-
Trace Elements and Health: An Environmental Risk in Nigeria
Issue:
Volume 2, Issue 3, June 2013
Pages:
66-72
Received:
4 May 2013
Published:
10 June 2013
Abstract: The concentration levels of trace elements in drinking water and food pose potential health risks to man and therefore require great attention. Studies on iodine deficiency disorders (IDD) indicate goiter prevalence in areas underlain by metamorphic Basement and Younger Granite rocks and its near absence in the sedimentary terrains. There are cases of dental fluorosis resulting from the excessive ingestion of fluoride in both children and adults living in both the crystalline and sedimentary terrains in Nigeria with none reported from the coastal areas. Mining/mineral processing predisposes these trace elements to weathering whereby they are released into the environment in the soil and water bodies. The incidence of abnormally high natural radiation (radon gas) associated with most rocks and the exceptionally higher natural radiation associated with cassiterite mill tailings of the Jos Plateau, north central Nigeria, is a source of worry. Epidemiological records have indicated the increasing rate of lung cancer prevalence on the Jos Plateau and studies carried out elsewhere in Europe have linked about 13% of deaths associated with lung cancer to exposure to natural radiation. Preliminary hydro-geochemical study indicates high concentrations of potentially harmful elements (PHE) (Pb, Cu, Zn, As, Cd, Hg, V, Co, Cr, Ni, etc.) in the soils and water bodies in the crystalline and inland sedimentary terrains especially close to sulfide mineralization. In addition, high levels of these elements from anthropogenic sources have also been reported in soils and water in most mining/mineral processing sites and urban centres. The knowledge of the relationships between trace elements and human health issues is at its infancy in Nigeria. To adequately understand these relationships, there is need for geoscientists to intensify research on trace elements in the environment and together with professionals in community health so as to identify health issues arising from trace elements in the environment.
Abstract: The concentration levels of trace elements in drinking water and food pose potential health risks to man and therefore require great attention. Studies on iodine deficiency disorders (IDD) indicate goiter prevalence in areas underlain by metamorphic Basement and Younger Granite rocks and its near absence in the sedimentary terrains. There are cases...
Show More
-
Seismic Slope Stability of the Tipaimukh Dam of North-Eastern India: A Numerical Modelling Approach
Md. Rafiqul Islam,
Mohammed Omar Faruque
Issue:
Volume 2, Issue 3, June 2013
Pages:
73-87
Received:
30 May 2013
Published:
20 June 2013
Abstract: This article represents the seismic slope stability analysis of earth core rock-fill Tipaimukh Dam under static and dynamic loading conditions. The Tipaimukh area is located at the triple junction of the three continental plates- Indian, Eurasian and Burmese tectonic plate. The area is frequently interrupted by unanticipated geological discontinuities, such as regional and local-scale faults and fractures that behave as a strike-slip and extensional movements. Two kinds of numerical models (A and B) are presented here. Both models consist of five zones and each zone has individual rock mechanical characteristics. Model A assumes safety factor of dam slope associated with impervious core including clay material. Model B assumes also safety factor associated with masonry wall as an impervious core. The present numerical modeling results reveal that under static condition of the dam the safety factor ranges from 2.56 to 2.69. On the contrary, under seismic/dynamic loading conditions associated with earthquake M6.0 to M8.5, the safety factor ranges from 1.60 to 0.98 for model A, and from 1.66 to 0.98 for model B. The past records of the historical earthquakes in north-eastern India reveal that the recurrence period of intensive magnitude earthquakes, as experienced in Assam, Shillong plateau and Manipur area, is 38 to 53 years. The calculated safety factor of the Tipaimukh Dam implies that the dam would be destroyed if it would be affected by earthquakes magnitude over 7.0 throughout its operational life, which is usually extent from 50 to 100 years.
Abstract: This article represents the seismic slope stability analysis of earth core rock-fill Tipaimukh Dam under static and dynamic loading conditions. The Tipaimukh area is located at the triple junction of the three continental plates- Indian, Eurasian and Burmese tectonic plate. The area is frequently interrupted by unanticipated geological discontinuit...
Show More
-
Suitability of Bentonite Clay: An Analytical Approach
Md. Abdullah Asad,
Shantanu Kar,
Mohammad Ahmeduzzaman,
Md. Raquibul Hassan
Issue:
Volume 2, Issue 3, June 2013
Pages:
88-95
Received:
11 June 2013
Published:
30 June 2013
Abstract: Bentonite is a type of clay with a very high proportion of clay mineral montmorillonite, resulting from the decomposition of volcanic ash. With high plasticity, Bentonite is highly water absorbent and has high shrinkage and swelling characteristics. Bentonite slurry is often used to solve problems in the construction of borings or excavating trenches in water- saturated soils. Over time, the uses of bentonite spread into more current applications including papermaking tech-nology, cut-off walls, wastewater purification and even into different aspects of nano-technology because of nano-sizes of bentonite particles. Due to its vast engineering applications, it is of highly research interest. In this present study, an analyt-ical approach has been made to find a suitable bentonite sample from three different types of bentonite samples (China, Pakistan and India) by analyzing their engineering properties and economy as well. Finally, China Bentonite sample is found to be most suitable with good engineering properties and economy than other samples.
Abstract: Bentonite is a type of clay with a very high proportion of clay mineral montmorillonite, resulting from the decomposition of volcanic ash. With high plasticity, Bentonite is highly water absorbent and has high shrinkage and swelling characteristics. Bentonite slurry is often used to solve problems in the construction of borings or excavating trench...
Show More
