International Research Journal of Engineering Science, Technology and Innovation (IRJESTI) Vol. 1(5) pp. 130-141, August 2012
Available online http://www.interesjournals.org/IRJESTI
Copyright © 2012 International Research Journals
Full Length Research Paper
Elemental analysis of soil characteristics due to
municipal solid waste in Port Harcourt City
*Ukpaka C. P. and Pele A.
Department of Chemical/Petrochemical Engineering, Rivers State University of Science and Technology,
Nkpolu, P.M.B. 5080, Port Harcourt, Nigeria
Accepted 03 August, 2012
The study on the elemental analysis of soil characteristics due to municipal solid wastes was carried
out in selected dump sites located within Port Harcourt City in Rivers State of Nigeria. Samples
obtained from the different dump-sites were analyzed for the concentration of parameters such as soil
pH, calcium, copper, iron, lead, manganese, magnesium, nickel, sodium, phosphorus and zinc. Control
samples were taken at 1000m away from the dumpsites and were also analyzed for the presence of
these elements. The result of the analysis shows a significant difference between the concentration of
these elements in the dump sites and control site – 1000m away from the dump sites. The dump sites
were found to contain significant amount of toxic and essential elements hence sorting of municipal
solid wastes at the point of collection and lining of landfills are therefore recommended so as to
prevent environmental pollution.
Keywords: Solid waste, Port Harcourt city, Elemental analysis, Municipal, Characteristics.
INTRODUCTION
Municipal solid wastes could be defined as any useless,
unwanted or discarded material with insufficient liquid
content to be free flowing (Eddy et al., 2006). These solid
wastes are or discarded materials that arise from man’s
activities and cannot be discarded through a sewer pipe.
The non-free flowing or sticky nature of the solid wastes
give rise to the accumulation of solid waste in some
habitable parts of urban centers such as Port Harcourt
city. Places with accumulated solid wastes are called
refuse dumps but a designed place for dumping of refuse
is known as dump site.
Although municipal solid waste is an asset when
properly managed, its volume has continued to increase
tremendously in recent times in Nigeria as a result of
increase in population and socio-economic development
including wage increase. The discriminate disposal of
waste also contributes to worsen the situation. In Nigeria,
much has been, and is being invested on municipal solid
wastes management in cities; in a bid to protect the
environment and human health. But, little progress has
*Corresponding Author E-mail: chukwuemeka24@yahoo.com
been made because of severe financial, technological
and institutional constraints within the public and the
private sectors apart from the erratic growth of housing
units in the inner core of urban cities (Ojeshina 1999;
Ademoroti, 1993; Hickman, 2006; Hickman, 2006;
Moughalu, 1998; Gilbert, 1987; Christian, 2004; Ukpaka,
2009, 2010; Bhatia, 2009).
In developing countries, municipal solid wastes consist
mainly of organic materials and smaller amount of nonbiodegradable wastes. The organic or biodegradable
materials are decomposed by microorganisms and mixed
with the soil thereby enriching soil quality. Nonbiodegradable wastes are materials that do not decay
such as: recyclable materials: Paper, glass, bottles,
cosmetics and plastics; inert waste: construction and
demolition waste, dirt, rocks, debris; composite waste:
waste clothing, tetra packs, toys; domestic hazardous
wastes: Paints, light bulbs, spray can, batteries etc
(Eddy et al., 2006; Rigg, 1968; Okpala, 1986, Ojeshina,
1999; Waite, 1995; Tan, 1996).
