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© 2020 by the authors; licensee Asian Online Journal Publishing Group 
 

Asian Review of Environmental and Earth Sciences 
Vol. 7, No. 1, 79-86, 2020 

ISSN(E) 2313-8173 / ISSN(P) 2518-0134 
DOI: 10.20448/journal.506.2020.71.79.86 

© 2020 by the authors; licensee Asian Online Journal Publishing Group 

  
 

 
 
 
Assessment of Environmental Impacts of Limestone Exploitation in Igarra, Nigeria  

 
Ogundele J.O.1 

Olotu .Y.2 
Parker-Ikharo F.3  
Sanni E.B.4 
Yusuf I.5 
Eremiokhale, J.I6 

 

 
( Corresponding Author) 

1,4,5Department of Mineral & Petroleum Engineering Technology, Auchi Polytechnic, Auchi, Nigeria. 
2Department of Agricultural Engineering, Auchi Polytechnic, Auchi, Nigeria. 

 
3Department of Civil Engineering, Auchi Polytechnic, Auchi, Nigeria. 
6Department of Architectural Technology, Auchi Polytechnic, Auchi, Nigeria. 

 
Abstract 

The exploration of limestone is the nerve of socio-economic integration of the Igarra community. However, 
the exploration activities have been linked with several adverse effects on human health and the 
deterioration of the surrounding environment. This research work investigates the quality of air in the 
study area.  Dust emission was measured using a digital air quality monitor of model HP 5800D PM2.5-10 
with an accuracy of ±5% or ±4ug/m3 and measuring and detection ranges of 0.3 ug/m3 and 0-999.9 ug/m3. 
The dust level readings using PM2.5 and PM10 at 1 km apart from the three selected exploration sites in 

Igarra at a 60-minute interval was taken. Quarry one (Q1) recorded the lowest dust level of 20.6 μg//m3 for 

PM2.5 and 72.5 μg//m3 for PM10 in the early hours before exploration. The general outputs show that 
exploration sites (Q2) and (Q3) produced a high degree of polluted air than site Q1. A higher dust level of 

966.0μg/m3 was recorded for PM10. The overall dust level measurements for PM2.5 and PM10 are higher 

than the recommended 70.0-80.0 μg/m3 by the World Health Organization (WHO) and the Environmental 
Protection Agency (EPA). It is projected that continuous emission of dust at Igarra could lead to an 
increasing number of diseases such as asthma, catarrh, and breathing problems. In conclusion, an integrated 
exploration mechanism is essential to improve air quality and substantially reduce air related pollution. 

 
Keywords: Limestone, Dust emission, PM2.5-10, Environment, Igarra. 

 
Citation | Ogundele J.O.; Olotu .Y.; Parker-Ikharo F.; Sanni E.B.; 
Yusuf I.; Eremiokhale, J.I (2020). Assessment of Environmental 
Impacts of Limestone Exploitation in Igarra, Nigeria. Asian Review 
of Environmental and Earth Sciences, 7(1): 79-86. 
History:  
Received: 29 October 2020 
Revised: 17 November 2020 
Accepted: 7 December 2020 
Published: 22 December 2020 
Licensed: This work is licensed under a Creative Commons 

Attribution 3.0 License  
Publisher:  Asian Online Journal Publishing Group 
 

Acknowledgement: All authors contributed to the conception and design of 
the study. 
Funding: This study received no specific financial support. 
Competing Interests: The authors declare that they have no conflict of 
interests. 
Transparency: The authors confirm that the manuscript is an honest, 
accurate, and transparent account of the study was reported; that no vital 
features of the study have been omitted; and that any discrepancies from the 
study as planned have been explained. 
Ethical: This study follows all ethical practices during writing.   

 

 

Contents 
1. Introduction ...................................................................................................................................................................................... 80 
2.  Methodology .................................................................................................................................................................................... 80 
3. Results and Discussion ................................................................................................................................................................... 82 
4. Conclusion ......................................................................................................................................................................................... 86 
References .............................................................................................................................................................................................. 86 
 

 
 
 

 

 

 

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Contribution of this paper to the literature 
This study contributes to existing literature by investigating the quality of air in the study area.  Dust 
emission was measured using a digital air quality monitor of model HP 5800D PM2.5-10 with an 
accuracy of ±5% or ±4ug/m3 and measuring and detection ranges of 0.3 ug/m3 and 0-999.9 ug/m3. 

