Water Pollution

Permanent URI for this collection

https://repository.nrf.go.ke/handle/123456789/19

Browse

Now showing 1 - 20 of 152

Analysis of Spatial and Temporal Levels of Heavy Metals in Water, Sediments and Fish in Sosiani River
(Science and Education publishing (SciEP), 2019-10-09) Shieunda, Ogara Rose; Neyole, Edward; Omuterema, Stanley; Orata, Francis
The objective of the study was to examine spatial and temporal levels of heavy metals in water, sediments and fish in Sosiani River. This study was an experimental design approach in which a scientific analysis was done involving sample collection, preparation and laboratory work to determine Pb, Cd and Cr concentrations in fish water and sediments. The main Sosiani river flows from the Keiyo escarpment at the far South East through Uasin Gishu plateau to Turbo which is in the North West. The units of analysis used in the study included two species of fish, water and sediment; whereby water and sediment were sampled from eleven sampling locations (SR0 – SR10) and fish from ten sampling points (SR1 – SR10) along river Sosiani catchment. Sample analysis was done using Atomic Absorption Spectrometry. Data analysis was done using the statistical program for social sciences (SPSS) version 23. Inferential (ANOVA), regression and descriptive statistics were used to analyse data. Spatial and temporal levels of heavy metals in water, sediments and fish were the outcomes. In the upper Sosiani, SR3 (Chepkorio) registered the highest lead levels in the wet season of 0.127 mg/l. In both dry and wet seasons, and in all the sites, lead values in water were above the NEMA and WHO thresholds of 0.01 mg/l. In the analysis of cadmium concentrations, it was observed that in wet season water had all 50% of the sites above the NEMA and WHO thresholds while all the sites were had values below the limits during the dry season. Cr in water was high for 90% of the sites. Sediment had the highest lead values of 1.744mg/l. Barbus (Barbusbarbus) fish had high lead, cadmium and Cr values in both wet and dry seasons. In both seasons, catfish (Clariusgariapinus) had low values of lead and cadmium below the NEMA and WHO limits for most of the sites but high levels of Chromium. Spatial and temporal variations in heavy metal concentration were observed between the water, sediment and the two species of fish within the catchment. This study recommended mandatory measures (enforcement) to control the increased heavy metal concentration downstream the basin.
Open Defaecation and Its Effects on the Bacteriological Quality of Drinking Water Sources in Isiolo County, Kenya
(Sage Journals, 2017-09-09) Okullo, Joab Odhiambo; Moturi, Wilkister Nyaora; Ogendi, George Morara
Background information: The post-2015 Sustainable Development Goals for sanitation call for universal access to adequate and equitable sanitation and an end to open defaecation by 2030. In Isiolo County, a semi-arid region lying in the northern part of Kenya, poor sanitation and water shortage remain a major problem facing the rural communities.Objective: The overall aim of the study was to assess the relationship between sanitation practices and the bacteriological quality of drinking water sources. The study also assessed the risk factors contributing to open defaecation in the rural environments of the study area.Methods: A cross-sectional study of 150 households was conducted to assess the faecal disposal practices in open defaecation free (ODF) and open defaecation not free (ODNF) areas. Sanitary surveys and bacteriological analyses were conducted for selected community water sources to identify faecal pollution sources, contamination pathways, and contributory factors. Analysis of data was performed using SPSS (descriptive and inferential statistics at α = .05 level of significance).Results: Open defaecation habit was reported in 51% of the study households in ODNF villages and in 17% households in ODF villages. Higher mean colony counts were recorded for water samples from ODNF areas 2.0, 7.8, 5.3, and 7.0 (×103) colony-forming units (CFUs)/100 mL compared with those of ODF 1.8, 6.4, 3.5, and 6.1 (×103) areas for Escherichia coli, faecal streptococci, Salmonella typhi, and total coliform, respectively. Correlation tests revealed a significant relationship between sanitary surveys and contamination of water sources (P = .002).Conclusions: The water sources exhibited high levels of contamination with microbial pathogens attributed to poor sanitation. Practising safe faecal disposal in particular is recommended as this will considerably reverse the situation and thus lead to improved human health.
Simulation of the Hydraulics and Treatment Performance of Horizontal Subsurface Flow Constructed Wetland Treating Greywater
(Science Publishing Group, 2018-05-10) Raude, James Messo; Mutua, Benedict Mwavu; Kamau, David Ngugi
Constructed wetlands (CWs) have evolved as some of reliable wastewater treatment technologies. Various types of CWs differ in their main design characteristics and in processes responsible for pollutant removal. Classification of CWS is based on the type of vegetation used and hydrological parameters involved and can thus be classified as free water surface or subsurface flow systems. Further, subsurface flow systems can be classified according to flow direction as vertical or horizontal. This study considers horizontal subsurface flow constructed wetlands (HSFCWs) which introduces the mechanistic, dynamic compartmental model-Constructed Wetlands 2D (CW2D). The model has successfully been utilized to evaluate the performance of vertical flow constructed wetlands and is being tested on HFCWs. An outdoor pilot scale HSFCW system was established in Nakuru, Kenya. CW2D was calibrated, validated and used to simulate hydraulic performance of HSFCW system. The model was used in predicting effluent concentrations of the main greywater pollutants. In general, the results obtained showed a good match with the measured data. CW2D is an effective tool for evaluating the performance of CWs and can provide insights in treatment problems at an existing CW. The same methodology can be used to optimize existing systems.
