2010 2nd International Conference on Chemical, Biological and Environmental Engineering (ICBEE 2010)

Investigation ofPb Dispersal and Accumulation around Untreated Former Tin Mines in Perak, Malaysia

Nurlidia Mansor , Muhammad Afiq Ziekry Mohd Shukry and Hafizah Afif Department of Chemical Engineering,

Universiti Teknologi PETRONAS 31750 Tronoh, Perak Daml Ridzuan, Malaysia

(e-mail: nurlidia_mansor@petronas.com.my;afiq.ziekry@gmail.com;hafizah.afif@gmail.com)

Abstract- There are approximately 114 000 ha of

former mining area left derelict after the tin mining

industry collapsed in Malaysia [1] These lands are

currently turned into agriculture and aquaculture farms.

Unfortunately, studies have indicated that crops

cultivated on tin tailings have been found to contain

alarming levels of Potentially Toxic Elements (PTEs).

Fish that are bred in slurry ponds and mine pools are

also not excluded from PTEs. This research aims to

determine and identify the atmospheric dispersal as well

as the accumulation of Pb from active and derelict

former tin mines in Perak, Malaysia. Samples of plants;

Melastoma sp. and Benincasa sp. and fish; Tilapia sp.

and Cichla sp. grown and bred in mining ponds were

collected from active farms in Location 1 and 2. Plants

and fish of the same species and grown naturally were

also taken from abandoned mine sites at Location 3 and

4. Atmospheric dispersal of heavy metals is also

investigated using available biomarkers. Tree bark from

Acacia mangium sp. is collected to represent heavy

metal dispersal from wind erosion of tin tailings from

the mine sites. The methodology for sample analysis was

done by using wet digestion analysis with nitric acid and

hydrochloric acid. Concentration of heavy metals was

determined using flame atomic absorption spectrometry

(F AAS). Pb concentration was found to be highest in the

root of Melastoma sp. at 57.62 mg/kg and in the muscle

of Cichla sp. at 27.28 mglkg. The results indicate

elevated Pb levels regardless of whether it is from active

or abandoned tin mine site. Heavy metal levels in all of

the plants and fish samples in this study were found to

be above the safe limit issued in the Food Acts 1983 and

Regulations 1985[2][14]. Appropriate measures should

be taken to further reduce the dispersal and exposure of

heavy metals from the former mine sites from entering

into the food chain and causing serious threat towards

health and safety.

Keywords- tin mine; tin tailings; potentially toxic elements; biomarkers; tree bark

978-1-4244-8749-3/10/ $ 26.00 © 2010 IEEE 43

I. INTRODUCTION

In Malaysia, tin mining was one of the first successful industries which contributed as a major economic pillar. As mentioned in [3], tin mining started since 1820s after the arrival of Chinese immigrants. Malaysia became one of the world's leading producers of tin accounting to about 31 percent of the world's output during the 1960s. However, the tin mining industry collapsed over the last 30 years due to the exhaustion of tin deposits, low tin prices and high operating costs.

Tin occurs chiefly as alluvial deposits in the foothills of the Peninsular on the western site. The most important area is the Kinta Valley, which includes the towns of Ipoh, Gopeng, Kampar and Batu Gajah in the state of Perak. Over the years, these former tin mine site are actively used as agriculture and aquaculture activities. Contamination from past mining activities had been a major concern for a long time since the early times when commercial mining were introduced. The process of mining exploitation and ore concentrating, mine tailing and wastewaters are created, and dust is emitted. This has resulted in the surrounding environment being severely polluted. A study on an abandoned mine (underground mining) at Sg. Lembing Malaysia found heavy metal levels exceeding the limit allowed in the Environmental Quality Act (1974) and contaminated soil standard [2]. The study concludes that there is an urgency to regulate the better closure of abandoned mine sites.

