Field Method of
Investigation
The field work was done in
four (4) stages
(1) Desk Studies: This involves all the preliminary work in the libraries and
various offices to consult the available literatures on the study area and
related sections.
(2) Reconnaissance Survey: In this stage, preliminary survey was done to identify with the
natives of the study area. Geologic spots were noted and also feasibility of
the designed geologic study.
(3) Detailed Mapping: In this stage, outcrops, exposures along mines, quarries, erosional
and stream channels as well as altitude of bedding plane, joint, vein and
inclined bedding were made. Pictures from different location visited were
noted. Fresh samples were also taken on this course.
(4) Bed Sediment Sampling: This involves the collection of 20 samples from stream sediments
which was later prepared and sent for geochemical analyses. The collection of
these 20 samples was done at the interval of 500mtrs with the aid of GPS. This
collection was aided by the use of shovel. GPS was used for the location of
longitude and latitude at which the samples were taken.
Laboratory Methods/Sample
Preparation
The Laboratory methods
includes the preparation of the twenty samples for analysis of the following
Elements: Lead (Pb), Zinc (Zn), Copper (Cu), Arsenic (As), Cadmium (Cd) and
Nickel (Ni). The sample preparation takes the following steps.
1). Drying: The fresh
samples were collected during the dry season. Thus, it was dried in the
laboratory for some days.
2). Homogenisation: The
samples were homogenized with the used of agate mortar and pestle.
3). Sieving: After the homogenization, the samples were sieved to obtain 100
mesh fraction by the use of polyethylene sieve.
4). Digestion: The samples were digested with the use of aqua regia. The choice of
this mixture is to its advantage of being kept at high temperature than other
acids (Levinsion, 1974), with its decomposition faster than most other
techniques.
In the digestion
proper, 1g of screened samples were weighed out and placed in 20ml beaker. 10ml
of aqua regia was added and stirred. This was gently heated on hot plate to a
volume of 2.5ml. After that, 10ml of de-ionized water was added and gently
heated to the volume of 5ml. This was sieved adding de-ionized water to make up
for 25ml. Thus, the analytical procedures.
Analytical Procedure
The digested sample was
analyzed for Cu, Pb, Zn, Cd, As and Ni by the Atomic Absorption Spectrophotometric
method, using Buck Scientific Atomic Absorption Spectrophotometer 210VGP. The
outline of this model basically consists of the light sources which are made up
of hallow cathode lamp that emits radiation at the resonance wavelength of each
element to be analyzed.