Department of Biology

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    ASESSMENT OF PHYSICO-CHEMICAL AND BACTERIOLOGICAL QUALITY OF DRINKING WATER SUPPLY, STATUS OF SANITATION AND HYGIENE PRACTICES: THE CASE OF BISHAAN GURRACHA TOWN, WEST ARSI ZONE, OROMIA REGIONAL STATE, ETHIOPIA.
    (Hawassa University, 2024-05) MATIYAS AZAGE BETANE
    Access to safe drinking water and adequate sanitation is essential for safeguarding public health. This study aimed to assess the physicochemical and bacteriological quality of drinking water supply and evaluate sanitation and hygiene practices in Bishaan Gurracha town, located in the West Arsi zone of the Oromia region, Ethiopia. The methodology involved selecting water sources and households for sample collection, employing data collection instruments including household surveys, key informant interviews, focus group discussions, and direct observations. Laboratory analyses were conducted to measure various physicochemical parameters such as pH, turbidity, TDS, EC, alkalinity, nitrates, chlorides, free chlorine, heavy metals, and bacteriological indicators including total coliforms and fecal coliform. Sanitation coverage and hygiene practices were assessed using appropriate questionnaires to ensure data suitability for statistical analyses. The results indicated that most physicochemical water quality parameters met the standard values recommended by WHO/ESA, except for temperature and turbidity. Temperature ranged from 24.33°C to 26.17°C, and turbidity ranged from 5.62 NTU to 6.73 NTU. Total coliforms were present in all water samples from source water and household storage containers, with a significant number of samples also testing positive for fecal coliforms. The mean total coliform counts varied between 18 CFU/100ml to 101 CFU/100ml for source water and 16 CFU/100ml to 81 CFU/100ml for household storage water. These findings suggest potential deterioration in the untreated drinking water distribution system within Bishaan Guracha town, as the total coliform and fecal coliform counts exceeded the recommended standards set by national and WHO guidelines. Inadequate sanitation facilities in many homes pose significant health risks to the community in Bishaan Guracha town. The absence of proper toilets and improved sanitation systems increases the likelihood of fecal contamination, leading to the transmission of waterborne diseases such as diarrhea, cholera, and typhoid fever. Immediate interventions are therefore necessary, including decontamination of water sources, repair of distribution lines, expansion of sanitation infrastructure, and increased awareness of hygiene practices. It is recommended to regularly monitor water quality and encourage community participation in sustainable water, sanitation, and hygiene services.
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    ASSESSMENTS OF HOSPITAL SOLID WASTE MANAGEMENT: THE CASE OF SAINT PAULS MILLENNIUM MEDICAL COLLEGE’S HOSPITAL AND GIRUM HOSPITAL, ADDIS ABABA, ETHIOPIA
    (Hawassa University, 2024-05) FEKEDE GELETA HORA
    With an emphasis on the potential threats hospital solid waste poses to healthcare personnel, the public, and the environment if improperly managed, the study assessed the solid waste management practices at St. Paul's Millennium Medical College and Girum Hospital in Addis Ababa, Ethiopia. The study's objectives were to characterize the types, determine the generation rates, assess the KAP of the hospitals administrative and health care workers, and investigate the challenges and opportunities in hospital solid waste management’s of the study Hospitals. A cross-sectional study was undertaken to assess HCW management methods and generation rate using direct observation, interviews, questionnaire surveys, and weighing scales, with data analyzed using SPSS 22. The Government Hospital (St. Pauli's) generated 882.30±49.54 kg/day of total solid waste, with an average of 1.757 kg/patient/day (1.6 kg bed day‒1 and 0.157 kg/outpatient/day) of 61.25% being classified as hazardous waste, and the remaining 38.75% being general waste. The private hospital (Girum) produced 124.81±65.24 kg/day of total solid waste, with an average of 2.12 kg/patient/day (1.8 kg bed‒1day-1 and 0.32 kg/outpatient/day) of 57.05% being classified as hazardous waste, while the remainder, 42.795%, was general waste. High hazardous waste generation rates exceed the WHO's 10–25% estimate, primarily due to inadequate waste source segregation. The Kruskal-Wallis test showed significant differences in waste generation rates between hospitals for all the HCW categories (P < 0.05). However, no significant difference was found in the mean generation rate of the HCW within the government hospital wards as well as within the private hospital wards (P˃ 0.05). Ward chiefs, medical directors, and department heads all have high KAP scores; however, "hospital administrators have a medium, and waste handlers have a low." The KAP scores of the private hospital outperformed that of the government. St. Paul's intermediate storage area converts all forms of waste (excluding sharp waste) into hazardous waste. St. Paul's inadequate placenta disposal, as well as Girum Hospital's feeding all types of produced trash into a low-combustion incinerator, may have endangered both the population and the environment. Inefficient waste management is caused by a lack of legislation and failure to follow guidelines.