Seasonal and Longitudinal Variations of Water Quality in an Urban Stream: Case Study of Sosiani River Uasin Gishu County, Kenya
(International Institute for Science, Technology and Education, 2017) Masakha, Edward J.; Moturi, Wilkister N.; Ogendi, George M.
The study sought to analyse longitudinal and seasonal variations in physico-chemical properties of water quality in Sosiani River in Eldoret town, Kenya. An experimental design was used to collect water samples upstream midstream and downstream of Eldoret town for a period of one year during the dry and wet seasons. Samples were collected from effluent discharge points in accordance with APHA, 2012 water sampling procedures. Sosiani River exhibited significant variation in physico-chemical water parameters along the river and during rainy seasons. TSS varied significantly across the river at F= 185.52 P < 0.001 and during the wet season (P< 0.045). TDS varied significantly along the river (F= 59.0129 at p<0.001) with a significant positive correlation at P< 0.001 during wet season. Turbidity varied significantly along the sampling points F= 32.41 P< 0,001 and varied significantly p<0.028 during the rainy season. BOD varied significantly along the river (F= 78.95 & P < 0.001) with a significant positive correlation P<0.038 during the rainy season. COD varied significantly along the river (F=77.64 & P<0.001) and during wet season. Water temperature varied significantly along the river (F=185.52, p<0.001) and with the onset of the rainy season (P<0.013). Water pH varied significantly along the sampling points (F= 159.85 & P <0.001). However, pH did not vary significantly during the wet season (P<0.616). This river is polluted, turbid with low dissolved oxygen and high BOD hence not suitable for aquatic life. However the water quality improves downstream perhaps due to self cleansing ability of the river. Hence the water is not suitable for human consumption and or recreation purposes. The water should be treated and municipal effluent channelled into effluent treatment works for pre-treatment.
Effect of drift sampler exposure time and net mesh size on invertebrate drift density in the Njoro River, Kenya
(Taylor & Francis group, 21/6/2018) Mureithi, PW; Mbaka, JG; M’Erimba, CM; Mathooko, JM
Although invertebrate drift is an important ecological process in lotic ecosystems, very little is known about it in Kenyan rivers. The primary aim of this study was to investigate the effect of driftnet mesh size and exposure duration on drift density in 2017. Drift samples were dominated by Chironomidae, Baetidae, Simuliidae, Caenidae and Culicidae. The 100 µm mesh driftnet had the highest mean invertebrate density, followed by the 250 µm and 500 µm nets. Invertebrate drift densities decreased with increased exposure time. This study demonstrates that sampler mesh size and exposure time should be taken into account when characterising invertebrate drift in streams. Future studies should consider sampling different biotopes and during different seasons.
The Occurrence of Viable Helminthes Ova in Pit Latrine Faecal Sludge In Nakuru Sub County, Kenya
(IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT), 2018-12-03) Maingi J.M; Moturi W.N; Muchiri E.W
Pit latrines eventually fill up and mostly have to be disludged for continued reuse of the facility. Disludging and disposal of pit latrine contents may expose the public and disludgersto harmful pathogens. Helminthes have been found to exist in faecal sludge and are the most resilient hence their elimination would render the faecal sludge safe upon exposure. Little is known on the occurrence of helminthes parasites and their magnitude in Kenya. It’s on these facts that this research is based upon to find out the various helminthes species present in faecal sludge and their occurrences in regard to pit latrine depth. Thirty five pit latrines were selected purposively and sampled at various depths and analyzed for viable helminthes ova using the floatation method. One way analysis of variance was used to determine significant differences in the occurrence of various helminthes ova versus pit latrine depth. Where significant differences were found, a post hoc test (fishers exact and Tukey) was done to establish the exact depth at which the significance occurred. Results indicate that among the 128 samples collected, 23% were found to bear viable helminthes ova. Seven helminthes species were established; Ascaris lumbricoides, Trichuristrichiura, Schistosomahaematobium, Schistosomamansoni, Taeniasp, Enterobiusvermicularies and Necatoramericanus. A statistical significant difference in the occurrence of total viable helminthes ova was found to occur. A statistical significant difference in the occurrence of Ascaris ova in regard to pit latrine depth was also found to occur. Pit latrine sludge in Nakuru was thereforefound to contain numerous infective helminthes parasites and the fact that they exist even at deeper depths despite significant differences in their occurrence renders pit latrine sludge hazardous upon exposure to disludgers, public and the environment. Proper care should thus be ensured when handling and disposing raw sludge from pit latrines in Nakuru Sub Count
Physical Chemical Parameters of Wastewater: A Case Study of Njoro Sewage Works, Nakuru, Kenya
(Journal of Environment and Earth Science, 2018) Chege, Bancy Gathoni; Moturi, Wilkister N.; Makindi, Stanley M.
