Water Pollution

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    Effects of Agricultural Nutrients Influx on Water Quality in Thiba River basin, a sub-catchment of Tana River Basin in Kirinyaga County, Kenya
    (East African Nature & Science Organization Journals, 2022-04-21) Njue, Joseph Mugendi; Magana, Adiel Micheni; Githae, Eunice Wamuyu
    Excessive enrichment of waters with nutrients and the associated adverse biological effects leads to eutrophication, which is one of the major environmental problems across the world. Various studies have revealed the overuse of inorganic fertilizers to increase agricultural productivity in Kenya contributes to pollution of water bodies. In order to meet increasing demand for clean water, sustainable use and conservation of available water resources is therefore paramount. This study was done to find out effects of agricultural nutrient pollution in Thiba River, a sub-catchment of Tana River Basin, located in Kirinyaga County, Kenya. The study area was divided into four distinct agro-ecological zones based on different anthropogenic activities. Ecological survey design was used in the study. Sampling was done during the wet and dry season. Water samples were analysed for temperature, transparency, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), dissolved oxygen (DO), biological oxygen demand (BOD), phosphates, nitrates, nitrites, ammonia, and toxic microalgae. All parameters showed both spatial and temporal variations with statistically significant differences (p˂0.01). Temperature of the river ranged from 14.57 0C to 28.08 0C due to climatic changes along the agro-ecological zones. The pH ranged from 7.02 to 8.51. The DO values decreased from the highlands to lowland within the range of 9.00 mg/l at the reference site to 5.43 mg/l at the most polluted site. EC ranged from 20.54 µScm-1 at the reference site during the wet season to 251.2 µScm-1 at the rice irrigation scheme site during dry season. The TDS ranged from 16.9 ppm at the reference site to 167.05 ppm at the most polluted site. Salinity also had a high variation with a range of 0.01 ppt at the reference site to 0.07 ppt at the most polluted site. The highest values of BOD (3.49 mg/l) were recorded at the rice irrigation scheme during the wet season and the lowest (0.22 mg/l) at the forest edge reference site. The lowest levels of NH4, P, NO2 and NO3 were recorded at the forest edge reference site at 1.088 µg/l, 1.177 µg/l, 0.217 µg/l and 0.148 µg/l respectively during the dry season while the highest values for the same nutrients were recorded at the rice irrigation site at 11.439 µg/l, 4.933 µg/l, 1.518 µg/l and 2.721 µg/l in the same order. There was a high peak of all nutrient levels at the rice irrigation scheme zone which was attributed to the extensive use of inorganic fertilizers. Dam water samples were analysed for members of Cyanobacteria group of microalgae which are bio-indicators of eutrophic waters. Out of the seven members of this group that were identified four were toxic genera. These were Nostoc, Oscillatoria, Anabaena and Microcystis. During the wet season Nostoc had the highest population followed by Oscillatoria and Anabaena. No Microcystis was observed during the wet season. There was a steady increase of all the genera during the dry season with Microcystis making appearance. Microcystis and Oscillatoria had a very high correlation. This study concludes that various anthropogenic activities especially agriculture along the study site are the main factors of Thiba River pollution hence a major threat to human, livestock and aquatic organisms. Environmental protection laws should be enforced by the government
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    Phthalate Levels in Wastewater Treatment Plants of Lake Victoria Basin
    (Applied Ecology and Environmental Sciences., 2021-12-16) Onchiri, R.; Mayaka, A.; Majanga, A.; Ongulu, R.; Orata, F.; Getenga, Z. M.; Gichumbi, J. M.
    Phthalates are examples of EDCs, which have been used as plasticizers for longtime worldwide. However, their occurrence in these environments causes adverse effects such as congenital anomalies, endocrine disruption and chronic toxicity. Wastewater is the source of these phthalates in the environment. The main aim of this study was to determine the levels of dimethyl phthalate (DMP), benzyl butyl phthalate (BBP) and bis (2-ethylhexyl) phthalate (BEHP) in wastewater sampled from wastewater treatment plants (WWTPs) of Nyalenda, Homabay and Kisii, in Kenya during wet and dry seasons. Thermos Scientific Dionex UltiMateTM 3000 HPLC system was used to analyze the residue levels at 0.004 and 0.005 mg/L limits of quantification during wet and dry seasons, respectively. Most sites sampled had detectable levels of DMP, BBP and BEHP. Higher concentrations were detected during wet season compared to dry season. At Nyalenda treatment plant, DMP was detected at 0.99 ± 0.0005 mg/L and 0.79 ± 0.0005 mg/L at the inlet sampling point during the wet and dry seasons, respectively. The concentrations detected were high at the inlet and lowest at the outlet sampling points. The residue levels obtained showed significant differences at 5% confidence limits with Zcalculated for DMP at Nyalenda, Homabay and Kisii WWTPs obtained as 0.2650, 0.2183 and 0.1983, respectively. These Z-score values (Zcalculated) were less than the critical value (Zcritical = 1.96). Similar observations were observed with BBP and BEHP.