 
1. Introduction 

The exploitation of mineral resources has assumed prime importance in several developing countries, including 
Nigeria. Nigeria is endowed with abundant mineral resources, contributing immensely to the national wealth with 
associated socio-economic benefits. Mineral resources are an essential source of wealth for a nation, but before they 
are harnessed, they have to pass through the stages of exploration, mining, and processing [1] Natural resources 
can be classified into two groups: renewable and non-renewable resources. Renewable natural resources are 
replenished on short time scales of a few months or years—for example, wind, hydraulic and solar energies. Non-
renewable resources are contained in the earth in fixed quantities and are not replenished by natural processes 
operating on short time scales [2, 3]. Examples are oil, natural gas, coal, metals, and mineral products produced 
from the earth. The formation period of oil, gas, metals, and minerals is very long (i.e., over tens of millions of 
years), vastly slower than the rates at which we mine these materials. The resources we obtain from the earth's 
crust today are products accumulated over the last billions of years. Most non-renewable natural resources are also 
mineral resources, both organic and inorganic in origin. Resources can also be classified into three major use 
groups: metallic, energy, and non-metallic mineral resources [1]. 

Nigeria's environment (at urban and rural levels) has suffered an accelerated decline in air quality, soils, 
biodiversity, and water resources [4]. It is clear that sound natural resources management and planning are 
essential to tackling the problems above and to promote sustainable development [4, 5]. Mining activities 
represent human actions that cut through the landscape, scarring, and interfering with the natural habitat 
conditions as well as micro-climatic conditions. Specifically, the environmental effects of limestone mining and 
cement production are known to impoverish flora and fauna of host environment, result in sediments deposition in 
riverine systems, create mining spoil mounds and deep mining lakes mainly, result in loss of timber resources and 
another vegetal cover, toxification, and pollution due to chemical wastes or weathering of mining spoils, cause 
changes in micro-climate, and several others [2, 6]. These effects on the ecosystem are not only on-site but also 
occur off-site as well. These, in turn, significantly alter the environmental spheres of the affected areas. 

Quarrying is obtaining quarry resources; usually, rocks are found on or below the land surface. Quarrying 

generates a lot of particulate matter (dust) with a diameter of 1-75 μm (micron) [7, 8]. Particles with aerodynamic 

diameters of less than 50 μm (termed Total Suspended Particulate matter, or TSP) can become suspended in the 

atmosphere, and those with aerodynamic diameters of less than ten μm termed PM10 (inhalable particles) can be 
transported over long distances and enter the human respiratory system [9, 10]. Many researchers have reported 
these processes to have responsibility for several health problems.  
 

2.  Methodology 
2.1. Study Area 

The study area is located at Igarra in Akoko Edo local Government of Edo-State, Nigeria. Figure 1 shows the 
map of Nigeria, Edo state and the study area (Igarra). Table 1 shows the codes used in describing the sampling 
sites. Igarra is located between Latitudes 07º 08 16 and 07º 31 58, and Longitudes 08º 37 46 and 09º 10 31. The 
study area is located within a sub-humid tropical region with mean annual temperature ranging from 29ºC to 30ºC, 
and is characterized by two distinct seasons: the dry season and rainy season. The mean annua1 precipitation is 
about 1,370mm, with an average wind speed of 1.50 m/s. 

 
2.2. Experimental Design 

Data on the impact of limestone mining (extraction) activities on the com-munities in the study area (Igarra) 
were collected using two methods known as primary and secondary data collections.  

i. Primary data collection: This involved measurement of air quality/ dust level using digital particulate 
matter instrument (PM2.5).  

ii. Secondary data collection: data collected from health records in the clinics/hospital most patronized by the 
people. Social survey was also conducted by questionnaire administration in the communities sampled. 

 
2.2.1. Descriptions of Particulate Matter (PM2.5 and PM10) 
        The instrument is an of high-tech air quality to measure the PM2.5 and PM10. It uses a laser PM2.5 sensor, 
single-chip microcomputer technology and high visibility dot matrix LCD. This instrument is of high precision, 
short measuring time, stable performance, strong function, easy operation, low power consumption, with function 
of time display, real time measurement very suitable for indoor and outdoor environment monitoring, can also be 
used in the detection of air purification machine to air purification effect. The instrument is shown in Figure 2 and 
3.  
 

