Determination of essential and heavy metals in Kenyan honey by atomic absorption and emission spectroscopy

Due to the nutritive and medicinal value of honey for both man and animals, qualitative and quantitative analyses of the minerals is of great importance. Heavy metals and high concentration of essential metals can be toxic both to man and animals. Rapid increase in industrialisation in Kenya has led to environmental pollution, hence increase of these metals in honey. In this project, honey samples collected from different parts of Kenya, namely, Laikipia, Baringo, Nairobi, Ngong, Mbeere, Embu, Kitui, Kibwezi and Lamu were analysed to determine the levels of selected heavy metals (Pb, Cd, Zn, Cu, As) and essential metals (K, Na, Ca, Mg, Fe). The samples were analysed using flame atomic absorption spectroscopy (FAAS) and flame atomic emission spectroscopy (FAES). Hydride generation -atomic absorption spectroscopy (HG - AAS) was used to determine  arsenic. Results obtained from this study showed that K, Na, Ca and Mg had mean values ranged from 781.52±0.09 to 172.83±0.02 ppm, 269.1 to 98.04±0.03 ppm, 70.17±3.9 ppm to 19.33±4.07 ppm and 41.88 ±0.92 to 12.64 ±0.43 ppm respectively. Most of the samples had a high level of Zn with mean value 0.19±0.06 ppm followed by Pb with of mean value  0.16±0.10 ppm, then Cu with a mean value of 0.02±0.01 ppm followed by Cd with a mean value of 0.02±0.01ppm and finally As with a mean value of 0.01±0.01 ppm. The concentration of Pb in most samples was found to be above the World Health Organisation (WHO) and Kenya Bureau of Standards (KEBS) limits of 0.1 ppm in food products

Biosorption of Selected Heavy Metals by Green Algae, Spirogyra Species and Its Potential as a Pollution Biomonitor

In this paper, adsorption features of freshwater green algae as a function of contact time, initial pH and initial metal ion concentrations were studied using model solutions of metal ions with subsequent determination by flame atomic absorption spectrometry (FAAS). Green algae samples were employed as bioindicators of selected heavy metals in environmental water samples with determination using FAAS and ICP-OES (inductively-coupled plasma-optical emission spectrometry). The optimum pH for cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) biosorption were found to be 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process follows second order kinetics and is well described by the Langmuir isotherm model. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 mg/L. Biomonitoring studies revealed great potential for freshwater green algae as a bioindicator with mean concentration factors in the range of 367-7154 for the selected elements, the uptake being mainly via a metabolically mediated pathway. This work has demonstrated the potential of freshwater green algae as both a biosorbent and a bioindicator for heavy metal pollution in water systems. Keywords: Green algae, Biosorption, Biomonitoring, Toxic metals, FTIR, ICP-OES

Determination of Physico-Chemical Properties Of Sources of Water In Narok North Sub-County, Kenya

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Frequency and impact of suboptimal immune recovery on first-line antiretroviral therapy within the International Epidemiologic Databases to Evaluate AIDS in East Africa

