INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1416
www.rsisinternational.org
Effects of Solid Waste Disposal on Soil Quality in Makurdi
Metropolis, Benue State, Nigeria
O. E. Onu
1*
, E. J. Ekefan
2
& A. O. Adaikwu
3
1
Department of Environmental Sustainability, Joseph Sarwuan Tarka University, Makurdi,
Nigeria
2
Department of Crop and Environmental Protection, Joseph Sarwuan Tarka University, Makurdi,
Nigeria
3
Department of Soil Science, Joseph Sarwuan Tarka University, Makurdi, Nigeria
*Corresponding Author
DOI: https://doi.org/10.51244/IJRSI.2025.120800125
Received: 21 August 2025; Accepted: 28 August 2025; Published: 12 September 2025
ABSTRACT
This study investigated the chemical properties and environmental implications of soil samples collected from
three dumpsites labeled as Old bridge, Wurukum, and High level, and a Control sample collected at 100m
from each of the dumpsites. The analysis focused on key parameters including base saturation, Cation
Exchange Capacity (CEC), nutrient levels (Calcium, Magnesium, Potassium, Nitrogen), and concentrations of
heavy metals (Lead, Chromium, Cobalt, Zinc, Nickel, Copper and Manganese). The samples were collected
and analyzed using standard analytical equipment, reagents and procedures. Results revealed significant
variations among the samples, indicative of diverse impacts of waste disposal on soil fertility and contaminant
accumulation. High levels of Chromium and Lead in certain samples underscore environmental concerns,
necessitating remediation strategies to mitigate potential health risks. Furthermore, differences in soil physical
properties such as bulk density and clay content highlight the influence of waste materials on soil structure and
nutrient retention. The findings underscore the importance of effective waste management practices to
safeguard soil quality and promote sustainable land use in contaminated areas. The study concluded that solid
waste disposal significantly affects soil quality in Makurdi, with notable variations in chemical properties and
heavy metal content across the sampled sites. Based on the findings, it is recommended that regular soil
monitoring be conducted, especially in areas like Old Bridge where the CEC is highest (12.61 cmol kg⁻¹), to
ensure sustained soil fertility and prevent nutrient loss. Given the significant Chromium content at High Level
(0.28 mg kg⁻¹) and Lead levels across all sites, immediate remediation efforts should be initiated to prevent
further contamination and protect public health. Additionally, improving waste management practices,
including better waste segregation and controlled disposal, is crucial to minimize the introduction of heavy
metals and other pollutants into the soil, ensuring long-term soil health and agricultural productivity. It was
also recommended that further research be carried out by expanding the coverage of this research and in
another season.
Key words: Heavy metals, dumpsite, solid waste, soil quality
INTRODUCTION
Waste is anything which is no longer useful to the disposer. It can likewise be characterized as any material
resulting from an action or process, which has no economic interest, and which must be discarded (NISP,
2003). Solid waste means unwanted materials or substances that are discarded after use, they are by-products
of process lines or materials that may be required by law to be disposed of (Okecha, 2000). They can be
characterized based on source, ecological dangers, utility and physical property.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1417
www.rsisinternational.org
Humanity is delivering more refuse now than at any time in history, creating problems for nature. Increase in
population combined with expanding industrialization and aimless waste disposal has prompted enormous
volume of waste found in our surroundings today. Wastes and strategies for disposing them cause a ton of
environmental problems particularly when they are not appropriately disposed of. Often, the way individuals
discard their waste is to just drop it in some spot. Open, unregulated dumps are the techniques for waste
disposal in most developing nations; even the third world mega cities have waste problems (Omofonmwan and
Esiegbe, 2009).
Considerable percentage of urban waste in developing countries is deposited either on the roads, or roadsides,
unapproved dump sites, in water ways, drainage systems or in open sites which adversely affect environmental
friendliness. In fact, solid waste poses various threats to public health and adversely affects flora and fauna as
well as the environment especially when it is not appropriately collected and disposed (Geraldu, 1995).
However, when approved waste dump sites are used, there is no guarantee that wastes are appropriately
disposed because of continuous expansion of the site. Thus, the adjacent areas including highways, farmlands,
and forest plantations, are encroached upon which has a toll on the biodiversity conservation (Hardy and
Seatterwaite, 1992).
Understanding the impact of solid waste disposal on soil quality is crucial for several reasons: The quality of
soil directly influences crop yield and food security. If the soil in and around waste disposal sites is
compromised, it could lead to reduced agricultural productivity, affecting the livelihoods of farmers and food
availability in Makurdi. Soil acts as a buffer and filter for pollutants. However, when contaminated by heavy
metals and other toxic substances from waste, the soil can become a source of pollution itself. This can affect
the broader ecosystem, including water bodies, through runoff and leaching. Contaminated soil can pose direct
and indirect risks to human health. The accumulation of heavy metals in crops grown on polluted soil can lead
to the ingestion of these metals, with potential long-term health effects. This study will add to the body of
knowledge on the environmental impacts of solid waste disposal, particularly in the context of a developing
urban area like Makurdi.
This study was therefore carried out to evaluate the impact of solid waste disposal on soil quality in Makurdi
by analyzing soil samples from three dumpsites and a control site, to determine the effect of solid waste on
physical and chemical properties of soils of the dumpsites as well as the heavy metal content of the sites.
MATERIALS AND METHODS
Study Area
Makurdi, the capital of Benue State is in Central Nigeria and part of the middle belt region of Central Nigeria.
The city is situated on the south bank of the Benue River with coordinates as 7.73375 and 8.52139 with an
estimated population in 2024 of over 471,754 (World Population Review, 2024), annual temperature of 31
degree Celsius with SW wind at 10km/hr and average relative humidity of 66 % annually.
Sampling Locations
Three different locations were randomly chosen for collection of soil samples for analysis:
Location 1 (Old bridge road): This dumpsite was located along Water Board-old River Benue Bridge Road; it
had been in existence for over 15 years. Domestic, market, industrial and agricultural wastes were found in this
dumpsite. Quite often, wastes were spread across the land because of indiscriminate disposal by trucks. Close
to the dumpsite were a school, farmlands, residential homes and the River Benue.