2.2.2. Measurement of Particulate Matter (PM2.5 and PM10)  
PM2.5/10 was used to monitor air quality (µ/mg) at Igarra near Freedom Quarry for 10-day.  PM2.5/10 was 

sampled for a period of 6-hour at 30 minutes intervals per day. Measured dust levels at every interval were 
recorded.  PM10 was empirically estimated using Equation 1:  

                                                                                                        (1) 

PM10 = Particles with aerodynamic diameter of 10 microns. 
M1 = Weight of filter paper before sampling (g). 
M2 = Weight of filter paper after sampling (g). 
FR = Average flow rate (l/min or m3/min). 



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T = Sampling duration in minutes [2]. 
PM2.5 and PM10 was calibrated using the expression in Equation 2. 

             (2) 

 
Figure-1.  Map of study area. 

     Source: ESMHW [11]. 
 

 
Figure-2a.  Air quality monitor. 

Source : Salvi and Holgate [12]. 
 

 
Figure-2b.  Dust level measurement. 

 Source: Field work, 2018. 

 



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2.2.3. Climate Variables 
Field climatic parameters (minimum and maximum temperature, relative humidity) of the study area were 

measured with digital thermometer model CX 201A. Current climatic data (1975-1985) and (1990-2005) were 
obtained from Nigerian Meteorological Agency (NMET). Future projected climatic data (2030-2045) of Igarra was 
downscaled using Centre of Canadian Climate Modelling & Analysis (CCCMA) under Representative 
Concentration Pathways (RCP 4.5).  
 

2.2.4. Health and Agricultural Data Collection  
Structural questionnaires were used to obtained health and agricultural information in the study area. These 

data were collected to establish the relationship between exploration activities and the health of the dwellers and 
also to determine the link between quarrying activities and crop yield as indicated in Table 1. 
 

Table-1. Code for the sampling of study area. 

Area Code Sampling Sites 

Q1 Exploration site          1 
Q2 Exploration site          2 
Q3 Exploration site          3 

 

3. Results and Discussion 
3.1. Dust Level Measurement 

Digital air quality monitor was used to measure and evaluate particle concentration variations within a pre-set 
time interval. Tables 2-4 show the results of dust level measurement using PM2.5 and PM10 from three limestone 
exploration sites at Igarra. The measurement was carried at a 30-minute interval for 6-hour daily. It is observed 

that Q1 recorded lowest dust level of 19.6 μg/m3 for PM2.5, 59.6 μg/m3 and 62.5 μg/m3 for the PM10. This 
indicates that the air quality is good and healthy around this period. The result is in agreement of Najime, et al. 
[9]; Musa and Jiya [10]; Yoon and Brimblecombe [13]. 

The concentration dust particle starts to rise between 10.00 am to 10.30 am and reduced to 56.6 μg/m3 which 

corresponds to 365μg/m3 for PM10. The highest concentration of 529.1 μg/m3 and 864.3 for PM2.5 and these values 

correspond to 0.0μg/m3, 3280.0μg/m3 and PM10 and estimated PME10 respectively (Table 2 and Figures 3-4). The 

maximum dust level measurement for digital dust monitor HP 5800D PM-10 is 9990μg/m3, based empirical 
equation was applied to compute the values that could not be easily monitored from the digital equipment. 

0.0μg/m3 indicates out of measurement range for PM10. The overall results show that exploration site two and 

three produced a high degree of dust. Dust level of 5917.2μg/m3 was generated from PME10 which corresponds to 

0.0μg/m3 and 906.0μg/m3 of PM10 and PM2.5 (Figures 2-5; Table 3). The results are similar to previous studies 
[1, 4, 9]. 

Table-2. Dust level reading in exploration one (Q1). 

Time (Mins) Duration PM2.5 (ug/m3) PM10 (ug/m3) 

9.30 0.00-30.0 19.6 59.5 
10.00 30.0-60.0 126.0 739.3 
10.30 60.0-90.0 143.9 892.2 
11.00 90.0-120.0 56.6 365.5 
11.30 120.0-150.0 529.1 0.0 
12.00 150.0-180.0 19.8 119.8 
12.30 180.0-210.0 10.8 61.3 
1.00 210.0-240.0 143.9 892.2 
1.30 240.0-270.0 99.6 685.6 
2.00 270.0-300.0 92.2 513.4 
2.30 300.0-330.0 24.1 178.8 
3.00 330.0-360.0 864.3 0.0 

                      
Table-3. Dust level reading in exploration site two. 

