Zaini Hamzah1, Noor Azimah Darus2,4,
Ahmad Saat3,*,
Zakaria Tajuddin2
1Faculty of Apied Sciences,
2Faculty of Agrotechnology
3Institute of Science
Universiti Teknologi MARA
40450 Shah Alam, Malaysia.
4Universiti Teknologi MARA
Cawangan Pahang, Kampus Jengka
26400 Jengka, Malaysia.
*Corresponding:
ahmad183@salam.uitm.edu.my
ABSTRACT
To reduce the dependency on conventional fuel
many palm oil mills nowadays used palm waste materials like fiber and shell as
their source of fuel. However the emission of fumes and fly ashes from the
mills raised some concern on their effect to the environment adjacent to the
vicinity of the mills. Especially when these emissions and fly ashes are known
to contain heavy metals, which some of them could pose health risk to people
living around the mills. A study was carried out on one such mills and it
surrounding areas, to determine the heavy metal and As contents in the waste
fiber, shells and ashes as well as airborne deposition onto plants and soils.
The mill is located in Perak, Malaysia. Debris and soils samples were collected
in the north, south, east, and west direction relative to the mill, at
distances 0.1, 0.5, 1.0, 2.0 and 3.0 km from the mill. The debris was collected between oil palm
frond and trunk of about 3 to 4 years old trees. The elements (As, Cu, Ni, Co, V, Hg, Zn, and
Mn) concentrations in the samples were determined by using Energy Dispersive
X-rays Fluorescence (EDXRF) technique. Results showed that except for As, Ni,
Zn and Hg, other metals exhibit increment in concentration from fiber and shell
to fly ash. Metals and As on debris showed varied distribution trends towards
the four direction studied, which imply the effects of wind direction on the
area. Generally, northerly concentrations showed higher concentration compared
to other directions. Although the
elements might be attributed to both fly ash and application of fertilizers and
pesticides, similar distribution trends for metals and As were also observed on
soils. Plots of distribution pattern of elements on soil and plants enable the determination
of “hot spots” for such elements.
Keywords: palm
oil mill, heavy metals, EDXRF
INTRODUCTION
Palm oil industry in Malaysia
is a success story. It has becomes an important economy sector, as Malaysian is
one of the world’s major palm oil producer. Plantation companies vary
considerably in size, from a few hundred hectares to more than 100,000 hectares
either smallholder or commercial plantation. In 2009 about 4.49 million
hectares of land in Malaysia under oil palm cultivation are producing 17.73
million tonnes of palm oil and 2.13 tonnes of palm kernel oil (MPOC, 2009).
To reduce the dependency on
the conventional energy source, many palm oil mills recycled their production
waste (fiber and shells) as biofuel to supply energy for the mills’ operation.
Unfortunately the emissions in the form of fly ash from the fuel combustion and
incineration may contained pollutants that that are deposited into the
environment and administered to the ground (Subramaniam
et al., 2008).
These emissions would not only affect the environment but may also posing
threat to human health (Yaccob et al.,
1989).
Heavy metals such as cadmium,
lead and mercury are common air pollutants and are emitted mainly into the air
as a result of diverse industrial and human activities. Nowadays, heavy metal
is causing concern due to the potential effects on human health and the
possible long-term sustainability of food production in impure areas (Zarcinas et al., 2004). Toxic heavy metals in
air, soil and water also provide global problem that are growing threat to
humanity (Matlock et al., 2001).
This study
focused on the determination of elemental composition palm oil waste and fly
ash. This will then be related to the airborne deposition of heavy metals and
arsenic in debris and soil samples collected in the study area around the palm
oil mill.
MATERIALS AND METHODS
The
study was done on the FELDA Nasaruddin Palm Oil Mill, in Bota, Perak located at
the mid-western side of Peninsular Malaysia. Debris and soil samples were
collected in about 3 km radius oil palm plantation area around the mill,
assuming the mill as a single emission point source of the area. The soils and
debris samples were collected at 0.1 km,
0.5 km, 1 km, 2 km and 3 km from palm oil mill towards north, south, east and
west directions. The mill is using palm oil waste as energy source.