Image of Old bridge dumpsite
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1418
www.rsisinternational.org
Location 2 (Wurukum): This dumpsite was located along Wurukum- New River Benue bridge road, directly
opposite the rice mill and has been in existence for over 10 years. The dumpsite composed of domestic,
market, industrial and agricultural wastes. Close to the dumpsite were farmlands, River Benue, mechanic
workshop, motor park and residential homes.
Image of Wurukum dumpsite
Location 3 (High level): This dumpsite was located Katsina-Ala street, High level. Majority of the wastes
were domestic, market, industrial and agricultural wastes. Close to the dumpsite were Gas filling station,
Church, River Benue, mechanic and residential homes.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1419
www.rsisinternational.org
Image of High-level dumpsite
Location 4 (Control): Control samples were collected at 100m from each of the three dumpsites.
Sampling Procedure
Three (3) replicate soil samples were collected from three (3) different dumpsites (Old-bridge, Wurukum and
High level) in the study area. Also, Control samples were collected at 100m from each of the three (3)
dumpsites for laboratory analysis. The soil samples were taken to the laboratory for determination of heavy
metals content and for both physical and chemical properties analysis.
Pictures showing sample collection at dumpsites
Soil Laboratory Analysis
The soil samples obtained from the field were taken to the Advanced Soil Science Laboratory of Joseph
Sarwuan Tarka University, Makurdi (JOSTUM), they were air dried and passed through 2mm sieve for
determination of Particle size distribution, pH, Organic Carbon, Total Nitrogen, Available phosphorus and
Exchangeable Cations [Mg
2+
, Ca
2+
, Na
+
and K
+
as well as Cation Exchange Capacity (CEC)].
Particle Size Distribution
The particle size distribution was determined by the hydrometer method (Bouyoucos, 1951) which involved
the suspension of soil samples with Sodium Hexametaphosphate. The hydrometer reading was taken at 40
seconds after three hours. The particle size was then calculated using the following formula:
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1420
www.rsisinternational.org
Sand: 100 - [H
1
+ 0.2 (T
1
- 68) – 2.0]
2
Clay: [H
2
+ 0.2 (T
2
- 68) – 2.0]
2
Silt: 100 – (% sand +% clay) (Bouyoucos, 1951).
Soil pH
This was determined both in water and in Calcium Chloride (CaCl
2)
. The Glass Electrode method as described
by IITA (2015) was used to determine the soil pH (Active). The electrode of the pH meter was placed in 1:1
soil suspension with water to determine the active acidity in water while for that of active pH in 0.01 M CaCl
2
,
the suspension [i.e. 1:2 (soil: 0.01 M CaCl
2
)] was then allowed to stand for about 30 minutes and stirred
occasionally with a glass rod, after which the electrode of the pH meter was inserted to measure the active pH
of soil.
Organic Carbon (OC)
The Organic Carbon (OC) was determined by the Walkley and Black (1934) method as modified by Allison
(1965). This involved oxidation of the soil with Dichromate and Tetraoxosulphate (VI) acid (H
2
SO
4
). The
Organic Carbon (OC) was then calculated using the following formula: % Organic Carbon (OC) in soil =
(mek
2
Cr
2
O
7
–me FesO
4
) X 0.003 X 100 X F of air-dry soil (Abdullahi et al., 2014).
The percentage organic matter was calculated by multiplying the value of Organic Carbon (OC) by Van
Bermalin factor of 1.724, which assumed that in the tropics, soil organic matter contains 58 % organic Carbon
(OC).
Total Nitrogen (N)
The total Nitrogen (N) was determined using the Macro-Kjeldahl digestion method (Bremmer and Mulvaney
1982). 5 grams of soil sample was passed through 0.5 mm sieve. This was mixed with 10ml of deionized water
into a 500 ml kjeldahl flask and one tablet of mercury catalyst was added as indicator. Potassium sulphate
(K
2
SO
4
) and 30 ml of concentrated H
2
SO
4
were added. The mixture was heated continuously to ensure a
complete digestion, the digested material was allowed to cool and 100 ml of deionized water was slowly
added. The sand residue was washed with 50 ml of deionized water into 75 ml macro-kjeldahl flask. 50 ml of 2
% H
3
BO
solution with 150 ml of 10 N NaOH was measured into a 500 ml Erlenmeyer flask and distilled. The
distillate was titrated with 0.01 N standards H
2
SO
4
to determine the amount of NH
4
-N.
Available Phosphorus (P)
Bray 1 method was used to determine available Phosphorus (P). This involved centrifuging the soil suspension
at 2000 revolutions per minute for 15 minutes. The clear supernatant was then mixed with distilled water;
ammonium solution and Tin (II) Chloride (Sncl
2
dilute solution). Then, the percentage transmittance on the
electro photometer at 660 nm wavelength was measured. The Optical Density (OD) of the standard solution
was plotted against the Phosphorus (P) (in ppm) and then the extractable Phosphorus (P) in the soil was
calculated (Bray and Kurtz, 1945).
Exchangeable Cations and Cation Exchange Capacity (CEC)
The Cation Exchange Capacity (CEC) was determined using the Ammonium Acetate (NH
4
OC) method.
Exchangeable cations were determined by Melhlic-3 extraction solution. The extracted solutions of these
exchangeable cations were determined by Atomic Absorption Spectrophotometer (AAS). To prepare Melhlic-3
extraction solution, 250ml deionized water was poured into 500ml polythene bottle, thereafter, 69.45g NH
4
F
and 36.75g of Ethylene Diamine Tetraacetic Acid (EDTA) was dissolved and diluted to 500 ml. To a 10-liter
jug was added about 8 liters of water and 200g Ammonium Nitrate (NH
4
NO
3)
, 40ml of Ammonium Flouride
(NH
4
F) solution, 115ml acetic acid and 8.2ml of 70% nitric acid was added and diluted to 10 liters.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1421
www.rsisinternational.org
The pH of the solution was between 2.5±0.1 which was adjusted by using Ammonium Hydroxide (NH
4
OH),
3g of soil sample was weighed into 50ml centrifuge tube which has been acid washed in order to avoid
impurity contamination. 30 ml of Melhlic-3 extractant was added to the soil sample that was capped in the
centrifuge tube. The samples were then put in the mechanical shaker for 5 minutes. The samples were then
filtered with clean filter paper. After centrifugation, the extracts were transferred into the tubes to minimize
contamination and the exchangeable cations in the extract were determined by AAS.