OBJECTIVE: To describe patterns of suboptimal immune recovery (SO-IR) and associated HIV-related-illnesses during the first 5 years following first-line antiretroviral therapy (ART) initiation across seven ART sites in East Africa. DESIGN: Retrospective analysis of data from seven ART clinical sites (three Uganda, two Kenya and two Tanzania). METHODS: SO-IR was described by proportions of ART-treated adults with CD4 cell counts less than 200, less than 350 and less than 500 cells/μl. Kaplan-Meier survival analysis techniques were used to assess predictors of SO-IR, and incident rates of HIV-related illnesses at CD4 cell counts less than 200, 200-350, 351-499, and >500 cells/μl, respectively. RESULTS: Overall 80 843 adults initiated non-nucleoside reverse transcriptase inhibitor-based first-line ART; 65% were women and median CD4 cell count was 126 [interquartile range (IQR), 52-202] cells/μl. Cumulative probability of SO-IR <200 cells/μl, <350 cells/μl and <500 cells/μl, after 5 years, was 11, 38 and 63%, respectively. Incidence of HIV-related illnesses was higher among those with CD4 cell counts less than 200 and 200-350 cells/μl, than those who achieved CD4 counts above these thresholds. The most common events, at CD4 < 200 cells/μl, were pulmonary tuberculosis [incident rate 15.98 (15.47-16.51)/100 person-years at risk (PYAR), oral candidiasis [incident rate 12.5 (12.03-12.94)] and herpes zoster [incident rate 6.30 (5.99-6.64)] events/100 PYAR. With attainment of a CD4 cell count level 200-350 cells/μl, there was a substantial reduction in events/100 PYAR - by 91% to 1.45 (1.29-1.63) for TB, by 94% to 0.75 (0.64-0.89) for oral candidiasis, by 84% to 0.99 (0.86-1.14) for Herpes Zoster, and by 78% to 1.22 (1.07-1.39) for chronic diarrhea. The incidence of all events decreased further with CD4 counts above these thresholds. CONCLUSION: Around 40% of adults initiated on ART have suboptimal immune recovery with CD4 counts <350 cells/μl after five years. Such patients will require closer monitoring for both HIV-related and non-HIV-related clinical events

Larval habitats of Anopheles gambiae s.s. (Diptera: Culicidae) influences vector competence to Plasmodium falciparum parasites

<p>Abstract</p> <p>Background</p> <p>The origin of highly competent malaria vectors has been linked to productive larval habitats in the field, but there isn't solid quantitative or qualitative data to support it. To test this, the effect of larval habitat soil substrates on larval development time, pupation rates and vector competence of <it>Anopheles gambiae </it>to <it>Plasmodium falciparum </it>were examined.</p> <p>Methods</p> <p>Soils were collected from active larval habitats with sandy and clay substrates from field sites and their total organic matter estimated. <it>An. gambiae </it>larvae were reared on these soil substrates and the larval development time and pupation rates monitored. The emerging adult mosquitoes were then artificially fed blood with infectious <it>P. falciparum </it>gametocytes from human volunteers and their midguts examined for oocyst infection after seven days. The wing sizes of the mosquitoes were also measured. The effect of autoclaving the soil substrates was also evaluated.</p> <p>Results</p> <p>The total organic matter was significantly different between clay and sandy soils after autoclaving (P = 0.022). A generalized liner model (GLM) analysis identified habitat type (clay soil, sandy soil, or lake water) and autoclaving (that reduces presence of microbes) as significant factors affecting larval development time and oocyst infection intensities in adults. Autoclaving the soils resulted in the production of significantly smaller sized mosquitoes (P = 0.008). Autoclaving clay soils resulted in a significant reduction in <it>Plasmodium falciparum </it>oocyst intensities (P = 0.041) in clay soils (unautoclaved clay soils (4.28 ± 0.18 oocysts/midgut; autoclaved clay soils = 1.17 ± 0.55 oocysts/midgut) although no difference (P = 0.480) in infection rates was observed between clay soils (10.4%), sandy soils (5.3%) or lake water (7.9%).</p> <p>Conclusion</p> <p>This study suggests an important nutritional role for organic matter and microbial fauna on mosquito fitness and vector competence. It shows that the quality of natural aquatic habitats of mosquito larvae may influence malaria parasite transmission potential by <it>An. gambiae</it>. This information can be important in targeting larval habitats for malaria control.</p

Lessons Learned Developing a Diagnostic Tool for HIV-Associated Dementia Feasible to Implement in Resource-Limited Settings: Pilot Testing in Kenya