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    Perfluoroalkyl acids in selected wastewater treatment plants and their discharge load within the Lake Victoria basin in Kenya
    (Springer, 2015-04-11) Chirikona, Florah; Filipovic, Marko; Ooko, Seline; Orata, Francis
    A major ecological challenge facing Lake Victoria basin is the influx of chemical contaminants from domestic, hospital, and industrial effluents. Determined levels of perfluoroalkyl acids (PFAAs) in wastewater and sludge from selected wastewater treatment plants (WWTPs) in Kenya are presented and their daily discharge loads calculated for the first time within the Lake Victoria basin. Samples were extracted and separated using solid-phase extraction and ultra-performance liquid chromatography (UPLC)-MS/MS or LC-MS/MS methodology. All sewage sludge and wastewater samples obtained from the WWTPs contained detectable levels of PFAAs in picogram per gram dry weight (d.w.) and in nanogram per liter, respectively. There was variability in distribution of PFAAs in domestic, hospital, and industrial waste with domestic WWPTs observed to contain higher levels. Almost all PFAA homologues of chain length C-6 and above were detected in samples analyzed, with long-chain PFAAs (C-8 and above chain length) being dominant. The discharge from hospital contributes significantly to the amounts of PFAAs released to the municipal water systems and the lake catchment. Using the average output of wastewater from the five WWTPs, a mass load of 1013 mg day−1 PFAAs per day discharged has been calculated, with the highest discharge obtained at Kisumu City (656 mg day−1). The concentration range of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in wastewater was 1.3–28 and 0.9–9.8 ng L−1 and in sludge samples were 117–673 and 98–683 pg g−1, respectively.
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    Occurrence and Distribution of Per-and Polyfluoroalkyl Substances from Multi-Industry Sources to Water, Sediments and Plants along Nairobi River Basin, Kenya
    (MDPI, 2022-07-23) Chirikona, Flora; Quinete, Natalia; Gonzalez, Jesleen; Mutua, Gershom; Kimosop, Selly; Orata, Francis
    Per-and polyfluoroalkyl substances (PFAS) are ever-present pollutants in the environment. They are persistent and bio-accumulative with deleterious health effects on biota. This study assesses the levels of PFAS in environmental matrices along the Nairobi River, Kenya. An aggregate of 30 PFAS were determined in water, while 28 PFAS were detected in sediments and plants using solid phase extraction then liquid chromatography-mass spectrometric techniques. In water, higher levels of perfluoroundecanoic acids of up to 39.2 ng L −1 were observed. Sediment and plant samples obtained in the midstream and downstream contained higher levels of perfluorooctanoic acid of up to 39.62 and 29.33 ng g −1 , respectively. Comparably, levels of long-chain PFAS were higher in water and sediments than in plants. Sediment/water log distribution of selected PFAS ranged between 2.5 (perfluoroundecanoic acid) and 4.9 (perfluorooctane sulfonate). The level of perfluorooctane sul-fonate (1.83 ng L −1) in water is above the acceptable level in surface water posing high human health and ecological risks. The observed PFAS concentrations and distribution were attributed mainly to multi-industries located along the river, among other sources. The knowledge of PFAS occurrence and distribution in Nairobi River, Kenya, provides important information to local regulatory agencies for PFAS pollution control.
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    Residue levels and discharge loads of antibiotics in wastewater treatment plants (WWTPs), hospital lagoons, and rivers within Lake Victoria Basin, Kenya
    (Springer Nature, 2016-08-23) Kimosop, Selly Jemutai; Getenga, Z. M.; Orata, F.; Okello, V. A.; Cheruiyot, J. K.