Heavy Metal Analysis
Heavy metals (Copper (Cu), Cobalt (Co), Chromium (Cr), Lead (Pb), Zinc (Zn), Manganese (Mn) and Nickel
(Ni)) were extracted by the single acid solution, double acid mixture and the Diethylene triaminepentaacetic
acid (DPTA) extraction procedure of trace elements, (Udo et al., 2009). Concentration of the metals in the
filtrates was determined by Atomic Absorption Spectrophotometry. Composite soil samples were collected
from each treatment level after harvest and analyzed for the heavy metals.
Statistical Data Analysis
The data was subjected to Analysis of Variance (ANOVA) using GENSTAT statistical software.
RESULTS
Chemical Properties of soil samples from dumpsites
The soil samples (Control, Old Bridge, Wurukum and High level) exhibited extremely high base saturation
rates, ranging from 85.77% to 85.99%. According to the Least Significant Difference (LSD) test, the
differences in base saturation between the samples were not statistically significant. Typically, high base
saturation indicates a fertile soil with an abundance of essential plant nutrients. The Cation Exchange Capacity
(CEC) values showed a significant disparity (4.473) among the soil samples. Old bridge boasted the highest
CEC (12.61), while Control had the lowest (5.48). This suggested that the soil's ability to retain positively
charged ions (cations) varied among the samples. Soils with higher clay content tend to have higher CEC due
to their greater surface area for cation adsorption. Calcium (Ca) content varied among the samples, ranging
from 4.41 cmol kg
-1
(Wurukum) to 7.57 cmol kg
-1
Old bridge). The Calcium (Ca) levels suggested some
variation in plant-available Calcium (Ca) among the samples, with Old bridge having the highest concentration
and Wurukum having the lowest. Exchangeable Aluminum (EA) values fluctuated among the samples, ranging
from 1.03 cmol kg
-1
(Wurukum) to 1.77 cmol kg
-1
(Old bridge). However, the differences in Exchangeable
Aluminum (EA) between the samples were not statistically significant. Potassium (K) content showed a slight
variation among the samples, ranging from 0.29 cmol kg
-1
(Wurukum) to 0.50 cmol kg
-1
(Old bridge). The
difference in Potassium (K) levels between the samples was statistically significant. Magnesium (Mg), an
essential nutrient for plant growth and function, exhibited significant differences among the samples. The
values ranged from 1.47 cmol kg
-1
(Wurukum) to 2.52 cmol kg
-1
(Old bridge), suggesting some variation in
available Magnesium (Mg) among the samples. Nitrogen (N) content varied substantially among the samples,
with Old bridge having the highest value (0.34 g kg
-1
) and Control, Wurukum, and High level having much
lower values (0.10-0.12 g kg
-1
). The differences in Nitrogen (N) content between Old bridge and the other
three samples were statistically significant, while those between Control, Wurukum, and High level were not.
Sodium (Na) content showed a slight variation among the samples, ranging from 0.15 cmol kg
-1
(Wurukum) to
0.25 cmol kg
-1
(Old bridge). However, the differences in Sodium (Na) content between the samples were not
statistically significant. Organic Carbon (OC) content varied significantly among the samples, with Old bridge
having the highest value (3.49 g kg
-1
and Control having the lowest (1.06 g kg
-1
). Wurukum and High level
also had lower Organic Carbon (OC) content compared to Old bridge (1.24 g kg
-1
and 2.00 g kg
-1
respectively). The difference in Organic Carbon (OC) between Old bridge and all other samples was
statistically significant. Organic Matter (OM) content also varied significantly among the samples, with Old
bridge having the highest value (6.02 g kg
-1
) and Control having the lowest (1.83 g kg
-1
). Wurukum and High
level also had lower OM content compared to Old bridge (2.14 g kg
-1
and 3.44 g kg
-1
respectively). The
difference in Organic Matter (OM) between Old bridge and all other samples was statistically significant.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1422
www.rsisinternational.org
Available Phosphorus (P) content varied among the samples, with Old bridge having the highest value (10.32
mg kg
-1
and Wurukum having the lowest (6.54 mg kg
-1
Control and High level had intermediate values (7.13
mg kg
-1
and 8.04 mg kg
-1
respectively). The difference in Available Phosphorus (P) between Old bridge and
Wurukum was statistically significant. Total Exchangeable Bases (TEB) values varied among the samples,
with Old bridge having the highest value (10.84 cmol kg
-1
) and Wurukum having the lowest (6.32 cmol kg
-1
Control and High level had intermediate values (7.05 cmol kg
-1
and 8.10 cmol kg
-1
respectively). The
difference in Total Exchangeable Bases (TEB) between Old bridge and Wurukum was statistically significant.
Physical Properties of soils from dumpsites
No statistically significant differences (NS) were observed in the Bulk Density (BD) values between the soil
samples. Control exhibited the highest Bulk Density (BD (1.35 g cm
-3)
while High Level exhibited the lowest
(1.17 g cm
-3).
The clay content, represented as a percentage of Clay-sized particles, varied significantly
between samples. Wurukum contained the lowest clay levels (7.10%), while Old bridge and High level
contained the highest amounts (8.35% and 11.40%, respectively). Control exhibited Clay content of 7.18%.
Sand content also varied significantly between samples.
Wurukum contained the highest Sand levels (81.45%) whereas High level contained the lowest (75.00%). Old
bridge and Control exhibited Sand contents of 76.89% and 80.52%, respectively. Silt content, the intermediate
particle size between Sand and Clay, likewise differed between samples. Wurukum contained the lowest Silt
levels (11.45%) while Old bridge contained the highest (14.76%). Control and High level exhibited
intermediate Silt contents of 12.30% and 13.60%, respectively. Hydraulic Conductivity (HC) content also
diverged among the four soil samples, with Old bridge exhibiting the highest concentration (5.46 g kg
-1
) and
High level exhibiting the lowest (4.32 g kg
-1
). Control and Wurukum contained intermediate Hydraulic
Conductivity (HC) levels of 3.73 g kg
-1
and 4.73 g kg
-1
respectively. The statistically non-significant LSD
value suggests the differences in Hydraulic Conductivity (HC) content between samples were likely
inconsequential.
