Water Pollution

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A review of the impacts of invasive aquatic weeds on the bio- diversity of some tropical water bodies with special reference to Lake Victoria (Kenya)
(Biodiversity, 0020-12-30) Aloo, Peninah; Ojwang, William; Omondi, Reuben; Njiru, James Murithi; Oyugi, Dalmas
Aquatic weeds may be defined as troublesome or unsightly plants growing in abundance inaquatic situations where they are not wanted. These plants are either adapted to continuoussupplies of water or are at least tolerant to waterlogged soil conditions for substantial periodsof time. The wide range of adaptation to varying amounts of water, and the impossibility ofsharply distinguishing between aquatic and terrestrial environments, makes it difficult toprecisely define an aquatic plant. The menace of water weeds is reaching alarming proportions in many parts of the world, especially in tropical water bodies where they have led toserious ecological and economic losses. Lake Victoria, Kenya, which is the largest freshwaterbody in the tropics, has undergone serious ecological changes including over-exploitationof its fishery resources, degradation of the catchment area, introduction of exotic fish speciesand invasion by the water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae),among others. The presence of the weed in the lake has led to many problems includingblockage of water pumps, reduced fishing activities and increase in water borne diseasessuch as schistosomiasis. Positively, aquatic weeds constitute a free crop of great potentialvalue; they are a highly productive crop that requires no tillage, fertilizer, seed, or cultivation.Moreover, these plants have the potential for exploitation as animal feed, human food, sourceof food to some aquatic organisms, soil additives, fuel production, wastewater treatment,source of raw materials and habitat to many organisms. This paper reviews the effects ofaquatic weeds in aquatic systems with examples from some selected waterbodies and specialreference to Lake Victoria.
A review of the changes in phytoplankton community structure and ecology in lake naivasha, kenya
(Academic Journals, 1970-01-01) Argwings Owino Omondi, Steve Opiyo Balaka, George Ogendi Mokua, James Onchieku Mokua, Steve Oduor Omondi
Phytoplankton community structure plays a vital role in freshwater ecosystems. Besides the provision of dissolved oxygen through photosynthesis, they also form an important diet for several fish and zooplankton species. Plankton are also used as biological indicators of water quality. The objective of this paper is to provide a comprehensive review on the changes in phytoplankton community structure and their ecological functional roles. Phytoplankton are the primary producers in Lake Ecosystem. The diversity, distribution, and abundance of phytoplankton are influenced by both abiotic and biotic factors. Lake Naivasha has undergone drastic ecological changes due to the growth in human population, horticultural and floricultural developments and changes in its fisheries. Lake Naivasha is surrounded by horticultural farms that are greatly influencing its ecosystem health and the major fish species in the lake are of introduced species. These anthropogenic activities together with hydrological changes are expected to play a role in the changes in phytoplankton community structure. Previous investigations indicate that there are more than 143 species of phytoplankton and seasonal shift in phytoplankton dominance overtime between Chlorophyta, Bacillariophyta, and Cyanophyta. Due to various limnological, hydrological, and ecological changes being witnessed in the Lake, there is need for the monitoring of phytoplankton community structure. Such information would be useful in the Lakeâ€™s management and conservation.
Effects of Zinc, Lead and Copper Concentration Levels on the Distribution of Macro Invertebrates: A case Study of River Sosian, Eldoret Town, Kenya
(journal of the kenya chemical society, 2004-08) Osano, Aloys; L.L., Cheruiyot
The relationship between zinc and copper concentration levels and the distribution of benthic macro-invertebrates in river Sosiani, Eldoret has been investigated. Atomic Absorption Spectrophotometry (AAS) and the Dip-net method have established the concentration of zinc and copper and the number of macro-invertebrates respectively. The study showed that the concentration of both copper and zinc were higher than the threshold levels and that the macro-invertebrate species were fewer in the more polluted regions of the river. Thus, zinc and copper concentration levels play a role in the distribution of macro-invertebrates.
