Interior floor dust is found to be one of the major pathways of childhood exposure to indoor air pollutants. This study aims to carry out a general survey of heavy metals (Al, Ba, Cr, Cu, Fe, Ni and Pb) contamination at selected nursery school buildings in Shah Alam, Selangor and to study their relationship with the surrounding environment. The samples were collected using a brush and a plastic dust pan, after which the samples were digested using the wet digestion method. The heavy metal concentration was determined by inductively coupled plasma – optical emission spectrometer (ICPOES). The results show that the heavy metal concentrations at nursery school building were in the range 901.2 - 1510.0, 13.3 - 76.7, 12.0 - 22.6, 22.2 - 42.7, 1489.0 - 7919.0, 5.5 -14.4, 13.2 - 64.6, 93.3 - 220.4mg kg-1 for Al, Ba, Cr, Cu, Fe, Ni and Pb respectively. The heavy metal concentration in the investigated areas followed the order Fe > Al > Zn > Pb > Ba > Cu > Cr > Ni. Principal Component Analysis (PCA) was carried out to ascertain the possible contributing factors towards the metal concentrations and thereby determine which metals have a common origin. PCA analysis indicated that three factors indicated source of mixed origin including mobile vehicle, street dust and natural sources

Ismail, Zitty Sarah

Muhamad-Darus, Fairus

Nasir, Rabiatul Adawiyah

Omar, Nur Aliah

Sumari, Siti Mariam

English

Universiti Teknologi MARA Institutional Repository

63 
Nursery Schools: Characterization of heavy metal 
content in indoor dust 
Fairus Muhamad-Darus1, Rabiatul Adawiyah Nasir2,
Siti Mariam Sumari1, Zitty Sarah Ismail1, Nur Aliah Omar1
1Faculty of Applied Sciences, 
2Faculty of Architecture, Planning & Surveying, 
Universiti Teknologi MARA, Malaysia  
fairusmd@salam.uitm.edu.my 
Abstract 
Interior floor dust is found to be one of the major pathways of childhood exposure to indoor air pollutants. 
This study aims to carry out a general survey of heavy metals (Al, Ba, Cr, Cu, Fe, Ni and Pb) 
contamination at selected nursery school buildings in Shah Alam, Selangor and to study their 
relationship with the surrounding environment. The samples were collected using a brush and a plastic 
dust pan, after which the samples were digested using the wet digestion method. The heavy metal 
concentration was determined by inductively coupled plasma – optical emission spectrometer (ICP-
OES). The results show that the heavy metal concentrations at nursery school building were in the 
range 901.2 - 1510.0, 13.3 - 76.7, 12.0 - 22.6, 22.2 - 42.7, 1489.0 - 7919.0, 5.5 -14.4, 13.2 - 64.6, 
93.3 - 220.4mg kg-1 for Al, Ba, Cr, Cu, Fe, Ni and Pb respectively. The heavy metal concentration in the 
investigated areas followed the order Fe > Al > Zn > Pb > Ba > Cu > Cr > Ni. Principal Component 
Analysis (PCA) was carried out to ascertain the possible contributing factors towards the metal 
concentrations and thereby determine which metals have a common origin. PCA analysis indicated 
that three factors indicated source of mixed origin including mobile vehicle, street dust and natural 
sources. 
Keywords: Indoor dust, Heavy metal, Nursery school, Principal component  analysis 
eISSN 2514-751X © 2017 The Authors. Published for AMER ABRA by e-International Publishing House, Ltd., UK. 
This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-
nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour 
Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-
Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.  
https://doi.org/10.21834/aje-bs.v2i5.223 
Muhamad-Darus, F., et.al. / Asian Journal of Environmen-Behaviour Studies, ajE-Bs, 2(5) Oct / Dec 2017 (p.63-70) 
 