Njoro sewage works is the main sewage work for Nakuru urban town that receives about 90% of industrial wastewater and 10 % domestic wastewater. In-sufficient pre-treatment of industrial wastewater, may affect the normal functioning of sewage works and the aquatic life (flora and fauna) of the receiving water body. The underground water aquifer may also be contaminated by both chemical elements and microbial through percolation. This study aimed at assessing the efficiency of the sewage works by analysing the physical and chemical parameters of wastewater from the inlet and outlet of Njoro sewage works. The study involved test analysis of the physical and chemical parameters in the laboratory and in-situ test. This study employed composite sampling method in the collection of samples. Data collection was done using experimental method while data analysis was done using descriptive statistics. This study found that BOD concentration was 400 mg/l for the influent and 150mg/l for effluent. COD concentration was 1399 mg/l for the influent and 222 mg/l for the effluent. DO concentrations were lower (0.05 mg/l) for influent and effluent. Traces of heavy metals were also found both for the influent and effluent. Njoro sewage works could not effectively reduce organic load in wastewater.
Microbiological contamination of water pans in Baringo County
(IWA Publishing, 2017-07-17) Kurui, Edith J.; Ogendi, George M.; Moturi, Wilkister N.
Water pans constitute the main source of rural water supply in Baringo County. This study sought to assess the spatial-temporal variation of total coliforms, Escherichia coli, Fecal streptococcus and Salmonella species in the water pans. A sanitary survey was conducted to observe the potential sources of microbial contamination on the water pans. Water was sampled from one protected and five unprotected water pans (n = 6) in the study area for a period of 4 months (June–October 2015). A total of 72 water samples were sampled in triplicate from the water pans for microbial analyses, membrane filtration technique was used in assaying for microbial counts of total coliforms, E. coli, F. streptococcus and Salmonella species in water samples. The results show that there was a significant spatial variation in F. streptococcus amongst the protected and the unprotected water pan sampled sites (p = 0.008), and there was a statistically temporal significant difference (p = 0.001) for total coliforms and Salmonella species during the dry seasons, respectively. Given the prevalence of the selected diseases causing pathogens in water above the WHO drinking water quality guidelines, households are advised to treat the water before use.
Endo-helminths Infestation in Nile Perch, Lates niloticus, (L.,) and Nile Tilapia, Oreochromis niloticus(L.,) in Winam Gulf of Lake Victoria, Kenya
(Egerton University, 2017-01-18) Thon, C. C.; Otachi, O. E.; Oldewage, A. A.
Nile tilapia, Oreochromis niloticus (L., 1758) and Nile perch, Lates niloticus (L., 1758) were introduced into Lake Victoria in 1950, mainly to boost the fishing economy. Parasitic infections remain a major concern to the fish industry. It has recently been identified as an important public health problem with considerable economic impact. Data on parasitic infections on the two fish species is scarce; particularly in the Winam Gulf of Lake Victoria. Therefore, this study aimed at investigating the prevalence, mean intensity and mean abundance of endo-helminths infecting O. niloticus and L. niloticusin the Gulf. A total of 320 fish comprising 151 O. niloticus and 169 L. niloticus were caught weekly and transported alive to Egerton University. Prior to examination, fish were killed humanely by cervical dislocation. The total length were taken using a calibrated dissecting board and weights were obtained using a sensitive weighing balance (Sartorius ED4202S). Fish were dissected immediately and subjected to parasitological examination using standard procedures. Eleven parasite taxa were recovered from O. niloticus, with Tylodelphys sp. dominating the community. On the other hand, six parasite taxa were recordedfrom L. niloticus, with Armithalingamia macracantha dominating (P =5.3% MI = 4.6 and MA = 0.2). We conclude that L. niloticus had a poor parasite fauna, while O. niloticus had a rich parasite fauna. Despite the low infection level of Bothriocephalus acheilognathi and Heterophyes sp., are still the major parasites of concern, especially considering their potential zoonotic effect.
Characteristics, disposal methods and management of plastic waste in Watamu, Kilifi County, Kenya
(Egerton University, 2019-04) Gwada, Brenda C.