    The detection of antibiotics in water systems has instigated great environmental concern due to the toxicological effects associated with these compounds. Their discharge into the environment results from the ubiquity of use in medical, veterinary, and agricultural practices. Some of the effects of antibiotics include development of antibiotic-resistant bacteria, making it difficult to treat diseases, variation in natural microbial communities, and enzyme activities. In this study, the first comprehensive survey of some frequently used antibiotics namely ampicillin (AMP), amoxicillin (AMX), sulfamethoxazole (SMX), chloramphenicol (CAP), and ciprofloxacin (CPF) within Lake Victoria Basin of Kenya is presented. Sludge and wastewater samples were collected from wastewater treatment plants (WWTPs) and hospital lagoons within the study area. Samples were extracted and cleaned by solid-phase extraction, and analysis was carried out using high-performance liquid chromatography (HPLC). All wastewater samples and sludge collected contained quantifiable levels of the selected antibiotics. The highest concentrations were recorded for AMP with WWTPs and hospitals having 0.36 ± 0.04 and 0.79 ± 0.07 μg/L, respectively. In sludge samples, SMX recorded the highest concentrations of 276 ± 12 ng/g. The high levels in sludge indicate the preferential partition of antibiotics onto solid phase, posing great danger to consumers of crops grown in biosolid-amended soils. The daily discharge loads of antibiotics from nine WWTPs ranged between 80.75 and 3044.9 mg day−1 with a total discharge of 6395.85 mg day−1, signifying a high potential of water resource pollution within the region. This report will aid in the assessment of the risks posed by antibiotics released into the environment.
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    Simulation guided prediction of zeolites for the sorption of selected anions from water: Machine learning predictors for enhanced loading
    (Elsevier, 2022-06-01) Sifuna Wanyonyi, Fred; Fidelis, Timothy Tizhe; Louis, Hitler; Kyalo Mutua, Gershom; Orata, Francis; Rhyman, Lydia; Ramasami, Ponnadurai; Pembere, Anthony M. S.
    The development of highly efficient adsorbents, especially those that can harvest anions like CrO42−, AsO43−, NO3– and PO43−, is one of the principal challenges in the water treatment field. The current study utilized a screening process involving an initial selection of zeolites based on the pore-limiting diameter, followed by GCMC (Grand Canonical Monte Carlo) simulations to identify high-performing zeolites for anion removal. CLO, LTN, MWF, TSC, ITV, PAU, FAU and DFO zeolites are the best performing in terms of loading while several zeolites like ANA, DFT, BIK, SBN and JNT gave no loading at all. In addition, quantum chemical calculations revealed that after adsorption of the anions on the zeolite, there is charge transfer between the zeolite and the anion. The CLO cluster has a charge of 0.64 before adsorption. After adsorption, it attains a charge of −0.06, suggesting that the phosphate ion acts as an electron donor while the CLO cluster, as an electron acceptor. Finally, machine learning was employed to rank the importance of the various descriptors that have influence on the removal of anions in water. Largest overall cavity diameter, mass and accessible pore volume appeared to be the three most important descriptors, thus, tuning the sphere cavity and inter channel diameter as well as engineering the accessible volume of zeolite architectures are of utmost important toward harvesting the desired anions.
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    (juniper publishers, 2017-05-30) .V, Tamizhazhagan; .k, Pugazhendy; Sakthidasan, V; Jayanthic; Sawicka, Barbara; Humphrey, Agevi; C, Vasanth; Kasinathan, M; M Baranitharan Ph D, Dr
    This study was undertaken to find out the Catla catlafresh water fish biochemical changes in the fish muscles, liver, and kidney. Toxicity were calculated probit analysis, The total carbohydrate contented was estimated by the technique of Roe , Protein was estimated by Lowry method and total lipids were estimated by the method of floch methods. The results shown on total carbohydrate level in muscle 6.43 mg/g after treatment 2.70 mg/g, liver carbohydrate control 17.55mg/g after treatment 16.10 mg/g changes accrued 7.41 %and kidney carbohydrate control 1.44mg/g after treatment 0.53mg/g was gradually decreased. Then total protein in muscles23.20 mg/g after sublethal concentration at 96 hours treated 17.80mg/g decreased and liver protein 23.12mg/g treated fish 19.40 mg/g changes accrued 13.58% kidney protein level 9.60 mg/g after treatment in sublethal concentration in 96 hours 6.24 mg /g were decreased and Total lipid level are in muscles 1.78mg/g after 96 hours 0.89mg/g liver lipid 7.10 mg/g after treatment 4.35mg/g then kidney 2.09mg/g 0.92 mg/g simultaneous gradually decreased muscles, liver and kidney. The Monocrotophos affects not only fishes but also organisms in the food chain through the procedure of expenditure of one by the other those human begins affected various genetic disorders absolutely insecticides.