Despite the best attempt at waste avoidance,
reduction, reuse and recovery (recycling, composting and
energy recovery), landfill and waste disposal sites are still
the principal focus for the ultimate disposal of residual
wastes and incineration residues (Waite, 1995). The
Ukpaka and Pele 131
placement and compaction of municipal waste in landfills
facilitates the development of aerobic and anaerobic
conditions that promotes the biological decomposition of
landfill waste. Thus, leachates of diverse compositions
are produced depending on site landfill method, climatic
and surface water ingress into the landfill. Natural
processes are relied upon to attenuate the leachate
contaminants in some unlined landfills before it reaches
the underground water. Soil plays a major role in these
natural attenuation processes through physical filtering,
adsorption, biodegradation and chemical precipitation
(Akaeze, 2001, Ukpaka, 2007, 2011, 2012; Skoog, West,
Holler & Crouch, 2004; Umeakuka and Mba, 1999;
Ogbonna, Amangabara, Ekere, 2002; IESL, 2010;
Golueke, 2006, George, 1997; Etekpo, 1999 & Edosowan
& Onwumah, 2008).
The organic fraction in municipal solid wastes has
been reported to increase crop yield in aluminum toxic
soils through organic matter complexing (Edosowam and
Onwumah, 2008). It is also useful in the amelioration of
nutrient deficiencies thereby enhancing crop growth and
yield. A municipal solid waste in the course of time
undergoes decomposition through the activities of
microorganisms (Akinsanmi, 2006). He also reported that
the composition of municipal solid wastes resulted in the
formation of organic matter which in turn releases
chemicals which dissolves soil minerals making them
available for plant uptake (Awake, 2002).
Obviously, these qualities of solid wastes can serve as
a pool of resources if they are properly harnessed. This
can be achieved with the adoption of good municipal
solid waste management techniques by the government,
waste management authorities and the public (Akpan,
2001 & Ukpaka, 2007a, 2009b).
A study on the analysis of soil characteristics due to
municipal solid waste is indispensable to the sustenance
of the environment and human health. This stems from
the fact that determining the potency of the waste and
some pollutants effect on soil through soil analysis will go
a long way to provide information needed for the
development of techniques for tackling the problem of soil
pollutants and effects of solid wastes in the environment
through
proper
programmer
and
planned
disposal/management strategies. Municipal solid waste
could be beneficial to humans as well as the
environment, if properly managed. It could also lead to
environmental problems ranging from soil and water
pollution, repulsive sight, offensive odour and even
increase in ambient temperature levels if not properly
disposed off or managed. Thus, this study seeks to
determine the effects of solid waste on the soil by
analyzing samples obtained from selected refuse dumps
or dump sites in Port Harcourt city to serve as a
benchmark so that solid waste could be analyzed for their
physiochemical parameters before they are disposed at
the dump sites (Akinsami, 2006).
The aims of this study is to determine the soil concen-
tration due to elements present in municipal solid waste
at the selected dump sites; to examine the potential of
municipal solid waste as a nutrient source; to compare
the concentration levels of elements at the dump site and
the control area and to examine the potential of waste as
pollutants.
Municipal solid waste is a serious issue that affect all
the inhabitants of an area especially in the urban centers.
This study is therefore significant as it will help to expose
the dangers of indiscriminate dumping of waste in the
inhabited parts of the city as well as provide valuable
data that will assist the government and waste managers
in adopting best practices in the management of
municipal solid wastes. That is, enlightening all
stakeholders on the need for proper waste management
and disposal since the waste influence the underground
water quality as well influence the environment greatly
(Ukpaka, 2006).
Several studies have been conducted on the
management of municipal solid waste in many urban
centers. However, this study will build in these past works
by presenting concrete and reliable data from the
analysis of soil samples in selected dump sites that will
serve as a benchmark for future studies on municipal
solid waste management in Port Harcourt city. The study
will be centered around the collection of samples from
selected dump sites in Port Harcourt city such as
Mechanic Village, Orazi refuse dump and Iwofe dump
site, and the laboratory analysis of these samples to
determine the concentration of some parameters such as
pH, calcium (Ca), copper (Cu), iron (Fe), lead (Pb),
manganese (Mn), magnesium (Mg), nickel (Ni), sodium
(Na), phosphorus (P) and zinc (Zn). The laboratory
results are subjected to statistical analysis in order to
evaluate the impact of these parameters on the soil in the
sampled areas. This study took into consideration the
effect of municipal solid waste on the soil in the areas
that were studied. The effects of these parameters on the
borehole (or underground water) in these areas were not
considered.
