Abstract Concentration levels of tin (Sn), antimony (Sb), titanium (Ti), bismuth (Bi) and thallium (Tl)   were assessed in refuse dump and background soils in urban (Accra and Kumasi) and rural (Sataso) communities in Ghana using a ThermoFinnigan Element 2 high resolution inductively coupled plasma mass spectrometric (HR-ICP-MS) instrument. Concentrations of the metals were lower than known normal mineral soil levels, however, based on the Igeo scale the refuse dump soils from Accra and Kumasi (urban communities) were &apos;Moderate to strongly polluted&apos; with Sn and Sb while that from Sataso a rural community was classified as &apos;Moderately polluted&apos; with Sn and Sb. The refuse dump soils from the urban communities were &apos;Unpolluted to moderately polluted&apos; with Ti and that from the rural community was classified as &apos;Practically unpolluted&apos; with Ti. All the refuse dump soils were, &apos;Practically unpolluted&apos; with Bi and Tl. Differences in the pollution levels may probably be assigned to differences in population and activities in the communities

Balázs Berlinger

Emmanuel Dartey

Kofi Agyarko

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ARCH. ENVIRON. SCI. (2011), 5, 101-105 
101 
Assessment of metal levels of some refuse dump soils in Ghana 
Kofi Agyarko
1
*, Emmanuel Dartey
1
 and Balázs Berlinger
2
 
1College of Agriculture Education, University of Education, Winneba, Mampong/Ash., Ghana 
2National Institute of Occupational Health, Oslo, Norway 
*To whom correspondences should be addressed 
E-mail: agyarkokofi@yahoo.com 
Received May 15, 2011, Revised manuscript received November 02, 2011, Accepted 05 November, 2011 
Abstract 
Concentration levels of tin (Sn), antimony (Sb), titanium (Ti), bismuth (Bi) and thallium (Tl) 
were assessed in refuse dump and background soils in urban (Accra and Kumasi) and rural (Sataso) 
communities in Ghana using a ThermoFinnigan Element 2 high resolution inductively coupled 
plasma mass spectrometric (HR-ICP-MS) instrument. Concentrations of the metals were lower than 
known normal mineral soil levels, however, based on the Igeo scale the refuse dump soils from 
Accra and Kumasi (urban communities) were ‘Moderate to strongly polluted’ with Sn and Sb while 
that from Sataso a rural community was classified as ‘Moderately polluted’ with Sn and Sb. The 
refuse dump soils from the urban communities were ‘Unpolluted to moderately polluted’ with Ti 
and that from the rural community was classified as ‘Practically unpolluted’ with Ti. All the refuse 
dump soils were, ‘Practically unpolluted’ with Bi and Tl. Differences in the pollution levels may 
probably be assigned to differences in population and activities in the communities. 
Keywords: metals; refuse dump soil; background soil; Igeo scale; pollution level 
1. Introduction 
Refuse dump sites are common scenes in 
both urban and rural communities in most 
developing countries. These sites have become 
attractive spots for farming in urban and peri-
urban communities as a result of their high 
nutrient concentrations. 
Waste materials deposited in these dump 
sites have between 50 – 90% of organic 
materials which include raw kitchen waste 
generated in the preparation and consumption of 
food, such as food leftovers, rotten fruit, 
vegetables, leaves, crop residues, animal excreta 
and bones [1,2]. Though, large amounts of the 
waste comprise of organic materials, there could 
be considerable proportions of plastic, paper, 
metal rubbish and batteries which are known to 
be real sources of hazardous metals [3,4]. The 
wastes often contain metals in various forms 
and at different contamination levels. These 
metals can cause damaging effects even at very 
low concentrations; they tend to accumulate in 
the food chain and in the body. Exposure to 
these metals may lead to several human diseases 
such as development retardation or 
malformation, kidney damage, cancer, abortion, 
effect on intelligence and behaviour, and even 
death in some cases of exposure to very high 
concentrations [5,6]. 
Soils in their normal state have small 
amounts of hazardous metals [7-10], however, 
excessive amounts from sources such as, the use 
of agro-chemicals, industrial waste deposition, 
atmospheric precipitation and refuse dumping, 
are detrimental and can sterilize the soil [11]. 
Globally, soils are under increasing pressure 
from rising populations, the intensification of 
agriculture and contamination, and therefore 
studies geared towards the assessment of soil 
metal levels which contribute to contamination 
of the environment is imperative. 
The most important metals with regards to 
potential hazards and the occurrence in 
contaminated soils are As, Cd, Cr, Hg, Pb, and 
Zn [12] therefore, most studies have been done 
on such metals. However, if the other metals 
considered to be less toxic to man are 
unchecked, soil contamination can reach levels 
which would pose risk to humans and the wider 
environment. 
It is upon these premises that the current 
study was carried out to assess the levels of tin, 
antimony, titanium, bismuth and thallium in 
refuse dump soils in some urban and rural 
communities in Ghana. 
2. Materials and methods 
2.1. Publication Output 
ARCH. ENVIRON. SCI. (2011), 5, 101-105 
102 
Background and refuse dump soils were 
collected in May, 2008 from three locations, 
Accra (≈ longitude 0°25’W and latitude 5°56’N) 
the largest city and the capital of Ghana, 
Kumasi (≈ longitude 1°55’W and latitude 
6°54’N) the second largest city in Ghana and 
Sataso (≈ longitude 1°30’W and latitude 7°25’N) 
a village in the Ashanti region of Ghana. The 
soil samples were picked at 0 – 15 cm depth 
with a soil auger. At each of the dumpsites ten 
representative soil cores were picked at 2 m 
intervals randomly and placed in poly-bags. The 
background soils were picked more than 500m 
away from the refuse dumps in areas observed 
to have no records of refuse dumping in the 
same manner as described above. The samples 
were shade dried and crushed in a porcelain 
mortar to pass through a 2 mm mesh and placed 
in drug poly-bags of size 7 cm  10 cm, labeled 
and sealed. These prepared samples were sent to 
Norway for the analyses of tin (Sn), antimony 
(Sb), titanium (Ti), bismuth (Bi) and thallium 
(Tl). 
2.2. Sample Preparation and Analyses of Metals 
The soil samples were ground into fine 
powder. To each of the accurately weighed 0.3 
g portion of the soil samples was added 3.0 cm
3
 