Plastic waste has been and still is a major challenge and concern globally but more so in the developing countries. Plastic has been shown to impact negatively on marine life more specifically marine animals. Watamu ward, in Kilifi County, Kenya, is an important breeding ground for the critically endangered turtles and is being affected by plastic waste. The aim of this study was to assess the characteristics, disposal methods and management of plastic waste in Watamu, in order to contribute to an understanding of the plastic waste disposal practices in the country. The specific objectives were to characterize the plastic waste in Watamu, as well as their streams. Secondly, the study also assessed the factors influencing level of knowledge, attitude and perception among the general public with respect to plastic waste disposal. Thirdly, the study determined the factors that influence plastic waste disposal methods. Finally, the study assessed and described the existing plastic waste management methods in the study area. A social survey was conducted to characterize plastic waste and determine the existing plastic waste management methods in the study area. Stratified random sampling design was used to divide the population of Watamu into groups based on their sub-locations and simple random sampling was used to arrive at the sample for this study. Primary data were collected using observation, structured questionnaire and semi-structured interviews and secondary data from various sources. The data were analysed using descriptive and inferential statistics. The results show that 55.4% of the plastic waste discarded was low density polyethylene that was discarded by the public who were responsible for 69.3% of the plastic waste found discarded. According to the results, 50.7% of plastic wastes were disposed of at the open dumpsite at Timbotaka, in Watamu sub-location. Location of the respondents was a significant factor that influenced the level of knowledge, attitude and perception with respect to plastic waste disposal (FH = 25.729, p = 0.002; FH = 16.289, p = 0.033; FH = 24.145, p = 0.009). It also influenced the plastic waste disposal methods used by respondents (FH = 50.708, p = 0.000). Other factors that influenced plastic waste disposal methods include occupation FH = 30.082, p = 0.038), waste collection and presence of recycling centres. The existing plastic waste management methods are re -use and small-scale re-cycling done by locals and Eco-world respectively. In conclusion, the proximity of waste disposal sites determines the plastic waste disposal methods used by the locals. Therefore, for environmentally-sound management of plastic waste, disposal sites should be easily accessible. Further awareness campaigns and public education need also to be done on plastic waste management to facilitate proper disposal methods.
Polycyclic aromatic hydrocarbons in the bottom sediments of Elburgon River—Kenya: precursors for cancer
(Springer, 2019-09-24) Opuru, Francis E.; Kibet, Joshua K.; Kirkok, Samuel K.; Ngari, Silas M.
The exponential growth in the rate of industrialization is a serious precursor for contamination and deterioration of the environment. Water pollution, for instance, is expected to reach disturbing levels in the years to come. Polycyclic aromatic hydrocarbons (PAHs) in water systems are persistent contaminants not only in aquatic systems but also in soil, air and plant materials and are well-known initiators for cancer and gene mutation. Numerous human-dependent activities such as agriculture and suspected wood treatment works in Elburgon may lead to an increased PAH contamination of water in River Elburgon, especially when the internationally set limits are exceeded. The sediment samples were collected in May 2019 during the wet season and treated for analysis of PAHs using a gas chromatograph hyphenated to a mass selective detector. A total of 25 PAHs were quantified in this study out of which pyrene was the most abundant, contributing $$\approx \,17\%$$of the total concentrations of PAHs identified. The total concentration of the PAHs analyzed in this study was found to be $$\mathop \sum \nolimits_{25} {\text{PAH}} = 73.19 \pm 3.67\;\upmu{\text{g}}\;{\text{g}}^{ - 1}$$dry weight (dw) with pyrene contributing a total concentration $$\mathop \sum \nolimits_{\text{pyrene}} = 12.44 \pm 0.54\;\upmu{\text{g}}\;{\text{g}}^{ - 1 }$$ dw. On the other hand, benzo[a]pyrene (BaP)—a well-known carcinogen—was significantly high $$\mathop \sum \nolimits_{\text{BaP}} = 10.67 \pm 0.43\;\upmu{\text{g}}\;{\text{g}}^{ - 1 }$$. Other major PAHs detected included acenaphthene and 5,6-dihydrobenzo[de]anthracene, $$14.57\%$$and $$\approx \,11\%$$, respectively. The low concentration PAHs included 1-ethenylnaphthalene and 1,4,5-trimethylnaphthalene each at $$0.08\%$$. The presence of benzo[a]pyrene in significant amounts is of serious concern on the public health of the residents of Elburgon and its environs. Considering the high levels of PAHs in the sediments of River Elburgon, it is important to note with concern that the water in the river under study is not only be unsuitable for drinking but also unsuitable for other domestic purposes such as irrigation and laundry.
