Open Access Original Research Article

Flood Risk Assesment of Zaria Metropolis and Environs: A GIS Approach

W. T. Andongma, E. A. Kudamnya, J. N. Gajere

Asian Journal of Environment & Ecology, Page 1-8
DOI: 10.9734/AJEE/2017/32456

Delineation of flood prone areas within Zaria and environs was carried out. Spatial data such as elevation, slope, wetness and drainage distances was used to delineate flood prone areas. These data were reclassified and weighted using Analytical hierarchy procedue-multi criteria evaluation method. The resulting flood risk map reveals the central and north eastern part of the study area as highest flood risk zones, while the southwestern part of the study area as the lowest flood risk factor. Areas delineated as having very low flood risk account for 28.3% of the study area and covers some 86.88 km2. Areas delineated as having low flood risk accounted for 29.5% of the study area and covers 90.56 km2. Areas depicted as having high flood risk accounted for about 32.1% covering some 98.545 km2. Areas depicted as having very high flood risk accounted for 10% of the study area and covers an area extent of 31.007 km2. Future infrastructural development must be guided by technical reports forecasting high risk, flood prone areas.


Open Access Original Research Article

Assessment of the Radiation Hazard Indices from Terrestrial Radiation in Mining Sites in Benue State, Nigeria

A. I. Olanrewaju, G. O. Avwiri

Asian Journal of Environment & Ecology, Page 1-10
DOI: 10.9734/AJEE/2017/33373

The assessment of the radiation hazard indices of solid minerals and sand in mining sites of Benue State, Nigeria was carried out using well calibrated radalert-50 and 100 meters and a Global Positioning System (Garmin 765). The sites investigated are Lessle (Barite), Gboko (Limestone), Owukpa (Coal) and Akuana (Salt) deposits fields. The mean background radiation ionization exposure rate of 0.019±0.004, 0.019±0.004, 0.014±0.002 and 0.023±0.005 mRh-1 were obtained respectively. The mean of absorbed dose rates estimated for the mining fields are 161.53, 169.40, 120.35 and 201.84 nGy/hr respectively. Estimated values of the annual effective dose equivalent (AEDE) for outdoor exposures 0.25, 0.26, 1.61, and 2.71 mSv/yr respectively while the mean excess lifetime cancer risk calculated for the mine fields values are (0.82, 0.86, 5.33 and 8.94) x  10-3 respectively. The obtained values for background ionizing radiation were higher than the recommended standard limits by ICRP while the AEDE calculated in the entire mine fields are within safe values but the absorbed dose (D) and excess lifetime cancer risk (ELCR) estimated were higher than their world permissible values of 89 nGy/hr and 0.29 x10-3 respectively. The work indicated that there is tendency for the residents near the mining sites to get high radiation doses and could develop radiation-related illness after a long time exposure.


Open Access Original Research Article

Iron Ore Deposit and Its Tailing Impact on the Toxic Metal Level of Neighboring Agricultural Soils

A. U. Itodo, L. A. Egbegbedia, I. S. Eneji, A. A. Asan

Asian Journal of Environment & Ecology, Page 1-16
DOI: 10.9734/AJEE/2017/32900

Aim: This is one of our mineralogical study series aimed at the preliminary characterization of iron ore and its neighboring farmland soils, with focus on ore impact on soil quality, toxic metals concentration and the geo-accumulation status of pollutants.

Methodology: Mineral (Iron ore) samples and ore rich soils from neighboring farmlands, coded as I-Soil, I-soil-FLA, I-soil-FLB and I-soil-FLC were collected from Itakpe, Kogi State in North Central Nigeria. Samples were qualitatively characterized using Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM) and Ultraviolet Visible (UV-Vis) spectrometer for functional group analysis, micro-structural morphology and spectral profile respectively. Physico-chemical parameters were investigated following routine classical (wet) chemistry procedures. Levels of toxic metals including Iron (Fe), Lead (Pb), Manganese (Mn), Cadmium(Cd), Chromium (Cr), Zinc (Zn), Nickel (Ni) and Copper(Cu) in both ores and soils were estimated using Atomic Adsorption Spectrophotometer (AAS).

Results: The iron ore SEM images appeared compact with irregular shapes. UV –Visible Spectral shows that the mineral has possibly leached from the parent ore to the nearby soils at similar range. Highlights of this studies shows that the level of metals in farmland soils are statistically significant (p < 0.05) when compared with those of the mineral ores, and insignificant (p > 0.05) when compared to acceptable or threshold limits provided by the USEPA and WHO. Relying on geo-accumulation index values, this study classified the farmland soil with regards to the iron load as “extremely contaminated”. Investigated soil samples are “strongly contaminated” with Pb, “moderately contaminated” with Mn and Zn and “uncontaminated” with Cd and Cu.