Deposited
debris were collected between oil palm frond and trunk of oil palm trees of
about three to four years in age, at a height of about one meter from ground.
This would contain airborne deposition that has been accumulated over almost
similar period time. At the same sampling points soil samples was taken by using
hand auger to the depth of 15 cm. In the mill fly ash samples were collected at
the final stage where fly ash are being retained in the multi-dust cyclone
before emitted to the atmosphere. Raw palm oil fibers and shells were also
collected.
All
collected samples were oven dried at 60°C for at least 24 hours to remove water
content. The dried samples were pulverized by using agate mortar and sieved by
using 180 μm sieves. They were then pressed at 15 ton pressure to form pallet
of 2 cm diameter and about 2 mm thick, for analysis by using Energy Dispersive
X-rays Fluoresence (EDXRF) technique.
The instrument bench top PanAnalytical EDXRF spectrometer Model Minipal
4 was used to quantitatively determine As, Cu, Ni, Co, V, Hg, Zn, and Mn in the
samples. Duplicate measurements were carried out. The reliability of the
optimized analytical procedure was established by analyzing two certified
reference materials, Pine Needle, NIST 1575 a and Lichen, IAEA-336. The
recovery for various elements were found to ranged between 80% to 110% (Abdullah
et al., 2011)
RESULTS AND DISCUSSION
Table 1 shows the results for
elemental concentration in palm shell and fiber and the fly ash after the shell
and fiber being incinerated for energy production. In Table 2 the concentration
of eight elements studied in the debris and soil samples are presented. In the
tables the uncertainty values for the data were estimated based on the peak
height of the respective element peak in the fluorescence x-ray spectrum. They
were dependent on the elements, however generally they are less than 10% of the
quoted concentration values.
Fiber,
Shell and Fly Ash
In fiber and shell among all
elements manganese showed the highest concentration while mercury and cobalt shows
the least. Similar pattern is observed
in fly ash. Copper, vanadium, cobalt and manganese showed an increasing trend
of concentration from fiber and shell to fly ash, however arsenic, nickel and
mercury displayed an opposite trend. No appreciable changed in concentrations
were observed for zinc in fiber, shell and fly ash. Besides organic matter
being the main composition, results of the study are consistent with Law et al., (2007) that shows the principal
elements of oil palm fiber are copper (Cu), manganese (Mn) and iron. In this
study due to experimental constraint iron was not determined. As for elemental
concentration of elements in palm waste fly ash, the present study shows lower
concentration compared to the values quoted by Nugteren et al., (1999) for refinery fly ash. Much earlier study on palm oil
mills in Malaysia by Rashid et al., (1987)
showed several elements were found to be much higher concentration in ash
samples than our study. This observation might be attributed to the more
efficient emission control multi-dust cyclone technology used in FELCRA
Nasaruddin palm oil mill boiler. The contribution from the uptake elements in
fertilizer and pesticide by oil palm trees and accumulated to the fruit bunches
is inevitable.
Debris and
Soil
Results
in Table 2 showed a general pattern of concentration (ppm) variation in soil of
elements at all distance (0.1 km, 0.5 km, 1.0 km, 2.0 km and 3.0 km) in all direction (north, south,
east and west) that the higher concentration were manganese, zinc, and
vanadium. Meanwhile mercury and cobalt
showed lower concentration. Its worthwhile to mention here that the elemental
concentration in soil very much dependent upon the fertilizer application,
water runoff and soil structure and also airborne deposited on the soil. In
this study area the soil is peaty. The characteristic of peat soil are acidic, poor
storage qualities, high water table and deficient in nutrient. High acidity
will contributed to the high leaching that causing higher concentration of elements
being leach out. As a consequence of this relatively more fertilizer are being
applied to the plantation area.