Macrophytes of Lake Victoria and succession after invasion of Water Hyacinth
(AQUA DOCS, 2006) Omondi, Reuben; Kusewa, Mwende
The distribution of Lake Victoria macrophytes is described. Succession of macrophytes in the lake became more dramatic and dynamic after invasion of water hyacinth. The weed pushes and smothers other free-floating macrophytes like Pistia stratiotes. It then provides substrates for the emergent Vossia cuspidata, which later reduces its population by competition for light and nutrients. The noxious weed is believed to have led to extinction of Azolla nilotica in the lake.
Influences of land use/cover on water quality in the upper and middle reaches of River Njoro, Kenya
(Blackwell Publishing Asia Pty Ltd, 2007-04-20) Muchiri, Mucai; Shivoga, William A.; Kibichi, Samuel; Odanga, Jethro; Miller, Scott N.; Baldyga, Tracy J.; Enanga, Eric M.; Gichaba, Maina C.
Data from 10 sampling sites along the River Njoro are used to examine the contribution of nutrients from upstream land uses draining each of the sampling sites. The data also are used to assess whether both the proportion of land uses and the size of the subwatersheds account for the variability in water quality in the River Njoro watershed. Geographical Information System analysis was used to determine the spatial distribution of land-cover types and subwatersheds contributing run-off to the sampling sites in the River Njoro. Standard Digital Elevation Model-based routines were used to establish the watershed area contributing run-off to each sampling site. Water and sediment samples were collected for chemical analysis, and the nutrient levels were related to the upstream land-use types and the size of the subwatersheds. The mid-stream portion of the River Njoro (near Egerton University) accounts for the highest nutrient contributions. The percentage contribution is magnified by additions from industrial, human settlements and agricultural land uses around the University. There is a significant decrease in nutrient levels downstream, however, indicating natural purification as the river flows through an area of large-scale farming with intense, well-preserved riparian and in-stream vegetation. Steep slopes of the land upstream of Egerton University enhance erosion and nutrient losses from those subwatersheds. Mixed small-scale agricultural and bare lands contribute over 55% of the phosphorus load to the upper and mid-reaches of the River Njoro. The size of the subwatershed accounts for about 53% of the variability in the soluble phosphorus in the river. The land-use subwatershed proportions are important for characterizing and modelling water quality in the River Njoro watershed. Upland land uses are as important as near-stream land uses. We suggest that conservation of intact riparian corridor along the river and its tributaries contributes significantly to natural purification processes and recovery of the ecological integrity of the River Njoro ecosystem
Physico-chemical charecteristics of Nyanza gulf in lake Victoria, Kenya.
(Semantic Scholar, 2011) Misiko, Florence Monicah; Radull, John; Gichuki, John; Andika, Darius O.
Kisumu Bay is greatly impacted by pollution from anthropogenic activities around Winam Gulf and from increased levels of industrial and municipal discharges from Kisumu town. This has resulted in significant changes in the trophic state and general ecology of the bay, impacting negatively on water quality, fisheries and livehoods. This study, therefore, aimed at determining the levels of physic-chemical parameters,nutrients and chlorophyll a in Kisumu Bay. Water quality measurements were conducted from April 2009-April 2010. Physico-chemical parameters (turbidity, temperature, conductivity, alkalinity, dissolved and suspended solids, and dissolved oxygen concentration) were measured using a sea bird, mult-parameter water quality probe, whereas nutrients (nitrates, nitrites and Phosphorous were analyzed by spectrophotometric techniques. There were significant spatial differences in the dissolved oxygen concentrations (p<0.0001) within the bay. These differences were especially pronounced at the Kisat, Maboko and Yatcht club stations which are associated with sewage discharge in Kisumu town. Similarly, significant differences (<0.05) associated with discharge from Kisumu town and seasonal nutrients runoffs from storm water were also observed in the spatial and temporal distribution of phosphorous ,ammonia, nitrates, nitrites and silicates within the gulf. Significantly, higher chlorophyll a concentrations were recorded during the dry season compared to the rainy season, probably as a result of high turbidity during the rainy season which reduces light penetration into the water. The study attributes this state of affairs to high nutrient loads from anthropogenic activities and industrial and municipal wastes and recommends stricter enforcement of the established policies on the quality of discharges from municipal and industrial establishments. There is also a need for environmental education and awareness creation targeting the lake communities to abate pollution in the lake.
