Bio

Publications


2011

2010

2008

2007

2005

J., MRMANGALAMICHAEL, M. MRMAINADAVID.  2005.  Trace Elements in some selected dietary staples in Kenya. Inaugural National Nutrition Congress . : University of Nairobi.
M., MRMAINADAVID, J. MRMANGALAMICHAEL.  2005.  Urban Farming along Nairobi River: How Safe are the Food Crops. Inaugural National Nutrition Congress . : University of Nairobi. Abstract
Nairobi River originates from a swamp near Kikuyu town, about 24 kilometres west of Nairobi city centre and meanders across the city covering a stretch of about 30 kilometres. Within the city area, the river is contaminated by runoff waters; untreated effluent from residential areas and small-scale industries; and a significant volume of treated wastewaters from Kariobangi Sewerage Treatment Works. Its waters are used for various purposes, in particular agricultural, both within and outside the city environs. Most often the food crops grown along this river appear healthy and are attractive to customers. However, it is suspected that the waters used for irrigation purposes may contain high levels of heavy metals and these may end up being assimilated by these food crops and thereafter enter the food chain.

2004

J., MRMANGALAMICHAEL.  2004.  Assessment Of Ozone, Nitrogen Oxide, Air Particulate Matter(PM10) And Trace Elements Levels In The Ambient Air Of Nairobi City.. Workshop on Air Pollution Studies in Southern and East Africa, University of Botswana, Gaborone,. : University of Nairobi.

2003

J., MRMANGALAMICHAEL.  2003.  Analysis of Local mineral and tap waters samples using Total Reflection(TXRF) for Heavy metal content. 9th International Symposium on Radiation Physics, Protea Hotel President, Cape Town. : University of Nairobi.

2002

M., MRMAINADAVID, J. MRMANGALAMICHAEL.  2002.  Indoor Radon (222 Rn) Levels in Coastal and Rift Valley Regions of Kenya. International Atomic Energy Agency (IAEA), IAEA-CN-91/56, p. 401-405,. : University of Nairobi.

2001

J., MRMANGALAMICHAEL.  2001.  EDXRF analysis of local and imported pica soil samples. East African Journal of. : University of Nairobi.

2000

J., MRMANGALAMICHAEL.  2000.  Trace element analyses of pollen bee tissue and honey by total reflection and radioisotope exciled x-ray fluorescence spectrometr. Journal Of Trace Microprobe Techniques 18(2). 303 . : University of Nairobi.
J., MRMANGALAMICHAEL.  2000.  Uptake Characteristics Of Trace Elements: Lead, Zinc, Cadmium And Mercury By Selected Food Crops Grown Along Nairobi River. Proceedings of 5th Kenya Meteorological Society Workshop, Mombasa. : University of Nairobi.

1998

Hashim, NO, Kinyua AM, MANGALA MJ, Rathore IVS.  1998.  EDXRF analysis of lead and other toxic trace elements in soil samples along two major highways of Kenya. Abstract

Adjacent lands along most major highways of Kenya are left as open spaces, or used for small scale farming and grazing of cattle and livestock. Some grass and plants are expected to have high levels of lead and other toxic metals. So far, no study has been carried out to determine the concentrations of toxic metals in soil samples along Thika and Mombasa highways of Kenya. This work is important and essential to the study of the impact of pollution on health and the environment.

J., MRMANGALAMICHAEL.  1998.  Geostatistical Modelling of a High Background Radiation Area Geothermal Field Matrix Trace Elements: The Goals and Challenges of Kerio Valley Geothermal Field P.O. Ogwari1, H. K. Angeyo1, A. O. Mustapha3 and J.M. Mangala2. X-ray Spectrometry, Vol. 27, 205 . : University of Nairobi. Abstract

Estimating spatial variability of trace geothermal signatures is an important factor is evaluating the geothermal field potential.  It is expected that a particular geothermal feature (hot spring, fumarole, geyser, etc.) exhibits unique 'marker' trace element/ and             radiogenic signatures that may be used to prospect the field over large spatial dimension (for example mapping of passive sites) based on the results of a few measurements on the feature.  Geostatistical methods provide means to study the heterogeneous nature of the 'marker' spatial distribution especially in an area of poor accessibility.  The geothermal signatures in this study are trace elements in thermal water that uniquely characterize the Kerio Valley geothermal field, which lies in the mid Rift System of Kenya.  The region has been associated with elevated background radiation to the extent that certain areas in have been characterized as high background radiation areas (HBRA) thereby providing a   perfect setting to understand the relations between geothermal characterizing trace elements and naturally occurring radioactive material (NORM) signatures.  X-Ray       Fluorescence (XRF) analysed Sr, K, Rb, Br, Ca and Cr showed a strong positive  correlation with water temperature and were considered for mapping their variability and  prediction of unsampled areas.  Variogram and Kriging analysis was performed using ArchMap 9.3.  The results show that the spatial distribution of the sampling points is insufficient to map the whole area of interest.  Various variogram models fit well for Sr, Rb and Cr.  However, a fitting model for K, Br, and Ca could not be found.  This is due to the unharmonized nature of the covariance between the sampled points.  The kriging maps, which are a product of the variograms, capture the sense  and importance of        sampling design (DoE) in geostatistical modelling.  This study therefore serves as a base for the design and systematic sampling approach for the sparse nature of the Kerio Valley goethermal signatures.  Springs of elevated thermal gradient have been identified as the sampling points.  Both water and soil (i.e. sediment) will be sample accordingly to 'markers' have shown a strong positive correlation with thermal gradient in water, and the soil has provided the same correlation pattern as the water.  Therefore in cases of dried springs, soil samples can confidently provide a good model.

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J., MRMANGALAMICHAEL, P PROFPATELJAYANTI, KALAMBUKA DRANGEYOHUDSON.  1998.  Radio Isotope Photon Excited Energy Dispersive X-ray Fluorescence Technique for the Analysis of Organic Matrices. X-ray Spectrometry, Vol. 27, 205 . : University of Nairobi.

1996

1994

Patel, JP, MANGALA MJ.  1994.  Elemental analysis of carbonatite samples from Mrima Hill, Kenya, by energy dispersive X-ray fluorescence (EDXRF). AbstractWebsite

A total of 30 radioactive carbonatite samples from four zones of the Mrima Hill were analysed using energy dispersive x-ray fluorescence technique. Thorium with a mean concentration of 770 μg/g is the main source of high environmental radiation. The concentration of cerium, barium, niobium and iron are significant and worth economic exploitation. For validity of the results, certified reference materials IAEA (Soil-7) and the Canadian (SY-3) samples were analysed by the same method

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