MATERIALS AND METHODS
Sample Collection
The soil samples used for the study were collected using
shovel and placed in aluminum foils and covered. The
samples were well-labeled as top and bottom for the
dump sites and control for the samples collected at
1000m away from the dump site where wastes have not
extended. The samples labeled as top were collected at a
depth of 0-30cm and the bottom samples from a depth of
30-60cm. The samples were transported to International
Energy Services Limited for laboratory analysis.
The analysis covers soil pH and metals which are
micro-nutrient such as copper, manganese, iron and zinc;
132 Int. Res. J. Eng. Sci. Technol. Innov.
metals that are toxic to plants such as lead and nickel
and exchangeable metallic cautions and non-metals such
as calcium, magnesium, sodium and phosphorus are
presented in this paper.
Determination of Soil pH and Method: APHA 4500 H +
B, ASTM D1293
Site Description
The following apparatus and materials were used such
as: pH meter, weighing balance, Distil water, Glass
beaker, test sieves; Reagent: Buffer solution 4.0, 9.2 and
7.0
Site One
Procedure
This refuse dump is situated at mechanic workshop
at Mile 3 in Port Harcourt city. It is about 200m long
and 150m wide located at the eastern end of
the workshop. Residential buildings are situated close
to the refuse dump. It is an old refuse dump that has
not been cleared. At the time of sampling, refuse
were still dumped there. Wastes commonly dump at
the site include motor tyres, cans, domestic
wastes, bottles, plastics, leather materials and metal
objects.
10g of the air-dried and sieved sample is weighed using a
weighing balance and placed into a glass beaker. 20ml of
distilled water was added to it and the solution is stirred
to obtain a uniform composition. The probe of the pH
meter, well calibrated with buffer solution of known
calibration standard is used. The electrode is washed
with distilled water and immersed into the solution and
the pH value of the sample is obtained as displayed on
the screen. The procedure was repeated for different
samples.
Site Two
Determination of Phosphorus Concentration and
Method: APHA 4500-PE
The landfill is located at Oroazi town in Mile 4,
Port Harcourt city. Initially, the site was a burrow pit
and was used as a dump site. At present, it has
been compacted and waste are no longer dumped
there. Its about 125m long and 115m wide
with residential buildings situated close to it. Waste
dumped at this site includes broken bottles, carton,
domestic wastes, plastic materials and less of metal
objects.
Site Three
This burrow pit of about 115m deep and 130m wide
is located in a high density area of the city, Iwofe
along the busy University of Education road. It is
currently being used by the Rivers State Environmental
Sanitation Authority as a dumpsite. The ditch
was excavated to source materials for road construction
in the area. At the time of sampling, a portion of the
pit was filled with water being drained from the road
and
fresh
wastes
has
just
being
dumped
awaiting compaction. Wastes dumped at the site
includes domestic wastes, motor tyres, plastic materials,
cartons, leather materials, cans, clothing and market
waste.
The apparatus and materials were used such as:
Glass wares, volumetric flask (500ml), Pipette, UV
spectrophotometer, Oven and Reagents.
Sulphuric acid (H2SO4) 5N 70ml of the acid was
diluted to 500ml with distilled water, Ammonium
molybdate solution, 20g of (NH4)6 Mo7.4H2O was
dissolved in 500ml distilled water and stored in glass
stoppered bottle, Ascorbic acid 0.1M, 1.76g of ascorbic
acid was dissolved in 100ml of deionized water,
Potassium antimony tartrate solution, 1.3715g of the
solution was dissolved in 400ml distilled water in 500ml
volumetric flask and diluted to volume.
Procedure
500ml of the digested sample was pipette into 125ml
Erlenmeyer flask. 0.05ml (a drop) of phenolphthalein
indicator was added to the sample. A red colour
developed and 5N H2SO4 solution was added in drops to
discharge the colour. 8ml of the combined reagent was
added and mixed thoroughly for 30 minutes. The
absorbance of each sample was measured at 880nm
using reagent blank as reference solution; and the result
tabulated. The procedure was repeated for all the
samples.