The Efficacy of a Tropical Constructed Wetland for Treating Wastewater During the Dry Season: The Kenyan Experience
(Springer Nature, 2011-06-17) Kelvin, Khisa; Tole, Mwakio
Constructed wetlands have recently received considerable attention as low cost and efficient means of cleaning up many different types of wastewaters at secondary and tertiary levels. This is an environmentally sound method of wastewater treatment that does not use hazardous chemicals, and is based on the high productivity and nutrient removal capability of the wetland that strongly relies on its intricate ecosystem structure and function. Research work was conducted on a tropical constructed wetland to establish its capability to treat wastewater during the dry season. A comparison of its efficacy with that of conventional wastewater treatment plants was made on the basis of the measured water quality parameters. Temperature, pH, dissolved oxygen, and conductivity were measured in situ. Total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus, ammonia, and nitrites were analyzed in the laboratory. Fecal coliforms were enumerated and Escherichia coli counts were determined. The TSS values reduced from a mean of 102 mg/l at the influent point to 16 mg/l at the effluent point, depicting a reduction of 84.3%. Influent TDS averaged 847 mg/l, while the effluent averaged 783 mg/l. Dry season BOD5 levels were reduced from an average of 286 at the inlet point to 11 mg/l at the outlet representing a reduction efficiency of 96.2%. COD levels were reduced from a mean of 2,002.5 to 47.5 mg/l depicting a removal efficiency of 97.6%. Phosphorus was reduced from a mean of 14 to 11 mg/l representing a percentage removal of 21.4%. Levels of ammonia reduced from a mean of 61 at the influent point to 36 mg/l at the effluent point representing a percent reduction of 41.0%. There was a 99.99% reduction for both the fecal coliforms and E. coli counts. Conductivity of wastewater increased from 1.08 to 1.98 mS, while the pH increased from 6.23 at the inlet point to 7.99 at the outlet of the system. Temperature and dissolved oxygen measurements showed a diurnal variation. The dry season wastewater heavy metal concentrations were in the following ranges: Pb (0.7–6.9 ppm), Cr (0.2–0.5 ppm), Zn (0.1–2.3 ppm), Ni (0.1–1.3 ppm) with Cd and Cu not being detected in the wastewater streams. Overall, tropical constructed wetlands are effective in treating wastewater streams and they perform a lot better than the popularly used waste stabilization ponds. This paper recommends that they can be widely used within the tropics.
Water hyacinth Eichhornia crassipes (Mart.) Solms-Laubach dynamics and succession in the Nyanza Gulf of Lake Victoria (east Africa): implications for water quality and biodiversity conservation
(Hindawi Publishing Corporation, 2012) Gichuki, John; Omondi, Reuben; Boera, Priscillar; Okorut, Tom; Matano, Ally Said; Jembe, Tsuma; Ofulla, Ayub
This study, conducted in Nyanza Gulf of Lake Victoria, assessed ecological succession and dynamic status of water hyacinth. Results show that water hyacinth is the genesis of macrophyte succession. On establishment, water hyacinth mats are first invaded by native emergent macrophytes, Ipomoea aquatica Forsk., and Enydra fluctuans Lour., during early stages of succession. This is followed by hippo grass Vossia cuspidata (Roxb.) Griff. in mid- and late stages whose population peaks during climax stages of succession with concomitant decrease in water hyacinth biomass. Hippo grass depends on water hyacinth for buoyancy, anchorage, and nutrients. The study concludes that macrophyte succession alters aquatic biodiversity and that, since water hyacinth infestation and attendant succession are a symptom of broader watershed management and pollution problems, aquatic macrophyte control should include reduction of nutrient loads and implementing multifaceted approach that incorporates biological agents, mechanical/manual control with utilization of harvested weed for cottage industry by local communities.
