Water Pollution

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An Overview of Heavy Metal Pollution in the Western Indian Ocean (WIO) region of Kenya: A Review
(Journal of Aquatic Terrestrial Ecosystems, 2023-06-20) Nyamora, Jane Moraa; Njiru, James; Nyakeya, Kobingi; Getabu, Albert; Muthumbi, Agnes
This study is a review on heavy metal pollution in the Western Indian Ocean (WIO) region of Kenya. The review examines heavy metal pollution of copper, lead, cadmium, iron and zinc that are toxic to marine life and human health; and identifies gaps for future monitoring and assessment. Each pollutant was addressed in order to determine their status in the environment, sources and their effect on biological systems, marine organisms, and human health. Although the concentration levels of these metals are still low and within the recommended standards of global regulating bodies, there is little information in relation to their effects along the food web, human health and how they affect the population dynamics of fish species. Apart from regular monitoring and assessment further research on their effects in the food web and an assessment of human health is recommended.
Effects of point source pollution on water quality, phytoplankton diversity and abundance in lake Victoria, Kenya
(Semantic Scholar, 2015-05-01) Babu, J. M.; SitokiL, M.; Ogendi, G. M.; Getabu, A.; Akunga, P. N. G. N. B.; Nyaundi, J.; Njiru, J.; Mwayuli, G.; Olilo, C.
Water quality deterioration remains a major problem in most fresh water lakes. This study was conducted to establish the extent of water quality deterioration in Kisumu Bay of Winam Gulf, Lake Victoria. The overall objective was to assess the effects of point source pollution on water quality and phytoplankton community structure. Sampling stations were selected randomly all over the bay and marked with a global positioning system (G.P.S). Triplicate samples of dissolved oxygen concentration, conductivity, ammonia, nutrients, chlorophyll-a and phytoplankton were taken for laboratory analysis. Mean overall dissolved oxygen concentration was 7.41±1.39 mg l-1. Mean conductivity level was 142.39±63.786 µScm-1 whereas mean soluble reactive phosphorus level was 330.02±311.9 mg l-1. The mean overall chlorophyll a level was 592.9± 604.4 mg l-1 indicating that the bay is eutrophic. The Duncan multiplernrange test showed significant variability of the means of this parameters at different sampling sites at p=0.005. At 46%, the diatoms were the most dominant phytoplankton family in the bay. There were significant differences in distribution of different phytoplankton taxa at different sampling sites (p=0.0001). The results of this study can be used to formulate management options for the improvement of water quality in the Kisumu Bay of Lake Victoria.
Occurrence and distribution of Organochlorine Pesticide Residues in Water and Sediments of Earthen Fish Ponds in South Western Kenya
(Africa Journals Online, 2019) Nyaundi, Joseph Kiyuka; Getabu, Albert; Onchieku, James; Kinaro, Zachary; Bassa, Samuel; Nyamweya, Chrisphine; Nyaboke, Hilda; Getenga, Zachary
Persistent organochlorine residues in the environment are a threat to ecological health of aquatic organisms and pose a health risk to both animals and human consumers. Organochlorine pesticides were determined in water and sediments collected during wet and dry season from selected riverine and earthen fish pond sites in high altitude catchment areas within Kuja River (Kenya) between August 2016–May, 2017. Analysis of DDT and metabolites, Hexachlorocyclohexanes (HCHs) isomers and cyclodienes using a gas chromatograph (GC), and electron capture detector (ECD), confirmed using GC - Mass Spectrometry (MS). Mean (± Standard error) results of DDTs, cyclodienes and HCHs in pond waters were:- below detection level (BDL) to 0.27±0.03µg/L, BDL to 0.11±0.00µg/L, and 4.39±1.01µg/L respectively; and BDL to 0.23±0.01µg/L, 1.20±0.005µg/L, and 1.71±0.02µg/L in river water respectively. Sediment mean OCPs contents were significantly (p<0.05) higher for Dieldrin (3.043±0.43µg/kg), Endrin (2.56±0.460µg/kg), Heptachlor (3.61±0.02µg/kg) DDT (2.97±1.32µg/kg), Endosulfan (6.31.27±1.051µg/kg), Methoxychlor (2.15±1.641µg/kg) and Lindane (2.96±1.32µg/kg), respectively. A longitudinal spatial distribution pattern was noted for both water and sediment OCPs contents, demonstrating that cyclodienes are predominant contaminants in point and non-point sources in water courses. The study recommends continuous monitoring of OCPs in upstream catchment areas for informed management and policy decisions on pesticide use.Keywords: Kuja-Migori River; Organic contaminants; Organochlorine Pesticide.