Laboratory Analytical Methods and Procedures
Digestion of Soil Samples for Metals Analysis, and
Method: ASTM D1971B
The different methods and materials used in the
laboratory analysis of the samples for the different
parameters are given below:
Apparatus
Steam bath or hot plate,Weighing balance, Glass beaker/
Ukpaka and Pele 133
digestion bottles, Distil water, Filter paper (fine textured,
ashless), Reagents: Concentrated Hydrochloric acid
(HCl) and Concentrated Nitric acid (HNO3)
Arithmetic Mean
This refers to the sum of the measured value divided by
the number of events. It is the same as the average.
Mathematically expressed,
Procedure
Mean
0.5g of the homogeneous, finely ground and sieved
sample is weighed and placed in a glass beaker
or digestion bottle. 100ml of distilled water and 0.5ml of
HNO3 are added to it. 5ml of HCl is added to the solution
in the beaker and heated on a steam bath or hot plate in
a well ventilated hood until the volume has reduced to 15
or 20ml while ensuring that the sample does not boil. The
mixture is allowed to cool and filtered to remove solids.
The sample is quantitatively transferred to a 100ml
volumetric flask or other suitable size and the volume is
adjusted (diluted with water to appropriate volume). The
sample is now ready for assaying using atomic
absorption spectrophotometer (flame atomization).
Metals Analysis, Method: ASTM 2010
Apparatus
Atomic absorption spectrophotometer (AAS), Hollow
cathode lamps, Glass wares, Sample bottles, Reagents:
Standard solutions, Deionized water.
Procedure
The AAS was calibrated with the different standards prior
to metals analysis. The sample solution is sprayed into
the flame by aspiration. The solution becomes
vapourized and finally atomized thereby absorbing
radiation of a specific wavelength characteristic of that
element. The light source is produced by the hollow
cathode lamp of the element. Another standard was used
for quality assurance and control after a number of
samples have been analyzed to determine the
concentration of the element. The monochromator and
the detector detect the desired spectral line produced by
the absorbance of the radiation. The intensity of the
radiation is measured with the sample to obtain the
absorbance and the concentration of the element of
interest is determined by comparing that reading to one
obtained for a standard of the metal as displayed by the
readout.
X =
∑
X
N
,
where
Σ = Summation
X = Individual measured valve
N = Total number of events
X = Mean.
t-test
This t-test is used to determine if two sets of
measurements are statistically different or not. A
statistical t value is calculated and compared with a
tabulated value for a given number of test at the desired
confidence level. If the calculated t value exceeds the
tabulated t value, then there is a significant difference
between the results at the confidence level. If it does not
exceed the tabulated value, then there is no significant
difference between the results. Mathematically, t-test is
expressed:
t =
X1 − X 2
Sp
N1 N 2
N1 + N 2
where X 1 , X 2 are the mean values of each set of data.
Sp - The pooled standard deviation
N1, N2 - Number of samples in each set.
The pooled standard deviation is expressed as:
Sp
∑ (X
=
) ∑ (X
2
1
− X1 +
2
− X2
)
2
N1+ N 2 − 2
Where,
Σ - Summation of the mean deviation
X1, X2 - Individual values in each set
X 1, X 2 - Mean of each set of analysis
N1, N2 - Total number of samples in each set
Graphs
These are used to illustrate the trend of the results
obtained from the analysis of the samples parameters. It
aids in the interpretation of the data by visual inspection.
Statistical Methods
Description of the Study Area
The different statistical methods used for determining the
concentration of the parameters include; the arithmetic
means, T-test and graphs.
Port Harcourt city is the capital of Rivers State, the
Treasure Base of the Nation, and hosts many multina-
134 Int. Res. J. Eng. Sci. Technol. Innov.
Figure 1. The Port Harcourt Metropolis (Source: Ogbonna et al., 2002).
tional oil and gas companies operating in Nigeria. It is
also the home of the second largest seaport in Nigeria
and has an international airport. According to the 2006
census figure, Port Harcourt city has a population of 2.4
million and contributes over 60% of oil and gas resources
to the Nigerian economy.
