Trace Elements in the Soil of Phumi Khleang Village, Kandal Province, Cambodia

Alireza Yavar, Sukiman Bin Sarmani, Ainon Hamzah, Jamal Hisham Hashim, Syed Mohamed Aljunid, Khoo Kok Siong

  Open Access OPEN ACCESS  Peer Reviewed PEER-REVIEWED

Trace Elements in the Soil of Phumi Khleang Village, Kandal Province, Cambodia

Alireza Yavar1, Sukiman Bin Sarmani2, Ainon Hamzah3, Jamal Hisham Hashim4, Syed Mohamed Aljunid4, Khoo Kok Siong1,

1School of Applied Physics, Faculty of Science and Technology, The National University of Malaysia (UKM), 43600 Bangi, Selangor, Malaysia

2School of Chemical Sciences & Food Technology, Faculty of Science and Technology, The National University of Malaysia (UKM), 43600 Bangi, Selangor, Malaysia

3School of Biosciences and Biotechnology, Faculty of Science and Technology, The National University of Malaysia (UKM), 43600 Bangi, Selangor, Malaysia

4United Nations University-International Institute for Global Health (UNU-IIGH), Jalan Yaacob Latiff Bandar, Tun Razak, Cheras, 56000 Kuala Lumpur, Malaysia


A credible database of the elemental concentrations in the soils of a region is essential for monitoring changes in elemental contamination. Naturally occurring toxic elements in the environment are a serious problem in at least 10 provinces of Cambodia, and Kandal is one of the most greatly affected. We used the k0-instrumental neutron activation analysis (k0-INAA) method to determine the concentrations of As, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Ir, K, La, Lu, Mn, Na, Pa, Pm, Sc, Sm, and Zn in 8 soil samples from Phumi Khleang Village, Cambodia. The accuracy of the method was appraised by analysing IAEA-Soil 7, IAEA-SL 1, NBS SRM 1633A-1, and IAEA-Soil 375 as the reference materials. The baseline concentrations of 4 potentially toxic elements were as follows: As, 15.90–17.03 mg/kg; Cr, 48.89–80.45 mg/kg; Mn, 620–719 mg/kg; and Zn, 61.52–150.20 mg/kg. The consumption of toxic metals in soil is a risk to public health in the studied regions.

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Cite this article:

  • Yavar, Alireza, et al. "Trace Elements in the Soil of Phumi Khleang Village, Kandal Province, Cambodia." Journal of Environment Pollution and Human Health 2.3 (2014): 63-68.
  • Yavar, A. , Sarmani, S. B. , Hamzah, A. , Hashim, J. H. , Aljunid, S. M. , & Siong, K. K. (2014). Trace Elements in the Soil of Phumi Khleang Village, Kandal Province, Cambodia. Journal of Environment Pollution and Human Health, 2(3), 63-68.
  • Yavar, Alireza, Sukiman Bin Sarmani, Ainon Hamzah, Jamal Hisham Hashim, Syed Mohamed Aljunid, and Khoo Kok Siong. "Trace Elements in the Soil of Phumi Khleang Village, Kandal Province, Cambodia." Journal of Environment Pollution and Human Health 2, no. 3 (2014): 63-68.

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1. Introduction

Soils differ across the landscape and contain unique concentrations of elements that were derived from parent materials or were added to or removed from the soil. Elements discharged into the environment usually sink in soil. This is because cation exchange occurs in soils, as does the complexing of organic substances, oxides, and carbonates. Soils also have a high retention capacity for metals. Therefore, soil samples are among the best materials for monitoring environmental trace elements [1, 2, 3].

