Publications


2016

and Muthama, AKH, W MJ, N MUTHAMAJ.  2016.  Long Term Change Point Detections in Total Ozone Column over East Africa via Maximal Overlap Discrete Wavelet Transform. American Research Journal of Physics. 2(2):1-9.
Kalambuka Angeyo, H, Odumo BO’, Carbonell G, Patel JP, Torrijos M, Martín JAR.  2016.  Impact of gold mining associated with mercury contamination in soil, biota sediments and tailings in Kenya. Environmental Science and Pollution Research. Abstract

This work considered the environmental impact of artisanal mining gold activity in the Migori–Transmara area (Kenya). From artisanal gold mining, mercury is released to the environment, thus contributing to degradation of soil and water bodies. High mercury contents have been quantified in soil (140 μg kg−1), sediment (430 μg kg−1) and tailings (8,900 μg kg−1), as expected. The results reveal that the mechanism for transporting mercury to the terrestrial ecosystem is associated with wet and dry depositions. Lichens and mosses, used as bioindicators of pollution, are related to the proximity to mining areas. The further the distance from mining areas, the lower the mercury levels. This study also provides risk maps to evaluate potential negative repercussions. We conclude that the Migori–Transmara region can be considered a strongly polluted area with high mercury contents. The technology used to extract gold throughout amalgamation processes causes a high degree of mercury pollution around this gold mining area. Thus, alternative gold extraction methods should be considered to reduce mercury levels that can be released to the environment.

Kalambuka Angeyo, H, Kaniu I, Darby IG.  2016.  Radiological Mapping of the Alkaline Intrusive Complex of Jombo, South Coastal Kenya by In-Situ Gamma-Ray Spectrometry. EGU General Assembly 2016. AbstractWebsite

Carbonatites and alkaline intrusive complexes are rich in a variety of mineral deposits such as rare earth elements (REEs), including Nb, Zr and Mn. These are often associated with U and Th bearing minerals, including monazite, samarskite and pyrochlore. Mining waste resulting from mineral processing activities can be highly radioactive and therefore poses a risk to human health and environment. The Jombo complex located in Kenya's south coastal region is potentially one of the richest sources of Nb and REEs in the world. It consists of the main intrusion at Jombo hill, three associated satellite intrusions at Mrima, Kiruku and Nguluku hills, and several dykes. The complex is highly heterogeneous with regard to its geological formation as it is characterized by alkaline igneous rocks and carbonatites which also influence its radio-ecological dynamics. In-situ gamma spectrometry offers a low-cost, rapid and spatially representative radioactivity estimate across a range of landscapes compared to conventional radiometric techniques. In this work, a wide ranging radiological survey was conducted in the Jombo complex as follow up on previous studies[1,2], to determine radiation exposure levels and source distributions, and perform radiological risk assessments. The in-situ measurements were carried out using a 2.0 l NaI(Tl) PGIS-2 portable detector from Pico Envirotec Inc integrated with GPS, deployed for ground (back-pack) and vehicular gamma-ray spectrometry. Preliminary results of radiological distribution and mapping will be presented. [1] Patel, J. P. (1991). Discovery and Innovation, 3(3): 31-35. [2] Kebwaro, J. M. et. al. (2011). J. Phys. Sci., 6(13): 3105-3110.

2015

Angeyo, KH, Kaniu MI.  2015.  Challenges in rapid soil quality assessment and opportunities presented by multivariate chemometric energy dispersive X-ray fluorescence and scattering spectroscopy. Geoderma. 241–242:32–40. Abstract

There is, especially in precision agriculture, an increasing demand world over for affordable sensors for in situ (field deployable) soil quality assessment (SQA) applicable at an ecological scale due to the interplay between soil quality and environmental degradation. Although spectrometric (particularly optical) techniques offer the opportunity to meet this demand due to their high analytical versatility, their utility in rapid SQA is limited by the complexity of the soil matrix, and the interpretation of the resulting spectra and (usually) multivariate quality assurance (i.e. SQA) data. In this paper, we examine the utility of spectrometric techniques for soil analysis and critique their applicability to rapid SQA; in particular, we appraise their potential for development towards intelligent portable SQA systems for in situ application. We then evaluate in this perspective the applicability of a new method we have recently developed namely chemometrics energy dispersive X-ray fluorescence and scattering spectrometry (EDXRFS) for SQA, emphasizing its potential for realizing rapid intelligent sensor architecture for in situ SQA. We conclude that a point of care soil sensor that infers soil properties, and intelligently modulates precision agriculture may be realized by integrating the EDXRFS spectroscopy method to a portable XRF spectrometer.