Survival and avoidance response of the freshwater gastropod Melanoides tuberculatus (Muller) to different concentrations of tobacco waste
(Aquaculture Research, 2012) Ogello, Erick Ochieng; Omondi, Reuben; Opiyo, Mary A.; Charo‐Karisa, Harrison; Munguti, Jonathan; Aura, Christopher Mulanda
The Gastropod Melanoides tuberculatus plays a significant role in hampering fish larval production in earthen ponds. This study investigated use of tobacco waste to assess behavioural and survival responses of M. tuberculatus at different concentrations of tobacco waste solution of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2 g L−1. Mean escape time varied significantly among concentrations (P < 0.05). Escape time decreased in 1‐, 2‐ and 3‐day‐old solutions. Percentage survival decreased significantly with increasing concentrations of tobacco waste solution and exposure time (P < 0.05). Concentrations of 1.75 g L−1 and 2.0 g L−1 had high hazard ratios and low survival rates of gastropods and were the most effective in eradication of M. tuberculatus, hence recommended dose for preparing ponds for stocking. We conclude that tobacco waste solution can be used for control of M. tuberculatus.
Physico-chemical and bacteriological quality assessment of shallow wells in Kitui town, Kenya
(Journal of Water Resource and Protection, 2012-01) Abila, Romulus; Mutemi, Muthangya; Mutuku, Eunice; Mutati, Kennedy; Munguti, Mutinda; Musyoka, Cecilia
Kitui town, a small but fast growing town in arid south-eastern Kenya faces unreliable water supply and residents are highly dependent on shallow wells as the main source of water for domestic use. A study was carried out to assess the physical-chemical and bacteriological quality of water from shallow wells within the town's main residential areas. 96 water samples were collected from 8 main residential estates within the town between May and July 2011 and analysed for physical-chemical characteristics and bacterial quantity and species. Water analysis revealed presence of 9 pathogenic genera including Salmonella, Escherichia coli, Vibrio, Listeria, Staphylococcus, Streptococcus, Enterobacter, Klebsiella and Pseudomonas. Multiple-tube fermentation technique was used to enumerate coliform bacteria in water. Total aerobic bacterial load ranged from 3.70 x10 2 to 2.352 x10 3 CFU/ml. E. Coli was isolated from Majengo and Mjini estates only and the bacterial load estimated as 1.10 x10 2 CFU/ml and 0.20 x10 2 CFU/ml respectively while Salmonella sp. was isolated from water samples from Kunda Kindu, JICA and Mjini estates. Conductivity and pH levels were above World Health Organization acceptable levels for drinking water in all samples. All samples tested did not meet the WHO bacteriological standards for drinking water. The presence of Salmonella, Vibrio, Listeria and E. Coli should particularly raise serious public health concerns over the quality of the town's shallow wells water. Intervention measures including creating awareness and educating residents on shallow well construction, citing and care, boiling of water and improving sanitation should be urgently instituted. There is also need to construct sewerage works for the rapidly expanding Kitui town to reduce incidences of contamination from septic tanks.
Faecal Contamination of Drinking Water von Maureen Stella Olunga - 978-3-8484-1889-3
(LAP Lambert Academic Publishing, 2012-03-14)
Faecal contamination of water can introduce a variety of pathogens into water ways, including bacteria, viruses, protozoans and parasitic worms. Poor excreta disposal is often associated with lack of adequate water supplies, poor sanitation facilities and low economic status populations. In this study water samples were collected from wells, taps and harvested rain water containers in Kimumu area of Eldoret municipality in Kenya and analyzed using standard bacteriological and parasitological methods. The quality of tap and rain water was found to be acceptable. The presence of Escherichia coli in well water was an obvious indication of faecal contamination. Faecal parasites observed were Entamoeba histolytica, Ascaris lumbricoides, Giardia lamblia, Necator americanus, Ancyclostoma duodenale, Fasiola hepatica, Taenia saginata and Taenia solium. To control infestations with faecal intestinal parasites, provision of treated piped water to all homesteads, consultation of water engineers and/or health inspectors before well construction and creation of public awareness are recommended. Scholars of microbiology and parasitology and parasitologists will find this book resourceful.