64 
1.0 Introduction  
Dust consist of solid matter or particulates in the form of fine powder (less 100 µm), lying 
on the ground or on the surface of objects or blown about by natural forces or mechanical 
forces (Adekola & Dosumu, 2001). Indoor dust is present in the indoor environment as a 
composite of particulate matter derived from interior and exterior sources. Dust can enter an 
indoor environment in several ways such as infiltration from outdoor sources and internally 
from smoking, incense burning, buildings and furniture materials, consumer products and 
occupant activities (Al- Rahji and Seaward, 1996; Turner & Simmonds, 2006). Indoor dust is 
a repository for environmental pollutants such as heavy metals that may accumulate 
indoors and is an important pathway of exposure to metal for humans. There is an increasing 
concern about heavy metals contamination in indoor environment since most people spend 
a great extent of their time indoors (Klepeis et al., 2001; Sharpe, 2004). 
A number of studies have suggested that there is a possibility that metals in the indoor 
dust can accumulate in humans, either directly or indirectly by inhalation, ingestion as a result 
of hand-to mouth activity or via dermal contact absorption (Al-Rahji & Seaward, 1996; 
Molhave et al., 2000). Young children, especially toddlers, can easily ingest soils or indoor 
dusts unintentionally since they spend most of their time indoors and much of this time is 
spent in contact with floors, engaging in mouthing of hands, toys and other objects or the 
consumption of food contaminated by hands (Mohd Tahir, 2007; Adekola & Dosumu, 2001). 
Heavy metals have an effect on biochemical mechanisms, especially because they can 
be bioaccumulated. An infant or child is extremely vulnerable to environmental 
interference because their organs are developing rapidly at early stage of development, 
making them more susceptible to functional damage or disorders (Yaaqub et al., 1991). 
These groups are also vulnerable to heavy metal poisoning since this is the period for 
maximal brain growth and differentiation (Tong & Lam, 2000). Besides, the rate of 
absorption of heavy metals from the digestion system and the hemoglobin sensitivity to 
these metals in children is much higher than in adults (Tong & Lam, 1998). It is now widely 
accepted that dust and soil are the predominant sources of heavy metals to which young 
children are exposed by mouthing of contaminated indoor dust (Chatterjee & Banerjee, 
1999; Tong & Lam, 2000; Chattopadhyay et al., 2003). 
Considerable attention has been paid to the study of metal pollution in city air, 
roadside dust and soils. However, there is a lack of concern on the presence of heavy metals 
in indoor dust in buildings such as in the nursery schools in Malaysia. Since there is limited 
data on dust contamination in the nursery schools, this study is important. 
 
 
2.0 Methodology 
 
Site sampling 
Shah Alam is located in the center of the west coast of Peninsular Malaysia, at an altitude of 
Muhamad-Darus, F., et.al. / Asian Journal of Environmen-Behaviour Studies, ajE-Bs, 2(5) Oct / Dec 2017 (p.63-70) 
 
65 
75 m, being about 25 km from Kuala Lumpur, capital city of Malaysia. It is the capital city of 
Selangor state, the fasters growing state which has experienced rapid urbanization and 
industrialization in the last decades, with a present population estimated at 584,350. The 
nursery school buildings selected for this study lie mainly in the Shah Alam city. The 
schools sites were located at three different land use types; nursery 1 located inside 
residential area (Section 7), nursery 2 located close to commercial area (Section 9) and 
nursery 3 located close to industrial areas (Section 17). Table 1 shows the site description of 
selected nurseries. 
 
Table 1: Site description of the nursey schools 
 
 
 
Sample collection 
Indoor dust was collected from three nurseries representing three different background sites 
of different land use types within Shah Alam city area during March-April 2010. Using a 
clean plastic brush and pan, dust was collected inside the nursery building by sweeping the 
classroom floor which was most accessible to the children. The indoor dust was then 
transferred into a reseal able plastic bag, brought to the laboratory and placed in a 
desiccator for 24 h, sieved through a 100-m screen, and finally oven dried at 105oC for 24 h. 
 
Sample and data analysis 
Immediately after drying, about 0.3 - 0.5 g of the fine portion of the dust was then digested by 
using 3 mL of mixture solution (HCl-HNO -H O) in a ratio of 2 : 2 : 2 to form aqua regia 
acid at 95oC for at least one hour until white fumes appeared. The extract was cooled and 
was filtered through Whatman No. 42 filter papers. The filtrate was then made up to a volume 
of 50 mL in the volumetric flask with distilled water and was analyzed for metal content by using 
Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) to determine the 
Muhamad-Darus, F., et.al. / Asian Journal of Environmen-Behaviour Studies, ajE-Bs, 2(5) Oct / Dec 2017 (p.63-70) 
 
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concentration of Al, Ba, Cr, Cu, Fe, Ni, Pb and Zn heavy metals. The blank experiment was 
carried out by repeating the procedure for sample preparation without the sample. The 
composition of the blank solution was compared with the sample solution to identify the 
elemental composition of heavy metals in the dusts. 
Data were analyzed for analysis of variance (ANOVA), correlation functions and factors 
analysis using statistical functions in Microsoft Excel and Statistical Packages for the Social 
Sciences (SPSS), included. 
 
 
3.0 Results and Discussions 
 
Heavy metals concentration 
The mean concentrations of heavy metals in the indoor dust samples are summarized in 
Table 2. The concentration of heavy metals in nursery schools building were depends upon 
dustiness and ventilation of the building. The highest concentration heavy metal obtained 
was Fe with the mean concentration 4225.33 mg/kg and followed by Al with the mean 
concentration of 1229.58 mg/kg. Both Al and Fe are abundant elements in the Earth’s crust (Al-
Khashman, 2004; Hunt et al., 2008). These elements have been produced by alteraction 
(friction) and distributed or transported via wind blow and can be associated with soil or 
street dust. The result indicated that soil or street dust play an important role in the 
concentration build up in indoor dust in the nursery school  building. 
 