In recent years, studies and research on the presence of PTEs due to mining activity gained interest due to discoveries that aquatic life and crops bred and grown from former mines contain elevated levels of PTEs. Research of PTEs mining contamination in Malaysia [1] shows that the major elements available are lead (Pb), zinc (Zn) and copper (Cu), in the residual tailing of the mine. After the tin mining industry ceased in the state of Perak, most of the mining sites had to be shut down. Local settlers grew crops, breed fish and open orchards at the former mining sites due to the available spaces. However, most PTEs exposed during mining activities still exist and may not diminish over time. PTEs may be transported through soil and water and are accumulated within the living organisms. Products of vegetables and crops from the mine are eventually

2010 2nd International Conforence on Chemical, Biological and Environmental Engineering (ICBEE 2010)

distributed to consumers, thus allowing PTEs to enter the food chain. Implication from PTE accumulation in the body will cause various health problems depending on the type and concentration accumulated. These may include cancer, mental loss, organ deterioration and other implications [4]. In Perak, there are many former tin mining sites and almost 80% has been developed as active farms. From these sites, it is estimated that 75% of the total farm produce (including fish) will be distributed to consumers mainly for human consumption [4]. These figure shows that monitoring of former mining sites is vital to control its accessibility to enter the human food chain. Data on the concentration of PTEs and its impact on human health are crucial. Thus, the main objective of this study is to determine the concentration of PTE's, mainly Pb and Zn in Tilapia sp.(Talapia), Cichla (Peacock Bass), Melastoma (Senduduk) and Benincasa (Winter Melon) obtained from active sites at Bidor and Bemban, and derelict/inactive sites at Malim Nawar and Tronoh.

II. STUDY SITE

Sampling sites for this study consist of two parts -active and inactive. Criteria of differentiation include activity period, current condition, and location of the site. For example, Tronoh has been an active mining site for 20 years before being abandoned for the past 30 years. Current condition explains the current activity of the site at the time when samplings were done.

A. Location 1

Location 1 was one of the major tin mining sites during the booming tin industry era around 1950s. Most of the abandoned tin mine sites has been converted for agricultural usage. The Forest Research Institute Malaysia (FRlM) has a research field station of approximately 120 ha. where various studies regarding tin tailings had been undertaken near the site. The research station, known as Forest Research Station Bidor (FRSB) is actively developing appropriate forestry systems for rehabilitation of degraded lands. Amongst its main objectives are to carry out research in developing cost effective tree planting techniques on tin tailings, to conduct research in improving the site quality and to generate financial gains from utilization of the former mine site. The station has been undergoing phytoremediation efforts for the past 15 years. Phytoremediation is the use of plants to extract the ions from the soils using photosynthetic energy, which accumulates them in the biomass; roots, stems and branches according to its nutritional requirements [6]. The site is planted with various species of timber plants with high commercial value. A recent survey of Pinus, Flindersia brayleyana and Khaya ivorensis produced from FRSB estimated yields as high as USD 30 000 per 40 000 ha at 40 years after planting [7].

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B. Location 2

Last reported activities of mining at Location 2 were during the collapse of tin-industry in the 1980s. No agricultural sites were observed at the former mining pond which makes it a suitable location to study the concentration of Pb and Zn in crops and aquatic life without the disturbance from agricultural activities such as fertilizers, enhancers and other sources.

C. Location 3

Location 3 is active in agricultural activities and breeding fish. No major mining activities were reported during 1950s but residual activities due to the location from Kinta to the mining town in Tronoh, had made Location 3 to be included in the mining activities. Newly formed fish breeding site since 2007 makes it an ideal site for studying the presence of Pb and Zn within the area.

D. Location 4

Location 4 consists of vast land that is currently operational for various activities such as palm plantation, duck breeding, sand mining, and agriculture. There are also large areas of abandoned tin mine. According to personal accounts of locals within the area, Location 3 was no longer active in mining for almost 20 to 25 years, which is suitable as one of the sampling location for this study.

E. Tin Dredge Heritage (TDH)

Tin Dredge Heritage is situated in Batu Gajah, about 60 km from Ipoh. The site of the many active mining sites in the area maintains a tin dredge preserved for the purpose of historical value. Apart from the large mining pond, a small plantation of Annona squamosa was observed. Various dominant plants are also naturally available including the Acacia mangium trees for bark sampling.

III. METHODOLOGY

A. Sample Preperationfor Crops

Sample preparation procedure was carried out according to [8][9] and [10]. Aerial part of the plants were cut using sterilized scateurs at least 3cm above ground with composite weight of 0.5kg for lab treatment. The root section was handled carefully, digging around the root of plants and carefully removing it from the soil. Aerial parts of the plant (leaves, stems, shoots) were stored separately from roots during transportation, and sample was immediately transported to the lab after extraction. Samples were washed with tap water followed by distilled water to eliminate attached soil particulates. The samples were then freeze­dried and ground into powder by using pestle and mortar.