Survival and avoidance response of the freshwater gastropod Melanoides tuberculatus (Muller) to different concentrations of tobacco waste
(Wiley, 2012-09-13) Ogello, Erick Ochieng; Omondi, Reuben; Opiyo, Mary A.; Charo-Karisa, Harrison; Munguti, Jonathan; Aura, Christopher Mulanda
The Gastropod Melanoides tuberculatus plays a significant role in hampering fish larval production in earthen ponds. This study investigated use of tobacco waste to assess behavioural and survival responses of M. tuberculatus at different concentrations of tobacco waste solution of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2 g L−1. Mean escape time varied significantly among concentrations (P < 0.05). Escape time decreased in 1-, 2- and 3-day-old solutions. Percentage survival decreased significantly with increasing concentrations of tobacco waste solution and exposure time (P < 0.05). Concentrations of 1.75 g L−1 and 2.0 g L−1 had high hazard ratios and low survival rates of gastropods and were the most effective in eradication of M. tuberculatus, hence recommended dose for preparing ponds for stocking. We conclude that tobacco waste solution can be used for control of M. tuberculatus.
Status of water quality in the coal rich Mui basin on Kitui county, Kenya
(Asian Research Publishing Network, 2012-11-01) Muthangya, Mutemi; Samoei, David
The Kenyan population is growing at an alarming rate which has led to increase in demand for resources such as energy, food, and infrastructure. The discovery of coal in Mui Basin of Kitui County is so important in the realization of Kenya’s blue print vision 2030. Coal is a major source of energy, and is composed of Carbon, Hydrogen, and Oxygen, with lesser amounts of Sulfur and Nitrogen. Despite the high expectation from coal, the extraction of coal and its subsequent use as a fuel source of energy comes with a myriad of challenges which among them are the emissions of sulphur oxides from combustion of sulphur in coal. This study aimed at assessing the physiochemical status of the underground water utilized for domestic purpose in the coal rich Mui basin block D. The results of the minerals content were below detectable limits with only Magnesium being in the range of 4.14-50.18 mg/l. Since coal is a major environmental pollutant from the exploration, mining as well as utilization, this study recommend the application of modern and clean coal technology in order to reduce the emission of poisonous material that pollute the water bodies and the environment in general.
SPATIAL AND TEMPORAL VARIATIONS IN PHYSICO-CHEMICAL PARAMETERS, NUTRIENTS AND HEAVY METALS ALONG A GRADIENT OF ANTHROPOGENIC ACTIVITIES WITHIN KAPSABET RIVER, KENYA
(University of Eldoret, 2013) Limo, Eliud
Increased human activities have led to water pollution, especially metals and nutrients. Therefore, prudent management of aquatic environments require information on their quality status that can be estimated by monitoring water to determine extent of pollution. This study examined the spatial and temporal variations of heavy metals and nutrients in water, soil and sediments which were sampled along four sites (S1, S2, S3 and S4) as Kapsabet River flows from upstream to down stream for both dry and wet season. The parameters analyzed were: temperature, pH, chemical oxygen demand (COD), biological oxygen demand (BOD), total dissolved solids (TDS) and total suspended solids (TSS) while phosphates and nitrates were the nutrients analyzed. Heavy metals analyzed included Pb, Cu, Fe and Zn using atomic absorption spectroscopy (AAS). TSS and TDS were determined by gravimetric method, COD titrimetrically, BOD by incubation, phosphates and nitrates by colorimetric