Nitrogen loading and ground water contamination comparison among different farm sizes in Ainabkoi Sub-County, Uasin Gishu County,Kenya
(Egerton University, 2018-11) Kitonga, Lydiah Lucy Mbula
The mobility of nitrate-N (NO3-N), nitrite-N (NO2-N) and ammonium-N (NH4-N) down the soil profile and its ultimate presence in groundwater is aggravated by predisposing conditions such as farm agricultural activities and nitrogen fertilizer management, rainfall, seasons and well sanitary conditions. The main objective of the study was to assess the groundwater nitrogen loading compared in different farm sizes. The study was conducted in three agro-ecological wards of Ainabkoi sub-county. Each ward was identified as a homogenous stratum of same size-ranged farms. Farms in Ainabkoi ward were large, family-generations-owned mixed farm sizes and ranged 40-71 acres (16-29 ha) with an average farm acreage of 56 acres (23 ha). In Kaptagat ward farms were medium sized mixed farms on purchased settlement farms and ranged from 10-35 acres (4-14 ha). The small mixed farm sizes were located in Olare ward and ranged 2-10 acres (0.8-4 ha) in size. Farms in each ward were purposively selected such that only accessible farms that had access to either a privately owned or communal wells were selected. The study was carried out between 2012 and 2013. Onsite sanitary survey of the wells and the homesteads was carried out in each farm. A questionnaire was used to obtain general information on farm production and management, farm sizes, crops grown, crop acreage, cropping calendars, types and number of livestock animals kept, type and amount of fertilizer applied and well characteristics. The nitrate-N, nitrite-N and ammonium-N concentrations did not exceed the recommended maximum concentration by Kenya and WHO of 10mg/l, 3mg/l and 0.5mg/l respectively. The physico-chemical parameters were within the acceptable limits set by WHO except for turbidity. There was a positive linear relationship between the average fertilizer N amount at top dressing and the groundwater nitrate (Y = 0.0836x – 165.18 R2 = 0.31), hence N pollution is closely related to the amount and timing of fertilizer application. There were highly significant differences between precipitation and the N concentration although the trends were not clearly recognizable. There was a highly significant positive linear relationship between the monthly rainfall amount and NO3-N concentration in well water (Y = 0.1759x + 22.07 R2 = 0.23***). There were highly significant differences between the farm sizes in the sanitary contamination risk scores mainly due to individual farm endowments, well site environmental factors and ownership. Conclusively, precipitation, season and timing of fertilizer application were common significant predictors of the concentration levels of N in well water. The absence of any significant N contamination of groundwater in this study does not preclude it occurring in the future. Best nitrogen fertilizer management strategies should be adopted in order to synchronize N supply with crop seasonal demand such as timing and splitting of fertilizer N application and real-time monitoring of nitrogen in soil, plants and groundwater. Well conformity requirements with regard to the parameters of well construction and its vicinities are necessary.
Longitudinal and seasonal variations in physicochemical and microbiological properties of water quality of Sosiani River, Uasin Gishu County, Kenya
(IISTE, 2019-04) Masakha, Edward Juma
Water pollution is the change in physico-chemical and biological properties of water quality that is harmful to living things. It is caused by pollutants drawn from point and non-point sources of pollution including industrial and agricultural effluents. It can also be attributed to inappropriate use of chemicals and haphazard disposal of waste. It has become a global concern due to the lethal and sublethal effects on fauna and flora. Sosiani River traverses Eldoret town, draining effluent openly discharged. This river is an important source of industrial and domestic water for residents living in Eldoret, Turbo and along the riparian. This study assessed longitudinal and seasonal variations in physicochemical and microbiological water quality. Composite water samples were collected from 13 effluent discharge points along Sosiani River for one year and analyzed using American Public Health Association water sampling and processing procedures. Medical data was collected from health facilities in Eldoret Township. Data was managed using Statistical Packages for Social Sciences version 20. Both descriptive and inferential statistics like analysis of variance, correlation and regression analysis were used in analysing the resultant data. Sosiani River exhibited high mean levels of turbidity at 64 ± 53.4 Nephelometric Turbidity Units, high biological oxygen demand at 122.8 ± 123.8mg/L, high chemical oxygen demand at 205.0 ± 190.2 mg/L, high total suspended solids at 173 ± 34.14 mg/L, high total dissolved solids at 171.3 ± 11.66mg/L, Escherichia coli at 57.0 ± 54.3mg/L Colony Forming Units /100ml, total coliforms at 135.1 ± 119.6CFU/100ml and cadmium at 0.048 ± 0.07mg/L above National Environment Management Authority (NEMA) guidelines. Sosiani River exhibited significant differences in seasonal and longitudinal variations in physico-chemical and microbiological properties of water quality at P<0.005. The river exhibited significant seasonal and longitudinal variation in levels of Escherichia coli at F = 5.10 and P < 0.001. However, prevalent water borne diseases in the study area; diarrhea at t = 0.6387, P < 0.5374; dysentery at t = 1.2839 P < 0.2281 and typhoid at t = 0.3588, P < 0.7272 did not vary significantly during the dry and wet season. Water Resource Authority and NEMA should ensure all industries and hotels use constructed wetlands or are connected to the centralised sewerage system. The County Government should relocate Huruma dumpsite from the banks of the river and plant trees and grass along the river. Residents should treat drinking water sourced from Sosiani River at household level. Finally access to adequate sanitation should be increased to curb haphazard disposal of solid and liquid waste.
Levels of heavy metals in the straightfin barb Enteromius paludinosus (Peters 1852) from River Malewa, Naivasha, Kenya
(Springer, 2019-04-22) Ngesa, Elizabeth A.; Otachi, Elick O.; Kitaka, Nzula K.
