An algorithm for simulation of a Chemical Transport Equation in an Aquifer

Dynamical systems can be predicted using mathematical models. These models are usually Partial Different Equations (PDEs). Examples include the wave equation, equations for diffusive processes, and the heat conduction equation. Numerical solution of such PDEs describing a given system and its implementation using a suitable computer code can lead to numerous predictions on the dynamical system both in space and time. In this paper, the contaminant / chemical equation and the groundwater flow equation are solved numerically using the Integrated Finite Difference Method (IFDM) and the algorithms generated are simulated using an object oriented code. Generic results generated represent important predications on the fate and transport processes of a chemical in an aquifer   Keywords: Simulation procedure, integrated finite difference method, contaminant equation, discretizatio

Effect of Environmental Exposure on the Lead Levels in Human Blood in Kenya

Lead is one of the heavy metals associated with a number of health problems such as abdominal pains, constipation and loss of appetite, nausea, vomiting, insomnia, headache, irritability, dizziness and lead encephalopathy. The major source of lead into the environment is through emission from auto exhaust in countries still using leaded fuel, with other contributors being cigarette smoke, burning of lead battery castings, weathering, ceramic industries and paints. Therefore there is need for continued monitoring of the levels of lead in the environment and in people to determine the level of exposure. The aim of the study was to determine the effect of environmental exposure on the levels of lead in human blood in Nairobi City and Nyamira District, Kenya. The subjects who had lived in the study areas continuously for five years were randomly selected and recruited for the study. The study used a questionnaire to assess lead exposure factors of the recruits, while atomic absorption spectroscopy and differential pulse anodic stripping voltammetry were used for determining the lead levels. The subjects in Nairobi City Centre had the highest mean blood lead (BPb) level of 29.9 + 16.91 µg/l, while Nyamira Rural subjects had the lowest mean of 24.20 + 7.07 µg/l. The mean lead level of the subjects was statistically significant between Nairobi City Centre and Nyamira Rural (P < 0.01, df = 99). The smokers, those who travelled frequently, the users of glazed ceramics, those who worked in industries and those who lived near busy roads had higher levels of blood lead. The study provides an additional data pointing to elevated blood lead levels in environmentally exposed individuals. Keywords: Lead, environmental exposure, human blood, AAS, DPASV.

Effect of Occupation on the Levels of Lead in Human Blood in Kenya

The occupation an individual is involved in exposes him or her to different levels of lead from the work environment. The main occupation of the study subjects included working in the petrol stations, teaching, nursing, street hawking, doing clerical work, working in public vehicles, farming and schooling. The aim of the study was to determine the effect of occupation on the lead levels in human blood in Nairobi City and Nyamira District, Kenya. The subjects involved in the different occupations were randomly selected and recruited for the study. The study used a questionnaire to assess lead exposure factors of the recruits, while atomic absorption spectroscopy and differential pulse anodic stripping voltammetry were used for determining the lead levels. The street hawkers in Nairobi City centre had the highest mean blood lead level of 36.85?16.98 ?g/ dl while the teachers of Nyamira Town had the lowest mean blood lead level of 8.1?5.3 ?g/ dl. The study provides an additional data pointing to elevated blood lead levels in occupationally exposed individuals. Key words: Occupational exposure, BPb, AAS, DPASV

First comprehensive study on total contents and hot water extractable fraction of selected elements in 19 medicinal plants from various locations in Nyamira County, Kenya

A large number of medicinal plants is traditionally known in Kenya and used for treatment of various diseases, for example diabetes, where metals are supposed to be involved in pathogenesis and therapy. Therefore, detailed investigation of the concentration of a large number of metals in medicinal plants is required for improved understanding and optimisation of the therapeutic role of metals and also to exclude potentially toxic effects. Our study focused on the determination of 30 selected elements in 19 medicinal plant species each collected from 3 sampling locations in Nyamira County, Kenya. The obtained comprehensive data set showed large variability and multivariate data analysis revealed that the differences in the elemental composition were stronger dependent on the plant species than on the sampling location. In addition, hot water extractions were performed to mimic the traditional preparation of medicine from the plants. It was found that the mean extraction efficiencies were below 20% except for B, Mg, P, K, Mn, Co, Ni, Cu, Zn, Rb, Mo, Cd and Tl, which are mostly essential elements apart from Cd and Tl. Sequential (ultra)filtration of the extracts was applied as novel approach for molecular size-fractionation of the extracted elemental species. The results indicate more than 50% low molecular weight species (3 kDa up to <5 μm) were detected for V, Cu, Al and Fe