In addition to its use in environmental monitoring, information about the concentrations of elements in soil can be used to solve problems related to human and plant toxicity. Elements such as Zn, Mn, Cr, Co, and Fe are helpful to plants and humans, but are toxic at high concentrations. As has no biological role in humans. Exposure to As is very hazardous and causes skin and nail depigmentation and cancers [3]. Determining baseline concentrations of toxic metals is useful for the study of their geochemical behavior, including spatial distribution and probable enrichment pathways. Baseline metal concentrations can also be used to identify potential hotspots in the soil environment. Baseline concentrations have been utilized as a reference to verify clean soils and illustrate element concentrations in a particular area within a specific time [1, 2, 3]. Moreover, because the confort effects of high values can be decreased by log-transformation of the data [4], baseline concentrations have been suggested as an alternative norm for evaluation metal contamination in the soil [1, 2, 3]. The U.S. EPA lists Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, and Zn as potentially toxic elements [5].The natural background concentrations of these elements in soils can be used as a reference [6]. Without baseline data, unrealistically low guidelines may be created by regulators. It is therefore vital to determine the background concentrations of trace metals in the soils within each region and to record differences in these concentrations that may exist between soils in different soil classes or with different properties [7, 8, 9].

Natural As in groundwater is a problem in at least 10 Cambodian provinces and Kandal Province is one of the most heavily affected. Evaluation of groundwater quality and population data for Kandal indicates that more than 100,000 people are chronically exposed to hazardous levels of As [10]. Affected areas tend to be low-lying regions along the Mekong River and Bassac River. Several studies have described chemical, biological, and physical processes that contribute to the spatial distribution and heterogeneity of As in Cambodian groundwater [11-16][11]. However, there have been no evaluations of soil contamination in areas used for vegetable production in Phumi Khleang, a village in Kandal. Assessment of toxic metals in vegetable crop areas would permit estimation of dietary intake of As and other metals.

This study was conducted to establish baseline concentrations of As, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Ir, K, La, Lu, Mn, Na, Pa, Pm, Sc, Sm, and Zn in the soils of Phumi Khleang, with special attention to 4 potentially toxic trace elements: As, Cr, Mn, and Zn. This was done in order to establish guidelines for assessing metal contamination and to compare the concentrations of these metals in the soils of Phumi Khleang to those measured worldwide.

2. Materials and Methods

Thek0-instrumental neutron activation analysis (k0-INAA) method is a reference method that has been used extensively to determine the concentrations of many elements in environmental materials [17].

Soil samples were collected at depths of 0–15 cm from 8 selected locations in Phumi Khleang (Figure 1 and Table 1). Soil samples were weighed, cleaned, dried in an oven at 105°C, and re-weighed to determine the water content of the samples. The dried soil samples were then softly ground and homogenised in an agate mortar. Subsamples weighing 100.1–110.0 mg were packed for irradiation into polyethylene irradiation vials. In order to calculate channel standard deviation, soil samples were duplicated in each channel. For appraising the results of the Westcott and Høgdahl parameters, 4 certified reference materials were analyzed in duplicate. Certified reference samples included 93.7–109.4 mg IAEA-Soil 7, 93.7–105.4 mg IAEA-SL 1, 100.8–109.5 mg NBS SRM 1633A-1, and 106.1–115.2 mg IAEA-Soil 375. After weighing, the reference materials were heat-sealed in vials. The soil samples and reference materials were prepared for irradiation in 8 rotary rack (RR) channels, and irradiated for 3 h [18].

Figure 1. Map of studied region in Phumi Khleang village, Kandal Province, Cambodia

Table 1. The sample locations and coordinates of studied regions in present work

In order to obtain the short, medium, and long half-lives of the radionuclides, gamma activity in the soil and reference samples was counted at distances of 15.8 cm, 12.8 cm, and 9.8 cm after 1, 7, and 21 days of cooling, respectively. Gamma activity was counted using an HPGe detector coupled with a multichannel analyzer and gamma acquisition analysis was used for peak area evaluation. The Westcott formalism and Høgdahl convention were utilised to assess the concentration of elements in the soil reference samples [18].

3. Results and Discussion

In the present investigation, 8 soil samples from Phumi Khleang village, Kandal Province, Cambodia were collected and analysed by irradiating the samples in Malaysian Nuclear Agency (MNA) research reactor. Twenty elements were quantified in the soil samples by detecting gamma rays emitted from irradiated samples.