There have been several studies on heavy metals in Lake Naivasha. However, none of them has reported the levels of mercury (Hg), arsenic (As), and chromium (Cr). Moreover, there are no studies on the heavy metals’ concentrations in the straightfin barb (Enteromius paludinosus, Peters 1852), a fish species that hosts a parasite (Ligula intestinalis), the latter having been reported to have a high ability to absorb heavy metals from its host. This paper therefore addresses the accumulation of heavy metals, namely arsenic (As), chromium (Cr), lead (Pb), and mercury (Hg) in the tissues of straightfin barb, Enteromius paludinosus (Peters 1852) from the mouth of River Malewa in Lake Naivasha, Kenya. A total of 1307 fish were collected during the month of November 2017. Water samples, sediment samples, 25 fish muscle tissues, and its endoparasite, the cestode Ligula intestinalis, were isolated, and heavy metal concentrations were determined using the thermal-electron atomic absorption spectrophotometer at the Lake Nakuru Water Quality Testing Laboratory. The concentrations of heavy metals in the sediment were below the lowest effect level in sediment, threshold effect concentration in sediment, severe effect concentration in sediment, and the shale values of sedimentary rocks thus showing no sign of pollution. In the muscle tissues of the fish, As, Cr, Pb, and Hg showed high levels with mean concentrations of 5.0696, 22.0854, 45.2108, and 1.5458 mg/kg ww, respectively. Bioconcentration factors further supported the observation that trace element accumulation was higher in fish compared with sediment and water. The target hazard quotients of As, Cr, Pb, and Hg obtained for both the female and male were > 1 indicating a possible health risk associated with the consumption of E. paludinosus. The bioaccumulation factors (BAFs) for L. intestinalis were 2.4093, 2.1873, 5.8601, and 5.1395 for As, Cr, Pb, and Hg, respectively, indicating the potential of the cestode in the accumulation of heavy metals from the host; hence, it can be used as an accumulation bioindicator.
Microbiological contamination of water pans in Baringo County
(IWA Publishing, 2017-07-17) Kurui, Edith J.; Ogendi, George M.; Moturi, Wilkister N.
Water pans constitute the main source of rural water supply in Baringo County. This study sought to assess the spatial-temporal variation of total coliforms, Escherichia coli, Fecal streptococcus and Salmonella species in the water pans. A sanitary survey was conducted to observe the potential sources of microbial contamination on the water pans. Water was sampled from one protected and five unprotected water pans (n = 6) in the study area for a period of 4 months (June–October 2015). A total of 72 water samples were sampled in triplicate from the water pans for microbial analyses, membrane filtration technique was used in assaying for microbial counts of total coliforms, E. coli, F. streptococcus and Salmonella species in water samples. The results show that there was a significant spatial variation in F. streptococcus amongst the protected and the unprotected water pan sampled sites (p = 0.008), and there was a statistically temporal significant difference (p = 0.001) for total coliforms and Salmonella species during the dry seasons, respectively. Given the prevalence of the selected diseases causing pathogens in water above the WHO drinking water quality guidelines, households are advised to treat the water before use.
Occurrence of Pathogenic Bacteria Harboring Antibiotic Resistant Genes in River Njoro in Nakuru County
(Journal of Environment Pollution and Human Health, 2018) Itotia, T. K. 1; Muia, A. W. 2; Kiruki, S. K. 3; Getenga, Z. 3
Njoro River drains an agricultural catchment whose main livelihood activities are livestock rearing and employment in light industries. The limited quantities of piped water supplies coupled with inadequate sanitary facilities experienced in the area can contribute to the spread of antibiotic resistance from antibiotic use in agriculture and human. The objective of the current study was to isolate common waterborne enteric pathogens and test them for antibiotic resistance on some commonly used antibiotics. The organisms that were found to be resistant were also tested for the presence resistant genes. This was done by filtering known quantities of water through membrane filters and plating them on selective and differential media and these were tested for sensitivity to antibiotics. Isolates that showed antibiotic resistance were tested for the presence of tetracycline (Tet A), Sulfamethoxazole (Sul2) genes class 1 intergrase gene and SXT element resistance genes using PCR with appropriate primers. Pathogens including E. coli strains, Salmonella spp, Vibrio cholera and V. parahaemolyticus were recorded in this study. Sulfamethoxazole (Sul2) genes were detected in Klebsiella pneumonia, Klebsiella oxytoca isolates and Entero- aggregative strains of E. coli. Tetracycline (tet A) genes were detected in ETEC and EAEC pathogenic strains of E.coli. Class 1 integrase was detected in an EAEC strain. The SXT (int) element was not detected in any of the isolates tested.