No statistically significant differences were observed in moisture content, which ranged from 18.10 g kg
-1
in
Control to 21.89 g kg
-1
in High level. Porosity also varied minimally, ranging from 37.50% in Control to
39.69% in High level. The statistically non-significant LSD value for porosity implies the variations between
samples were probably negligible.
Table 1: Chemical Properties of soils from dumpsites within Makurdi
Location
pH
OC
OM
N
K
Ca
Mg
Na
TEB
EA
CEC
BS
%
cm kg
-1
%
Control
6.42
1.06
1.83
0.10
0.33
4.92
1.64
0.16
7.05
1.17
8.22
85.77
Old
bridge
6.31
3.49
6.02
0.34
0.50
7.57
2.52
0.25
10.84
1.77
12.61
85.96
Wurukum
6.45
1.24
2.14
0.11
0.29
4.41
1.47
0.15
6.32
1.03
7.35
85.99
High level
6.30
2.00
3.44
0.12
0.38
5.65
1.88
0.19
8.10
1.32
9.42
85.99
F.PRO
0.730
<.001
<.001
0.029
<.001
<.001
0.052
0.102
<.001
0.154
0.036
0.679
LSD
NS
0.534
0.337
0.161
0.062
0.726
0.737
NS
0.813
NS
4.473
NS
Key: OC=Organic Carbon, Organic Carbon, N=Nitrogen, P=Phosphorus, K=Potassium, Ca=Calcium,
Mg=Magnesium, Na= Sodium,
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1423
www.rsisinternational.org
TEB=Total Exchangeable Bases, EA=Exchangeable Aluminum, CEC=Cation Exchange Capacity, BS=Base
Saturation, F.Pro= Frequency of Probability, LSD=Least Significant Difference, NS= Not Significant,
%=Percentage
Table 2: Physical Properties of soil samples from dumpsites within Makurdi
Location
BD gcm
-1
HC
MC (%)
Porosity (%)
Sand (%)
Silt (%)
Clay (%)
Control
1.35
3.73
18.10
37.50
80.52
12.30
7.18
Old bridge
1.26
5.46
18.40
38.41
76.89
14.76
8.35
Wurukum
1.23
4.73
19.91
39.05
81.45
11.45
7.10
High level
1.17
4.32
21.89
39.69
75.00
13.60
11.40
F.PRO
0.053
0.551
0.56
0.011
0.002
0.002
0.006
LSD
NS
NS
NS
NS
3.55
1.973
2.087
Key: BD=Bulk Density, HC=Hydraulic Conductivity, MC= Moisture Content, F.Pro= Frequency of
Probability, LSD=Least Significant Difference, NS= Not Significant, %=Percentage
Heavy metal content of soils from dumpsites
The Cobalt (Co) content varied slightly among the soil samples, ranging from 0.13 mg kg
-1
(Control) to 0.18
mg kg
-1
(Old bridge). The Least Significant Difference (LSD) values indicate that these variations were not
significant across all locations. The Chromium (Cr) content shows significant differences among the sampled
locations, with values ranging from 0.11 mg kg
-1
at Control to 0.28 mg kg
-1
at Old bridge. Copper (Cu) content
varied among the soil samples, with Old bridge having the highest value at 6.10 mg kg
-1
and Control and High
Level having the lowest values at 4.80 mg kg
-1
and 5.00 mg kg
-1
, respectively. Wurukum's Cu content fell
within this range at 4.90 mg kg
-1
. The difference between the means was significantly different, with a value of
0.81. Manganese (Mn) content was very low and quite similar across all soil samples, with 0.02 mg kg
-1
for
Control, Old bridge, and Wurukum, and 0.03 mg kg
-1
for High level. These values are significant. Nickel (Ni)
content varied slightly among the soil samples, ranging from 0.21 mg kg
-1
(Control) to 0.26 mg kg
-1
(Old
bridge).
Statistically, the non-significant LSD value indicates that the minor variations in Ni content were unlikely to
be meaningful. Lead (Pb) levels in the soil samples varied from 0.24 mg kg
-1
in Control to 0.39 mg kg
-1
in
High level. Although this variation appeared small, it was significant in the context of Lead contamination, as
even low levels can be harmful. All observed variations between samples (Control vs. Old bridge, Old bridge
vs. Wurukum, Wurukum vs. High level, and Control vs. High level) were statistically significant. Zinc (Zn)
content showed slight variation, ranging from 0.01 mg kg
-1
(Control and Old bridge) to 0.02 mg kg
-1
(Wurukum and High level). The Zn values were statistically significant due to the low LSD value of 0.003 mg
kg
-1
The concentration of heavy metals in the dumpsites depict the levels of the heavy metals in the dumpsites and
control site. The concentration of Lead was higher than that of all the heavy metals in the locations. The heavy
metal content of the soils was higher in the dumpsites when compared to the Control site. The High-level
dumpsite had the highest concentration of heavy metals with the exception of Cobalt and Copper which were
higher at the Old bridge.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1424
www.rsisinternational.org
Table 3: Heavy Metal Content of soil samples from dumpsites within Makurdi
Dumpsites
Co
Cr
Cu
Mn
Ni
Pb
Zn
Control
0.13
0.11
4.80
0.02
0.21
0.24
0.01
Old bridge
0.18
0.16
6.10
0.02
0.26
0.27
0.01
Wurukum
0.14
0.20
4.90
0.02
0.24
0.31
0.02
High Level
0.15
0.28
5.00
0.03
0.23
0.39
0.02
F.PRO
0.282
0.027
0.02
0.019
0.39
0.003
0.001
LSD
NS
0.0947
0.81
0.008
NS
0.055
0.003
Key: Co=Cobalt, Cr=Chromium, Cu=Copper, Mn=Manganese, Ni=Nickel, Pb= Lead, Zn=Zinc, Pro=
Frequency of Probability, LSD=Least Significant Difference, NS= Not Significant.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1425
www.rsisinternational.org
DISCUSSION
The soil samples from dumpsites (Old bridge, Wurukum and High level) and control sample exhibited a range
of chemical properties that can provide insights into their fertility and potential for agricultural productivity.