Samples were placed in crucible for the ash process in the furnace with temperature of 500°C for a minimum period of 5 hours. Sample produced from the ash process was weighted and placed in a small beaker. lOml of 65% HN03 was added and the mixture was boiled for about 10-

2010 2nd International Conforence on Chemical, Biological and Environmental Engineering (ICBEE 2010)

15 minutes at temperature not exceeding 160°C. Beaker was covered with watch glass and the reaction was allowed to subside. Samples were then allowed to cool down. Another 5ml of 65% HN03 was added to the beaker and the mixture was re-heated for another 20-30 minutes at the same temperature as before. Sample was allowed to cool after the heating process after which 5ml of 37% HCI was added into the mixture. The mixture was then shaken gently and heated back for another 15 minutes at the same temperature as before. The solution was then filtered after cooling using Whatman No.2 filter paper and transferred to a 100mi volumetric flask and deionized water was added to mark.

B. Sample PreperationforFish

Fish taken from source location were stored on ice in an insulated box and immediately transferred to the laboratory. 3 - 5 samples of fish of the required species were prepared for composite sample regardless of the raw weight. Procedures were carried out according to [11] and [12]. The length of the fish samples were measured (standard and total lengths). The whole fish and fish head/viscera was weighted with digital analytical balance. The fish samples were dissected, separating the fish head/viscera from other parts. The fish head/viscera were washed thoroughly with distilled water before digestion. The samples were then freeze-dried and ground into powder by using pestle and mortar. 2 g of sample was placed in crucible for ash process in furnace with temperature of 500°C for a minimum period of 5 hours. The sample produced from ash process was weighed and placed in a 100mi beaker. Another 5ml of 65% HN03 was added to the beaker and the mixture heated for another 20-30 minutes at the same temperature as before. Sample was allowed to cool after the heating process and 5ml of 37% HCI was added into the mixture. The mixture was shaken gently and heated back for another 15 minutes at the same temperature as before. The solution was then filtered after cooling using Whatman No.2 filter paper and transferred to a 100ml volumetric flask and deionized water was added to mark.

C. Sample Preperationfor Bark

Bark samples of Acacia mangium from FRSB and TDH were removed using a stainless steel knife of approximately 15 cm x 15 cm area to a depth of approximately 1 mm. The bark was collected at a standard sampling height of 1.5 m above the ground. This height was chosen, based on previous studies, to avoid areas where soil particles may be splashed onto the trunk during periods of rainfall and reduce the influence of relative source position. Mosses on bark surfaces were also included in the samples as the study aims to determine the physically trapped elements on the tree bark surfaces. Tree bark samples were air-dried at room temperature for about 8-9 hours. Barks were then oven dried for about 8 hours at 110°C until constant weight was achieved. The barks were then crushed into smaller pieces and pulverized using 2 mm aperture. 2 g of bark was

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weighed and placed in the furnace for about 5 hours at 500°C to remove organic matter. The ash was then digested using 10% HN03, filtered after cooling using Whatman No.2 filter paper and transferred to a 100mi volumetric flask and deionized water was added to mark.

D. Heavy Metal Analysis

Metal analyses were performed using a flame atomic absorption spectrometer Shimadzu AA-6800 (Shimadzu, Japan). The limit of detection for Pb is O. lmg/ml.

IV. RESULTS AND DISCUSSION

The results for Pb and Zn concentration for plants and fish samples are as shown in Figures 1- 4 and Figures 5-8, res ectivel .

Pb Concentration Melastoma

• location 1 • Location 4

� 60 CD

.§. 50

.� 40

30

� 20 5 u 10

f 0

leaves Stem Roots

Figure 1. Pb concentration in Melastoma

Figure 1 shows the range of Pb concentration between 45-60 mg/kg in samples from Locations 1 and 4. Samples from Location 1 had concentration of Pb ranging from 8-20 mg/kg. However, Pb could not be detected at the roots of the sample from the same location. Results obtained from both locations comparatively shows that Pb concentration is quite high in melastoma obtained from Location 4 compared to the sample obtained from Location 1.

Heavy metal uptake of the plant shows the average level at all three parts of the plant (roots, stem and leaves). Sample from Location 1 shows lower concentration in Pb as compared to Location 4 probably indicating the effects of phytoremediation within the area.

Pb concentration in Benincasa

_location 4

� 40

... .§. 30 "

·2 � 20

� 10 0 U .0 Q.

