (Borković et al, 2008;Mohamed et al, 2017). For this reason, the utility of fish for assessing environmental conditions in aquatic ecosystems has gained prominence in previous years (Khallaf et al, 1998(Khallaf et al, , 2003Yilmaz, 2003;Budambula and Mwachiro, 2006;Adeniyi et al, 2008;Authman, 2008;Authman et al, 2008;Palaniappan et al, 2010;Authman et al, 2012Authman et al, , 2013aAuthman et al, , b, 2015Abdel-Tawwab et al, 2016).…”

Bioconcentration of zinc and its effect on the biochemical constituents of the gill tissues of Labeo rohita: An FT-IR study

“…The contamination of metals in fish indirectly affects the human beings [7]. For this reason, the utility of fish for assessing environmental conditions in aquatic ecosystems has gained prominence in recent years [8][9][10].…”

Challenges to surface water quality in mid‐sized African cities: conclusions from Awetu‐Kito Rivers in Jimma, south‐west Ethiopia

“…The Nairobi River was also found to have a nitrate level as high as 520.6 mg/L. The major sources of pollution in this river basin were identified to come from industrial effluent, effluent from petrol stations and motor vehicle garages, surface run-off from factories and other business premises, raw sewage from broken or overloaded sewers as well as raw sewage from informal settlements (Budambula & Mwachiro 2006).…”