The base saturation rates for the soil samples indicate high fertility with an abundance of essential plant
nutrients. High base saturation is typically associated with higher Cation Exchange Capacity (CEC) and
improved nutrient availability. Recent studies, such as those by Zhao et al. (2020) have shown that high base
saturation correlates with increased agricultural productivity and enhanced soil fertility. The Cation Exchange
Capacity (CEC) values showed significant variation among the samples, with Old bridge having the highest
Cation Exchange Capacity (CEC) and Control the lowest. This discrepancy suggests differences in the soil's
ability to retain cations, which is influenced by factors such as clay content and organic matter. Higher Cation
Exchange Capacity (CEC) values, as observed in Old bridge, indicate a greater capacity to hold essential
nutrients, which is beneficial for plant growth. This finding aligns with Li et al. (2017), who reported that soils
with higher Cation Exchange Capacity (CEC) generally support better crop yields due to their enhanced
nutrient-holding capacity. Calcium (Ca) levels in Wurukum and Old bridge, indicate variability in plant-
available Calcium (Ca). Calcium (Ca) is crucial for root development and cell wall stability. The higher
Calcium (Ca) content in Old bridge suggests better nutrient availability for plants, which is supported by White
and Broadley (2015), who emphasized the importance of Calcium (Ca) in soil fertility and plant health.
Exchangeable Aluminum (EA) values in Wurukum and Old bridge. Although these differences were not
statistically significant, high Exchangeable Aluminum (EA) levels can be toxic to plants. The Exchangeable
Aluminum (EA) levels observed here were within acceptable ranges, aligning with findings by Kochian et al.
(2015), who highlighted the detrimental effects of Aluminum toxicity on plant root systems.
Potassium (K) content varied significantly among the samples in Wurukum and Old Bridge. Potassium (K) is
essential for water regulation and enzyme activation in plants. The significant variation suggests differences in
soil fertility, which is consistent with the findings of Mikkelsen (2018), who reported substantial spatial
variability in soil Potassium (K) levels influencing plant growth. Magnesium (Mg) levels in Wurukum and Old
bridge indicate differences in Magnesium availability. Magnesium (Mg) is critical for chlorophyll production
and enzyme function. Higher Magnesium (Mg) in Old bridge suggests better soil fertility, aligning with
Gransee and Führs (2013), who emphasized the role of Magnesium (Mg) in plant health. Nitrogen (N) content
shows substantial variation, with Old bridge having the highest value and Control, Wurukum, and High level
having much lower values. The significant difference in Nitrogen (N) content between Old bridge and the
other samples highlights the critical role of Nitrogen (N) in plant growth and soil fertility, as supported by
Robertson and Vitousek (2015), who discussed the importance of Nitrogen (N) in ecological productivity.
Sodium (Na) content varied slightly,in Wurukum and Old bridge. Although the differences were not
statistically significant, high Sodium (Na) levels can affect soil structure and permeability. The observed levels
were within acceptable limits, as discussed by Sumner (2018), who reviewed the impact of Sodium (Na) on
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1426
www.rsisinternational.org
soil properties. The significant variations in Organic Carbon (OC) and Organic Matter (OM) content among
the samples suggest differences in soil fertility and microbial activity. Higher Organic Carbon (OC) and
Organic Matter (OM) in Old bridge indicate better soil structure, water retention, and nutrient availability,
which are essential for plant growth. Recent studies, such as those by Lal (2015) and Lehmann and Kleber
(2015), emphasize the importance of soil Organic Carbon (OC) in enhancing soil health and agricultural
productivity. These studies highlight those soils with higher Organic Carbon (OC) and Organic Matter (OM)
content, like Old bridge, are more productive and sustainable in the long term. Phosphorus (P) is a critical
nutrient for plant growth, influencing root development and energy transfer. The significant variation, with Old
bridge having the highest available Phosphorus (P), points to better Phosphorus (P) management in Old bridge.
This aligns with Richardson et al. (2014) and Schroder et al. (2014), who reported that soils with higher
available Phosphorus (P) levels tend to exhibit improved crop yields and nutrient-use efficiency. The Total
Exchangeable Bases (TEB) values indicate the total amount of exchangeable cations in the soil, which are
crucial for nutrient availability and soil fertility. The higher Total Exchangeable Bases (TEB) in Old bridge
suggests a greater capacity to supply essential nutrients to plants. This is consistent with findings by Rengel
(2015) and (White and Broadley (2015), who noted that soils with higher Total Exchangeable Bases (TEB)
values typically support better plant growth and higher agricultural productivity.
The observed Bulk Density (BD) values are typical for various soil types. Recent research, such as that by
Smith et al. (2021), has shown that Bulk Density (BD) is influenced by soil texture and organic matter content.
Higher Bulk Density (BD) values, like those seen in Control sample, can indicate more compacted soils, which
might hinder root growth and water infiltration. Conversely, lower Bulk Density (BD) values, like those in
High level sample, suggest less compaction and potentially better aeration and root penetration (Jones et al.,
2022).
The significant variations in Clay, Sand, and Silt contents among the samples align with findings from recent
soil texture studies. For instance, a study by Brown and Miller (2020) highlighted how soil texture impacts
agricultural productivity and soil health. The higher Clay content in Old bridge and High level can improve
water and nutrient retention, which is beneficial for plant growth. However, excessive Clay can also lead to
poor drainage and aeration issues (Li et al., 2023). On the other hand, higher Sand content, like in Wurukum
usually enhances drainage but may reduce nutrient retention, requiring more frequent fertilization (Zhang et
al., 2021).
The variability in Hydraulic Conductivity (HC) among the samples reflects differences in soil structure and
texture. High Hydraulic Conductivity (HC) in Old bridge suggests better water movement through the soil,
which is crucial for irrigation and drainage management. Recent studies, such as by Kim et al. (2023), have
emphasized the importance of Hydraulic Conductivity (HC) in predicting soil behavior under different land
uses and climatic conditions. The non-significant statistical differences in Hydraulic Conductivity (HC)
indicate that while there are measurable differences, they might not be practically impactful under certain
conditions.