Fruit Leaves Stem Roots

Figure 2. Pb concentration in Benincasa

2010 2nd International Conference on Chemical, Biological and Environmental Engineering (ICBEE 2010)

From Figure 2, the concentration of Pb in Benincasa is observed to be in the range of 25-40 mg/kg. The graph also illustrates that the accumulation of Pb is high in the fruit compared to other parts. The Pb accumulation in Benincasa is less than Pb found in Melastoma. This could be due to the fact that it has a smaller stem diameter compared to Melastoma, thus uptake from soil is less.

Pb Concentration in Cichla

.locat on 2 • Location 3

-.;

� 30

.§. 25 0 .9 20 �

� 15

0 10 0

u '"

5 0.

0

Muscle Viscera

Figure 3. Pb concentration in Cichla

Figure 3 shows concentration of Pb in muscle and viscera of Cichla found in Locations 2 and 3. The concentration of Pb in muscle sample from Location 2 was found to be slightly higher than that found in Location 3. In the viscera, Pb concentration was found to be lower in Location 2 of about 10 mg!kg.

Pb accumulation in muscle tissue of Tilapia is quite high for specimen from Location 1 compared to its viscera. However, specimen from Location 3 displays comparable concentration between its muscle tissue and its viscera. Concentration of Pb in viscera found in Tilapia from both locations showed similar result of approximately 16 mg/kg. However, Pb was undetected in muscle tissue from sample at Location 3. As shown in Figure 4, the sample location does not demonstrate any differences in concentration of Pb which may indicate that the heavy metals uptake for the same species at the different location is similar. The safe limit for Pb concentration for fish and crops are both at 0.5 mg/kg (FAO 1983, FAR 1985).

� Co 20 .§. � lS

_ 10 C � 5 o

PB Concentration in Tilapia

• Location 2 • location 3

� 0 .lL... ___________ ---'"

0. Muscle Viscera

Axis Title

46

Figure 4. Pb concentration in Tilapia

Based on the results obtained it is clearly shown that all of the samples contain Pb concentration over the safe limit set by FAO 1983 and WHO 2001[13][15]. To clearly visualize the content of PTEs consumed by the general public, it is estimated that an adult human consumes an average of 60 - 70 g of fish per day. Since Tilapia is a popular species to be sold locally, it is estimated based on the formula below, the consumption of a normal adult:

lrl'l1:s. (:�) = C<i>nwn:trfrt1o-n (mg/ikg)ls: (I:.(l:7kgJdI�

This equals to about 1.14 mg/day for Pb which has exceeded the minimum risk limit produced by the Agency of Toxic Substances and Disease Registry (ATSDR) of US Department of Health and Human Services [5]: Lead: 0.0000785 mg/day

The findings of this study clearly reveal the alarming level of heavy metal present in agriculture and aquaculture product from active and derelict mine site. The availability of PTEs and its direct link into the food chain raises health concern issues.

comparison between Pb concentration in TDH vs. FRSB

T4 70

0> 60 � 04

0> 50 E

c 40 0

'p 30 (1J lo

20 c '" v 10 c 0

0 v -"" CL

5 5 100 100

increase distance from source point (m)

Figure 5. Pb concentration in bark samples from TDH and FRSB

As depicted in Figure 5, bark samples from FRSB shows a decreasing trend with increasing distance from the point source. With the range of between 8-30mg!kg, the trend shows the influence of distance towards the atmospheric dispersal of the heavy metal. Samples from TDH however reveal a similar concentration of approximately 60 mg/kg for 3 samples and 15 mg/kg for one sample at 100m distance from the point source. This may indicate that the heavy metal dispersal is evenly distributed and non­dependant against the point source.

The Pb concentration result shows that the heavy metal concentration within FRSB is comparatively lower than TDH. Aerial dispersal trend at FRSB is more defined with influence from point source. This may indicate that the phytoremediation efforts have the potential to contribute towards controlling the dispersal pattern of airborne

2010 2nd International Conforence on Chemical, Biological and Environmental Engineering (ICBEE 2010)

particulates. As this is a preliminary study, it is recommended that further investigation is needed.

