ABSTRACT
Lake Victoria is the largest freshwater and fishery lake in Africa. Kisumu City on the Winam
Gulf has industrial activities that dispose of their effluents into the lake which may contaminate
aquatic species thus threatening human health. It is not known fully if these anthropogenic
activities adversely change the water quality and contribute heavy metal pollutants to the lake
water and/or cause high accumulation of the metals in sediments and fish from the gulf. The
study employed a three factor completely randomized design. Samples of water from Molasses
Plant, Rivers Kisat and Kisian and lakewater, sediments and fish species (Lates niloticus,
Oreochromis niloticus, Synodontis victoriae and clarias batrachus) were collected from Lake
Victoria shoreline near the city. The samples were digested and analyzed using Atomic
Absorption Spectrophotometer for heavy metals during wet (April-July 2013) and dry (Jan-Feb
2014) seasons to assess the influence of the anthropogenic activities within Kisumu City and
adjacent environment on heavy metal levels in aquatic samples and water physicochemical
parameters. The data was subjected to statistical analysis using MSTATC package at 95%
confidence level. The heavy metal levels (μg/L) in river and lake waters recorded ranges were
Cd (1.00 - 12.00), Cr (13.00 - 75.50), Cu (23.00 - 276.50), Fe (789.00 - 1050.50), Mn (452.50 -
2466.30), Pb (33.50 - 409.50), Zn (954.50 - 50.00) and Cd (0.20 - 1.30), Cr (21.00 - 55.00), Cu
(8.00 - 25.00), Fe (127.50 - 225.00), Mn (76.00 - 334.00), Pb (5.00 - 10.00), Zn (9.00 - 21.00)
respectively. The heavy metal levels in the water channels decreased (p ≤ 0.05) in the order Kisat
> Molasses > Kisian. River Kisat water was the most polluted. The levels of the heavy metals in
lake and river waters varied (p ≤ 0.05) with sites. Water from Kisat discharge point had levels
above the recommended WHO acceptable limits for aquatic life and domestic use. The metal
levels (μg/g in dry weight basis) in sediments were Cd (0.90 - 1.20), Cr (2.60 - 36.00), Cu (71.40
- 122.90), Fe (1283.40 - 1468.70), Mn (792.30 - 1631.20), Pb (61.80 - 181.00) and Zn (100.10 -
187.60). Heavy metal levels in River Kisat discharge point sediments were high (p ≤ 0.05)
compared to levels in sediments from River Kisian discharge point. The heavy metal ranges in
the edible fish tissues (μg/g on dry weight basis) across the caught fish species were Cd (0.60 -
0.70), Cr (0.60 - 0.80), Cu (2.90 - 3.70), Fe (33.70 - 36.90), Mn (74.70 - 90.90), Pb (0.40 - 0.70)
and Zn (31.30 - 41.20). The metal levels in fish were above international limits. The water
physicochemical parameter levels varied (p ≤ 0.05) with sites. Dissolved oxygen in lake water
was below the WHO recommended limits for fisheries. The high metal levels in aquatic samples
(water, fish and sediments) and deterioration of water quality parameters from the study area
were due to intense anthropogenic activities. Use of water from Kisat discharge point and
consumption of fish from the study area may pose health risks. Regular environmental
assessment of heavy metal levels in water, sediments and fish, and water quality
physicochemical parameters is recommended
KIEMA, F (2021). Assessment Of Levels Of Selected Metal Pollutants In Aquatic Samples Along Lake Victoria Shoreline From Rivers Kisat To Kisian Discharge Points, Kenya. Afribary. Retrieved from https://afribary.com/works/assessment-of-levels-of-selected-metal-pollutants-in-aquatic-samples-along-lake-victoria-shoreline-from-rivers-kisat-to-kisian-discharge-points-kenya
KIEMA, FRANCIS "Assessment Of Levels Of Selected Metal Pollutants In Aquatic Samples Along Lake Victoria Shoreline From Rivers Kisat To Kisian Discharge Points, Kenya" Afribary. Afribary, 06 May. 2021, https://afribary.com/works/assessment-of-levels-of-selected-metal-pollutants-in-aquatic-samples-along-lake-victoria-shoreline-from-rivers-kisat-to-kisian-discharge-points-kenya. Accessed 23 Dec. 2024.
KIEMA, FRANCIS . "Assessment Of Levels Of Selected Metal Pollutants In Aquatic Samples Along Lake Victoria Shoreline From Rivers Kisat To Kisian Discharge Points, Kenya". Afribary, Afribary, 06 May. 2021. Web. 23 Dec. 2024. < https://afribary.com/works/assessment-of-levels-of-selected-metal-pollutants-in-aquatic-samples-along-lake-victoria-shoreline-from-rivers-kisat-to-kisian-discharge-points-kenya >.
KIEMA, FRANCIS . "Assessment Of Levels Of Selected Metal Pollutants In Aquatic Samples Along Lake Victoria Shoreline From Rivers Kisat To Kisian Discharge Points, Kenya" Afribary (2021). Accessed December 23, 2024. https://afribary.com/works/assessment-of-levels-of-selected-metal-pollutants-in-aquatic-samples-along-lake-victoria-shoreline-from-rivers-kisat-to-kisian-discharge-points-kenya