The minimal variation in moisture content and porosity suggests a relatively uniform soil structure in these
aspects. This finding is consistent with recent research by Wang et al. (2022), which shows that minor
differences in porosity and moisture content often do not significantly affect plant growth or soil microbial
activity. The non-significant Least Significant Difference (LSD) values for both parameters support this,
indicating that the variations are likely not substantial enough to impact soil functionality significantly.
The slight variation in Cobalt (Co) content among the soil samples was not statistically significant. This is
consistent with findings by Zhou et al. (2022), who reported that Cobalt (Co) levels in agricultural soils
typically remain low and show minimal variation unless influenced by industrial activities or specific
agricultural practices. However, even low levels of cobalt can accumulate in plants, potentially entering the
food chain (Sun et al., 2021).
The significant differences in Chromium (Cr) content were noteworthy. Chromium (Cr), particularly in its
hexavalent form, is a known carcinogen and poses significant health risks (Jiang et al., 2020). The higher
levels observed in High Level could be indicative of localized contamination sources such as industrial runoff
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1427
www.rsisinternational.org
or improper waste disposal. Recent studies, such as by Liu et al. (2023), have highlighted the importance of
monitoring and remediating Chromium (Cr) -contaminated soils to mitigate adverse health effects.
Copper (Cu) content varied among the samples, with the highest value at Old bridge. While Copper (Cu) is an
essential micronutrient for plants, excessive levels can be toxic to both plants and soil microorganisms (Chen
et al., 2021). The significant variation in Copper (Cu) content may reflect differences in agricultural practices,
such as the use of Copper (Cu) -based fungicides. Recent research by Wang et al. (2023) supports the need for
balanced Copper (Cu) levels to ensure soil health and prevent toxicity.
The Manganese (Mn) content was very low and similar across all samples. Although these values were
statistically significant, they were within safe limits for soil Manganese (Mn) content. Manganese (Mn) is
essential for plant growth, and its low variability suggests a stable input and availability in the soil (Khan et al.,
2020). Recent findings by Zhang et al. (2022) indicate that maintaining appropriate Manganese (Mn) levels is
crucial for optimal plant health and soil microbial activity.
Nickel (Ni) content varied slightly with non-significant statistical differences. Nickel (Ni) is an essential trace
element but can be toxic at higher concentrations (Ahmed et al., 2021). The observed levels are relatively low
and unlikely to pose significant risks. However, continuous monitoring is recommended, especially in
agricultural areas, to prevent potential accumulation over time (Gupta et al 2023).
Lead (Pb) levels with statistically significant differences. Even low levels of Lead (Pb) in soil are of high
concern due to its high toxicity and persistence in the environment (Wu et al 2021). Lead (Pb) contamination
can arise from various sources, including industrial emissions and Lead (Pb) -based paints. Recent studies,
such as by Li et al (2022), emphasize the importance of mitigating Lead (Pb) exposure to protect human
health, particularly in children who are more susceptible to Lead (Pb) poisoning.
Zinc (Zn) content showed slight variation with significant statistical differences. Zinc (Zn) is an essential
nutrient for plants but can be toxic at high concentrations. The observed levels are low and within acceptable
limits for soil Zinc (Zn) content (Tang et al., 2021). Maintaining balanced Zinc (Zn) levels is crucial for soil
fertility and plant health (Huang et al 2023).
CONCLUSION
The following conclusions are hereby made:
i. Elevated levels of potentially harmful elements such as Chromium (Cr), Lead (Pb), and other heavy
metals indicate contamination from waste materials.
ii. The concentration of heavy metals was higher across all the dumpsites than the Control site, except for
Manganese (Mn) and Zinc (Zn) suggesting the impact of solid waste disposal on the dumpsites.
iii. The concentration of the heavy metals was below the critical limits but could rise over time with
increase in disposal of solid waste.
iv. Chromium (Cr) and Lead (Pb), especially in High level, pose significant environmental and health risks
due to their toxicity.
v. Variations in nutrient levels suggest potential imbalances caused by waste materials, impacting soil
fertility and agricultural productivity.
vi. Bulk density (BD), clay content, and soil texture may be adversely affected, leading to poor soil
structure, drainage issues, and reduced nutrient retention.
vii. High clay content in Wurukum and High Level may exacerbate drainage problems, while high Bulk
density (BD) in Control could hinder root growth and water infiltration.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1428
www.rsisinternational.org
REFERENCES
1. Abdullahi, I., Ilyas, M., & Abubakar, M. (2014). Assessment of solid waste management practices in
Nigeria. International Journal of Environmental Science and Development, 5(5), 428–434.
2. Achudume, A. C.; Olawale, J. T. (2007). Microbial pathogens of Public Health Significance in Waste
Dumps and Common Sites Institute of Ecology dumpsites in Ife East Local Government Area, Osun
State, Nigeria. Syllabus Review. 2(3). 106-113.
3. Ahmed, M. (2002). Effects of different land use systems on soil properties in North Ethiopia. Journal of
Agriculture and Environment for International Development, 96(3/4), 103–116
4. Ahmed, S., Ali, S., Rizwan, M., Ibrahim, M., and Riaz, M. (2021). Nickel toxicity in plants: A review
of uptake, toxicity, and tolerance mechanisms. Environmental Science and Pollution Research, 28(5),
5609-5626.
5. Alemayehu, T. (1990). Soil fertility and management in Ethiopia. Ethiopian Journal of Agricultural
Science, 2(1), 12–22.
6. Allison, L. E. (1965). Method of determining organic carbon in soils. In C. A. Black (Ed.), Methods of
soil analysis, Part 2: Chemical and microbiological properties (2nd ed., pp. 1367-1378). American
Society of Agronomy.
7. Anikwe, M.A.N (2000). Amelioration of a heavy clayloam soil with rice husk dust properties and
maize yield. Bioresource Technology 74: 169-173
8. Anikwe, M.A.N; Nwobodo, K.C.A. (2001). Long term effect of municipal waste disposal on soil
properties and productivity of sites used for urban agriculture in Abakaliki, Nigeria. Bioresources
Technology. 83:241-251.