2013

Angeyo, KH, Mukhono PM, Dehayem-kamadjeu A, Kaduki KA.  2013.  Laser induced breakdown spectroscopy and characterization of environmental matrices utilizing multivariate chemometrics. Spectrochimica Acta Part B: Atomic Spectroscopy. 87 Abstract

We exploited multivariate chemometric methods to reduce the spectral complexity and to retrieve trace heavy metal analyte concentration signatures directly from the LIBS spectra as well as, to extract their latent characteristics in two important environmental samples i.e. soils and rocks from a geothermal field lying in a high background radiation area (HBRA). As, Cr, Cu, Pb and Ti were modeled for direct trace (quantitative) analysis using partial least squares (PLS) and artificial neural networks (ANNs). PLS performed better in soils than in rocks; the use of ANN improved the accuracies in rocks because ANNs are more robust than PLS at modeling spectral non-linearities and correcting matrix effects. The predicted trace metal profiles together with atomic and molecular signatures acquired using single ablation in the 200–545 nm spectral range were utilized to successfully classify and identify the soils and rocks with regard to whether they were derived from (i) a high background radiation area (HBRA)-geothermal, (ii) HBRA-non-geothermal or (iii) normal background radiation area (NBRA)-geothermal field using principal components analysis (PCA) and soft independent modeling of class analogy (SIMCA).

2012

Angeyoa, KH, Garib S, Mustapha AO, Mangala JM.  2012.  Feasibility for direct rapid energy dispersive X-ray fluorescence (EDXRF) and scattering analysis of complex matrix liquids by partial least squares. AbstractWebsite

The greatest challenge to material characterization by XRF technique is encountered in direct trace analysis of complex matrices. We exploited partial least squares (PLS) in conjunction with energy dispersive X-ray fluorescence and scattering (EDXRFS) spectrometry to rapidly (200 s) analyze lubricating oils. The PLS–EDXRFS method affords non-invasive quality assurance (QA) analysis of complex matrix liquids as it gave optimistic results for both heavy- and low-Z metal additives. Scatter peaks may further be used for QA characterization via the light elements.

2011

2005

KALAMBUKA, DRANGEYOHUDSON.  2005.  Trace Element Analysis by Sliding Spark Spectrometry. J. Anal. Atom. Spectrom. (in press) 2005.. : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.
KALAMBUKA, DRANGEYOHUDSON.  2005.  Plasma-Radiative Modelling and Characterisation of the Sliding Spark Discharge: Implications for Direct Dielectric Solid Trace Quantitative Spectroscopy.. J. Radiative & Quantit. Spectres. (In Press), 2005.. : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.
KALAMBUKA, DRANGEYOHUDSON.  2005.  Spectral diagnostics of the sliding Spark plasma. J. Anal. Atom. Spectrom. (in press) 2005.. : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.

2002

KALAMBUKA, DRANGEYOHUDSON.  2002.  Sliding spark spectroscopy of sediment samples.. J. Anal. Bioanal. Chem., 374, 756 . : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.
KALAMBUKA, DRANGEYOHUDSON.  2002.  Sliding spark spectrometry: A pulsed plasma technique for the direct trace element analysis of non-conducting solids and dielectric surface layers.. Proceedings of the 2 nd International School on Plasma Diagnostics & Technology, 4 . : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.

1998

KALAMBUKA, DRANGEYOHUDSON, P PROFPATELJAYANTI.  1998.  Measurements of trace elements levels in Kenyan cigarettes with energy dispersive X-ray fluroscence spectroscopy technique. J. Trace & Microprobe Techniques, Vol. 16, No.2, 233 . : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.
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 . : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.
P, PROFPATELJAYANTI, KALAMBUKA DRANGEYOHUDSON.  1998.  Optimization of X-ray Fluorescence Elemented analysis.. An example from Kenya Applied Radiation & Isotopes, 49, 885 . : GIGA German Institute of Global and Area Studies, Hamburg, July 2009 Abstract
A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.

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