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    THE SYNERGISTIC ROLE OF ARBUSCULAR MYCORRHIZAL FUNGI, RHIZOBIUM INOCULATION, AND IN-FIELD RAINWATER HARVESTING TECHNIQUES IN GROWTH AND YIELD IMPROVEMENT OF MAIZE IN YIRBA DUWANCHO DISTRICT, SIDAMA REGIONAL STATE, ETHIOPIA.
    (Hawassa University, 2024-04) DINKNESH DIKALE
    Various climatic factors, such as temperature and rainfall variability, have a significant impact on rain fed agricultural productivity, especially in Ethiopia's water-stressed arid and semi-arid regions. The objective of this study was to assess the possible impact of arbuscular mycorrhizal fungus (AMF),Rhizobium® inoculation and in-field rain water harvesting system on maize (Zea mays) growth and production in a moisture-prone (low rainfall) location of Yirba duwancho village of Boricha woreda in Ethiopia. The experiment was laid out in a randomized complete block design (RBCD), with 8 treatments and 3 replication including the control. Consortia AMF inoculums and Rhizobia were used as bio-inoculants and a blended fertilizer in the form of NPSB was used as additional agricultural input. The highest height (140.6cm) growth was recorded for the maize-haricot bean intercropping treatment. This was followed by AMF+F (113.5cm) treatment. Stem collar diameter was bigger (1327mm) in maize-haricot bean intercropping followed by AMF+R (86.9mm). Records for Leaf area index, Shoot weight weight, Shoot dry weight, Root weight weight, and Root dry weight were inconsistent. The better (1853cm2) Leaf area index was recorded for R treatment. Shoot dry weight was better in AMF+R (830.6g) treatment. However, Root dry weight was higher (69.6g) in AMF+R+F treatment. Maize yield/plot and per hectare was higher for intercropping treatments followed by AMF+F and AMF+R respectively. For all control treatment was recorded the lowest values. Treatments on the Effect of the Suitability of In-field Rainwater Harvesting Technique with Respect to the Width of its Runoff Strips showed Application of Tide-Ride is the best technique to hold water in soil followed by IRWHI. The lower values were recorded for IRWH1.5 and the conventional broadcast treatment. This tells us the broader the width of runoff the least rain water retained in soil. Besides, better root colonization and spore density was recorded for intercropping followed by Sole AMF treatment, while mycorrhizal dependency and maize tissue nutrient uptake was much better in AMF+R treatment. However, in almost all cases the control treatment was inferior. Overall, results of this study suggest that mycorrhizal and rhizobium inoculation and application of infield rain water harvesting techniques enhances nutrient uptake and maximizes maize biomass under low soil moisture conditions. Mycorrhizal plants produced higher biomass, with greater tissue nutrient content than the control plants. These results indicate that establishing efficacious AMF and rhizobium with maize could be an efficient alternative for growers in drought prone areas than relying on fertilizer application and its associated costs and environmental concerns.