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    The quality of the Treated effluent, Raw Influent and Wastewater-polluted Water sources Used for Irrigation of Vegetables in Urban and Peri-Urban Areas of Nairobi County, Kenya
    (International Journal of Scientific and Research Publications, 2021-05) Rono, David; Gweyi, Joseph
    Nearly half of the wastewater generated in Nairobi ended up treated in the treatment facilities. However, cases of irrigating vegetables with raw influent and untreated wastewater water by urban and peri-urban farmers in Nairobi have been noted. Despite the importance of wastewater in in Kenya’s urban and peri-urban agriculture, information on the quality of water used for irrigation areas is lacking. This study sought to establish physicochemical and microbiological composition of water used for irrigating vegetables in Ruai ward, Nairobi County, Kenya. A preliminary survey was conducted to identify sources of water used for irrigation. Sources of water used for irrigation were then categorized into the treated effluent, raw influent and wastewater-polluted water sources. From these sources sampling points were randomly selected and georeferenced. Parameters investigated for physicochemical characteristics are total dissolved solids (TDS), aluminium (Al), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb). Microbiological organisms determined in the samples are total coliforms and Escherichia coli. Concentration of TDS was determined using evaporation method, while Al, Cd, Cr, Co, Cu, Zn and Pb concentrations were determined using atomic absorption spectrometry. Total coliforms and E. coli were determined through inoculation. The results revealed TDS were generally within the recommended level (1200 mg/l), except the raw influent, which recorded 1582 mg/l. Range in Al, Cd, Cr, Co, Cu and Zn was 2.8 – 13 mg/l, 3.6 – 4.2 mg/l, 1.2 – 5.0 mg/l, 3.2 – 5 mg/l, 0.4 – 5.0 mg/l, 0.4 – 6.8 mg/l, respectively. Lead with a concentration of 6.8 mg/l was detected only in the treated effluent sample. Recommended concentrations of Al, Cd, Cr, Co, Cu, Zn and Pb are 5, 0.5, 1.5, 0.1, 0.05, 2 and 5 mg/l, respectively. It was further observed total coliforms and Escherichia coli in the samples exceeded recommended concentrations of <1000 minimum probable number per litre (< 1000 MPN/l) and nil/ 100 ml, respectively. The results showed that most of parameters measured exceeded the recommended water quality limits. Therefore, the wastewater cannot for crop irrigation.
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    Titanium, Zinc, Lead, Chromium, Cadmium, Cobalt and Copper Concentrations in Vegetables Produced using Wastewater in Urban and Peri-Urban Areas of Nairobi City County, Kenya
    (Current Journal of Applied Science and Technology, 2021-03-02) Rono, David K.; Wakhungu, Jacob W.
    Vegetables are rich sources of vitamins, minerals and fibres. Ingestion of vegetables contaminated with heavy metals is one of the main routes through which heavy metals enter the human body and may cause diseases. In this study we investigated the concentrations of titanium, zinc, lead, chromium, cadmium, cobalt and copper in the commonly produced vegetables viz. Brassica sp.,Spinacia oleracea, Amaranthus sp. and Solanum sp. using wastewater in Ruai ward, Nairobi City County, Kenya. Atomic absorption spectrometry (AAS) was used to estimate the levels of these metals in vegetables sampled from five plots in the study area. The concentration status for each heavy metal in the samples was compared with the permissible levels for corresponding heavy metals set by the Food and Agriculture Organization and World Health Organization. Our findings indicated the presence of Ti, Zn, Cr and Cu in all the vegetable samples and their concentrations varied considerably, while Pb, Cd and Co were not detected in most samples. The presence of heavy metals in vegetables was in the order of Pb > Cd > Co > Cu > Cr > Zn > Ti. We concluded that vegetables produced using wastewater had elevated levels of the investigated heavy metals at the time of analysis beyond FAO/ WHO safe limits for corresponding metals in leafy vegetables.