It is situated about 60km from the open sea (Gulf of
Guinea) and bounded by longitude 6o 56′ to 7o 07′ East
and latitude 4o 44′ to 4o 52′ North of the equator, covering
2
a total distance of about 804km .
In terms of drainage, the area is situated on top of the
Bonny River and is entirely lowland with an average
elevation of about 15m above sea level. The topography
is under the influence of tides which results in flooding
especially during rainy season.
Climatically, the city is situated within the subequatorial region with the tropical monsoon climate
characterized by high temperature, low pressure and high
relative humidity all the year round. The mean annual
temperature, rainfall and relative humidity are 30oC,
2,300mm and 90% respectively.
The soil in the area is mainly silt-clay with interaction
of sand and gravel while the vegetation is a combination
of mangrove swamp forest and rain forest.
Above is a map of the study area - Port Harcourt city
(Figure 1).
RESULTS AND DISCUSSION
Results
The results of the laboratory analysis for the soil pH level
and the concentration of calcium, copper, iron, lead,
manganese, magnesium, nickel, sodium, phosphorus
and zinc in the soils at the different dump sites and
1000m away from the dump sites are shown in Table 1
below.
The concentrations of metals at the dump sites in
comparison with 1000m away from the dump sites
indicate that there is evidence of relative increase in the
concentration of heavy metals due to leachates. This
study considered the soil pH level and metals which are
micro-nutrient such as copper, manganese, iron and zinc
and the non-essential/toxic heavy metals which are toxic
to plants in the soil at concentrations above tolerance
level. This latter class of heavy metals includes lead and
nickel. Others are exchangeable metallic cautions and
non-metals and include calcium, magnesium, sodium and
phosphorus. These elements are highly needed by plants
Ukpaka and Pele 135
Table 1. Analysis results of soil samples from Mechanic Village, Orazi and Iwofe.
Parameter
pH
Calcium, Mg/Kg
Copper, Mg/Kg
Iron, Mg/Kg
Lead, Mg/Kg
Manganese, Mg/Kg
Magnesium, Mg/Kg
Nickel, Mg/Kg
Sodium, Mg/Kg
Phosphorus, Mg/Kg
Zinc, Mg/Kg
Method
ASTM D 1293B
ASTM D 511
ASTM D 1688
ASTM D 1068
ASTM D 3559
ASTM D 858
ASTM D 511
ASTM D 1886
ASTM D 3561
ASTM D 5996
ASTM D 1691
Top
3.8
6,820
66.0
18,600
195
7.0
1,860
42.0
580
8.0
16.7
for their normal growth.
Based on the results obtained, there was a
significant difference between the soil pH level
and the concentration of metals at dump sites
compared to the control. The graphs shown below
clearly depict the trend in variation of the different
parameters at the dump site and control.
From Figure 2 the pH value is more acidic at
the top samples than the bottom and control.
Results obtained from the Mechanic Village
indicate pHMVT > pHMVC > pHMVB, but for Orazi we
have pHORT > pHORB > pHORC whereas for Iwofe
pHIWT > pHIWB > pHIWC. The pH values of the
various sampled areas are acidic in nature. The
plants need alkaline for their effective growth and
performance in crop yield. If the soil
characteristics of the sampled area remain acidic
in nature, it means that the crops and the
underground water will not be good for human
utilization. This constant pH of acidic nature of the
area will as well influence other elements present
in the soil.