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    IMPACT OF LAND USE TYPE ON THE DIVERSTY AND ABUNDANCE OF ARBUSCULAR MYCORRHIZAL FUNGI IN LOKA ABYA, SIDAMA REGIONAL STATE, ETHIOPIA
    (Hawassa University, 2024-04) DILGASA TUSHURA
    Arbuscular mycorrhizal fungi play a crucial role in plant health by enhancing nutrient uptake, improving soil structure, and supporting ecosystem stability.This study investigates the role of AMF in the soil-plant interactions across different land-use types in Loka Abaya Woreda, Sidama Region, Ethiopia.The study examines the influence of soil physicochemical properties and plant species diversity on AMF distribution, spore density, and root colonization in agroforestry, natural forests, and cash crop systems.Soil characteristics, including pH, nitrogen, phosphorus, organic carbon, electrical conductivity, and texture, were analyzed across four land-use systems: agroforest, natural forest, cash crop, and grassland, revealing significant variation among different plant species. The soils were slightly acidic to neutral, with pH values ranging from 5.73 to 7.56 and phosphorus concentrations varying from 0.0100 mg/g to 0.3120 mg/g. Plant diversity was assessed using random sampling, resulting in the collection of 414 soil samples. Root colonization rates varied significantly, with Citrus sinensis exhibiting the highest colonization in field soil (94.5%), while Ehretia cymosa Thonn and Euphorbia abyssinica showed lower rates. In natural forests, Lennea schimper had 100% colonization, while Dodonaea angustifolia L.f. exhibited the lowest (84%). AMF colonization and spore densities were generally higher in trap cultures compared to field soils, with the highest spore densities in Psidium guajava (2251 spores/100 g) and Balanites aegyptiaca (1228 spores/100 g). Cash crops like Coffee arabica showed 100% AMF colonization and the highest spore density (838 spores/100 g in field soil). AMF analysis was conducted using Pearson's correlation, with data processed using SPSS software version 24.The study identified 30 AMF morphospecies from eight genera, with five genera Glomus, Acaulospora, Claroideoglomus, Enterophospora, and Rhizophagus intraradices showing significantly higher spore production, contributing 43.50%, 32.33%, 8.46%, 4.23%, and 3.62% of the total spore count, respectively. Notably, no single AMF species dominated across all land-use types, but four species Glomus sp.2, Claroideoglomus sp.1, Glomus mosseae, and Acaulospora sp.2 were commonly found, highlighting their ecological significance. The study found a positive correlation between spore density, root colonization, organic carbon, and nitrogen levels, while high phosphorus and soil pH negatively impacted AMF abundance. These findings emphasize the importance of agroforestry and natural forests in maintaining AMF diversity and enhancing soil health. The study recommends further research into AMF dynamics, particularly across different seasons and with molecular techniques, to enhance the understanding and application of AMF in agricultural systems.
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    Characterization, Symbiotic Effectiveness and Host range of Alfalfa Nodulating Rhizobia Isolated from Soils of Selected Kebele‘s in Hawella District, Sidama Regional State, Ethiopia.
    (Hawassa University, 2024-06) Bunamo Mitiku
    Feed shortage, low quality and seasonal fluctuations have constrained livestock production in Ethiopia. Using high-yielding, good quality and drought-tolerant forage legumes like alfalfa (Medicago sativa L.) has been suggested to overcome the feed constraints. Alfalfa is an important forage crop, which forms a symbiotic relationship with nodule-forming bacteria Sinorhizobum meliloti. The aim of this study was to characterize and evaluate the symbiotic effectiveness and host range of rhizobia isolated from smallholder farmers’ fields in Hawella District, Sidama Regional State of Ethiopia using Alfalfa as a trap plant. To this end, a total of 12 bacterial isolates were trapped from different soil samples. The isolates showed differences in various presumptive, cultural, biochemical characteristics and physiological tolerances. Six (50 %) of the isolates( ANR 9, ANR 8, ANR 2, ANR 1, ANR 5 and ANR 11) could nodulate alfalfa with significant difference (P<0.05) in their capacity to infect and effectively fix nitrogen as evidenced from variations in nodulation parameters, shoot dry weights and shoot length. Accordingly, the isolates induced nodulation with nodule number ranging from 25.67 (ANR 9) to 9.00 (ANR 11) nodule per plant; nodule dry weight of 0.07 mg per plant (ANR 9) to 0.03 mg per plant (ANR 11); shoot dry weight ranging between 0.96 (ANR 9) and 0.17 (ANR 4) mg per plant and shoot length ranging from 30.50 (ANR 9) cm -11.47 (ANR 4) cm per plant. Using shoot dry weight as an indicator of the relative effectiveness, it was found that 33.3% of the isolates were highly effective (SE > 85 %) and 8.3 % were effective (SE ranging from 55 to 85 %) on alfalfa. Furthermore, the isolates showed broad host ranges on three legume species, namely, faba bean (Vicia faba), common bean (Phaseolus vulgaris), and lentil (Lens culinaris). All the six isolates (100 %) formed nodules with effective nitrogen fixation in faba bean, common bean and lentils exhibiting varying levels of effectiveness. Five of the six rhizobial isolates, ANR 9, ANR 8, ANR 2, ANR 1 and ANR 5 exhibited high N2-fixation efficiency and are recommended for further evaluation to use them as inoculants for different legumes. We also recommend these isolates for molecular characterization to determine their phylogeny and taxonomic classes.