Organochlorine Contaminants in Nile Tilapia, Oreochromis niloticus (Linnaeus 1758) in Densely Populated Areas of South-Western Kenya
(2020) Nyaundi, Joseph; Getabu, Albert; Mwamburi, Job; Onchieku, James; Kinaro, Zachary; Ogendi, George; Babu, Miruka; Gichuru, Nicholas
Concentrations of OCP (Organochlorine Pesticide) residues were determined in cultured Nile tilapia (Oreochromis niloticus) fish in target stations within 1st order wetland of River Kuja, Kenya, between February-November, 2017. The aim was to assess the residue levels in wild and pond cultured fish within a heavily populated agricultural area of South Western Kenya. Biota samples were analysed for selected HCHs (Hexachlorocyclohexane) isomers, DDT (Dichlorodiphenyltrichloroethane) and metabolites and cyclodienes pesticide residues using GC-ECD (Gas Chromatography Equipped with Electron Capture Detector). Most of OCPs observed were BDL (Below Detection Limit) to detectable levels. Larger percentages (> 50%) of DDTs and HCHs were BDL and exhibited consistency, with significant (p < 0.05) differences in mean contamination levels in fish within the wetland, with average muscle tissue pesticides concentrate ranging between 0.229-2.541 g/kg for Nile tilapia. Most dominant isomer in target species was Lindane (-HCH) (3.417 ± 0.983 g/kg) and Endosulfans. Mean Endosulfan sulfate was 2.499 ± 0.071 g/kg d.w. and most frequently detected, and Methoxychlor (2.235 ± 1.459 g/kg), respectively. Mean Aldrin and Dieldrin was 2.028 and 0.574 g/kg d.w. Concentration for DDT and its metabolites was 0.27-3.71 g/kg for p, p’-DDE (DichlorodiphenylDichloroEthene), BDL-1.098 for p, p’-DDD (DichloroDiphenylDichloroEthane), and 0.105-3.518 g/kg for p, p’-DDT with significant differences in mean values and ranges whose levels were below the WHO (World Health Organization) maximum acceptable thresholds of 0.2, 2, 20 and 5.0 g/kg in fish and sea food.