concentrated HNO3 and 0.1 cm
3
 internal 
standard solution containing 1.0 mg/dm
3
 of Rh, 
Ir, Ga, and Y. The samples were digested in a 
Milestone UltraClave High Performance 
Microwave Reactor (Shelton, USA) system and 
diluted to 70 cm
3
 with deionized water (18.2 
MΩ cm). External calibration was made with 
acid-matrix matched multi-elemental standard 
solutions. These processes were carried out at 
the Norwegian Institute of life Sciences, 
Department of Plant and Environmental Science, 
Å s. 
The samples were analysed at the National 
Institute of Occupational Health, NIOH, Oslo, 
Norway to determine the metal levels using a 
Thermo Finnigan Element 2 (Bremen, Germany) 
high resolution inductively coupled plasma 
mass spectrometric (HR-ICP-MS) instrument. 
2.3. Data Analysis 
The data were subjected to analysis of 
variance (ANOVA) and LSD (P ≤ 0.05) for the 
separation of means using the MSTAT-C 
statistical software [13]. 
The degree of metal enrichment of the refuse 
dump soils were assessed using the Metal Ratio 
MR [7] and the Geo-accumulation Index, Igeo 
[8]. 
Metal  atio (M )    
Concentration of metal in the refuse soil sample
Concentration of metal in the bac g          
 