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    GROWTH RESPONSES OF TOMATO (SOLANUM LYCOPERSICUM L.) TO INOCULATION OF ARBUSCULAR MYCORRHIZAL FUNGI AND TRICHODERMA HARZIANUM AND APPLICATIONS OF BIOCHAR AND COMPOST IN THE PRESENCE OF FUSARIUM OXYSPORUM FORMAE SPECIALES LYCOPERSICI UNDER GREEN HOUSE, HAWASSA UNIVERSITY, ETHIOPIA
    (Hawassa University, 2024-03) BELETECH HABTE AWANO
    Tomatoes (Solanun lycopersicum) are one of the most widely cultivated vegetable crops in Ethiopia. Tomato yields in smallholder cropping systems are below the potential of the crop, due to pests and diseases. Therefore, the objective of this research is to study the effect of inoculation of Arbuscular mycorrhizal fungi (AMF) and Trichoderma harzianum and compost and biochar amendments on tomato biomass, fruit yield and control of Fusarium oxysporum f. sp. lycopersici pathogen under Hawassa University greenhouse. The plants were grown in plastic pots filled with sterilized soils, arranged in a fourteen treatments including the control. A completely randomized design was used and growth measurements and disease severity assessment were taken after 15, 30, and 45 days of transplantation for all growth parameters including fruit yield and effect of the pathogen were measured. During early days of growth for treatments AMF+Fusarium and AMF+Trichoderam was recorded the highest height, leaf area and stem collar diameter for Galilea variety and variable values for ROMA V.F.N variety. When compared to plants treated with F.oxysporum f.sp.l alone and control, improvement in the various growth parameters was recorded in the plants treated with AMF, T. harzianum, biochar, and compost sole and combined. Better fruit yield and pathogen resistance was recorded for Roma variety. In addition to growth parameters all AMF inoculated treatments demonstrated root colonization, and sporulated. Nutrient uptake was enhanced in all treatments except for sole Fusarium and control treatments. Mycorrhizal dependency was better for sole AMF inoculation treatment in both varieties. Disease severity was lower in ROMA variety while Galilea variety was found to be more susceptible to Fusarium pathogen. Accordingly, significant fruit loss was recorded for Galilea variety. AMF and Trichoderma inoculation and application of biochar and compost has improved performance of the two tomato varieties. In addition, it was recorded that ROMA variety is much more resistant to Fusarium pathogen as inoculated with the two bio inoculants, which indicates that different varieties show different resistance to Fusarium pathogen. Therefore, when growing tomato it is recommended to select the appropriate bio pesticides like that of AMF and T. harzianum and appropriate variety of tomatoes. Finally, as this study focused on only two tomato varieties and two bio-inoculants, wide coverage of other bacterial and fungal inoculants production and application in the small holder farms is also recommended.
