Okumu, MO, Mbaria JM, Gikunju JK, Mbuthia PG, Madadi VO, Ochola FO, Maloba KN, Nderitu JG.  2022.  Preclinical efficacy testing of three antivenoms against Naja ashei venom-induced lethality. Toxicon: X 14 (2022) 100124. .
Sherida, WP, Vincent MO, O WS, Duke Gekonge Omayio, Okumu MO.  2022.  Estimation and human health risk assessment of organochlorine and organophosphate pesticide residues in raw milk collected in Kenya. Research. .


Okumu, MO, Mbaria JM, Gikunju JK, Mbuthia PG, Madadi VO, Ochola FO, Jepkorir MS.  2021.  Artemia salina as an animal model for the preliminary evaluation of snake venominduced toxicity. Toxicon. DOI:
Mungai, GN, Njenga HN, MATHU ELIUDM, Madadi VO.  2021.  Trace Elements in Carbonated Cold Springs of Eastern Mt. Kenya, Meru County. Journal of the Kenya Chemical Society. 14(1):9-16.
Osoro, EM, Wandiga SO, Madadi VO, Abong’o DA.  2021.  Occurrence and Distribution of Polybrominated Diphenyl Ethers in Sediments from Nairobi River Basin, Kenya, East Africa. International Journal of Scientific Research in Science, Engineering and Technology. 8(1):274-286.PrintISSN:2395-1990|OnlineISSN:2394-4099.doi:


Mwenda, JN, Wandiga SO, Kariuki DK, Madadi VO.  2020.  Degradation of aflatoxin in maize using Ferulic acid (phydroxy-3-methyl cinnamic acid) catalyzed by Hydrogen peroxide. Journal of Food Sciences. 1(1):1-17.
Mungai, GN, Njenga HN, MATHU ELIUDM, Madadi VO.  2020.  Origin of Carbon dioxide in Selected Mofette Springs in the Eastern Mt. Kenya Region and Associated Characteristics. Africa Journal of Physical Sciences. 5:48-62.
Mwenda, JN, Wandiga SO, Kariuki DK, Madadi VO.  2020.  Occurrence and Distribution of Aflatoxin in Maize from Selected Counties, Eastern Region, Kenya. Journal of Agricultural Policy. 3(2)
Okumu, MO, Mbaria JM, Gikunju JK, Mbuthia PG, Madadi VO, Ochola FO.  2020.  Enzymatic activity and brine shrimp lethality of venom from the large brown spitting cobra (Naja ashei) and its neutralization by antivenom. BCM Research Notes. 13(25):1-7.
Bohlin-Nizzetto, P, Melymuk L, B.White K, Kalina J, Madadi VO, SamAdu-Kumi, Prokeš R, Přibylová P, Klánová J.  2020.  Field- and model-based calibration of polyurethane foam passive air samplers in different climate regions highlights differences in sampler uptake performance. Atmospheric Environment. 238(117742)
Bauza, V, Madadi V, Ocharo R, Nguyen TH, Guest JS.  2020.  Enteric pathogens from water, hands, surface, soil, drainage ditch, and stream exposure points in a low-income neighborhood of Nairobi, Kenya. Science of The Total Environment. 709:135344. AbstractScience of The Total Environment

Child exposure to fecal-oral pathogens occurs through several transmission pathways. However, the relative importance of different exposure points for pathogen transmission both inside and outside households is not well understood. We conducted a cross-sectional study in the urban slum of Kibera in Nairobi, Kenya, collecting 237 environmental samples from 40 households from source water, stored drinking water, caregiver hands, child hands, household surfaces, soil, standing water, open drainage ditches, and streams. We quantified the fecal indicator Escherichia coli and the enteric pathogens of adenovirus, Campylobacter jejuni, Shigella spp./enteroinvasive E. coli (EIEC), and Vibrio cholerae. At least one enteric pathogens was detected in 13% of household stored water, 47% of hand, 46% of table surface, 26% of plate surface, 75% of floor surface, 96% of soil, 56% of standing water, 77% of drainage ditch …


Bauza, V, Madadi V, Ocharo RM, Nguyen TH, Guest JS.  2019.  Microbial source tracking using 16S rRNA amplicon sequencing identifies evidence of widespread contamination from young children’s feces in an urban slum of Nairobi, Kenya. Environmental science & technology. 53(14):8271-8281. AbstractEnvironmental science & technology