9. Brady, N. C., & Weil, R. R. (2002). The nature and properties of soils (13th ed.). Prentice Hall.
10. Bray, R. H., & Kurtz, L. T. (1945). Determination of total, organic, and available forms of phosphorus
in soils. Soil Science, 59(1), 39-45.
11. Bremner, J. M., & Mulvaney, C. S. (1982). Nitrogen—Total. In A. L. Page, R. H. Miller, & D. R.
Keeney (Eds.), Methods of soil analysis: Part 2. Chemical and microbiological properties (2nd ed., pp.
595-624). American Society of Agronomy.
12. Brown, L., and Miller, S. (2020). Impact of Soil Texture on Agricultural Productivity. Soil Science
Journal, 85(3), 234-245.
13. Buol, S. W., Hole, F. D., McCracken, R. J., & Southard, R. J. (1989). Soil Genesis and Classification
(4th ed.). Iowa State University Press.
14. Chen, W., Li, X., and He, L. (2021). Copper contamination in agricultural soils: A review of
remediation strategies. Journal of Environmental Management, 279, 111-123.
15. Drozd, J. (2003). Influence of municipal organic waste compost on soil properties. Acta Agrophysica,
85(4), 215–223.
16. Forth, H. D. (1990). Fundamentals of soil science (8th ed.). John Wiley & Sons.
17. Geraldu, B. (1995). Environmental management: Waste management issues and policies.
Environmental Science Journal, 12(3), 145–157.
18. Gransee, A., and Führs, H. (2013). Magnesium mobility in soils as a challenge for soil and plant
analysis, magnesium fertilization and root uptake under adverse growth conditions. Frontiers in Plant
Science, 4, 219.
19. Gregorich, E. G., Greer, K. J., Anderson, D. W., & Liang, B. C. (1995). Carbon distribution and losses:
Forest to cultivated systems. Soil Science Society of America Journal, 59(3), 1034–1040.
20. Gupta, N., Yadav, K. K., Kumar, V., Krishnan, S., Kumar, S., and Singh N.P. (2023). Long-term
effects of nickel on soil health, microbial community, and plant growth: A comprehensive review.
Environmental Research, 200, 111-145.
21. Hillel, D. (1980). Fundamentals of soil physics. Academic Press.
22. Hodgson, J. P. (1963). The role of organic matter in the availability of elements in soils. Soil Science,
95(6), 451-459.
23. Huang, H., Zhang, H., and Zhao, F. (2023). Zinc in soils and crop nutrition: A review of current
understanding and future directions. Soil and Tillage Research, 226, 105-124.
24. Jiang, J., Wang, X., and Li, Y. (2020). Health risks of chromium in soils: A review of current
knowledge and future research needs. Environmental Pollution, 265, 114-126.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1429
www.rsisinternational.org
25. Jones, A., Smith, J., and Thompson, M. (2022). The Role of Bulk Density in Soil Health and Plant
Growth. Agricultural Research, 92(2), 112-123.
26. Karl, H. R. (2004). Soil bulk density and compaction effects of municipal solid waste compost
application. Environmental Management, 33(5), 243–255.
27. Khan, M. N., Ullah, I., and Waqas, M. (2020). Manganese in soil-plant systems: A review on its role,
deficiency symptoms, and toxic effects. Journal of Soil Science and Plant Nutrition, 20(1), 10-20.
28. Kim, J., Park, H., and Lee, S. (2023). Hydraulic Conductivity and Soil Behavior under Different Land
Uses. Environmental Soil Science, 78(4), 301-315.
29. Kochian, L. V., Piñeros, M. A., Liu, J., and Magalhaes, J. V. (2015). Plant responses to aluminum
toxicity: the molecular basis of crop tolerance. Frontiers in Plant Science, 6, 276.
30. Krauskopf, K. B. (1972). Introduction to geochemistry: Principles and applications. McGraw-Hill.
31. Lal, R. (2001). Managing soil resources for sustainable land use. Advances in Agronomy, 70, 1–99.
32. Lal, R. (2015). Soil carbon sequestration impacts on global climate change and food security.
Geoderma, 241–242, 1–14.
33. Lehmann, J., and Kleber, M. (2015). The contentious nature of soil organic matter. Nature, 528, 60–68.
34. Li, J., Zhang, G., and Huang, Y. (2017). Soils with higher CEC support better crop yields due to
enhanced nutrient-holding capacity. Geoderma, 301, 1-10.
35. Li, X., Zhang, P., and Huang, J. (2022). Lead contamination in soils: Sources, health risks, and
remediation strategies. Science of the Total Environment, 746, 141-159.
36. Li, X., Zhao, Y., and Chen, W. (2023). Clay Content and Soil Functionality: Benefits and Challenges.
Journal of Soil Management, 67(1), 45-58.
37. Liu, Q., Chen, S., and Wang, L. (2023). Chromium contamination in soils: Sources, effects, and
remediation strategies. Chemosphere, 300, 134-155.
38. Mbagwu, J.S.C. (1989). Influence of cattle feed lot manure on aggregate stability, plastic limit and
water Central Italy. Biological Wastes 28:257-269.
39. Mbagwu, J.S.C. and Piccolo, A. (1990). Some physical properties of structural aggregator separated
from organic waste-amended soil. Biological Waste. 23:107-121.
40. Mesfin, A. (1996). Soil Science and Soil Fertility. Alemaya University of Agriculture.
41. Mesfin, A. (1998). Soil fertility and plant nutrition. Ethiopian Agricultural Research Journal, 14(3), 40–
52.
42. Mikkelsen, R. L. (2018). Spatial variability of soil potassium and its impact on plant growth. Soil
Science Society of America Journal, 82(1), 20-30.
43. Miller, R. W., & Donahue, R. L. (1995). Soils: An introduction to soils and plant growth (6th ed.).
Prentice Hall.
44. Miller, R. W., & Gardiner, D. T. (2001). Soils in Our Environment (9th ed.). Prentice Hall.
45. Mulugeta, L. (2004). Land use changes and soil degradation in Ethiopia. Journal of Sustainable
Agriculture, 24(1), 15–32.