Mechanic village
Bottom
Control mean
5.8
4.2
2,850
1,830
35.0
27.0
11,900
10,500
<0.01
<0.01
2.0
3.0
642
240
21.0
8.0
500
540
21.0
11.0
11.4
49.3
Concentration of the parameters
Orazi (refuse dump)
Top
Bottom Control mean
4.4
5.1
6.0
8,410
3,460
2,200
34.0
<0.01
<0.01
10,800
6,190
4,200
<0.01
0.05
<0.01
2.0
2.0
2.0
2,190
720
553
38.0
14.0
12.0
500
467
580
55.0
30.0
34.0
44.9
15.4
19.4
There was a significant difference between the
soil pH in the dump site from the control and the
tcal = 4.93, when n=12. This might be due to
substances which may increase soil acidity that
were deposited at the dump sites. The
concentration of manganese in the various soil
sampled area is as stated below MnMVT > MnMVC >
MnMVB for Mechanic Village, for Orazi, MnORT =
MnORB = MnORC and for Iwofe, MnIWT > MnIWB >
MnIWC. These results obtained for manganese
indicate that less distribution has occurred in all
the dump sites investigated in Figure 2.
The permissible range for manganese
concentration in soils is 200 to 9,000ppm thus the
values of manganese in this study are below this
range. From the findings from studies at Elelenwo
dump site reported by Akaeze, (2001) the
concentration of manganese was relatively low.
There was significant difference between the
concentration of manganese in the dump sites
from the control and the tcal = 2.55, when n=12.
This shows that the observed concentration of
Top
3.8
2,140
94.0
3,450
<0.01
4.0
408
27.0
699
29.0
19.0
Iwofe (dump site)
Bottom
Control mean
4.0
4.6
3,230
3,240
240
<0.01
4,750
4,150
<0.01
<0.01
3.0
2.0
623
446
54.0
48.0
684
520
72.0
41.0
28.4
10.3
manganese might have been due to background
concentration. The equation of the best fit and
square root of the curve is given as Y = -0.0233x
+ 4.75 with R2 = 0.006 for pH, and Y =-0.25x +
4.25 with R2 = 0.1705 for Mn upon the influence of
various sampled area as presented in Figure 2.
From Figure 3, the concentration of
phosphorus increased from the top to the bottom
and decreased at the control samples in Mechanic
village; whereas at Orazi refuse dump, it
increases at the top and decreases at the bottom
and control samples. However, at Iwofe, it
increases from the top to the bottom and
decreases at the control. There is a marked
increase in the phosphorus concentration in the
bottom samples of all the dump sites compared to
the top and control samples. Phosphorus is an
essential nutrient needed for plant growth, thus
soil pollution by phosphorus is not a significant
environmental issue.
There was no significant difference between
the concentration in soils at dump site from the
136 Int. Res. J. Eng. Sci. Technol. Innov.
pH
8
Mn
Linear (pH)
Linear (Mn)
Parameters concentration (mg/kg)
7
y = -0.0233x + 4.75
R2 = 0.006
6
5
4
3
y = -0.25x + 4.25
R2 = 0.1705
2
1
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled area
Figure 2. pH level and Mn concentrations versus various dump sites.
P
80
Zn
Linear (P)
Linear (Zn)
y = 5x + 8.4444
R2 = 0.4483
Parameters concentration (mg/kg)
70
60
50
40
y = -1.0117x + 28.925
R2 = 0.038
30
20
10
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled Area
Figure 3. Concentrations of P and Zn versus various dump sites
control and the tcal = 2.04, when n=12. This shows that
the background concentration of phosphorus in the soil
may be high. The concentration of zinc decreases from
the top to the bottom and increases at the control in
Ukpaka and Pele 137
20,000
Ca
Fe
Linear (Fe)
Linear (Ca)
18,000
Parameters concentration (mg/kg)
16,000
14,000
y = -1665.8x + 16611
R2 = 0.8132
12,000
10,000
8,000
6,000
4,000
y = -312.83x + 5361.9
R2 = 0.1424
2,000
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled Area
Figure 4. Concentrations of Ca and Fe versus various dump sites.
control and the tcal = 2.04, when n=12. This shows that
the background concentration of phosphorus in the soil
may be high. The concentration of zinc decreases from
the top to the bottom and increases at the control in
Mechanic Village whereas it decreases from the top to
the bottom and increases slightly at the control at Orazi
refuse dump. At Iwofe, zinc concentration increases from
the top to the bottom and decreased at the control. The
natural range for the concentration of zinc in soil is 10 to
300ppm; thus the concentration of zinc in this study is
within the acceptable limit. Generally, the concentration
of zinc at dump site is higher than at the control indicating
that zinc might have been introduced into the soil during
decomposing.