Geo-accumulation Index (Igeo) = ln (Cn/1.5  
Bn) 
where: Cn = measured concentration of metal in 
the refuse dump soil (µg/g); Bn = background 
value of heavy metal (µg/g); and 1.5 = 
background matrix correction factor. 
3. Results and Discussions 
3.1. Metal Concentration in Soils 
Table 1 indicates the mean concentrations of 
tin (Sn), antimony (Sb), titanium (Ti), bismuth 
(Bi) and thallium (Tl) sampled from background 
and refuse dump soils from Accra, Kumasi and 
Sataso in Ghana. 
The concentrations (0.782, 0.713, and 0.129 
µg/g from Accra, Kumasi and Sataso 
respectively) of tin (Sn) from the refuse dump 
soils are significantly higher than their 
respective background soil values (0.068, 0.063, 
and 0.031 µg/g from Accra, Kumasi and Sataso 
respectively). Refuse dumps are recipients of 
waste substances, made up of materials such as, 
paints, bottles, glass, batteries, tyres, metal cans 
and containers, ashes and medical wastes which 
are sources of metals [4] and this might have 
resulted in the observed trend. Sn concentrations 
from both the background and the refuse dump 
soils are, however, below the normal Sn 
concentrations in soils of between 1 and 200 
µg/g [9]. 
Antimony (Sb) concentrations (0.060, 0.025, 
and 0.021 µg/g from Accra, Kumasi and Sataso 
respectively) in the refuse dump soils are 
significantly higher than their corresponding 
background values (0.002, 0.001, and 0.004 
µg/g from Accra, Kumasi and Sataso 
respectively). The same reason pertaining to Sn 
for the differences observed between the refuse 
dump soils and their background values could 
be assigned to Sb also. The concentrations of 
the metal from the background and the refuse 
dump soils are below the normal range of 0.2 – 
10 µg/g in soils [9]. 
ARCH. ENVIRON. SCI. (2011), 5, 101-105 
103 
A range of between 100 and 1000 µg/g of 
Titanium (Ti) is generally found in soils [14]. 
Both the recorded background values (0.030, 
0.029, and 0.042 µg/g from Accra, Kumasi and 
Sataso respectively) and the refuse dump soil 
values (0.058, 0.045, and 0.043 µg/g from 
Accra, Kumasi and Sataso respectively) are 
below the range generally found in soils. The 
refuse dump soils have higher Ti values than 
their corresponding background values, 
following the same trend as Sn and Sb. 
However, the background soil value and the 
refuse dump soil value for Ti are not 
significantly different. 
Bismuth (Bi) has a concentration of 1 µg/g in 
soils [10] with the world’s average 
concentration being 0.20 µg/g [15]. The 
concentrations of Bi from the background soils 
(0.134, 0.102, and 0.062 µg/g from Accra, 
Kumasi and Sataso respectively) and the refuse 
dump soils (0.092, 0.088, and 0.054 µg/g from 
Accra, Kumasi, and Sataso respectively) are 
below the world’s average level. The 
background values are higher than the values 
from the refuse dump soils, however, with the 
exception of the Accra values the rest of the 
values are not significantly different, which 
shows that the waste materials may not have or 
have trace amount of bismuth in them. 
Similar to Bi the background values (0.100, 
0.092, and 0.090 µg/g from Accra, Kumasi, and 
Sataso respectively) of Tl are higher than the 
refuse dump soil values (0.091, 0.068, and 
0.050 µg/g from Accra, Kumasi and Sataso 
respectively). With the exception of the Accra 
values, the differences between the background 
and the refuse dump soil values are significant. 
Thallium is naturally found in soil at levels from 
0.3 to 0.7 ppm [16]. The values of Tl in the 
samples are below the range found in soils. The 
change in pattern for Bi and TI as compared to 
the trends observed for the other metals, 
probably indicates that the metals might have 
been depleted by some processes not identified 
in the study. 
Within the metals, differences are found 
between the background values and also 
between the refuse dump soil values, which 
might be due to differences in parent materials 