Objective: To conduct a preliminary evaluation of the utility and reliability of a diagnostic tool for HIV-associated dementia (HAD) for use by primary health care workers (HCW) which would be feasible to implement in resource-limited settings. Background: In resource-limited settings, HAD is an indication for anti-retroviral therapy regardless of CD4 T-cell count. Anti-retroviral therapy, the treatment for HAD, is now increasingly available in resource-limited settings. Nonetheless, HAD remains under-diagnosed likely because of limited clinical expertise and availability of diagnostic tests. Thus, a simple diagnostic tool which is practical to implement in resource-limited settings is an urgent need. Methods: A convenience sample of 30 HIV-infected outpatients was enrolled in Western Kenya. We assessed the sensitivity and specificity of a diagnostic tool for HAD as administered by a primary HCW. This was compared to an expert clinical assessment which included examination by a physician, neuropsychological testing, and in selected cases, brain imaging. Agreement between HCW and an expert examiner on certain tool components was measured using Kappa statistic. Results: The sample was 57 % male, mean age was 38.6 years, mean CD4 T-cell count was 323 cells/mL, and 54 % had less than a secondary school education. Six (20%) of the subjects were diagnosed with HAD by expert clinical assessment. The diagnostic tool was 63 % sensitive and 67 % specific for HAD. Agreement between HCW and expert examiners was poor for many individual items of the diagnostic tool (K =.03–.65). This diagnostic tool had moderate sensitivity and specificity fo

Population-Based Biochemistry, Immunologic and Hematological Reference Values for Adolescents and Young Adults in a Rural Population in Western Kenya

BACKGROUND: There is need for locally-derived age-specific clinical laboratory reference ranges of healthy Africans in sub-Saharan Africa. Reference values from North American and European populations are being used for African subjects despite previous studies showing significant differences. Our aim was to establish clinical laboratory reference values for African adolescents and young adults that can be used in clinical trials and for patient management. METHODS AND FINDINGS: A panel of 298, HIV-seronegative individuals aged 13-34 years was randomly selected from participants in two population-based cross-sectional surveys assessing HIV prevalence and other sexually transmitted infections in western Kenya. The adolescent (/=18 years) ratio and the male-to-female ratio was 1ratio1. Median and 95% reference ranges were calculated for immunohematological and biochemistry values. Compared with U.S-derived reference ranges, we detected lower hemoglobin (HB), hematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), neutrophil, glucose, and blood urea nitrogen values but elevated eosinophil and total bilirubin values. Significant gender variation was observed in hematological parameters in addition to T-bilirubin and creatinine indices in all age groups, AST in the younger and neutrophil, platelet and CD4 indices among the older age group. Age variation was also observed, mainly in hematological parameters among males. Applying U.S. NIH Division of AIDS (DAIDS) toxicity grading to our results, 40% of otherwise healthy study participants were classified as having an abnormal laboratory parameter (grade 1-4) which would exclude them from participating in clinical trials. CONCLUSION: Hematological and biochemistry reference values from African population differ from those derived from a North American population, showing the need to develop region-specific reference values. Our data also show variations in hematological indices between adolescent and adult males which should be considered when developing reference ranges. This study provides the first locally-derived clinical laboratory reference ranges for adolescents and young adults in western Kenya

Spatial Ambient Air Quality Analysis and Its Effects on the Traffic Police Officers Within the Central Business District in Nairobi, Kenya

Every person in Kenya is entitled to a clean and healthy environment. This includes access to the various public elements or segments of the environment for recreational, educational, health, spiritual and cultural purposes. As a practice, the traffic police officers (TPO’s) spend most of their time on the road controlling traffic a routine that exposes them to automobile emissions. This study was therefore carried out to investigate the levels of exposure to automobile emissions and to determine the health effects of exposure. Emissions of carbon monoxide (CO), carbon dioxide (CO2) and oxides of nitrogen (NOx) from vehicles in the Central Business District in Nairobi were sampled. A gas aspiration pump AP-20 together with detector tubes were used to determine the levels of NOx, CO emissions while Testo 435 multi-function measuring instrument was used to determine CO2 levels, wind velocity and temperature at ten purposely selected sites within the Central Business District. The results showed that CO2, CO and NOx sampled had means of 634.80 parts per million (ppm), 12.74 ppm and 2.56 ppm respectively. These results demonstrated that the TPO’s were exposed to CO, CO2 and NOx levels that were above the recommended occupational exposure limits-control limit for the gases according to Legal Notice No. 60 of 2007 (GOK, 2007)