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    Virulence and antimicrobial resistance genes are enriched in the plasmidome of clinical Escherichia coli isolates compared with wastewater isolates from western Kenya
    (Elsevier, 2021-02-27) Wawire, Sifuna Anthony; Reva, Oleg N.; O'Brien, Thomas J.; Figueroa, Wendy; Dinda, Victor; Shivoga, William A.; Welch, Martin
    Many low-middle income countries in Africa have poorly-developed infectious disease monitoring systems. Here, we employed whole genome sequencing (WGS) to investigate the presence/absence of antimicrobial resistance (AMR) and virulence-associated (VA) genes in a collection of clinical and municipal wastewater Escherichia coli isolates from Kakamega, west Kenya. We were particularly interested to see whether, given the association between infection and water quality, the isolates from these geographically-linked environments might display similar genomic signatures. Phylogenetic analysis based on the core genes common to all of the isolates revealed two broad divisions, corresponding to the commensal/enterotoxigenic E. coli on the one hand, and uropathogenic E. coli on the other. Although the clinical and wastewater isolates each contained a very similar mean number of antibiotic resistance-encoding genes, the clinical isolates were enriched in genes required for in-host survival. Furthermore, and although the chromosomally encoded repertoire of these genes was similar in all sequenced isolates, the genetic composition of the plasmids from clinical and wastewater E. coli was more habitat-specific, with the clinical isolate plasmidome enriched in AMR and VA genes. Intriguingly, the plasmid-borne VA genes were often duplicates of genes already present on the chromosome, whereas the plasmid-borne AMR determinants were more specific. This reinforces the notion that plasmids are a primary means by which infection-related AMR and VA-associated genes are acquired and disseminated among these strains.
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    Water Quality of Selected Fishing Beaches of Lake Victoria Kenyan Gulf
    (Scientific Research, 2020-01) Orina, Paul S.; Onyango, David M.; Lungayia, Henry; Oduor, Andrew; Sifuna, Anthony W.; Otuya, Petronila; Owigar, Rosemary A.; Kowenje, Chrispin B.; Hinzano, Sheban M.
    Lake Victoria the second largest fresh water body in the world located in East Africa is a shared resource between Kenya, Tanzania and Uganda and enjoys a wide range of streams and rivers from as far as Burundi and Rwanda. The lake has environmentally undergone physical, chemical and biological changes in the last four decades, particularly rise in its trophic condition and decline in oxygen level, which affects the water quality and fish population dynamics. This study therefore set out to determine the quality of water in selected fishing beaches of Lake Victoria, Kenya with a view to report the possible pollution levels. pH was highest at Nyamasari and Kotieno (9.3 ± 0.1) and lowest at Nyachebe and Kichinjio (7.08 ± 0.1) whereas temperature was highest at Nyamasari (29.5°C ± 0.0°C) and lowest at Kichinjio (23.4°C ± 0.2°C). DO was highest at Kotieno (10.3 ± 0.2 mgL) and lowest at Seka (2.4 ± 0.1 mgL). Turbidity was highest at Uyoga (125.5 ± 0.90 NTU) and lowest at Osieko (2.7 ± 0.1 NTU). Ammoniacal nitrogen was highest at Dunga (1278.3 ± 0.8 μ∙gl-1) and lowest at Nyamasari (12.4 ± 0.8), all a factor of human activities, lake substratum and effluents from rivers and surface runoff. All parameters assessed showed significant differences across sampling sites and depth except pH which did not vary significantly with distance from lakeshore. Further, all parameters did not show a clear pattern with respect to distance from the lakeshore possibly due to adequate mixing in the gulf. There is a need for further water quality monitoring by seasons to inform policy decisions towards sustainable lake exploitation.
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    Green Remediation of Carbamazepine from Water Using Novel Magnetic Iron Modified Carbonized Baggasse: Kinetics, Equilibrium and Mechanistic Studies
    (Chemical Science International Journal, 2017-03-15) Kimosop, Selly Jemutai-; Okello, Veronica A.; Orata, Francis; Getenga, Zachary M.; Shikuku, Victor O.
