157 research outputs found
GROUNDWATER CONTAMINATION: PERFORMANCE, EFFECTS,LIMITATIONS AND CONTROL
The decisive role of groundwater as a decentralized source of
drinking water both in rural and urban settings cannot be underrated. It
accounts for nearly 80 percent of the rural domestic water needs, and 50
percent of the urban water needs. The inevitable importance of
groundwater to humankind has led to its over-exploitation which is now
resulting to aquifer contamination. Although many cases of contaminated
groundwater have occurred throughout the globe, few successful
experiences in remediating the problems are identifiable at this time.
Many countries are in the early process of identifying their potential
groundwater contamination problems while others are seeking for its
remedy. At present, many innovative technologies are being evaluated for
their usefulness and swift responses to groundwater contamination
control as the conventional extraction and treatment processes have often
proven to be very expensive and slow with respect to remediating th
GROUNDWATER POLLUTION AND CONTROL: AN OVERVIEW
The pollutant creates a contaminant plume within an aquifer.
Movement of water and dispersion within the aquifer spreads the
pollutant over a wider area. This Chapter is aimed at reviewing the
groundwater pollution sources, solid wastes and control measures for
groundwater pollution. Pollution can occur from on-site sanitation
systems, effluent from wastewater treatment plants, landfills, leaking
sewers, petrol stations or from over application of fertilizers in
agriculture. Pollution (or contamination) can also occur from naturally
occurring contaminants, such as fluoride or arsenic. Using polluted
groundwater causes hazards to public health through poisoning or the
spread of disease. In spite of various awareness embarked upon by
various government agencies and non-governmental agencies, some
Nigerians still cultivate the habit of disposing wastes indiscriminately.
Government agencies should be more funded, gear up to rise to the
occasion by combating this seemingly intractable problem. Conclusively
Estimation of overburden thickness of industrial estate Ogbomoso, Southwestern Nigeria
Vertical Electrical Sounding (VES) geophysical method was used to delineate Oyo State Industrial Estate,
Ogbomoso South Local Government Area, Southwestern Nigeria. The study area falls within latitude 080 06′ 07.4″
and 080 06′ 25.4″ and longitude 0040 15′ 03.3″ and 0040 15′ 49.0″. The research was conducted with a view to
estimating the overburden thickness and to know the competent zones with respect to engineering purpose in the
study area. Ten Vertical Electrical Soundings (VES) were carried out across the area using the schlumberger
electrode array configuration with current electrode separation (AB) varying from 130m to 200m. Nine out of the
ten modeled curves were H-type where the remaining one was KH-type. The geoelectric sections obtained from the
sounding curves revealed 3-layer and 4-layer earth models respectively. The models showed the subsurface layers
categorized into the topsoil/first layer, second layer, third layer (which only revealed beneath one VES station), and
the last layer (which is either fractured basement or fresh bedrock). Areas with thick overburden and those with
fractured basement are the areas that factories making use of heavy machines should not be built on it. This is
because the continual vibration of the heavy machines might cause subsidence in the factories in the future which
might lead to loss of life and properties
Geoelectric assessment of groundwater prospect and vulnerability of overburden aquifers at Adumasun Area, Oniye, Southwestern Nigeria
Adumasun lies on a Precambrian basement complex of Southwestern Nigeria. Some kilometers away from the study
area especially at Igangan is characterized by outcrops of crystalline basement rocks. Inadequate municipal water
supply from State Water Corporation, coupled with hydrogeologically difficult nature of the terrain, individuals and
corporate bodies indiscriminately sink tube wells and boreholes within the unconsolidated overburden materials,
with glaring lack of concerns for the vulnerability status of aquifers, and possible environmental risk. Vertical
Electrical Sounding method was used to map Adumasun area, Oniye, Oyo State with a view to assessing the
groundwater prospect, focused on the thickness of the unconsolidated materials overlying the crystalline bedrock.
The resistivity parameters of the geoelectric topmost layer across the area were also used to assess the vulnerability
of the underlying aquifers to near-surface contaminants. The thickness of the unconsolidated overburden varies
from 3.1m to 20.1m, where about 60% falls within the 10m-14.9m brackets. This shows that unconsolidated
materials are not thick and hence averagely low groundwater prospect. 80% of the topmost geoelectric layer in the
study area has resistivity mostly within the range of 1-100Wm. Resistivity values within these brackets tend to
indicate silt or clay sequence, which can constitute effective protective geologic barriers for the underlying aquifers.