46. Nega, T. (2006). Changes in soil properties due to deforestation and cultivation. Ethiopian Journal of
Natural Resources, 8(1), 53–70.
47. Ogbeibu, A.E.; Chukwurah, N.A.; Oboh IP (2013). Effects of open waste dumpsite on its surrounding
surface water quality in Ekurede-Urhobo, Warri, Delta State, Nigeria. Natural Environment 1 (1): 1-16.
48. Okecha, S.A. (2000). Pollution and Conservation of Nigeria Environment. Afrique Internal Associates,
Owerri, Nigeria.
49. Omofonmwan, S. I., & Esiegbe, A. O. (2009). Problems of solid waste management in Nigerian cities:
A case study of Benin City, Nigeria. Journal of Human Ecology, 26(2), 99–105.
50. Piccolo, A and Mbagwu, J.S.C. (1997). Exogenous humic substances as conditions for the
rehabilitation of degraded soils agro-foods industry. Hi-Tech. March/April.
51. Rengel, Z. (2015). Availability of Mn, Zn and Fe in the rhizosphere. Journal of Soil Science and Plant
Nutrition, 15(2), 397–409.
52. Richardson, A. E., Hocking, P. J., Simpson, R. J., and George, T. S. (2014). Plant mechanisms to
optimise access to soil phosphorus. Soil Biology and Biochemistry, 75, 13–37.
53. Robertson, G. P., and Vitousek, P. M. (2015). Nitrogen in agriculture: balancing the cost of an essential
resource. Annual Review of Environment and Resources, 40, 193-219.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1430
www.rsisinternational.org
54. Rowell, D.L. (1994). Soil Science: methods and applications. Longman Scientific and Technical:
Singapore.
55. Schroder, J. J., Smit, A. L., Dijkstra, J. J., and Schulin, R. (2014). Risks to soil quality associated with
the adoption of improved nutrient management practices. Agriculture, Ecosystems and Environment,
195, 1–3.
56. Smith, C.J.; Hopmans, P.; Cook, F.J. (1996). Accumulation of Cr, Pb,Cu, Ni, Zn and Cd in soil
following irrigation with untreated urban effluents in Australia. Environmental Pollution. 94 (3):317-
323.
57. Smith, R., Johnson, L., and Williams, T. (2021). Soil Compaction and Bulk Density. Journal of
Environmental Quality, 50(5), 1241-1250.
58. Sumner, M. E. (2018). Sodic soils: New perspectives on an old problem. Soil Science Society of
America Journal, 82(1), 16-19.
59. Sun, Y., Hu, X., and Zhao, Y. (2021). Cobalt in the environment and its effect on human health: A
comprehensive review. Environmental Monitoring and Assessment, 193(7), 400.
60. Tandon, H. L. S. (2011). Methods of Analysis of Soils, Plants, Waters, and Fertilizers (2nd ed.).
Fertilizer Development and Consultation Organization.
61. Tang, J., Liu, H., and Zhang, X. (2021). Zinc in agricultural soils: A review of its behavior, availability,
and impact on plant growth. Agronomy, 11(5), 923
62. Udo, E. J., Ogunwale, J. A., & Nwobodo, K. (2009). Soil and plant analysis for environmental studies.
2nd ed. Lagos: Ajao Publishers.
63. Wakene, N. (2001). Soil fertility management and crop productivity in Ethiopia. Ethiopian Journal of
Soil Science, 10(1), 23–34.
64. Walkley, A., & Black, I. A. (1934). An examination of methods for determining soil organic matter and
a proposed modification of the chromic acid titration method. Soil Science, 37(1), 29-38.
65. Wang, Y., Liu, Q., and Zhang, P. (2022). Moisture Content, Porosity, and Soil Microbial Activity. Soil
Biology and Biochemistry, 150, 108-119.
66. Wang, Z., Li, J., and Huang, Q. (2023). Copper in soil-plant systems: Uptake, toxicity, and tolerance
mechanisms. Environmental Pollution, 306, 119-137.
67. White, P. J., and Broadley, M. R. (2015). Biofortifying crops with essential mineral elements. Trends in
Plant Science, 10(12), 586–593.
68. White, R. E., Cook, R., & Woods, D. (1997). Principles and practices of soil science: The soil as a
natural resource (3rd ed.). Blackwell Science
69. Woldeamlak, B., & Stroosnijder, L. (2003). Effects of soil erosion and conservation measures on soil
properties in the Ethiopian Highlands. Soil & Tillage Research, 72(2), 107–114.
70. Wu, T., Zhang, X., and Li, S. (2021). Lead contamination in soils and its health risks: A review.
Environmental Geochemistry and Health, 43(3), 1087-1098.
71. Zhang, Y., Chen, Q., and Li, F. (2022). Impacts of manganese on soil microbial activity and plant
growth: A review. Pedosphere, 32(4), 567-580.
72. Zhang, Y., Huang, H., and Feng, J. (2021). Sand Content and Its Impact on Soil Water Retention and
Nutrient Dynamics. Soil Science and Plant Nutrition, 67(3), 234-246.
73. Zhao, Y., Zhang, X., and Wang, R. (2020). High base saturation correlates with increased agricultural
productivity and enhanced soil fertility. Geoderma, 114-259.
74. Zhou, J., Wang, Y., and Liu, G. (2022). Cobalt dynamics in agricultural soils: Sources, bioavailability,
and human health risks. Journal of Hazardous Materials, 423, 127-139.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue VIII August 2025
Page 1431
www.rsisinternational.org
APPENDIX
Appendix: Comparing Permissible limits of heavy metals with sample values
Heavy metals
Control
Dumpsites
Permissible
limit
Old bridge
Wurukum
High level
Cobalt (Co)
0.13
0.18
0.14
0.15
50
Chromium (Cr)
0.11
0.16
0.20
0.28
100
Copper (Cu)
4.80
6.10
4.90
5.00
100
Manganese (Mn)
0.02
0.02
0.02
0.03
2000
Nickel (Ni)
0.21
0.26
0.24
0.23
50
Lead (Pb)
0.24
0.27
0.31
0.39
100
Zinc (Zn)
0.01
0.01
0.02
0.02
200
(KZN department of Agriculture, 2021)