    Baggasse derived biochar magnetically modified with iron (α-Fe2O3-CBG) was fabricated, characterized and applied as a low-cost adsorbent for the removal of carbamazepine (CBZ), a pharmaceutically active compound which has been reported as an emergent water contaminant. Characterization of the synthesized (α-Fe2O3-CBG) composite showed that iron was effectively impregnated onto the carbonized bagasse network. The composite was able to achieve 60.9 % CBZ removal within a period of 4 hours. The time-dependency adsorption data followed the pseudo-second order kinetic law while the intraparticle diffusion model indicated that pore diffusion is not the sole operative rate-determining mechanism with significant boundary layer effects. Freundlich model best explained the equilibrium sorption data. The adsorption extent was also strongly pH-dependent though adsorption mechanism is significantly driven by electrostatic interactions at lower pH. Furthermore, magnetic separation of the contaminant-laden adsorbent was successfully accomplished.
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    Water quality status of a stream receiving fish pond discharge using physicochemical indicators in lake Victoria catchment, Kenya
    (International Journal of Fisheries and Aquatic Studies, 2019) Masaba, Jonathan; Wangila, Barasa; Lung’ayia, Henry
    This study assessed the water quality of a stream receiving discharge from Tilapia and catfish fish ponds using some physicochemical parameters as key indicators. Measurements were done both in the field and in the laboratory using portable multi-parameter meter and standard methods by APHA (1998). Systematic sampling design was applied. Significant differences were noted among the parameters in the sampling sites up-stream, in the ponds and downstream. Temperature, Phosphate-Phosphorus, Total dissolved solids, Turbidity, Ammonia-Nitrogen, had higher values in the ponds and Sampling site 4 downstream (p˂0.05). Spatial variations that were within acceptable water quality standards in aquaculture, corresponding with changes caused by inflow from fish ponds, were observed.
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    Fish Tissue Bio-concentration and Interspecies Uptake of Heavy Metals from Waste Water Lagoons
    (Journal of Pollution Effects & Control, 2016-01) Orata, Francis; Birgen, Faith
    Fish products may be important vectors of human exposure to heavy metals. However the understanding of how heavy metals bioconcentrate in different fish species (sp.) through contaminated environments such as wastewater treatment lagoons is very limited. In this study bioconcentration and Interspecies Uptake of Heavy Metals by three fish species (Oreochromis niloticus, Clarius gariespinus and Protopterus aethiopicus) receiving naturally contaminated wastewater was investigated. Tissue bioconcentration factors (BCFs) were estimated within a typical municipal wastewater lagoon, in Kenya. It was assumed that the three fish species were able to reach steady state with their dietary intake of heavy metals and through aqueous contact. Heavy metals concentration of up to 11.72, 11.27, 5.29, 4.12 and 4.74 mg/kg for, muscle, skin, liver, scales and gills respectively were obtained through analysis using ICP-MS instrumentation. The results showed variation in the estimated BCFs obtained for O.niloticus as compared to those obtained for P.aethopicus and C.gariespinus. The tissue BCFs ranged from 0.20 for Cd in scales of C. gariespinus to 11.27 for Zn in muscles of P.aethipicus. Results suggest that heavy metals uptake by the fish sp. and their transfer to various tissue organs do not exclusively depend on concentration levels by aqueous exposure alone but largely depends on their feeding mode, diet and biochemical needs of individual fish sp. Elevated concentrations of Pb and Cd in scales and skin were more than those obtained in muscles and liver which suggested depuration process, considering that Pb and Cd are non-essential metal ions to these fish sp. Fish need to be carefully screened to ensure that unnecessary high level of some toxic trace metals are not transferred to man. The bio concentration and interspecies uptake data estimated here provide a useful tool for predicting human exposure to Heavy metals via fish under different contamination scenarios
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    Faecal pollution and solar purification of community water sources within Lake Naivasha basin, Kenya
    (IWA, 2015-06-01) Omondi, Donde O.; Wairimu, Muia A.; Aketch, Wanga L.; William, Shivoga A.; Trick, Charles G.; Creed, Irena F.
    As in other parts of Africa, and in other developing nations, the rise in the human population and anthropogenic activities within the Lake Naivasha basin is causing an increase in human health risks due to faecal contamination of domestic water sources. This study investigated faecal pollution of community water sources within the Lake Naivasha basin by measuring the densities of total coliforms, Escherichia coli, intestinal enterococci, Clostridium perfringens and heterotrophic bacteria in Lake Naivasha, the Malewa and Gilgil Rivers, and boreholes using membrane filtration techniques and heterotrophic plate count procedures. Selected physico-chemical parameters were also measured in situ from all the water sources sampled. Lakes and rivers had significantly higher microbial abundances than boreholes. Unlike boreholes, surface sources (rivers and lake) showed significant variation with respect to sampling sites for all the microbiological parameters (P < 0.05). The use of solar radiation in water disinfection with temperatures of 75 °C after 30 minutes from pasteurization point (time zero) fully eradicated E. coli and total coliforms from all the water sources. In conclusion, there is faecal pollution in water sources used by communities within the Lake Naivasha basin. The use of solar radiation is therefore recommended for water purification to reduce likely incidences of waterborne diseases.