For debris, fluctuations of
elemental concentrations according to distance (0.1 km, 0.5 km, 1.0 km,
2.0 km and 3.0 km) and direction depend
on the host particulate size of the elements, wind speed and direction,
rainfall as well as age of tree that airborne deposition accumulated. Heavy
rainfall may result in the runoff of airborne dust that trapped at the oil palm
tree. Meanwhile, older trees will increase would accumulate more deposition.
Wind direction and speed would bring together more fly ash particulate to
certain directions than others. Zinc, manganese and vanadium can be categorized
as higher concentration group for airborne deposition and as well as in soil
samples. While, mercury, arsenic and cobalt, belongs to the lower concentrations
group.
Comparison on average
concentration of elements in soil and debris shows that arsenic, copper, nickel
and vanadium are always higher in soil than debris. The opposite is observed
for manganese and mercury. Average concentrations of zinc and cobalt are
identical for both soil and debris. However, statistical study on the
correlation of elemental concentrations between elements in soil to the
respective element in debris shows no significant correlation. These
observations might be explained by the combined effects of soil type,
application of fertilizers and pesticides, rainfall as well as wind.
Spatial distributions of
elements in debris around the 3.0 km radius about the mill are shown in Figure
1 and Figure 2. Assuming the emission of the palm oil mill is the main point
source of these elements, the north and south directions of distribution are
dominant for copper, nickel, and manganese, and arsenic. Of the two directions,
southerly is more dominant. Cobalt, mercury, and vanadium show easterly
distributions. This observation is consistent with the fact that Peninsular
Malaysia experiences two monsoons seasons; the north-east monsoon and the
south-west monsoon. The resultant effect of annual wind-rose for direction and
speed are in these directions.
Based from the distribution
according to distance from the mill in Figure 1, except for mercury and zinc,
all other elements show highest concentration in debris collected at 1.0 km
away either southerly or easterly. The trend of increasing concentration with
distance, reaching maximum and then decreasing is consistent with “umbrella
effect” as described by Mohd Zahari et
al., (2012) in his study on emission from an oil refinery. Briefly the maximum
concentration is 17.05 ppm southerly for arsenic, 103.8 ppm southerly for
copper, 24.2 ppm southerly for nickel, 0.86 ppm easterly for cobalt, 168.0 ppm
easterly for vanadium and 1464 ppm southerly for manganese. Mercury showed
highest concentration (0.10 ppm) at 0.1 km easterly, while zinc showed relatively
uniform distributions (averaged about 245 ppm) towards all direction.
CONCLUSION
The
study has shown that although the use of oil palm waste for energy production
for palm oil mill operation is economically noble approach, and able to reduce
environmental impact of the abundance waste, other side effects need to be
considered as well. The fly ash of the burnt waste was found to contain heavy
metals and elements that might be harmful if emitted to the environment. No
correlation has been found between the concentrations of the studied elements
found in soil and airborne debris collected on the oil palm trees. However,
accumulations of some toxic elements of anthropogenic origins were found in the
airborne debris deposited on the oil palm trees.
ACKNOWLEDGEMENTS
The authors would like to thank Universiti
Teknologi MARA, Malaysia for the fund, and facilities to carry out the study.
CITED
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Matlock, M. M., K.R. Henke, D.A. Atwood,
(2001). Effectiveness of Commercial Heavy Metal Chelators with New Insights for
the Future in Chelate Design. Department of Chemistry, University of Kentucky,
pp1-13
Mohd. Yaacob
K., Abdul. Rahman and Mohd.
Rashid M. Yusof, (1989). Air pollution control in palm oil mill industry in Malaysia.