Time (Min) Duration PM2.5 (ug/m3) PM10 (ug/m3) PME10 (ug/m3) 

8.00 0.00-30.0 75.4 529.2 696.2 
8.30 30.0-60.0 99.6 685.6 785.6 
9.00 60.0-90.0 139.5 828.5 988.5 

9.30 90.0-120.0 92.2 513.4 767.4 
10.00 120.0-150.0 24.1 178.8 199.8 
10.30 150.0-180.0 906.0 0.0 5617.2 
11.00 180.0-210.0 864.3 0.0 5358.7 
11.30 210.0-240.0 674.7 0.0 4183.1 
12.00 240.0-270.0 99.6 685.6 889.6 
12.30 270.0-300.0 126.0 59.5 70.5 
1.00 300.0-330.0 143.9 0.0 892.2 
1.30 330.0-360.0 19.8 169.8 199.8 

 



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Figure-3. Comparison of PM 10 results measured from three quarry sites (Q1-Q2- 

 
However, Quarry (3) shown the similar increasing trend of dust level as in Quarry (2). Q3 recorded higher 

values both at 11.00 am (180.0-210.0) and 11.30 am (210.0-240.0) and least unhealthy air of 80.6 μg/m3,499.7 

μg/m3 and 599.7 μg/m3 for PM2.5, PM10 and PME10 respectively. The higher particulate matter (PM) shows the 
peak of limestone exploration activities during the day Figure 5.  

 
3.2. The Impact of Climate on Dust Concentration 
 

 
Figure-4. Comparison of PM 2.5 results measured from three quarry sites (Q1-Q2-Q3). 

 
The weather data was taken in-situ along with dust level. The results show that the climate is very warm in all 

the quarry sites with the minimum temperature from 26.40C to 27.7oC and maximum temperature from 37.8oC to 
40.1oC for Q3, Q2 and Q1 respectively. However, Q3 has a higher relatively relative density of 57.0% over Q2 and 
Q1(Table 4). During the dry season (warmer climate) the air moisture content is very low and this allows dust to be 
accumulated and easily dispersed, whereas dust particles are being trapped during the wet season.  Tables 5-6 show 
the baseline climate of the study area for before and during the limestone exploration. The result of the future 
projected climate of Igarra using Centre of Canadian Climate Model & Analysis under the climate change scenario 
(RCP 4.5).  
 

Table-4. Annual average climate data of Ikpeshi during pre-limestone exploration(1970-1985). 
Year Tmin(oC) Tmax(oC) Prec(mm) 

1970 19.0 31.0 1111.3 

1971 19.9 31.5 1228.0 

1972 20.3 31.7 1367.2 

1973 20.0 31.9 1306.6 

1974 19.1 32.3 1091.8 

1975 18.5 30.8 1393.0 

1976 20.1 31.0 1172.9 

1977 19.7 31.6 1352.2 

1978 19.1 31.5 1053.4 

1979 20.1 31.3 1309.8 

1980 20.1 31.7 1278.8 

1981 19.0 31.3 1091.0 

1982 20.2 31.9 1254.3 

1983 20.5 31.9 1394.4 

1984 20.6 31.8 1222.4 

1985 19.0 31.2 1230.8 
       Source: Yoon and Brimblecombe [13]. 

 
 
 



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Table-5. Annual average climate data of ikpeshi during limestone expliotation (1990-2005) 

Year Tmin(oC) Tmax(oC) Prec(mm) 

1990 19.8 32.8 1435.1 

1991 26.1 32.1 1508 

1992 20.5 32.2 1138 

1993 18.7 31.4 1258.8 

1994 19.5 31.6 1393.6 

1995 19.8 32.3 1269.7 

1996 21.3 33 1001.2 

1997 20 33.1 1071.2 

1998 19.2 32.1 1115.4 

1999 18.6 31.8 1250.3 

2000 20.2 32.5 1216.6 

2001 20.7 32.6 1464.1 

2002 20.9 33 1005.5 

2003 19.8 32.5 1326.2 

2004 20.2 32.7 1417.3 

2005 19.8 32.6 1321.9 

                                       Source: Yoon and Brimblecombe [13]. 

 

 

Figure-5. Climatic (Temp) analysis of study area during pre-limestone 
exploration. 