Assessment of Kangemi sewage treatment works efficiency and the impact of the effluent on water quality of Chania River Nyeri, Kenya
(Egerton University, 2019-10) Kariunga, Saeed Hassan
Sewage treatment plants (WTPs) use a combination of physical, chemical and biological processes to reduce the pollutant loads in wastewater. The treated wastewater is then either discharged to surface water or is reused. Successive stages in wastewater treatment plants reduce the quantity of suspended solids, biological contaminants, organic matter content and nutrient constituents in sewage. Changes in the properties of the effluents can occur along the treatment process leading to reduction or little change in effluent quality based on the effectiveness of the treatment process. The discharge of inadequately treated sewage from ineffective WTPs into the rivers and other receiving water bodies are both potential health risk and environmental hazard to both adjacent and downstream communities. This study estimates the efficiency of Kangemi Sewage Treatment Works (KSTW) in pollutant removal and the impact of its effluent on water quality of Chania River (CR). For environmental quality assurance, the plant’s performance requires consistent monitoring to evaluate the impact of the effluents to the receiving waters. Key nutrients (Nitrogen and Phosphorus), total suspended solids (TSS) and biological oxygen demand (BOD5) were determined using American Public Health Association (APHA, 2005) standard methods. Kruskal-Wallis test was run at p<0.05. Nitrogen, BOD5 and TSS indicated a significant difference between the sites (P<0.05). Physico-chemical parameters varied significantly, however, no significant difference for TP (Kruskal Wallis, 4.515, P=0.341) and SRP (Kruskal Wallis, 2.160, P=0.696) respectively across sites in KSTW. Removal efficiency for BOD5, TSS, NH4 and TN were 60%, 85%, 59% and 54% respectively. The KSTW had high removal efficiency for N but low for P but it was a source of nitrate, nitrite and TP. Organic-N was the most dominant form of N in KSTW, while P was mostly inorganic. In CR, the confluence (S8) recorded highest concentrations for most parameters (N, P, BOD5 and TSS). Inorganic-N in the CR was more than organic-N after effluent discharge point. Nitrate-N was the most common species of the dissolved nitrogen in CR. All parameters measured in CR showed a significant difference except TSS (Kruskal Wallis, P=0.733). Nutrients and organic matter in both the KSTW and Chania River indicated a strong correlation with temperature, DO and pH. Both for N and P, the organic form was dominating in CR. In conclusion, Pollution impact was highest at the KSTW point of effluent discharge (S8), with, the river indicating quick recovery downstream. In contrast, TSS indicated a progressive increase in concentration downstream from S8-S10. For recommendation, long-term surveys should be conducted to capture temporal efficiency and impact of KSTW effluent on Chania River.
Effect of net mesh size, exposure duration and net positioning on macro invertebrate drift densities in the Njoro River, Kenya
(Egerton University, 2018-03) Mureithi, Priscilla Wangari; Otuoma, Sanya
Macroinvertebrate drift is a phenomenon that has fascinated and occupied ecologists for a longtime and has produced varied results. Drift samples were collected in a riffle and pool biotopes in the Njoro River between 3rd January and 28th March 2017 with a sole objective of determining whether drift net mesh size, positioning and variation in exposure time could have significant influence on drift densities. Purposive systematic random sampling was employed to collect samples using six nets of 100 ìm, 250 ìm and 500 ìm mesh sizes for three consequent days always alternating the nets at the right, middle and left banks respectively, during seven sampling occasions. The nets were emptied at intervals of 5, 10, 15, 20, 25 and 120 minutes. Benthic samples were also collected during each sampling for quantification of the proportions of benthos that drifted. The mean drift densities (pooled data) between the pool (20.73 ± 0.10 ind.m-3) and riffle (38.79 ± 5.15 ind.m-3) was statistically significant (t-value = 2.821, d.f = 754, P < 0.05). The difference in drift densities among the 100 ìm, 250 ìm and 500 ìm nets was very highly significant (P < 0.001). The 500 ìm net collected the lowest drift densities, followed by the 250 ìm net Tukey’s Honestly Significance Difference (HDS) test, (P < 0.001). Drift densities decreased significantly with increase in exposure time in all the three nets in both biotopes (P < 0.001). Drift densities differed significantly with the net positions at the riffle (One – way ANOVA, F (2,375) = 11.43, P < 0.001) with the left bank having significantly higher densities than the mid-stream and the right bank. One – way ANOVA indicated insignificant difference in mean drift densities among the three positions in the pool (F (2,375) = 0.839, P > 0.05). There was no significant interaction observed among drift net mesh size, drift net position and exposure time in the riffle (Three way- ANOVA, F(20,324) = 0.375, P > 0.05) and pool (Three way- ANOVA, F(20,324) = 0.374, P > 0.05) biotopes. Mean proportion of benthos differed significantly between the riffle and pool biotopes (t = -9.473, d.f = 106, P < 0.001) with the pool having higher proportions than the riffle. This study demonstrates that drift net mesh size, position and exposure time should be taken into account when characterizing invertebrate drift in streams. Maximum drift densities can be obtained by sampling for 5 minutes irrespective of the mesh size used. Future drift studies should consider reduction of sampling time below five minutes as this was omitted in this study. Future studies should also consider drift sampling as a standard complementary tool to benthic sampling in bioassessment protocols of tropical streams.
