Analysis of Heavy Metals in Water and Surface Sediment in Five Rift Valley Lakes in Kenya for Assessment of Recent Increase in Anthropogenic Activities

Abstract

The concentrations of heavy metals Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn were analysed in water and surface sediments of five Rift Valley lakes Nakuru, Elementaita, Naivasha, Bogoria and Baringo in Kenya. The dissolved mean concentration levels (mug/L) in water ranged within 13.0-185.0 (Ag), 2.0-43.0 (Cd), 5.0-316.0 (Co), 25.0-188.0 (Cr), 4.7-100.0 (Cu), 50.0-282.0 (Mn), 19.0-288.0 (Ni), 25.0-563.0 (Pb), 300.0-1050.0 (Sn) and 29.0-235.0 (Zn). The mean sediment concentrations (in mug/g (dry weight)) ranged within 0.1-0.35 (Ag), 0.05-1.18 (Cd), 0.17-1.38 (Co), 1.94-4.91 (Cr), 1.46-20.95 (Cu), 667.7-3946.8 (Mn), 11.69-39.72 (Ni), 10.92-38.98 (Pb), 17.21-56.52 (Sn) and 96.2-229.6 (Zn). The data indicate that some of the sites analysed, especially in Lake Nakuru, had relatively higher concentration levels of heavy metals Cd, Co, Cu, Pb, Ni, and Zn in the water which points to anthropogenic addition. However, potential influence of geochemical processes on the concentration levels in sediment is also shown in Co, Ni, and Cu which were more concentrated in the remote Lake Baringo sediment as well as in Pb and Mn which were more concentrated in the remote Lake Bogoria sediment. Data on some important limnological parameters including pH, salinity, electrical conductivity and temperature are also presented.

Ecological risk assessment of heavy metals and water bird distribution in rift valley lakes, Kenya

“…Cd was also not detectable in water samples from all the six lakes. This was in agreement with the results obtained by Tenai (2015) but contrary to those obtained by Ochieng et al (2007) who recorded traces of Cd levels in water samples (2.0 to 5.0 µg/L) in Lake Baringo, (5.0 to 41.0 µg/L) in Lake Bogoria Bogoria (1.3918 ppm), Crater (1.3658 ppm) and Oloiden (3.0 to 43.0 µg/L) in Lake Nakuru and (3.0 to 25.1 µg/L) in Lake Elementaita. Dilution as a result of rising water levels in Kenyan Rift Valley Lakes may be responsible for undetected Cd.…”

“…Lake Bogoria recorded the highest Mn mean sediment concentrations of 3676 ppm; Lake Nakuru gave highest mean sediment concentrations of Co (100 ppm) and Lake Oloiden recorded highest mean concentrations of Pb (42 ppm) in sediments. The mean sediment levels of Mn in Lake Bogoria are within the ranges obtained by Ochieng et al (2007) who obtained Mn mean sediment concentration of 3947 ± 121 ppm. The mean sediment concentrations for Cu, Zn, As and Cr were very low in all the six lakes (Table 2 to 4).…”

“…The results on Cd concentrations in sediments differ from those obtained by Tenai (2015) who found traces of Cd (0.0004 to 0.076 ppm) in Lakes Crater, Elementaita, Nakuru and Oloiden. Ochieng et al (2007) also obtained high levels of Cd (1.18 ppm) in sediment from Lake Elementaita. Cd was also not detectable in water samples from all the six lakes.…”

The development of probiotics for women’s health

“…Carrying this concept to Kenya where aflatoxins produced by Aspergillus on maize cause death and morbidity following consumption, a pilot study of school children showed that daily intake of the probiotic yogurt can reduce toxin uptake (Nduti et al 2016). Given the use of pesticides, the high amounts of heavy metals in lakes and the problem of aflatoxins in food in eastern Africa (Ochieng et al 2007;Kilonzo et al 2014;Kang et al 2015;Okonya and Kroschel 2015;Arinaitwe et al 2016), any method of lowering risk of toxicity must be considered and pursued.…”

Proximate composition, microbiological safety and heavy metal contaminations of garri sold in Benue, North-Central Nigeria

“…Lead causes neurological impairment and central nervous system (CNS) damage by its ability to mimic and inhibit the actions of calcium in its neurotransmission function (Markus and McBratney, 2001;Nadal et al, 2004). Some heavy metals such as cobalt, copper, iron, manganese and zinc are essential micro-elements for living things; however, they are toxic at high concentrations (Nadal et al, 2004;Ani, 2006;Ochieng et al, 2007).…”