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    ISOLATION, CHARACTERIZATION AND EVALUATION OF SYMBIOTIC EFFICIENCY OF INDIGENOUS RHIZOBIA FROM TRAP CULTURES IN BORICHA AND LOKKA ABAYA DISTRICT, SIDAMA REGION, ETHIOPIA
    (Hawassa University, 2024-11) WAKWAYYA AMSALE
    The excessive use of chemical fertilizers to boost crop yields has significant environmental drawbacks, including soil degradation, water contamination, and greenhouse gas emissions. Additionally, these fertilizers are often costly, making them inaccessible to many smallholder farmers. Leguminous crops play a crucial role in sustainable agriculture, contributing to soil fertility and crop productivity through their symbiotic relationship with rhizobia, which fix atmospheric nitrogen. Identifying and utilizing effective indigenous rhizobia is vital for improving legume yields, as these microorganisms are well-adapted to local environmental conditions, offering a cost-effective and eco-friendly alternative to chemical fertilizers. This study was aimed at isolation and characterization of indigenous rhizobia from soils in Boricha and Lokka Abaya districts in Sidama, Ethiopia, using groundnut and chickpea plants as a trapping host. Fourteen rhizobial isolates were successfully obtained after presumptive and authentication tests. All isolates tolerated alkaline conditions at pH 8, with 10 showing acid tolerance at pH 4. Most isolates grew at pH 5, except NiG2, NiG8, and NiC12, while nine tolerated pH 10. None of the isolates grew at pH 11. Notably, NiG8 was the only isolate capable of solubilizing tri-calcium phosphate. In metal resistance assessments, most isolates demonstrated growth on YEMA medium with aluminum, copper, and zinc, with 10 showing tolerance. Eight isolates exhibited resistance to manganese, and six to cobalt, while only NiG5, NiG8, and NiC12 tolerated mercury. Host range tests revealed significant host specificity and variability; Eight isolates nodulated soya bean effectively, six nodulated the common bean variety "Tafach," seven the "Nasir" variety, and five were effective on fava bean. No isolates nodulated lentil. Further analysis of symbiotic effectiveness showed significant differences (p<0.05) in nodule number, nodule dry weight, and shoot dry weight in fava bean, soya bean, groundnut, Tafach and Nasir. Most isolates exhibited high symbiotic effectiveness, often surpassing the nitrogen control and commercial inoculants. Isolates NiC4 and NiC7 demonstrated high effectiveness on chickpea, with values of 129% and 99.1%, respectively. On groundnut, NiG3 and NiG8 reached 103.4% effectiveness, with NiG6 also achieving 120% on the "Tafach" variety. For variety Nasir NiG6 showed 118.9% effectiveness, and NiG10 recorded 95.9%. These findings highlight the diversity and potentials of indigenous rhizobia to enhance legume productivity and soil fertility.
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    STUDIES ON THE REPRODUCTIVE BIOLOGY AND FEEDING HABITS OF SOME FISH SPECIES AND DETERMINATION OF SOME PHYSICO-CHEMICAL CHARACTERISTICS OF LAKE BOYO, ETHIOPIA
    (Hawassa University, 2024-11) TAMIRAT HANDAGO SADE
    Lake Boyo is among the few neglected and unexplored small lakes in the Central Ethiopian Rift Valley Region. It is a shallow and turbid lake with surface area of 3.2 square kilometres and surrounded by wetland. Three fish species are known to exist in the lake, namely Nile Tilapia Oreochromis Niloticus (Linnaeus, 1758), the straightfin barb Enteromius paludinosus (Peters 1852) and the lapping minnow Garra quadrimaculata (Rüppell, 1835). Neither fishery activity nor fishery research has ever been conducted so far in Lake Boyo. This research was conducted to provide baseline information on some aspects of the reproductive biology and feeding habits of fish species, and physicochemical characteristics of the lake. All the data for this study were collected and analyzed using standardized methods and sampling techniques. For the analysis of reproductive biology and feeding habits, samples of the three fish species were collected from two sites (littoral and open) of the eastern part of the lake from May 2021 to May, 2022 using gill nets of 6, 8, and 10 cm mesh size and a beach seine of 6 mm mesh size. A total of 379 O. niloticus, 513 E. paludinosus, and 290 G. quadrimaculata samples were examined. The water samples for the analyses of physicochemical parameters were collected from two selected sampling sites (littoral and open water area) in wet months (June to September), and dry months (October to December) of 2022. The three fish species breed throughout the year and showed a bi-modal major and minor breeding period. The first peak breeding months occur from February to March and the second minor peak from July to September for O. niloticus, whereas the main breeding season for E. paludinosus was between October and January with a less pronounced reproductive period between March and April. On the otherhand, the first peak breeding period was from June to September and the second peak from January to February for G. quadrimaculata. The