This suggests that aquifers within the unconsolidated overburden at Adumasun are mostly capped by
impervious/semi-pervious materials, geologically protecting the underlying aquifers from near-surface
contaminants
Groundmagnetic survey to investigate on the fault pattern of industrial estate Ogbomoso, Southwestern Nigeria
Groundmagnetic method was used to investigate on the fault pattern of industrial estate Ogbomoso which falls
within latitude 080 06′ 07.4″ and 080 06′ 25.4″ and longitude 0040 15′ 03.3″ and 0040 15′ 49.0″ Southwestern Nigeria,
with a view to determining the competency of the basement. This is to know whether the basement will be competent
enough to withstand the construction of the factories in the study area or not. A total of four traverses were
established for the purpose of the groundmagnetic study, and the results were presented as groundmagnetic profiles
of varying magnetic intensities. Result from first vertical derivative revealed that the intensities and characteristics
nature of the magnetic anomalies as expressed by all profiles are indicative of the different rock types producing
them. Qualitative and quantitative interpretation of individual magnetic anomaly and geological knowledge of the
survey area yielded information on the depth of geological features (e.g. rock contact, faults or fractures), structures
and magnetic properties of rock units. From the preliminary interpretation, the existence of some structural features
such as a likely fault and relatively mineralized zones that might contain magnetic minerals of essential magnetite
origin is revealed. It was also revealed that industrial estate Ogbomoso is averagely competent for engineering
purpos
SEISMICITY ANOMALIES OF M 5.0+ EARTHQUAKES IN CHILE DURING 1964-2015
The study of magnitude-frequency distribution of earthquake hazards in a region remains a crucial analysis in seismology. Its significance has varied from seismicity quantification to earthquake prediction. The analysis of seismicity anomalies of magnitude M => 5.0 earthquakes in Chile from 1964 to 2015 was undertaken by the present study with a view of reporting the trend of earthquake occurrences in the region. Chile has an area of about 756, 950 km2 with an extensive coastline of
approximately 6,435 kms. It is situated in a highly seismically and volcanically active zone with a long, narrow strip of land between the Andes Mountains to the east and the Pacific Ocean to the west.It borders Peru to the north, Bolivia to the northeast, Argentina to the east and the Drake Passage in the far south. Of a total of 3,893 earthquakes that have been documented historically, magnitudes Richter 5.0 to 5.9 represent 92.6%, magnitudes 6.0 to 6.9 represent 6.8%, magnitudes 7.0 to 7.9 represent 0.6%, and magnitudes 8.0 to 8.9 about 0.1%. The quantity of earthquakes (a-value)
revealed an estimate of 8.4. The b-value was estimated using Gutenberg-Richter (GR) and the Maximum Likelihood Estimation (MLE) methods. The estimated b-value using GR and MLE methods are 0.97 and 1.1 respectively, with an estimated average b-value ≈ 1. The present studies
supprort the conclusion that Chile is seismically very active and prone to the recurrence of moderateto-great
earthquakes in the future
AN OVERVIEW OF MAGNETIC METHOD IN MINERAL EXPLORATION
In modern times, the economic strength of a nation, the standard of living and independence of her citizens
depend on the nation's industrial strength and her economic buoyancy. These two parameters, that is, the
nation's industrial strength and the buoyancy of the industries in each country, sometimes form the bases for
classifying the countries as "developed" (e.g., America and Japan) or "developing" (e.g., Nigeria and Ghana)
with every nation striving to achieve the former status. The availability of the raw materials needed by most
industries is one of the primary factors for the establishment of the industries. The raw material needs of most
industries occur sporadically in one form or the other inside the earth's crust and the search for them as been one
of man's major concerns. This paper gives the literature report about the use of magnetic method in mineral
exploration. Magnetic exploration also referred to as “potential field” exploration is used to give geoscientist an
indirect way to “see” beneath the Earth’s surface by sensing physical properties of rocks (magnetization).
Magnetic method exploration can help locate minerals. Potential field survey is relatively inexpensive and can
quickly cover large areas of ground. The method is relatively cheap, non-invasive and non-destructive
environmentally speaking
Heavy metals' data in soils for agricultural activities
In this article, the heavy metals in soils for agricultural activities were analyzed statistically. Ten(10)soil samples were randomly taken across the agricultural zones in Odo-Oba, southwestern Nigeria. Ten(10)metals; namely : copper(Cu), lead(Pb),chromium(Cr), arsenic(As), zinc(Zn), cadmium(Cd),nickel(Ni),antimony(Sb), cobalt(Co) and vanadium(V) were determined and compared with the guideline values.When the values were compared with the international standard,none of the heavy metals in the study area exceeded the threshold limit.However,the maximum range of the samples showed that Cr and V exceeded the permissible limit which could be associated with ecological risk.The data can
reveal the distributions of heavy metals in the agricultural top soil of Odo-Oba, and can be used to estimate the risks associated with the consumption of crops grown on such soils
Groundwater Prospect in a Typical Precambrian Basement Complex using Karous-Hjelt and Fraser Filtering Techniques
Electromagnetic survey was carried out at Ibodi, village, Ilesa in Atakunmosa West Local government area with a view to determining the probable locations for groundwater exploration in the study area. Ibodi falls within latitude 70 35′ 35.21″ North and longitude 40 40′ 48.28″ East. The development and increase in immigrants at Ibodi has necessitated this study. A total of five profiles from North to South directions were occupied. It was discovered that distances (100.0-140.0) m, 40.0 m, 80.0 m and 35.0 m on profiles 1, 3, 4 and 5 respectively revealed fractured zones which are suspected to be the best locations for groundwater prospects in the study area
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