method. Data was analyzed statistically using SPSS computer package. All parameters analyzed increased downstream, except Cu, with maximum mean values recorded in wet season. Their spatial and temporal values were: in water, pH (7.2 -10.3), TSS (110 -1301 mg/L), TDS (868 - 2990 mg/L), COD (6.0 – 67 mg/L), BOD (3.0 - 33.7 mg/L) PO43- (0.2 - 2.1 mg/L) and NO3- (0.6 - 4.5 mg/L), in soil and sediments, PO43- mean values were: 0.5-1.8 mg/L and 0.7 – 2 mg/L, respectively, while NO3- in soil and sediments were: 5-5.2 mg/L and 8-8.0 mg/L, respectively. For heavy metal, Fe had high concentration with mean values in water, soil and sediment being, 0.19 – 12.02 g/g, 1.15 – 38.78 g/g and 0.12 – 69.89 g/g, respectively, while Cu had the least concentration with mean values being, 0.017 - 0.174 g/g, 0.008- 0.424 g/g and 0.08 - 3.056 g/g in water, soil and sediments, respectively. There was significant (p < 0.05) spatial and temporal distribution of metals along the river profile. In both water and sediments, S3 and S4 contained significantly (p < 0.05) the highest concentrations of Pb, Fe and Zn associated with anthropogenic pollution. Based on the results obtained Kapsabet river water is not safe for drinking and other domestic uses and therefore, it is recommended that a for
POLLUTANT LEVELS IN WASTE WATER FROM TANNERY EFFLUENT: A CASE STUDY OF NAKURU TANNERS, KENYA
(University of Eldoret, 2013) Nyabaro, Obed Mainya
Wastewater from leather processing industries is very complex and leads to water pollution if discharged before treatment, especially due to its high organic loading and chromium content. Over the past years, Nakuru Tanners Ltd has been discharging raw effluents into the Ndarugo River causing pollution of surface waters, groundwater and soil. Since the water from this river is used for drinking, agricultural and industrial purposes, the assessment of the effluents is necessary. A study to determine the level of toxicants in Nakuru tannery wastewater discharged to the environment has been undertaken. Water samples from four sampling points (S1 – pre-tanning, S2 – tanning, S3 – post-tanning and S4 – drainage to the river) were collected and analyzed. A comprehensive experimental evaluation of tannery wastewater was performed as a basis for the determination of the levels of different pollutants, BOD, COD, pH, turbidity, TSS, NO3- and NO2- and the values obtained were compared to the standards set by NEMA and WHO. The levels of the metals chromium, iron and lead were determined using FAAS, Kjeldahl method was used for the quantization of NO3-, NO2- and P determined by Mehlich II extraction while UV-Vis was used in colour determination. The results show that sampling point S1 (wastewater from the pre-tanning stage) recorded the highest parameter levels for pH, TSS and SO42- of 11, 294.40 mg/L and 318.50 mg/L, respectively. Sampling point S2 had the highest levels of COD, BOD, Cr and Pb with corresponding values of 9,107 mg/L, 9,150 mg/L, 945 μg/L and 6.50 mg/L. Sampling point S3 recorded the highest parameters of temperature, DO, Fe, P and electrical conductivity of values 24.62 0C, 1.15 mg/L, 5.40 mg/L, 12.40 mg/L and 14720 μSCm-3 while S4 recorded the highest of NO3- and NO2- pollutants with respective values of 85.20 mg/L and 146.70 mg/L. These levels were, however, above the recommended values set by WHO and NEMA for such parameters in tannery waste water. The company should therefore take immediate counteractive actions to lower these levels of the toxicants in order to avert the associated effects to human and environment. This study has made various recommendations which if undertaken will help make the tannery effluents safe before disposal.