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towards the year 2000 and beyond, 1-6
Nugteren W H., J. M. Janssen,
and B. Scarlett (1999). Improvement of Environment
Quality of Coal Fly
Ash by Applying Forced Leaching. International
Ash Utilization Symposium 32. 1-6
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Sulaiman, (2008). Environmental performance of the milling process of Malaysia
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and G. Cozens (2004). Heavy metals
in soils and crops in southeast Asia. Environmental Geochemistry and Health
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Ahmad Saat and Zaini Hamzah, (2011). Optimization of EDXRF Spectrometer to
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Mohd Zahari Abdullah,
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bioindicator supported by multivariate analysis. Environ Monit Asses 184, 3959-3969.
Table 1. Elemental contents of shell, fiber and
fly ash.
|
Element
|
Shell
(ppm)
|
Fiber
(ppm)
|
Fly Ash
(ppm)
|
|
As
|
5.08
|
7.15
|
4.90
|
|
Cu
|
57.6
|
166.5
|
192.4
|
|
Mn
|
117.9
|
251.4
|
527.1
|
|
Ni
|
30.3
|
29.6
|
9.64
|
|
Co
|
0.19
|
0.39
|
0.47
|
|
V
|
11.37
|
34.87
|
35.74
|
|
Hg
|
0.02
|
0.03
|
0.01
|
|
Zn
|
246.1
|
250.7
|
246.6
|
Table 2. Distributions of various elements
concentration (ppm) in debris and soil according to direction and distance from
mill.
|
Arsenic
|
Copper
|
Nickel
|
Cobalt
|
||||||
|
Direction
|
Dist.
|
Debris
|
Soil
|
Debris
|
Soil
|
Debris
|
Soil
|
Debris
|
Soil
|
|
North
|
0.1km
|
11.19
|
11.45
|
86.46
|
7.68
|
10.32
|
17.82
|
0.33
|
0.74
|
|
0.5km
|
6.68
|
10.62
|
85.73
|
29.27
|
17.14
|
6.91
|
0.25
|
0.61
|
|
|
1.0km
|
6.79
|
11.66
|
29.27
|
19.76
|
12.82
|
11.00
|
0.25
|
0.49
|
|
|
2.0km
|
6.87
|
10.10
|
19.63
|
8.05
|
4.86
|
11.45
|
0.31
|
0.78
|
|
|
3.0km
|
5.31
|
14.95
|
86.46
|
18.29
|
11.68
|
11.45
|
0.11
|
0.28
|
|
|
South
|
0.1km
|
6.22
|
9.87
|
75.98
|
8.05
|
11.68
|
8.73
|
0.21
|
0.26
|
|
0.5km
|
10.18
|
8.01
|
16.71
|
6.10
|
9.86
|
6.45
|
0.51
|
0.22
|
|
|
1.0km
|
17.05
|
13.89
|
103.78
|
12.93
|
24.18
|
14.86
|
0.48
|
0.29
|
|
|
2.0km
|
9.90
|
26.06
|
18.17
|
31.34
|
12.59
|
36.91
|
0.52
|
0.25
|
|
|
3.0km
|
7.49
|
13.68
|
88.78
|
13.66
|
11.91
|
19.41
|
0.25
|
0.25
|
|
|
East
|
0.1km
|
6.37
|
42.23
|
53.78
|
19.02
|
17.59
|
24.41
|
0.15
|
0.20
|
|
0.5km
|
7.82
|
6.92
|
32.56
|
8.17
|
11.91
|
5.32
|
0.42
|
0.31
|
|
|
1.0km
|
10.23
|
16.81
|
16.46
|
12.07
|
13.73
|
10.32
|
0.86
|
0.45
|
|
|
2.0km
|
6.92
|
14.90
|
41.34
|
16.1
|
11.91
|
6.23
|
0.19
|
0.17
|
|
|
3.0km
|
9.51
|
13.91
|
30.98
|
21.22
|
9.18
|
8.50
|
0.52
|
0.25
|
|
|
West
|
0.1km
|
8.13
|
13.26
|
48.17
|
16.34
|
18.95
|
14.64
|
0.30
|
0.33
|
|
0.5km
|
7.90
|
18.29
|
25.61
|
13.17
|
9.41
|
26.91
|
0.31
|
0.40
|
|
|
1.0km
|
7.15
|
11.11
|
22.93
|
7.32
|
11.32
|
10.55
|
0.56
|
0.25
|
|
|
2.0km
|
7.49
|
10.88
|
19.39
|
7.68
|
10.32
|
11.68
|
0.65
|
0.36
|
|
|
3.0km
|
7.93
|
6.99
|
28.29
|
10.49
|
6.00
|
6.00
|
0.22
|
0.11
|
|
Zinc
|
Mercury
|
Manganese
|
Vanadium
|
||||||
|
Direction
|
Dist.