Child exposure to fecal contamination remains common in low- and middle-income countries after sanitation interventions. Unsafe disposal of children’s feces may contribute to this continued exposure, but its relative importance to domestic fecal contamination is not well understood. To address this gap, we interviewed and collected environmental samples (drinking water, caregiver hands, child hands, surfaces, soil, open drainage ditches, standing water, streams) from 40 households in Kibera, an urban slum in Nairobi, Kenya. To track young children’s feces (<3 years old) separately from other human-associated fecal sources, we validated distance-based and Bayesian (SourceTracker) microbial source tracking methods using amplicon-based sequencing of the 16S rRNA gene. Contamination by young children’s feces could be identified and distinguished separately from older child/adult feces with high …


Opanga, MA, Madadi VO, Wandiga SO, Nose HM, Mirikau CW, Umuro M.  2018.  Adsorption Studies of Trimethoprim Antibiotic on Powdered and Granular Activated Carbon in Distilled and Natural Water. IJSRSET. 4(11):223-230.
Ndunda, EN, Madadi VO, Wandiga SO.  2018.  Organochlorine pesticide residues in sediment and water from Nairobi River, Kenya: levels, distribution, and ecological risk assessment. Environmental Science and Pollution Research. 25(34):34510-34518. AbstractEnvironmental Science and Pollution Research

Production and use of most organochlorine pesticides (OCPs) was banned through the Stockholm Convention on persistent organic pollutants. However, appreciable amounts are still detected in the environment due to their persistence, illegal use, and releases from contaminated soils and obsolete stocks. The present study investigated the levels of OCP residues in Nairobi River. Sediment and water samples were collected from three sites along the river and screened for 17 OCPs using gas chromatography electron capture detector (GC-ECD). Mean pesticide residues ranged from 0.01 to 41.9 μg kg−1 in sediment and below detection limit to 39.7 ng L−1 in water. In sediment α-HCH, β-HCH, γ-HCH, heptachlor epoxide, and p,p′-DDD were detected in all samples, while α-HCH, γ-HCH, δ-HCH, heptachlor epoxide, endosulfan I, and endrin were detected in all water samples. Levels of OCPs in water …

Masenge, EM, Wandiga SO, Shiundu PM, Madadi VO.  2018.  Analysis of Total Petroleum Hydrocarbons in Water from Ngong and Mathare Rivers, Nairobi County, Kenya. IJSRSET. 4(8):252-256.


Masese, FA, Wandiga SO, Madadi VO, Mbui DN.  2017.  Water Quality Status of Selected Sources of Domestic Water in Kenya. International Journal of Scientific Research in Science, Engineering and Technology. 3(8):193-198.
Madadi, VO, Ngotho MW, Masese FA.  2017.  Drinking Water Quality Challenges in Nakuru County, Kenya. IJSRSET. 3(6):5-11.
Ondiere, VB, Vincent MO, Ochieng AA, Oduor FDO.  2017.  Assessment of Heavy Metals Contamination in Lake Elementaita Drainage Basin, Kenya. International Journal of Scientific Research in Science, Engineering and Technology. 3(5):283-289.
Mbugua, JK, Guto PM, Madadi VO, Kamau GN.  2017.  Modeling of Experimental Adsorption Isotherm Data for Chlorothalonil by Nairobi River Sediment. IJSRSET,. 3(5):259-268.
Kipngetich, B, Wandiga SO, Madadi VO, Mukabi M.  2017.  Dissipation studies of Amitraz in cattle dips in Bureti, Kericho county- Kenya. International Journal of Scientific Research in Science, Engineering and Technology. 3(5):248-253.
Kamau, BN, Wandiga SO, Madadi VO.  2017.  Dissipation Studies of Ridomil Gold Pesticide on Potatoes in Nyandarua County, Kenya. IJSRSET. 3(5):221-229.
Okworo, EK, Madadi VO, Abong’o DA, Ochieng A.  2017.  Assessment of the Level of Organochlorine Pesticides Contamination in Kales, Water and Soil from Naivasha, Kenya. International Journal of Scientific Research in Science, Engineering and Technology. 3(5):205-213.
Sherrif, SS, Madadi V.  2017.  Adsorption of Lambda Cyhalothrin onto Athi River Sediments: Apparent Thermodynamic Properties. International Journal of Scientific Research in Science, Engineering and Technology. 3(3):568-574.
Aucha, JK, Wandiga SO, bong’o DA, Madadi VO, Osoro EM.  2017.  Organochlorine pesticides in air and soil from nairobi and mount kenya region, kenya. IOSR Journal of Applied Chemistry (IOSR-JAC). 10((7)2):5-11.
Madadi, VO, Wandiga SO, Ndunda EN, Mavuti KM.  2017.  Analysis of Organochlorine Pesticides in Lake Naivasha Catchment. IJSRSET. 3(5):139-149.