THE SPATIAL AND TEMPORAL VARIATION OF SELECTED HEAVY METALS, NITROGEN AND PHOSPHORUS IN WATER AND SOILS OF YALA SWAMP, KENYA
(University of Eldoret, 2013) Onyango, Christopher Otonde
Studies involving pollutants in the environment have been used as an indicator of their accumulation resulting from human activities. A study of spatial and temporal variation of pollutants involving forty four water and soil samples collected from four different fields within the Yala swamp has been undertaken. The samples were collected in duplicates. Soil samples were dried in the open, crushed, sieved through 2 mm sieve, weighed and digested using the wet method in a block digester. Atomic Absorption Spectrometer was used to analyze heavy metals (Zn, Co, Mn, Cd, Cu, Pb, and Cr). Total N and P were analyzed using colorimetric technique. Respective average levels of Zn and Cu in water 0.505 ppm and 0.129 ppm which were much lower than the maximum values of 5.000 ppm and 1.000 ppm set by WHO/ FAO. Those for Co, Mn, and Cd were 0.219, 1.352 and 0.176 ppm, respectively and were higher than the respective WHO/FAO values. The respective values of Pb and Cr in water were 1.668 and 1.984 ppm, much higher than the maximum limits set by WHO/ FAO and KEBS of 0.010 and 0.050 ppm. The average value of Zn in soil was 0.415 ppm while Co, Mn and Cd had corresponding levels of 0.262, 1.491 and 0.117 ppm which were higher than the maximum set limits of 0.100, 0.100 and 0.003 ppm by WHO / FAO and KEBS. The average value of Cu in soil was 0.237 ppm while those for Pb and Cr were much higher at 1.820 and 5.005 ppm, respectively. The average level of N in water was 0.095 ppm while in soil was 0.118 ppm. The level of P in water was 0.063 ppm while in soil was 0.092 ppm. The results showed a general increasing trend in pollutant accumulation towards the lake hence posing a threat to aquatic life. Therefore, proper and continuous monitoring of pollutants should be done to avoid future dangers caused to the environment.
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.
Analysis of Constituent Chemicals and their Effects on the Physico-Chemical Properties of Spring Water in Ngariama location Gichugu Division Kirinyaga County of Kenya
(Journal of Natural Sciences, 2013-08) Ngari, Mwaniki; Wanjau, Tabitha; Njeru, Sospeter
Keywords: Ground water, Gichugu division has numerous springs, which are a manifestation of potentially high volumes of groundwater. This water is characteristically different from river water in terms of physical parameters like fizzling, characteristic taste and clarity chemistry was studied to explain the above differences. The study established that groundwater in Gichugu area is slightly a (pH 6.49), moderately hard (123.99 mg/l CaCO Cl-). These salts and the pH explained the taste of the water. Also, NaCl and other ionic compounds accounted for the relatively higher conductivity (4.700 Ec µS/cm) while such ions as Ca The percolation of this water through the surface soils of recharge areas generally results in significant purification hence clarity. Fizzling was as a result of dissolved gases such as carbon dioxide and oxygen as they escaped. It was also established that a common groundwater aquifer underlies the area. Iron (0.426 mg/1) and manganese (0.322 mg/1) were found in excess of WHO recommended limits (0.3 mg/1 and 0.1 mg/1 respectively) for potable water quality while fluoride was in relatively low amounts (0.642 mg/1). However, their levels in this water do not make this water unsuitable for drinking since they are still within the acceptable tolerance levels.