|
Debris
|
Soil
|
Debris
|
Soil
|
Debris
|
Debris
|
Debris
|
Soil
|
|
North
|
0.1km
|
254.0
|
245.0
|
0.03
|
0.03
|
962.9
|
29.44
|
29.44
|
4564
|
|
0.5km
|
253.3
|
244.9
|
0.03
|
0.02
|
653.6
|
27.48
|
27.48
|
1256
|
|
|
1.0km
|
246.8
|
244.9
|
0.05
|
0.04
|
111.8
|
27.27
|
27.27
|
363.9
|
|
|
2.0km
|
246.7
|
245.1
|
0.03
|
0.03
|
81.4
|
111.6
|
111.6
|
1276
|
|
|
3.0km
|
252.6
|
245.0
|
0.04
|
0.05
|
766.1
|
9.71
|
9.71
|
560.8
|
|
|
South
|
0.1km
|
250.7
|
245.2
|
0.03
|
0.03
|
468.9
|
38.83
|
38.83
|
1018
|
|
0.5km
|
245.9
|
244.9
|
0.03
|
0.03
|
254.6
|
117.5
|
117.5
|
1190
|
|
|
1.0km
|
253.4
|
245.4
|
0.03
|
0.03
|
1464
|
46.09
|
46.09
|
1323
|
|
|
2.0km
|
246.2
|
248.9
|
0.02
|
0.02
|
271.4
|
119.3
|
119.3
|
3508
|
|
|
3.0km
|
251.7
|
245.3
|
0.02
|
0.04
|
698.6
|
79.04
|
79.04
|
907.6
|
|
|
East
|
0.1km
|
250.2
|
245.0
|
0.10
|
0.05
|
142.1
|
11.55
|
11.55
|
929.4
|
|
0.5km
|
245.9
|
244.7
|
0.04
|
0.02
|
57.1
|
103.6
|
103.6
|
1210
|
|
|
1.0km
|
245.8
|
245.3
|
0.03
|
0.03
|
96.8
|
168.00
|
168.00
|
3979
|
|
|
2.0km
|
250.5
|
245.2
|
0.05
|
0.03
|
261.1
|
14.48
|
14.48
|
698.6
|
|
|
3.0km
|
247.9
|
245.4
|
0.04
|
0.04
|
172.9
|
77.13
|
77.13
|
2183
|
|
|
West
|
0.1km
|
246.9
|
245.1
|
0.03
|
0.03
|
197.9
|
134.4
|
134.4
|
1052
|
|
0.5km
|
246.9
|
246.0
|
0.03
|
0.03
|
137.9
|
100.2
|
100.2
|
2013
|
|
|
1.0km
|
246.7
|
245.0
|
0.02
|
0.02
|
151.8
|
135.2
|
135.2
|
3035
|
|
|
2.0km
|
246.1
|
245.1
|
0.03
|
0.02
|
87.9
|
160.0
|
160.0
|
3303
|
|
|
3.0km
|
246.2
|
244.9
|
0.04
|
0.02
|
70.7
|
142.57
|
142.57
|
327.6
|
 |
 |
 |
 |
Figure 1. Spatial distribution arsenic, copper,
nickel and cobalt in debris studied in the four directions.
 |
 |
 |
 |
Figure 2. Spatial distribution of vanadium,
mercury, zinc and manganese in debris studied in the four directions.
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