Macharia, JW, Wandiga SO, Njenga LW, Madadi VO.  2016.  Moringa oleifera and Ceramic Filters for Escherichia coli and Turbidity removal from drinking water. IOSR Journal of Applied Chemistry. 9(5):46-55.
Osoro, EM, Wandiga SO, Abong’o DA, Madadi VO, Macharia JW.  2016.  Organochlorine Pesticides Residues in Water and Sediment from Rusinga Island, Lake Victoria, Kenya. IOSR-JAC. 9(9):56-63..


Abong’o, DA, Wandiga SO, Jumba IO, den P PVBJ, Naziriwo BB, Madadi VO, Wafula GA, Kizza PN-, Henrik K.  2015.  Occurrence, abundance and Distribution of Benthic Macro-invertebrates in the Nyando River Catchment, Kenya. Africa Journal of Physical Sciences. 40(4):373-392.
Atieno, A’o D, Oyoo WS, Ogangu JI, den Paul VB, Bbosa NB, Odongo MV, Angoe WG, Henrik K, Peter N-K.  2015.  Organochlorine pesticide residue levels in soil from the Nyando River Catchment, Kenya. Africa Journal of Physical Sciences. 2.(1):18-32.
Ndunda, EN, Madadi VO, Mizaikoff B.  2015.  An alternative clean-up column for Polychlorinated Biphenyls in solid matrices. Environmental Science. Processes and Impacts, Royal Society of Chemistry. 17(12):2101-2109,.


Kemboi, AK, Mbugua JK, Madadi VO, Guto PM, Kamau GN.  2014.  Adsorption Characteristics of Captafol Pesticide by Sediment and Soil Samples: Apparent Thermodynamic Properties Using Spectroscopic Methods. International Journal of BioChemiPhysics. 22:61-68.
Mbugua, JK, Kemboi A, Michira IN, Madadi VO, Zaranyika MF, Kamau GN.  2014.  Adsorption of Atrazine pesticide by sediment and soil samples: Effect of Equilibration Time on the Freundlich Parameter (n). International Journal of BioChemiPhysics. 22:31-41.
Judth, K, Vincent MO, Geoffrey KN.  2014.  Impact of longterm Inorganic Fertilization with Emphasis on Heavy metals, Soil pH and Total Organic Carbon on Maize Farm soils in Trans Nzoia Kenya. . International Journal of Science and Technologe. 2(11):183-188. Abstract

This research was carried out to analyze the effect of long term use of inorganic fertilizers on the Cd, Cr, Cu, Pb, Zn, soil pH and TOC in maize farm soils in Kenya. Samples of soil were collected from 12 experimental sites from Kerita farm that has experienced more than 20 years of inorganic fertilizer application and 2 samples from the control site (Kiptuimet primary school), Trans Nzoia in Kenya while fertilizer samples were purchased from the nearby Kolongolo Market. Results obtained showed that the mean concentration for Cu, Pb, Cr and Zn in maize farm soils was 8.52±1.56mg/kg, 37.72±3.44 mg/kg, 42.11±3.25 mg/kg and 29.36±2.74 mg/kg, respectively while the mean concentration for Cu, Pb, Cr and Zn in the control soils was 5.12±0.71 mg/kg, 18.98±0.88 mg/kg, 19.15±1.56 mg/kg and 14.71±0.63 mg/kg respectively. The mean concentration for Cu in both the control site and maize farm soils was below the detectable limits of the instrument. Soil Ph in maize farm soils and control site was 5.034±0.25 and 6.35±0.21 respectively while soil TOC was 1.11±0.87% and 0.915±0.01% in maize farm soils and control site respectively. The results revealed that maize farm soils had higher levels of heavy metals than the control site suggesting that inorganic fertilizers had had an impact. However the concentration of these toxic elements after long term use of inorganic fertilizers did not exceed the maximum allowable levels set by the USEPA and WHO. Also the levels of these metals in the inorganic fertilizers used in the maize farms were within acceptable levels set by the USEPA and Kenyan standards. Soil pH levels showed a difference between the maize farms and the control site with control having higher pH values than the maize farm soils indicating long term application of inorganic fertilizers effect on soil pH. However both the two sites had generally a low pH of less than 7.0 which was attributed to the composition of the parent rock from which the soils were formed and inherent factors affecting soil pH
which cannot be changed. There was a difference in total organic carbon values between the maize farms and the control site with higher values of TOC in maize farm soils compared to the control site indicating that long-term chemical fertilizer application alone can increase soil total organic carbon.
Keywords: Heavy Metals, Soil pH, TOC, Fertilizers, Maize Farms, Kenya