Table 2: Descriptive statistics of indoor dust heavy metal concentration (mg/kg) (N = 9) 
 
 
Heavy metals find their way into indoor building or in this case children’s nurseries either as 
airborne dust or through items used or activities carried out within the nursery by occupant’s 
activities. In addition, activities carried out at surrounding area or in the vicinity also 
contribute to indoor dust and may direct or indirectly characterize the type of metals found 
indoor. The locations of all nursery schools were close to the main road with high traffic 
density and therefore it is expected to contain high lead (Pb) (31.24 mg/kg) in indoor dust 
related to the automobile emission (Chattopadhyay et al., 2003). Pb is a universal pollutant in 
an urban environment due to automobile emission (Al Rahji and Seaward, 1996), and despite 
the gradual shift from leaded to unleaded petrol as fuel for automobile, it still remains as a 
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67 
major pollutant for some urban areas including Shah Alam city. 
Other metals such as Zn, Cu, Cr, Ni and Ba were also related to automobile emission. As 
cited throughout the literature, the source of Zn in dust may have its origin from automotive 
sources i.e. wear and tear of vulcanized rubber tyres, lubricating oils and corrosion of 
galvanized vehicular parts (Li et al. 2001; Al- Khashman, 2004; Adachi and Tainosho, 2004). 
The source of Cu, Cr and Ni in dust is believed to be from car components, tyre abrasion, 
lubricants corrosion of cars, engine wear, thrust bearing, brushing, bearing metals and 
brake dust respectively (Al Rahji and Seaward, 1996; Al-Khashman, 2004; 2007). 
Although heavy metals in dust could be derived from indoor and outdoor sources, the result 
of this study indicated that major influence was from outdoor sources. The possible routes 
of heavy metals entering the schools building were through the open windows for cooling 
and ventilation (Komarnicki, 2005). While recognizing the fact that, the movement of 
occupant’s in and out from building also contributed the heavy metals concentration in the 
building, its contribution was less obvious from the contribution from ambient sources. 
 
Correlation coefficient analysis 
Pearson’s correlation coefficient can be used to measure the degree of correlation between 
logarithms of the heavy metals data. The correlations of heavy metals in indoor dusts of the 
nursery schools building are depicted in Table 3. All the metal pairs showed negative relations 
except for Al-Ni, Al-Zn, Cu-Fe and Ni-Zn pairs which were significant at 95% and/or higher 
confidence level. Al, Ni and Zn significantly correlated with each other (0.792 and 0.749) at 95% 
or higher confidence level, which may indicate a common sources origin, such as automobile 
emission. 
 
Factor analysis 
The principal component matrix analysis is given in Table 4. Principal Component Analysis 
(PCA) was carried out to ascertain the possible contributing factors towards the metal 
concentrations and thereby determine which metals have a common origin. 
 
Table 3: Correlation matrix for the heavy metal concentrations 
 
 
 
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Table 4: Factor loadings and communalities of heavy metals 
 
 
Three factors that have eigenvalues > 1 were extracted. The total variance explained by 
these three factors was 85.3%. The first factor explains the greatest amount of variance 
(40.2%) which is predominantly loaded by Ni, Zn, Al and Ba. This factor may indicate a 
source of mixed origin including air-borne emissions originated from mobile vehicle, street 
dust and soil dust. The second factor (27.3%) is characterized by high loading of Cu and Fe 
but moderately by Pb, which is characteristically identified with vehicles and street dust. 
Pb also has been distributed between the second and third factor with moderate load 
value. The third factor is indicative of automobile emission sources. 
 
 
4.0 Conclusions  
The chemical analysis of indoor dust sample in nursery schools building in this study 
showed the distribution and concentration of heavy metals within the area of study. The 
results show the concentration of heavy metals at three nursery schools building were in 
range of 901.2-1510.0, 13.3-76.7, 12.0 -22.6, 22.2 - 42.7, 
1489.0 -7919.0, 5.5 -14.4, 13.2 - 64.6, 93.3 - 220.4 mg kg-1 for Al, Ba, Cr, Cu, Fe, Ni and 
Pb respectively. The result of heavy metal concentration in investigated areas were in order 
Fe > Al > Zn > Pb > Ba > Cu > Cr > Ni. Data analyses indicate that automobile emission is 
the major source of these heavy metals in indoor dust. The concentrations of heavy metals in 
nursery schools building were influenced by the dustiness and ventilation of the  building. 
Since the health effects caused by contaminated dust may have long-term effects on 
the children, action should be taken to avoid or minimize the potential risks of this silent 
epidemic. Therefore a good housekeeping practice such as frequent wet mopping and 
vacuuming and good maintenance of the ventilation system by closing those windows that 
are facing major roads should be taken into consideration in order to reduce children 
exposure to contaminated dust by heavy metals in nursery school buildings. 
 
 
 
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69 
Acknowledgement 
The authors would like to thank the owners of the nursery schools for giving the opportunity 
and cooperation to successfully perform this  study. 
 
 
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