There was no significant difference between the
concentration of zinc at dump site from the control and
the tcal = 0.12 when, n=12. This shows that the
background concentration of zinc in the soil may be very
high. The result presented in Figure 3 illustrates the
mathematic evaluation on phosphorus (P) and Zinc (Zn)
concentration at various sampled area. The equation of
2
the best fit is given as Y = 5X + 8.444 with R = 0.4483
2
for phosphorus and Y = -1.0117x + 28.925 with R =
0.038 for zinc.
In Figure 4, the concentration of calcium increases at the
top and decreases from the bottom to the control at
Mechanic Village as well as in Orazi refuse dumps.
However, there is an increase from the top to the bottom
and control samples at Iwofe dump site. Generally, the
concentration of calcium increase at the top samples in
the dump sites was compared to other samples as
reported by various researchers. Calcium has not been
considered as a major pollutant in the environment
compared to other elements since it is an inherent
constituent of plant and animal tissues. There was a
significant difference between the concentration in soils
at dump from the control and the tcal = 3.06, when n=12.
This shows that the dump sites contribute significantly to
the calcium content of the soil.
The concentrations of iron in the figure above reveal
that it increases at the top and decreases from the
bottom to the control samples at Mechanic Village and
Orazi refuse dumps. However at Iwofe dump site, it
increases from the top to the bottom and slightly
decreases in the control samples. Generally, the
concentration at the dump sites increases over the
samples at the control. The natural range of the
concentration of iron in the soil is 3,000 – 500,000ppm.
138 Int. Res. J. Eng. Sci. Technol. Innov.
300
Cu
Pb
Linear (Cu)
Linear (Pb)
P a ra m e t e rs C o n c e n t ra t io n (m g / k g )
250
y = 7.5167x + 17.528
R2 = 0.0728
200
150
y = -13x + 86.672
R2 = 0.3
100
50
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled Area
Figure 5. Concentrations of Cu and Pb versus various dump sites.
The results reveal that the concentrations are within
the natural limit. Akaeze (2001) reported the result of a
study on Elelenwo dump sites with a concentration of 10,
300 – 31,000ppm. This result is high compared to the
result obtained in this study. There was a significant
difference between the concentrations of iron in dump
site from the control and the tcal = 2.55, when n=12. This
shows that substances that contribute significantly to the
iron content might have been dumped at the different
sites.
The equation of the best fit and square root of
the equation is given as Y = -1665.8x + 16811 with
2
R = 0.8132 for Iron (Fe) and Y = -312.83x + 5361.9
2
with R = 0.1424 for calcium (Ca) as presented in Figure
4.
A single trend is noticed in the concentration of copper
as shown in Figure 5. The concentration of copper
increased at the top and decreases from the bottom to
the control in all the dump sites. However, the
concentrations at the dump sites are higher than those at
the control.
The natural range for copper concentration in the soil
is 7 to 80 ppm. This result shows that concentration of
copper is within the acceptable limit at Mechanic Village
and Orazi but increased above the limit at Iwofe in the top
sample. This might be due to the indiscriminate disposal
of copper containing wastes at the dump site. There was
a significant difference between the concentrations of
copper at the dump sites from the control and the tcal =
2.72, when n=12. This shows that biodegradable wastes
dumped at the sites have increased the copper
concentration at the dump site above the natural levels
especially at Iwofe. The concentration of lead in the
Figure 5 assumed a unique pattern. It increased in the
top sample at Mechanic Village and decrease to a
constant value for all the other samples in the different
dump sites.