DETERMINATION OF SELECTED HEAVY METALS POLLUTANTS AND PHYSIO-CHEMICAL PARAMETERS IN SEDIMENTS AND WATER: A CASE STUDY OF RIVER ATHI MACHAKOS COUNTY
(University of Eldoret, 2013-11) Kosgey, Johnstone
The study set out to evaluate the effect of industrial activities by analyzing selected heavy metals and physicochemical parameters of water. Chemical survey was conducted in 9 selected sites (potential polluting sites) along Athi river to determine the levels of heavy chemical elements; lead (Pb), Copper (Cu), chromium (Cr), Nickel(Ni) Cadmium(Cd) and to asses water quality based on physicochemical parameters. The variation in concentration of these metals in the water and sediments as well as other water quality parameters was a key factor to establish the pollution levels in different parts of the river. The recommended WHO procedures of water sampling and analyses were followed. Atomic absorption spectrometry analytical technique was used in the determination of the heavy metal levels dissolved in the water and sediments samples. The results obtained in water samples ranged from Pb( 0.23-0.54mg/L),Cu(0.0082-0.0163mg/L), Ni(0.00810.0284mg/L), Cr(0.1363-0.3255mg/L), Cd(0.0117-0.0240mg/L) and for sediment samples Pb(0.1277-0.3513mg/L), Cu(0.0607-0.1386mg/L),Ni(0.0191-0.0498mg/L), Cr(0.0692-0.1329mg/L) and Cd(0.0108-0.0428mg/L). The values recorded for physicochemical parameters were pH(6.5-7.4), TDS(109-136mg/L), COD(66-102mg/L), BOD(6-15mg/L) and conductivity(155-206 µs/cm). From the results it was evident that the water was heavily polluted and not fit for domestic, agricultural and industrial purposes. Four of the analyzed heavy metals Pb, Cr, Cd and Ni surpassed the recommended WHO maximum permissible limits (0.01mg/L), (0.01mg/L), (0.003mg/L) and (0.001mg/L) respectively. Lead and chromium had the highest levelss in both sediments and water while Cd and Ni had the lowest concentrations. A Kruskal-Wallis test which, was conducted for the mean heavy metal concentrations, BOD, pH, Conductivity, TDS and COD to determine the significant difference of these water quality parameters in the nine different sampling locations showed significant differences between heavy metals in water and sediments and heavy metals in different stations(p<0.05). ANOVA test on pH did not reveal any significant difference (p<0.05) between the means of the various locations sampled and all results obtained fell within national and international standards of ESEPA/WHO. The BOD values were all higher than the normal BOD for unpolluted water of ≤ 2mg/L. The variation of electrical conductivity and TDS gradually decreased downstream with a slightly sharp rise at the middle of the sampling points; with observed TDS levels falling below the EPA's recommended maximum of TDS(500mg/L) in water. The COD values obtained were weak < 400mg/L.However, comparing all the observed values with the EPA regulations, the waters of this river is unsafe for domestic, industrial or agricultural use.
A review of the impacts of invasive aquatic weeds on the bio- diversity of some tropical water bodies with special reference to Lake Victoria (Kenya)
(Biodiversity Journal, 2013-12-30) Aloo, Peninah; Ojwang, William; Omondi, Reuben; Njiru, James Murithi; Oyugi, Dalmas
Aquatic weeds may be defined as troublesome or unsightly plants growing in abundance inaquatic situations where they are not wanted. These plants are either adapted to continuoussupplies of water or are at least tolerant to waterlogged soil conditions for substantial periodsof time. The wide range of adaptation to varying amounts of water, and the impossibility ofsharply distinguishing between aquatic and terrestrial environments, makes it difficult toprecisely define an aquatic plant. The menace of water weeds is reaching alarming proportions in many parts of the world, especially in tropical water bodies where they have led toserious ecological and economic losses. Lake Victoria, Kenya, which is the largest freshwaterbody in the tropics, has undergone serious ecological changes including over-exploitationof its fishery resources, degradation of the catchment area, introduction of exotic fish speciesand invasion by the water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae),among others. The presence of the weed in the lake has led to many problems includingblockage of water pumps, reduced fishing activities and increase in water borne diseasessuch as schistosomiasis. Positively, aquatic weeds constitute a free crop of great potentialvalue; they are a highly productive crop that requires no tillage, fertilizer, seed, or cultivation.Moreover, these plants have the potential for exploitation as animal feed, human food, sourceof food to some aquatic organisms, soil additives, fuel production, wastewater treatment,source of raw materials and habitat to many organisms. This paper reviews the effects ofaquatic weeds in aquatic systems with examples from some selected waterbodies and specialreference to Lake Victoria

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