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    Faecal bacterial contamination of borehole water between points-of-access and points-of-use in Naivasha, Kenya; Public health implication
    (Egerton Journal of Science and Technology, 2013-05-15) Donde, Oscar; Muia, Wairimu; Trick, Charles; Creed, Irena
    Microbiological assessment of drinking water at Point of Access (POA), vendors and household levels is a major issue due to realization of the impact of poor microbial water quality on the general public health. The impact is even greater in densely populated areas as in the case of Naivasha. Assessment on the effects of poor handling of drinking water at different domains aims at protecting consumers from waterborne diseases. The study investigated the bacterial water quality levels at different handling domains; borehole POA, vendors and household within three villages (Karagita, Mirera and Kamere). Membrane Filtration Technique (MFT) and heterotrophic Plate Count (HPC) procedure was used in estimating the densities of E. coli, total coliforms, intestinal enterococci, Clostridium perfringens and hetetrophic bacteria in water samples from all the above domains. In addition, selected physico-chemical parameters were measured in situ using appropriate measuring probes. Data was analyzed using Sigmaplot® analysis software version 12, with α = 0.05. All the water samples from borehole POA, vendors and households had bacterial quality of above the recommended standards for drinking water. Median values for E. coli, intestinal enterococci and C. perfringens were not significantly difference between the sites (P>0.05). Total coliforms and HPC were aecal bacterial contamination of borehole water between points-of-access Egerton J. Sci. & Technol. Volume 13: 165-184 ISSN No. 2073 - 8277 significantly different between the site (P<0.05). In conclusion, the study indicates that poor water handling has negative effect on the bacterial quality of drinking water, hence a public health concern. Hygienic water handling practices at both the supply sources and within households storage containers, proper sewerage systems and efficient pre-consumption water purification techniques are recommended.
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    Endocrine disrupting chemicals in wastewater treatment plants in Kenya, East Africa: Concentrations, removal efficiency, mass loading rates and ecological impacts
    (Elsevier, 2023-11-15) Ngeno, Emily; Ongulu, Roselyn; Orata, Francis; Matovu, Henry; Shikuku, Victor; Onchiri, Richard; Mayaka, Abel; Majanga, Eunice; Getenga, Zachary; Gichumbi, Joel; Ssebugere, Patrick
    This study investigated the levels, mass loadings, removal efficiency, and associated ecotoxicological risks of selected endocrine disrupting chemicals (EDCs), namely, dibutylphthalate (DBP), diethylhexylphthalate (DEHP), dimethylphthalate (DMP), linuron (LNR) and progesterone (PGT) in wastewater, sludge, and untreated dry biosolid (UDBS) samples from twelve wastewater treatment plants (WWTPs) in nine major towns in Kenya. Analysis was done using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS). All the wastewater influents had quantifiable levels of EDCs with DBP being the most abundant (37.49%) with a range of 4.33 ± 0.63 to 19.68 ± 1.24 μg L−1. DEHP was the most abundant in sludge and accounted for 48.2% ranging between 278.67 and 9243.49 ng g−1 dry weight (dw). In the UDBS samples, DEHP was also the most abundant (40%) of the total EDCs detected with levels ranging from 78.77 to 3938.54 ng g−1 dw. The average removal efficiency per pollutant was as follows: DMP (98.7%) > DEHP (91.7%) > PGT (83.4%) > DBP (77.9%) > LNR (72.2%) which can be attributed to sorption onto the biosolid, biological degradation, photolysis, and phytoremediation. The pH was negatively correlated to the EDC concentrations while total dissolved solids (TDS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and electrical conductivity (EC) were positively correlated. The mass loadings were as high as 373.33 g day−1 of DBP in the treatment plants located in densely populated cities. DEHP and PGT had their Risk Quotients (RQs) > 1, posing a high risk to biota. DMP, DBP, and LNR posed medium risks as their RQ values were between 0.1 and 1. EDCs are therefore loaded to environmental compartments through either the effluent that loads these pollutants into the receiving aquatic ecosystem or through the UDBS, which are used as fertilizers in agricultural farmlands causing potential toxicological risks to aquatic and terrestrial life.