fecundity of O.niloticus ranged from 216 to 1,157 eggs per fish while it ranged from 1,078 to 9,683 eggs per fish for E. paludinosus. The result of length at first maturity (Lm50) depicted that the fishes reached sexual maturity at a smaller size and shows early maturity of all the fish species in the lake. The results of the analysis of sex ratio for the fish species examined showed that the distribution of male and female fishes in the lake was not significantly different from the hypothetical 1:1(Male: Female) ratio for O. niloticus and E. paludinosus (1:0.92, p>0.05 and 1:1.03, p>0.05, respectively), while it was significantly different for G. quadrimaculata (1: 0.73, p<0.05). The results of the length weight relationship (LWR) of the fish species suggested a curvilinear relationship (R2= 0.9911, 0.9812 and 0.9766 for O.niloticus, E. paludinosus and G. quadrimaculata, respectively) and, a positive allometric growth pattern (b= 3.1268 and 3.1042 for O.niloticus, E. paludinosus, respectively) while nearly isometric growth pattern (b= 2.977) for G. quadrimaculata. The result of Fulton`s conditon factor (FCF) for the fish species revealed that O.niloticus and E. paludinosus had moderate body condition (FCF= 1.73 and 1.77 for males and females of O.niloticus, respectively, and 1.21 and 1.27 for males and females of E. paludinosus, respectively), while it was low for G. quadrimaculata (FCF= 0.011 and 0.0112 for males and females, respectively). The feeding habits of the fish species showed that the fishes feed on a variety of food items including detritus, phytoplankton, macrophytes, insects and zooplankton and they are ominivorous in their feeding habits. Detritus was the main food item for the fish species in general. The fishes showed seasonal variations in feeding habits during the dry and wet months. From these results it was concluded that the fishes are omnivorous in Lake Boyo. The results of the physical and chemical features of the lake shows that the lake water was slightly warm, alkaline, contained more TDS and EC, very turbid, low transparency and with relatively high inorganic nutrients (NO3- and PO4 3-) which support most of the aquatic life. Generally, based on the results it is concluded that Lake Boyo is a low productive inland freshwater ecosystem in the Ethiopian Rift Valley basin. The high amount of detritus in the stomachs/guts of the fishes and lower condition factor of the fish with reference to other lakes indicate that productivity of Lake Boyo is low. Further research is recommended on macrophyte, phytoplankton and zooplankton composition, biomass and productivity of Lake Boyo.
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    ASSESSMENT ON COMMUNITY AWARENESS AND PRACTICES TO INDOOR AIR POLLUTION IN JIMMA TOWN AND SURROUNDING RURAL KEBELES, OROMMIA REGIONAL STATE, ETHIOPIA
    (Hawassa University, 2024-11) HARUNE ABAFOGI
    Most households in Africa including Ethiopia still use biomass fuel to cooking their food and for heating in poorly ventilated houses. Indoor air pollution (IAP) is the presence of one or more contaminants in the indoor environment that has a degree of human health risk. The main objective of this study was to investigate community perception and level of community awareness towards IAP in Jimma town and surrounding rural kebele. Cross-sectional research design was used to achieve the study. Structured questionnaires, FGD and household observation were used as the data collection tools. Representative samples 360 households were included by systematic random sampling. Data were analyzed by SPSS both bivariate correlation and logistic regression was applied for the statistical test. The results majority of respondents (74.45%) the main source of energy for cooking was fire wood (88.6%) and charcoal (74.4), traditional type of stoves was made of cooking by majority (88.6%), in average (71.9%) respondents were aware of the source of IAP, most of (72.5%)household the two social groups were aware of the route of exposure and effects of IAP, largely (84.4%) respondents knew that exposure to IAP can affect human health and cause diseases, and lastly average (57.9%) of respondents knew that to reduce and prevent IAP. Majority (98.6%) of the respondents thinks that using cooking fuel that emits less smoke could prevent IAP. Other preventive mechanisms reported include: prohibiting cigarette smoking in living houses (98.0%), cooking always outside living houses (94.6%), avoiding living with domestic animals (95.2%) and keeping windows/doors open most of the time (91.2%). The households in this study had (71.9%) good awareness about the source of IAP, adverse health effects of IAP exposure and preventing measures of these adverse health effects, however, (84.4%) majority of them were still living with the risk factors associated with IAP in their daily living. There is need to provide education/awareness creation regarding air quality and its effects on health would be important and this can be implemented through community-based organizations that have wide acceptance in the study communities.