Spatial-temporal composition, abundance and diversity of algal communities in River Malewa of Lake Naivasha Ramsar Basin, Kenya
(Integrity Research Journals, 2022-04-30) Obegi, Beatrice; Njiru, James; Getabu, Albert; Gichana, Zipporah
ABSTRACT: Algae and algal communities are potentially vulnerable to climate change and consequently can be depleted or be extinct hence the current debate on global biodiversity. Using a 30 µm phytoplankton net, triplicate samples were picked monthly from 10 stations in River Malewa from November 2020 to December 2021. A total of 360 samples were picked the whole study period. The study examined taxonomy, composition, abundance, diversity, and distribution. Counting and identification was done using Sedwick- rafter cell counting chamber with a Binocular compound microscope. Results indicated 89 species of phytoplankton were identified. 86 species were identified in the river while additional 3 more species were identified in the lake. Bacillariophyceae (Diatoms) dominated in lotic sites with 50%, Cyanophyceae was 17%, Chlorophyceae 16% and Myxophyceae was 6% while the least dominant was Euglenophyceae with 4%, Chrysophyceae (3%), Xanthophyceae, Rhodophyceae and Dinophyceae with 1% each. Two points at the lake showed a high dominance in Chlorophyceae with 63%, Xanthophyceae 21% and Chrysophyceae 14%, while Bacillariophyceae was 1% and the rest of the groups were 0%. The abundance showed RM1 and RM4 had abundance of 4.8 x 105 cells/mm3. Site RM9 and RM10 being lacustrine recorded highest abundance with 1.24 x 106 and 1.29 x 106 respectively. RM3 recorded abundance of 6.2 x 105 cells/mm3, RM3 was 7.3 x 105 cell/mm3 and RM5, RM6, RM7 and RM8 recorded abundance of 8.5 x 105, 9.2 x 105, 7.5 x 105 and 7.9 X 105 cell/mm3 respectively. High value of Shannon-Wiener's index (H ') was recorded in RM6 (1.556), followed by RM4 (1.521), RM7 (1.504), and lowest was RM 10 (1.141), RM5 (1.299), RM1 (1.398), RM3 (1.403), RM2(1.474) and RM8 (1.473). Management issues and effects of existing human pressures, such as damping, urbanization and nutrient enrichment on river ecosystems should be studied to fill gaps in knowledge on phytoplankton monitoring on rivers and streams.
Water quality, phytoplankton composition and microcystin concentrations in Kisumu Bay (Kenya) of Lake Victoria after a prolonged water hyacinth infestation period
(Lakes and Reservoirs: Research and Management, 2021-12-01) Miruka, Jared Babu; Getabu, Albert; Sitoki, Lewis; James, Onchieku; Mwamburi, Job; George, Ogendi; Chrisphine, Nyamweya; Odoli, Cyprian
The production of phytoplankton (algal) toxins and their control is of concern because of the need to reduce their negative impacts on water quality and facilitate effective management of algal blooms. The present study was conducted between September 2017 to May 2018, focusing on Kisumu Bay in the Kenyan portion of Lake Victoria, in order to establish the magnitude of potential impacts on phytoplankton composition and microcystin following a prolonged presence of water hyacinth coverage between 2013 and 2018 within the gulf, with an estimated coverage range varying between 644 and 1224 ha. Triplicate samples of physico‑chemical parameters, nutrients, phytoplankton, chlorophyll‑a and algal toxins (N = 88) were collected at eleven sampling sites to determine their spatio‑temporal variability. The main identified algal taxa comprised Cyanophyceae, Bacillariophyceae, Chlorophyceae, Euglenophyceae, Zygnematophyceae and Dinophyceae. The most dominant algal species were Microcystis aeruginosa (25%), Merismopedia spp. (23%) and Anabaena flos‑aquae (16%). Enzyme‑linked immunosorbent assay (ELISA) technique was used to determine microcystin (MC) toxins in the water. Mean MC‑LR and MC‑YR concentrations were significantly correlated (R2 = 0.972), exceeding WHO standards at three sampling sites (Coca Cola, 2.84 ± 4.76; Kisumu pier, 1.78 ± 1.87; Midpoint, 1.44 ± 2.71 μg/L MC–LR). There were significant temporal variations (p < .05) in the SRP, TN, NO3‑N, NO2‑N, NH4‑N, SiO2‑Si, MC‑LR, MC‑YR, dissolved oxygen (DO), total dissolved and suspended solids (TDS; TSS), turbidity, electrical conductivity, Secchi depth, temperature and pH levels. The water depth, TP and DO also vary spatially. The nitrogen to phosphorus concentration ratios differed from the expected N:P ratio of 16:1, indicating a highly eutrophic status. The disproportionate ratio of total phosphorus and total nitrogen in the bay may be responsible for the enhanced cyanobacterial blooms it exhibits. The results of the present study provide useful information and data for formulating regulations for water quality management.

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