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    Effects of Sand-Harvesting on River Water Quality and Riparian Soil Physico-Chemical Properties
    (Scientific Research, 2022) Lwanga, Aquila; Tsingalia, Mugatsia; Humphrey, Agevi; Shilenje, Zablon W.
    he widespread distribution of river sand-harvesting activities continues to degrade river water quality and the surrounding riverine environments. This study determined practical effects of sand-harvesting on two rivers in Kakamega County Kenya. Water samples were tested for turbidity and total suspended solids (TSS). For riparian soils, nitrogen (N), phosphorus (P), pH, organic carbon (OC), moisture content and textural class were determined on composite samples obtained from the field. Two control sites not affected by sand-harvesting were also used for comparison. Results indicate TSS concentrations increased during the rainy season when sand-harvesting was occurring, with significant differences between the control and sand-harvesting sample groups. Between seasons—dry and wet—in natural circumstances, the riparian soil moisture and phosphorus contents increased significantly. The study shows that river sand-harvesting degrades the aesthetic value of riparian areas, and makes rivers prone to bank erosion, and silt. This increases river water turbidity. The study concludes that sand-harvesting does not directly affect the riparian soil moisture content, total N, P, pH, OC or textural class, but reduces productivity of riparian land and puts the riverine ecosystems at risk.
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    Effects of Oil Exploration on Surface Water Quality – A Review
    (IWA, 2016-02-14) Luswetia, Elizabeth; Kandab, Edwin Kimutai; Obandoa, Joy; Makokhaa, Mary
    The oil industry is a source of revenue and foreign exchange for an economy. Nevertheless, oil exploration is an inherent risk tothe environment due to the pollution of water resources, especially surface water resources. The main waste is producedwater, which is increasing around the world. As a consequence, water pollution resulting from normal oil drilling, refining, distribution, and accidents is the principal concern of oil exploration in the environment. Oil pollution is associated with ecologicalcontaminants such as heavy metals and organic compounds which are the primary contaminant of surface water resources.Often this results in toxicity accretion in the food chain, and their non-biodegradable nature is of great concern to bothhuman and aquatic life. Therefore, this review evaluates existing knowledge on the effect of oil exploration on surface waterquality, hydraulic fracturing technique/chemicals, and composition of produced water. This review also recommends furtherresearch on the physicochemical characteristics, analysis of heavy metals in water/sediments, and characterization ofhydro-chemical facies of surface water resources around oil exploration sites to enable effective policy development.
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    Effect of vegetated filter strips on transport and deposition rates of Escherichia coli in overland flow in the eastern escarpments of the Mau Forest, Njoro River Watershed, Kenya
    (Springer Link, 2016-06) Olilo, C. O.; Onyando, J. O.; Moturi, W. N.; Muia, A. W.; Ombui, P.; Shivoga, W. A.; Roegner, A. F.
    The fate and transport of Escherichia coli (E. coli) in lotic waters through vegetated filter strips (VFSs) was evaluated in a field model pasture, utilizing VFSMOD Windows along with direct pathogen testing. This study assessed effects of VFS on transport and deposition rates of E. coli in lotic overland flow waters. The VFS measured 44 m long by 40 m wide, covering an area of 1584 m2 and land slope of 15 %. Cowpat was applied onto the model pasture and washed by overland flow into the VFS. The 4-methylumbelliferyl β-D-glucuronide substrate confirmed the identity of E. coli prior to cowpat application and after isolating them from soil using centrifugation and membrane filtration techniques. Napier grass root system recorded the highest recovery rates of E. coli at 99.9 % along the length of VFS III. This efficiency reduced significantly (p < 0.05; df = 29) to 95 % in Kikuyu grass and 75 % in Couch grass-Buffer grass. The data demonstrated similarity in transport of manure-borne E. coli and organic carbon (OC) through all the simulated VFS. These results indicated that OC could be used as a true natural tracer of manure-borne E. coli, a pollution indicator organism of lentic and lotic surface waters provided the OC release kinetics from cowpat were similar to that of E. coli kinetics. Thus, efficient filtering to reduce E. coli concentrations and load in overland flows requires managing combined grass species, agro-pastoral systems models and dispersed or preferential flows to enhance surface water quality standards.