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    ECOLOGICAL AND HUMAN HEALTH RISK ASSESSMENTS BASED ON HEAVY METAL AND PESTICIDE RESIDUES IN SOIL AND VEGETABLES AROUND LAKE ZIWAY, ETHIOPIA
    (Hawassa University, 2024-09) ASRAT FEKADU DEMSIE
    The excessive use of pesticides can lead to harmful residues accumulating in vegetables, posing risks to human health. Therefore, regular monitoring and assessment of these potential health hazards are crucial. This study utilized the QuEChERS extraction method to analyze 15 composite samples (vegetables and soil). It employed an inductively coupled plasma optical emission spectrometer (ICP-OES) to detect heavy metal contamination in 18 composite samples of vegetables and soil. The findings revealed that some pesticide residues exceeded safety limits in tomatoes and onions. In tomatoes, α-endosulfan (0.58 mg/kg), β-BHC (beta-benzene hexachloride) (0.04 mg/kg), heptachlor (0.02 mg/kg), and Malathion (0.03 mg/kg) surpassed safety limits. Similarly, the average concentrations of heptachlor epoxide (0.04 mg/kg) and propargite (0.11 mg/kg) exceeded safety limits for onions. The study also evaluated potential health risks for adults and children, identifying both carcinogenic and non-carcinogenic risks. Non-carcinogenic health risk estimates indicated that onion heptachlor epoxide posed a systemic health risk for adult and child consumers with THQ (Target hazard quetient) > 1. Carcinogenic health risks (CHRs) revealed that heptachlor epoxide was present in levels exceeding acceptable limits (10–4) for both adults and children, while the CHRs of tomatoes and onions surpassed acceptable limits only for children. Additionally, heavy metal contamination of vegetables presents a significant concern, especially in areas with prolonged irrigation. The excessive use of agrochemicals particularly impacts the central region of the Rift Valley in Ethiopia. In a study of a soil-vegetable system irrigated by Lake Ziway in Ethiopia, researchers analyzed the levels of nine heavy metals (As, Cd, Cr, Co, Cu, Hg, Ni, Pb, and Zn). The analysis revealed that the concentrations of lead (Pb), arsenic (As), mercury (Hg), and chromium (Cr) in all tomato and onion samples exceeded the thresholds set by the FAO/WHO. In addition, the average ix concentrations of Zn, Pb, Cd, and Hg in all soil samples under tomato and onion plants were found to be above the recommended levels. This poses significant health risks, including systemic and cancerous effects. Moreover, traditional farming methods in the region were found to pose a high ecological risk to non-target soil species due to the use of common pesticides. The study aimed to assess the ecological risks that pesticides could pose to soil biotas, such as earthworms, springtails, and nitrogen mineralization organisms. The evaluation was based on the use of toxicity exposure ratios (TERs) and risk quotient (RQ) methodologies to determine general and worst-case scenarios, respectively. Of the detected pesticides, α-BHC, heptachlor, fenthion, parathion, and propoxur were detected at a rate of 100%. The highest concentration of 119.9 μg/kg was found for p,p'-DDE. Fenthion and Chlorpyrifos methyl posed a chronic exposure risk to F. candida (TERmax=0.86) and N mineralization organisms (TERmax=1.2), respectively. Non-target soil species are at high ecological risk (RQs > 1) due to Alpha endosulfan, which contributes to more than 90% of the risk than the other pesticides. The ecological risk assessment (ERA) reported that the overall pesticide mixture in soil poses a high ecological risk ∑RQ=5.3 in both scenarios. Conventional farming practices in the study area put soil organisms at risk. Therefore, it is crucial to establish effective monitoring protocols and raise awareness among stakeholders to ensure the preservation of the environment and the population's well-being. Furthermore, replacing harmful pesticides with low-risk alternatives is recommended to mitigate these risks. Urgent policies for awareness and surveillance are necessary to protect public health within and beyond the research field.