V. CONCLUSION

The study indicates that there are PTEs, specifically Pb present in agriculture and aquaculture produce grown and breed on former tin mining land regardless of whether the site is active or derelict. In all species involved regardless of parts, concentration of Pb is unacceptably high compared to the safe limit issued by WHO and F AO for food contamination [15]. The concentration of PTEs is at a level that could cause health hazard to humans when ingested. Comprehensive analytical studies should be incorporated in future work to find related concentration trend and PTE levels at other former tin mine sites. The tree bark analyses have given an insight into the aerial dispersal of Pb and Zn within the mine site. Plantation of timber trees or phytoremediation efforts from FRIM indicates its potential use in controlling the aerial dispersal of heavy metals in the atmosphere. In the interest of human health and safety, an alternate solution of replacing the current activities with other economically viable activity within former mine sites must be addressed. For instance, Taiping Lake Garden which was once a tin mining site has now been converted into tourism spot. As for a more technical solution, the former tin mine sites can still be used for agricultural purposes via remediation techniques of the land. Although it will take a fairly long time to be completed and will incur high costs, nevertheless this solution is technically feasible to be implemented and ethically sound.

ACKNOWLEDGMENT

Appreciation is recorded to Dr. Ang Lai Hoe from FRIM for his consistent support and vast experiences in this field and the usage of FRSB for sampling purposes. The author also acknowledges Universiti Teknologi PETRONAS for supporting the research work conducted under the FYP scheme.

REFERENCES

[I] 1. H. Ang, T. B. Ang and L. T. Ng .. Site toxicity of tin tailings and its implications on land use in Peninsular Malaysia, Proceedings of Malaysian Science and Technology Congress 98, Kota Kinabalu, Sabah, 1998.

[2] F.Y. Alshaebi, W.Z.w. Yaacob, A. R. Samsudin, E. Alsabahi, "Risk assessment at abandoned tin mine in Sungai Lembing, Pahang, Malaysia" Journal of Geotechnical Engineering, Vol 14 E, 2009, pp 1-9.

[3] J. R. Lee, "Historical tin mining in Malaysia, The Mandala Projects", The School of International Service, American University 2000. MALAYTIN

[4] 1. H. Ang & R. Mohd Osman, "The occurrence of some important potentially toxic trace elements in an ex-mining land located in Bidor, Perak. Proceedings of Malaysian Science and Technologyy Congress 1999. 8-IOth November, Hilton Kuching, Sarawak, 1999, ppI20-127.

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[5] Agency of Toxic Substances and Disease Registry (ATSDR) of US Department of Health and Human Services.

[6] B.K Roy, R. Prasad, Gunjan, "Heavy metal accumulation and changes in metabolic parameters in cajanas cajan grown in mine spoil" Journal of Environmental Biology, Vol 31:5, September 2010, pp 567-573.

[7] P. Veronica, "The Art of Mining Trees" FRIM In Focus, 2000.

[8] H. Zeng-Yei, "Evaluating heavy metal contents in nine composts using four digestion methods" Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Taiwan, 2003.

[9] D. Kanakaraju, N. A. Mazura, A. Khairulanwar, "Relationship between metals in vegetables with soils in farmlands of Kuching, Sarawak" Department of Chemistry, Faculty of Resource Science and Technology, University of Malaysia Sarawak, 2007.

[10] M. S. Subramanian, "Module 6.1: Analysis of soils, sediments and siological specimens" Indian Institute of Technology Madras, 2005.

[II] J. C. Nnaji, A. Uzairu, G. F. S. Harrison, M. 1. Nalarabe, "Evaluation of cadmium, chromium, copper, lead and zinc concentrations in the fish head/viscera of Oreochromosis niloticus and Syndontis schall of River Galma, Zaria, Nigeria, National Institute of Freshwater Fisheries Research, New Bussa. Department of Chemistry, Department of Biological Sciences, Ahmadu Bello Univeristy, Zaria, 2007.

[12] F. E. Olaifa, A. K. Olaifa, T. E. Onwude, "Lethal and Sub-lethal Effects of Copper to the African Catfish (Clarias Gariepinus) Juveniles, Department of Wildlife and Fisheries Management, Department of Veterinar Surgery and Reproduction, Univeristy of Ibadan, 2004.

[13] FAO, "Compilation of legal limits for hazardous substances in fish and fishery products" FAO Fishery Circular no. 464,1983, pp5-100.

[14] Food Act 1983 and Food Regulation 1985. Food Act and Regulation Kuala Lumpur, Dewan Bahasa dan Pustaka.

[15] World Health Organization (WHO) Environmental Health Criteria 221, Zinc and Lead, Geneva., 2001