 

 Figure-6. Climatic (Temp) analysis of study area during pre-
limestone exploration. 
Source: Sensitivity analysis, 2018 

 
Table-6. Annual average climate data of ikpeshi during limestone expliotation (2030-2045) 

Year Tmin(oC) Tmax(oC) Prec(mm) 

2030 20.1 30.3 1387.8 

2031 25.7 31.1 573 

2032 25.5 30.7 2105.8 

2033 26.1 31 1920.7 

2034 25.9 31.6 151.4 

2035 25.5 30.9 1641.9 

2036 26.7 28.7 1595.9 

2037 26 291.9 1609.2 

2038 26.2 31.3 1606.2 

2039 25.7 31 1636.9 

2040 26.1 31.3 2007 

2041 26.7 31.6 1547.2 

2042 26.5 31.3 1705.1 

2043 25.8 30.2 1531 

2044 26.2 31 1743.6 

2045 26.1 31.7 1764.4 

                                       



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Figure-7. Climatic (Temp) analysis for projected (temp) from CCCMA-RCP 4.5 for the study area. 

 

It is clear that Tmax increased with 0.120C per year from 1985 to 2010 and this trend is projected with marginal 
increase of 0.06770C annually for the period 2028 to 2046, while increase of 0.32oC was projected for the minimum 
temperature Figures 6-8. Any large-scale impacts of dust on atmospheric temperatures in these periods would have 
potentially important implications for atmospheric stability and ultimately for the ability of the atmosphere to 
foster conditions conducive to rainfall generation. Dust is a major natural source of atmospheric aerosols that can 
potentially affect clouds. The effect of dust concentration on precipitation was not known before the TRMM 
satellite was launched and applied to clouds forming in dust-laden air [6, 7]. The large sizes of some of these dust 
particles had led to the assumption that dust would enhance precipitation rather than decrease it. The result of 
rainfall analysis in Figures 8-9 indicate variation of rainfall distribution before, during and projected future climate 
in the study area.  
 

 Figure-8. Precipitation analysis during pre-limestone exploration 
era                                                                                                                                                                       Figure-9. Precipitation analysis during limestone exploration era 

 

3.3. Dust Concentration and Human Health 
Dust is a common air pollutant. Dust particles vary in size from coarse (non-inhalable), to fine (inhalable), to 

very fine (respirable).  Coarse dust particles generally only reach as far as the inside of the nose, mouth or throat. 
Smaller or fine particles, however, can get much deeper into the sensitive regions of the respiratory tract and lungs. 
These smaller dust particles have a greater potential to cause serious harm to your health. The potential health 
effects of some common dusts in mines and quarries are analysed as shown in Figure 10. 
 

 
Figure-10. Health conditions of the dwellers of study area. 

 
The results of the analysis indicate that four out of six most commonly reported diseases in Igarra are dust-

pollution related diseases. Above 50% of the respondents claimed to have suffered asthmatic attacks, while over 
60% and above have suffered catarrh, difficult breathing and headache respectively. However, 28% of heart attack 
cases had been reported. In most cases each of the diseases goes along with malaria parasites. In addition, the  most 
common symptoms experienced during a dust storm are irritation to the eyes and upper airways infants, young 
children  and the elderly are most  vulnerable. 



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4. Conclusion 
The study of limestone exploration on the prevailing climate of Igarra was carried out by measuring the air 

pollution of the study area with PM2.5 and PM10 at 30 minutes interval respectively.  Empirically-based model was 
also used to compute PM10 in order to create robust dataset since the digital air monitor was not calibrated to 

measure above 999.0(μg/m3). Results from annual PM2.5-10 and PME10 data confirm the air quality in the study 
zones is highly hazardous to human health and this may probable the result of high cases of illness in the region. 
The implication is that the observed daily average values of both PM2.5 and PM10 are higher than the WHO and 70 

μg/m3 set by EPA, permissible limits for all stability classes.  Additionally, results confirm the interdependent 
importance of relative humidity, minimum and maximum temperature in PM2.5-10 concentration from Igarra. 
Effects of variability of precipitation (distribution and intensity) should also be considered. The output of the health 
analysis shows deadly effects of limestone exploration activities on the dwellers in Igarra. There has been a sharp 
rise in dust and water related or borne diseases since the advent of limestone mining commenced in Igarra and its 
environs. Water resources (surface and underground) have been polluted and this has made safe drinking water 
unavailable and inaccessible. Moreso, the settling of dust particle on the roof surface of most homes further 
complicate rain harvesting system. 
 

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