of the soils and differences in waste materials in 
the communities respectively.  
Most of the metal values are below the 
normal ranges in soil which is in line with the 
observation of Stewart et al. [14] where 
extracted metals have been found to be lower 
than the total mineral metal concentrations. 
Table 1. Metal levels of background and refuse dump soils from some communities in Ghana 
Source of soil Metal 
Sn Sb Ti Bi Tl 
Accra Background soil 0.068 d 0.002 c 0.030 bc 0.134 a 0.100 a 
Refuse dump soil 0.782 a 0.060 a 0.058 a 0.092 b 0.091 a 
Kumasi Background soil 0.063 d 0.001 c 0.029 c 0.102 b 0.092 a 
Refuse dump soil 0.713 b 0.025 b 0.045 ab 0.088 b 0.068 bc 
Sataso Background soil 0.031 e 0.004 c 0.042 abc 0.062 c 0.090 ab 
Refuse dump soil 0.129 c 0.012 bc 0.043 abc 0.054 c 0.050 c 
LSD 0.012 0.017 0.018 0.015 0.022 
Figures in the columns followed by the same letter(s) are not significantly different (P ≤ 0.05) 
3.2. Metal Ratio and Geo-Accumulation Index 
The Metal Ratio and Geo-accumulation 
Index measure the degree of enrichment of the 
metals in the refuse dump soils. 
The Metal Ratio (MR) (Table 2) which is the 
ratio of metal concentration in the refuse dump 
soil to its concentration in the background soil 
shows that the refuse dump soils have ratios of 
Sn, Sb, and Ti to be ˃ 1, while Bi and Tl have 
ratios of ˂ 1. The refuse dump soils are 
therefore polluted with Sn, Sb, and Ti, but are 
not or little polluted with Bi and Tl. 
Table 2. Metal Ratio (MR) 
Source of 
soil 
Metal 
Sn Sb Ti Bi Tl 
Accra 11.50 30.00 1.93 0.69 0.91 
Kumasi 11.32 25.00 1.55 0.86 0.74 
Sataso 4.16 5.25 1.02 0.87 0.56 
The extent of the pollution is measured by 
the Geo-accumulation Index (Igeo) (Table 3). 
ARCH. ENVIRON. SCI. (2011), 5, 101-105 
104 
The Igeo has a scale consisting of seven grades 
(0 － 6) ranging from practically unpolluted to 
very strongly polluted [8]. Based upon the Igeo 
scale the refuse dump soils from Accra and 
Kumasi (urban communities) may be classified 
as ‘Moderate to strongly polluted’ with Sn and 
Sb while the refuse dump soil from Sataso a 
rural community is classified as ‘Moderately 
polluted’ with Sn and Sb. The refuse dump soils 
from the urban communities are ‘Unpolluted to 
moderately polluted’ with Ti while the refuse 
dump soil from the rural community is 
classified as ‘Practically unpolluted’ with Ti. 
The low population and industrial activities in 
Sataso, a rural area, may be the reasons behind 
the lower levels of metals in its refuse dump soil 
as compared to those in the urban communities. 
The refuse dump soils from all the three 
community are found to be ‘Practically 
unpolluted’ with Bi and Tl. 
Table 3. Geo-accumulation Index (Igeo) 
Source 
of soil 
Metal 
Sn Sb Ti Bi Tl 
Accra 2.04 3.00 0.25 - 0.78 - 0.50 
Kumasi 2.02 2.81 0.03 - 0.55 - 0.71 
Sataso 1.02 1.25 - 0.38 - 0.54 - 0.99 
4. Conclusions 
The study revealed that the refuse dump soils 
from the urban communities (Accra and Kumasi) 
and the rural community (Sataso) are polluted 
with Sn, Sb, and Ti. The pollution level is 
higher in the urban communities than in the 
rural community. The refuse dump soils are, 
however, not polluted with Bi and Tl. Though 
the Igeo scale indicates pollution of some metals 
in the refuse dump soils, the absolute 
concentrations of the metals are even lower than 
normal ranges in world soils. 
Acknowledgments 
The authors are thankful to the Norwegian 
Institute of life Sciences, department of plant 
and environmental Science, Å s and the National 
Institute of Occupational Health, NIOH, Oslo, 
Norway for allowing their laboratories to be 
used for the research. 
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Assessment of metal levels of some refuse dump soils in Ghana

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Assessment of metal levels of some refuse dump soils in Ghana

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