Figure 2. Elemental concentration of soli in 8 locations of Phumi Khleang village, Kandal province of Cambodia

Figure 2 illustrates the concentrations of the 20 elements in soil samples from the 8 selected locations. In order to calculate the concentrations of the elements by k0-INAA, it is first necessary to obtain the parameters of the Westcott formalism and Høgdahl convention. These parameters were carried out by our research group and published by Yavar [18]. The concentrations of elements in IAEA-Soil 7, IAEA-SL 1, NBS SRM 1633A-1, and IAEA-Soil 375 as reference materials were calculated to evaluate the results of the Westcott and Høgdahl parameters. The results showed a high level of consistency [18]. Subsequently, these parameters were used to calculate concentrations of elements in soil samples in the present work. As shown in Figure 2, among these elements were four toxic metals: As, Cr, Mn, and Zn. As was found only at locations L5 and L7, at concentrations of 15.90 and 17.03 mg/kg. Cr was found in all locations except L3, and the concentrations were 48.89, 53.27, 52.45, 80.09, 80.45, 76.35, and 72.74 mg/kg. Mn was detected only at L1 and L2, and the concentrations were 620 and 719 mg/kg. Zn was present in all locations, except L3, and the concentrations were 63.30, 112.93, 107.88, 61.74, 61.52, 150.20, and 124.77 mg/kg. This indicates that L5 and L7 are potential hotspots, as samples from these locations contain a higher concentration of toxic elements than those from other sites. In contrast, no toxic elements were found in L3, which suggests that it is the safest region.

The concentrations of all 20 elements in the soil in Phumi Khleang are listed in Table 2. Wide divergence is recorded in the levels of elements tolerated in soil in different countries. However, because weather and environmental conditions are identical in Bangladesh and Cambodia, it can be useful to compare our results with those from Bangladesh. As shown in Table 2, the concentrations of all elements examined in the present study, with the exception of Fe and Zn, were similar to those reported for Bangladesh. The As concentrations in soil from Cambodia showed that the average value of As (16.46 mg/kg) exceeded the typical concentrations of all comparison data except Luxembourg (58 mg/g). A previous study [10] of soils in Phumi Khleang found an average concentration of 9.89 mg/kg As (range, 5.34–27.81 mg/kg As). The level of Cr in the present study (66.32 mg/kg) was lower than the typical values elsewhere, except in China (53.9 mg/kg), Madrid(15 mg/kg), and the USA (54 mg/kg). The average concentration of Mn in our study (669 mg/kg) was lower than that in Luxembourg and the rest of the world at 1364 and 761 mg/kg. The average concentration of Zn in our study area was 97.48 mg/kg, which was higher than all comparison data except those for Luxembourg (224 mg/kg) and California (145 mg/kg). The high concentrations of As, Mn, and Zn in our study area constitute a human health hazard.

Table 2. Concentration of elements in Phumi Khleang village, Kandal Province of Cambodia soil (mg/kg) with comparison data from different published sources

The elevated concentrations of As, Cr, and Zn are due to their strong affinity to the organic matter content of soil in our selected regions, hydrous oxides of Fe and Mn, and clay minerals [2, 3, 19]. Soil contamination can result from chemical alters of the agricultural fertilizers and pesticides used in regions like Phumi Khleang [20]. In addition, there are two seasons in Cambodia: the dry season and the rainy season. In the rainy season, there is heavy rainfall and the soil leeches basic nutrients such as Ca and Mg. These elements are replaced by the acidic element Fe.

4. Conclusion

We determined background concentrations of 20 trace elements in the soils of Phumi Khleang Village, Kandal Province, Cambodia. We analyzed the As, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Ir, K, La, Lu, Mn, Na, Pa, Pm, Sc, Sm, and Zn concentrations in soil samples from 8 selected sites. These concentrations likely reflect natural variation in the soils. Comparisons of our results to those obtained in a variety of other countries indicate that the soil concentrations of these elements vary widely. However, our results were comparable to those reported for a nearby country (Bangladesh). The results of this study will be valuable for environmental pollution studies and for health, agriculture, forestry, and wildlife management. Regular studies, conducted every 2 or 3 years, are essential for monitoring the region’s soils.


We thank the personnel of the MNA research reactor, The National University of Malaysia and UNU-IIGH for their participations. This work was also partly supported by project funding of FRGS/1/2013/SG02/UKM/02/2.


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