Characterization of Egerton University wastewater stabilization ponds and assessment of substrate size efficiency in reduction of faecal pollutants in a constructed wetland mesocosm
(Egerton University, 2018-04) Lukhabi, Dorothy Khasisi
The aim of this study was to determine variations in concentration of Pathogen Indicator Organisms (PIOs) namely total coliforms Escherichia coli and heterotrophic bacteria; Biochemical Oxygen Demand (BOD) in Egerton University Wastewater Stabilisation Ponds (WSPs) and the effect of substrate sizes on wastewater treatment. Sampling at the WSPs was done on weekly basis for one month from mid-Nov to mid-Dec 2017 using standard procedures for examination of water and wastewater. A mesocosm study imitating a vertical sub surface flow constructed wetland was conducted to determine the most efficient substrate size in removal of these pollutant indicators. Total coliforms (TC) and E. coli were isolated using selective and differential media following membrane filtration method Colonies were enumerated on chromocult agar. Heterotrophic bacteria (HPCs) were enumerated using standard pour plate method on plate count agar. Biochemical Oxygen Demand was determined by incubating samples in a cabinet whose room temperature ranged between 20 °C to 25 °C for 5 days. For the mesocosm study, three sets of experiments with different gravel aggregate sizes were set up in triplicates. Wastewater from SMP was introduced and settled for six weeks to enable micro-organisms to establish and stabilize, before collection of water samples for analysis on weekly basis for eight weeks. The highest concentration of both PIOs and BOD was in the inlet, and this reduced along the pathway towards the outlet. Apart from BOD5, there was a significant difference between the influent and effluent in all the parameters (p<0.05). The range for TC, E. coli, HPCs and BOD5 was 5.5 x 106 - 2.9 x 1011, 4.4 x 104 - 1.9 x 1010CFUs / 100 ml, 4.5 x 106 - 5.0 x 109 CFUs / ml and 142.8 - 163.6 mg/l respectively. Removal efficiencies ranged between 99.8-99.9 % (3 log units) for both TC and E. coli in both First Maturation Pond and Second Maturation Pond. Heterotrophic Plate Counts reduced in concentration along the treatment pathway by 2 log units. In the mesocosm study, percentage reduction efficiency for TC for different substrate sizes was recorded as 95.3, 90.4 and 88.8 % for small, medium and large gravel aggregate respectively, while E. coli was recorded as 95.2, 94.3 and 88.4 % and HPCs was 99.8, 99.7 and 99.5 %. Furthermore, removal of organic matter was recorded as 15.9, 9.9 and 8.4 % for BOD5 while TSS was 72.7, 56.6 and 52.4 % for small, medium and large sized gravel aggregates respectively. In conclusion, WSPs at Egerton University performed well in removal of PIOs. Heterotrophic bacteria levels indicated presence of pollution with easily degradable organic matter, while BOD5 levels did not. In addition, none of the substrate sizes employed in mesocosm study performed better than the other in removal of PIOs and organic matter
Taxonomic status of fish parasites in Kenyan inland water systems and their significance on the freshwater fisheries and aquaculture productivity within the region
(Wiley, 2019-10-06) Kibet, Caroline Jepkorir; Donde, Oscar Omondi; Okwiri, Brian; Otachi, Elick Onyango
Fish are a resource with great economic, nutritional and recreational benefits to humans on a global scale. In Kenya, fish represent an important source of food and income through trade and employment to many communities. In fact, fish are an important alternative source of animal protein, especially in famine-tolerant arid and semi-arid regions such as Turkana, Marsabit, Pokot and Baringo Counties, where annual drought periodically hampers traditional livestock keeping destitute. Kenya freshwater fishes have remained vulnerable to a variety of parasites and related diseases. Approximately 119 fish parasites have been reported in the country, with about 83 being identified to species level and 35 to genus level. Out of the reported parasites, 77% were detected in wild fish, 8% in farm fish and 15% in both wild and farmed fish. The parasites identified by various studies include protozoa (7), myxozoa (7), nematode (20), monogenean (33), digenean (16), cestoda (15), acanthocephalan (6) and crustacean (15). The highly commercialized fishes, such as Oreochromis niloticus and Clarias gariepinus, harbour the highest number of parasites, which greatly hinder fisheries and aquaculture productivity through retarded growth, mechanical damages, reduced reproduction rates and increased mortality of the fish hosts. Thus, there is need for adequate information on the taxonomy and ecology of these parasites as a basis for developing appropriate management and policies to control them. This review article is meant to provide an overview of the distribution, occurrence of fish parasites and their impacts on inland water fisheries and aquaculture in Kenya, while also highlighting the available gaps warranting further studies, with the goal of developing appropriate and accurate control measures to improve the region's fisheries and aquaculture productivity and food security.

Browse

Recent Submissions