Conclusion: The parametric factors of the soil samples, soil quality and metal distribution among ore-rich soils showed levels that could be linked to both geogenic and anthropogenic activities. Furthermore, the farmland soil’s toxic metal levels in the study area might be enriched by either mine tailing from the mineral ore depot or anthropogenic. Our recommendation is strictly on continuous environmental impact assessment, environmental monitoring, environmental auditing and environmental awareness campaign.  


Open Access Original Research Article

Correlate Mapping of Impervious Surfaces as Flood Risk Assessment Strategy in Owerri, Southeastern Nigeria

John D. Njoku, Kingsley O. E. Ukaegbu, Ikenna E. Osumgborogwu, Anayo D. Udeh, Mercy Telu

Asian Journal of Environment & Ecology, Page 1-11
DOI: 10.9734/AJEE/2017/33974

Owerri is rapidly growing in population and built environment, with corresponding, high increase in pavements or paved surfaces. This study explores the integrated approach of Remote Sensing (RS) and Geographic Information systems (GIS) techniques in flood management with the goal of mapping areas vulnerable to flood hazard and, increase in paved surfaces. Digital elevation dataset from Shuttle Radar Topographical Mission (SRTM) were downloaded from USGS explorer. Also, Landsat 5 ETM of 1986, Landsat 7 ETM+ of 2000 and Landsat 8 ETM+ of 2016 imageries were obtained and subjected to supervised classification, using maximum likelihood classifier with ERDAS Imagine 2014. The derived map displayed the spatial and statistical variations of the classified Land Use and Land Cover (LULC) of 1986, 2000 and 2016. The result showed impervious surface rising from 1986 values of 31,625.93 Ha, to 47,979.09 Ha in 2000 and 50,297.33 Ha in 2016, implying approximately 31.2% in 1986, 47.31% in 2000 and 49.61 in 2016. The mean change in impervious surface from 1986 to 2000 was 16.1% compared with 2.3% between the periods. This implies the measure and spate of land conversion in Owerri between the periods showed upward swing. The mean percentage change from 1986 to 2016 revealed increases from 31.2% to 47.31% and to 49.61% for 1986, 2000 and 2016, respectively. Digital Elevation Model was developed with ArcGIS to identify flood prone areas within the study area. A flow accumulation model was created using the DEM before re-classification into high risk, moderate risk and low risk zones using contours and based on elevation. This was overlaid on the impervious layer of the area, to produce a vulnerability map showing locations at a particular level of risk, according to their proximity and extent of paved surface area. This confirms that changes in impervious surfaces, significantly, produce corresponding effect in flood vulnerability. This study recommended that adequate land use planning be enforced.


Open Access Review Article

Environmental Laws in Nigeria and Occurrence of Some Geohazards: A Review

I. E. Osumgborogwu, C. N. Chibo

Asian Journal of Environment & Ecology, Page 1-12
DOI: 10.9734/AJEE/2017/34045

Nigeria as a country is blessed with an abundance of both human and natural resources. Exploitation of natural resources in Nigeria over the years with little or no regard for the environment has increased susceptibility of parts of the country to identified geohazards. A suite of environmental laws exist in Nigeria, all these aimed at protecting both the environment and its inhabitants. The aim of this paper is to review existing environmental laws in Nigeria, and occurrence of identified geohazards as a result of absence or non-implementation of these laws. Data for this study were obtained primarily from secondary sources. They are published government reports, journal articles, books, as well as other resources on the environment of Nigeria. Results show that Nigeria as a country has suitable existing and well-meaning environmental laws. The country also has many agencies charged with the responsibilities of implementing these environmental laws and policies. However, the non-implementation and non-existence of identified environmental laws and policies has increased both exposure and vulnerability of parts of the country to geohazards. The effects of these include; loss of means of livelihood, environmental degradation leading to Badlands in parts of the country, as well as death in extreme cases. It is recommended in this paper that adherence to existing environmental laws and policies as a panacea to mitigating identified geohzards is important. It is further recommended that amendment of already existing environmental laws to capture contemporary realities be made. This paper concluded by calling for more investment in the use of remote sensing and GIS tools such as LiDAR technology in the study of geohazards.