The natural range for the concentration of lead in soils
is 15 to 25 ppm. The concentration of lead in the top
sample of the Mechanic Village exceeds the natural limit
while the other samples are below the range. Lead is a
cumulative pollutant and thus poses serious problem to
the environment. There was no significant difference
between the concentrations of lead in dump sites from
the control and the tcal = 0.017, when n=12. This shows
that the isolated increase in lead concentration at the top
Ukpaka and Pele 139
2,500
Na
Mg
Linear (Mg)
Linear (Mg)
Parameters Concentration (mg/kg)
2,000
Linear (Na)
1,500
y = -116.9x + 1438.1
R2 = 0.2189
1,000
y = 11.833x + 504.17
R2 = 0.1578
500
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled Area
Figure 6. Concentrations of Na and Mg versus various dump sites.
sample in Mechanic Village is because wastes at the
dump site contain significant amount of lead.
Sodium and Magnesium Concentration
The results of sodium and magnesium concentration are
presented in Figure 6.
The equation of the best fit and square root of the
equation is given as Y = -13x + 86.672 with R2 = 0.3, for
lead (Pb), and Y = 7.5167x + 17.528 with R2 = 0.0728 for
copper (Cu) as presented in Figure 5 for various sampled
area.
The concentration of sodium increased in the top
sample, decreased slightly in the bottom and increased
slightly at the control in Mechanic Village and Orazi
refuse dumps. At Iwofe dump site, the concentration
increase at the top, decreased at the bottom and
decreased sharply at the control. There was a significant
difference between the concentrations of sodium at the
dump site from the control and the tcal = 7.14, when n=12.
This indicates that the wastes at the dump sites contain a
high proportion of sodium containing waste.
The
concentration of magnesium as depicted above showed a
marked increase in the top, a decrease at the bottom and
a sharp decrease at the control for Mechanic Village and
Orazi refuse dumps. Contrary to this trend, the
concentration decreased at the top, increased at the
bottom and decreased at the control samples at Iwofe
dump site. In general, the concentration increased
remarkably at the dump sites than the control.
The natural range for the concentration of magnesium
in the soil is 1,000 – 35,000ppm. The result obtained in
this study is within the acceptable limit. There was a
significant difference between the concentrations of
magnesium in the dump sites from the control and the tcal
= 2.72, when n=12. This might be due to the
indiscriminate disposal of magnesium containing waste at
the various dump sites.
The equation of the best fit and square root of the
curve is given as Y = -116.9x + 1438.1 with R2 = 0.2189
for sodium (Na) and Y = 11.833x + 504.17 with R2 =
0.1578 for magnesium as presented in Figure 6 for
various sampled area.
The concentrations of nickel as depicted above shows
that the concentration increase at the top and decrease
at the bottom and a sharp decrease at the control at
Mechanic Village. The same trend is observed at Orazi
refuse dump but with a slight decrease at the control. The
concentration increases from the top and peaked at the
bottom and finally decreases at the control at Iwofe dump
site. The natural range for the concentration of nickel is 0
to 100ppm. The values obtained in this study are within
the acceptance level.
There was a significant difference between the
concentrations of magnesium at the dump sites from the
control and the tcal = 2.89, when n=12. This revealed that
the uncontrolled disposal of wastes into the environment
can significantly increase the background concentration
of nickel thereby resulting to environmental problems.
Similar findings have been reported by Aluko et al.,
(2003).
140 Int. Res. J. Eng. Sci. Technol. Innov.
Ni
60
Linear (Ni)
P aram eter Conc entration (m g/k g)
50
y = 2.25x + 18.083
R2 = 0.1345
40
30
20
10
0
MVT
MVB
MVC
ORT
ORB
ORC
IWT
IWB
IWC
Sampled Area
Figure 7. Concentrations of Ni versus various dump sites.
The equation of the best fit and square root of the
equation is given as Y = 2.25x + 18.083 with R2 = 0.1345
is presented in Figure 7 for Nickel (Ni).
implying that the elements have not been sufficiently
leached to the subsurface.
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