Abong’o, DA, Wandiga SO, Jumba IO, Madadi VO, Kylin H.  2014.  Impacts of Pesticides on Human Health and Environment in the River Nyando Catchment, Kenya. Best: International Journal of Humanities, Arts, Medicine and Sciences (BEST: IJHAMS) ISSN( E): 2348-0521. 2(3):1-14. Abstract

River relies on rain fed agriculture. Important crops grown include cereals, cash crops fruits and vegetables. Farming is one of the contributors’ of pollution to Lake Victoria. Organophosphates and other banned organochlorine pesticides such as lindane, aldrin and dieldrin were used by farmers. The pesticides transport was by storm water run-off and air drift into the lake. Environmental risk assessment background information was collected through questionnaire and interviews of farmers to determine knowledge and safe use of pesticides. Fourteen pesticides were identified as commonly used of which four are toxic to bees and five to birds. The farmers identified declines in the number of pollinating insects, the disappearance of Red-billed Oxpecker (Buphagus erythrorthynchus) and wild bird’s fatalities. The general knowledge among farmers about chemicals risks, safety, and chronic illnesses was low. Activities that increases environmental awareness and safety of pesticides should be initiated by the agrochemical firms and government
KEYWORDS: Environment, Farming, Lake Victoria, Pesticides


Gall, AM, Madadi V, Shisler JL, Mariñas BJ.  2013.  The Safe Global Water Institute: An integrated, collaborative approach for improving drinking water and sanitation globally. Water Environment Federation, Disinfection 4. :184-187., USA: Water Environment Federation


Mbugua, JK, Michira IN, Kagwanja SM, Madadi VO, Zeranyika M, Kamau GN.  2012.  Adsorption of 2,4,4,5,6-Tetrachloroisophthalonitrile (Chlorothalonil) by Nairobi River Sediments: Adsorption characteristics and Related Thermodynamic Data. International Journal of BioChemiPhysics. 20:25-37.


Naiziriwo, BB, Wandiga SO, Madadi VO, Abongo DA.  2009.  Physicochemical parameters and magnetic speciation of Iron in Nakivubo Channel and Lake Victoria waters. Lakes and Reservoirs. 14:127-137. Abstract

Magnetic speciation technique was used for the determination of iron species in Nakivubo Channel and Lake Victoria waters. The method consisted of a column of supported Dowex 1-X18, 20–50 US mesh (Cl) surrounded by movable permanent magnets. Dowex was supported by a porous material to permit adequate passage of the eluent through the column. In the presence of an external magnetic field, enhanced capacity for adsorption of iron III was observed. The enhanced capacity is primarily due to the magnetic field produced and ion exchange sorption mechanism. The results show that, most of the Iron in Nakivubo Channel waters is in reduced ferrous form while, in the Lake Victoria waters, it exists in the oxidized ferric form. Physicochemical parameters for the field samples are discussed in this study. Turbidity levels in catchments with substantial vegetation were significantly lower than those without. pH values up to 13 was observed for some of the point source. The physicochemical parameters along Nakivubo Channel waters were relatively higher than the Lake Victoria waters indicating slow increasing pollution load along the Nakivubo Channel.

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