Water-Quality Assessment of the Langat River at Kilometre 7, Jalan Kajang-Bangi, Selangor, Malaysia

Muhammad Barzani Gasim, Mazen M. Jamil and Sahibin Abd Rahim School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor Darul Ehsan, Malaysia Mohd. Ekhwan Toriman School of Social Development and Environmental Studies, Faculty of Social Science and Humanities,Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor Darul Ehsan, Malaysia

The Langat River is one of the main sources of Key words: Langat River, river pollution, water water supply for the Selangor area. For water- analysis, water-quality classification, Malaysia quality analysis, water sampling was carried out at five stations during the wet (November 2009) La Langat River est l’une des principales and dry (February 2010) seasons. These five sources d’approvisionnement en eau de la stations are located along the river, with the région de Selangor. Pour l’analyse de la qualité exception of station 3. Station 1 and station 2 are de l’eau de la Langat River au kilomètre 7, des located upstream station 3, while station 4 and échantillons ont été prélevés à cinq points station 5 lie downstream of station 3. Station 3 pendant la saison humide (Novembre 2009) et differs from the other four stations because it is a pendant la saison sèche (Février 2010). Ces cinq discharge from Universiti Kebangsaan Malaysia stations de mesure sont situées le long de la campus. This study was conducted to determine rivière à l’exception de la troisième : la première water quality as well as levels of pollution, et la seconde sont situées en amont de la based on the Water Quality Index (WQI) and the troisième, et la quatrième et la cinquième en Malaysian Interim National Water Quality aval. La troisième station diffère des quatre Standard (INWQS), of the Langat River at Km 7. autres car elle est située sur un écoulement du A total of 14 water-quality parameters—temper- campus UKM. Cette étude a été menée pour ature, pH, dissolved oxygen (DO), conductivity, déterminer la qualité de l’eau ainsi que les chemical oxygen demand (COD), biochemical niveaux de pollution, utilisant l’Indice de qualité oxygen demand (BOD), total suspended solids de l’eau (Water Quality Index - WQI) et la

(TSS), total dissolved solids (TDS), PO4, NO3-, Norme nationale malaysienne intérimaire de la NH3-N, SO4, oil and grease, and E. coli—were qualité de l’eau (Malaysian Interim National selected and analyzed in situ and in the labora- Water Quality Standard - INWQS),. Un total de tory. The laboratory work was carried out 14 paramètres—temperature, pH, oxygène according to Hach and American Public Health dissous, conductivité, demande chimique Association (APHA) methods. All 14 water-qual- d’oxygène, demande biochimique d’oxygène, ity parameters were found to be within the total des solides suspendus, total des solides normal range according to INWQS, with the dissous, PO4, NO3-, NH3-N, SO4, huiles et graisses, exception of NH3-N, PO4, and E. coli, all of et E. coli—ont été sélectionnés et analysés in which exceeded the recommended levels. Based situ et en laboratoire. Les études de laboratoires on the WQI classiﬁcation, the Langat River can ont été conduites selon les méthodes HACH et be categorized as moderately polluted, or Class APHA. Pour les 14 paramètres de qualité de III, at all sampling stations, except at station 3 l’eau, les données sont dans les fourchettes during the ﬁrst sampling (November 2009), normales de la norme malaysienne INWQS, à where it is categorized as Class II. l’exception de NH3-N, PO4, et de E. coli, qui ont des valeurs dépassant le niveau recommandé.

En suivant la classification de l’Indice de qualité the river’s catchment area has been subject de l’eau, la rivière Langat peut être classée to deforestation, intensification of agricul- comme étant moyennement polluée, ou en ture, soil erosion, urbanization, and industri- Catégorie III, dans les cinq stations, sauf pour le alization; as a result, water pollution and premier échantillon prélevé à la troisième water shortages have now become a severe station qui est de catégorie II. problem (Muhiyuddin and Rainis 2002; Mots-clés : Langat River, pollution fluviale, Elfithri et al. 2002), drawing attention from analyse hydraulique, classification de la qualité the public and the government. These prob- de l’eau, Malaisie lems have raised ethical issues with respect Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 to how people can make good use of a huge Introduction and complex data set containing a large number of physicochemical parameters. The Langat River is located in the western Further-more, water has been the main part of Peninsular Malaysia, lying within commodity for economic development in latitudes 2°40’152” N to 3°16’15” N and Malaysia, frequently described as the bind- longitudes 101°19’20” E to 102°01’10” E. ing force, fuel, or basic infrastructure for The Langat Basin occupied an area of about development (Abdullah and Jusoh 1997). 2 938 km2 and had an estimated population Thus, Noorazuan and Kadaruddin (1999) of about 962 694 in 1998 (Nordin et al. predicted that the increase in population in 1999). The Langat River basin is unique in the Langat River basin would cause water that it passes through three distinct adminis- deficit by 2010. It is important to study the trative regions: the federal territory of water quality of the river by measuring Putrajaya and Cyberjaya, the state of water-quality characteristics through Selangor, and the state of Negeri Sembilan conventional techniques that give direct (Nordin and Azrina 1998). The entire basin results on pollution status. covers slightly less than 2 400 km2; its The Langat River basin is a major centre uppermost stretch originates from the of manufacturing industries in the state of Titiwangsa main range in the state of Selangor (Fariz and Nordin 2000), and this Selangor and Negeri Sembilan. The total development increasingly attracts people to length of this river has been recorded at the basin from other parts of the country to 200 km; the river ends at the Strait of take advantage of job opportunities. The Malacca. The Langat River has several trib- Langat River plays a significant role in the utaries, the principal ones being the ecology of the basin, providing potable Semenyih, Lui, and Beranang Rivers. There drinking water to residents within the basin are two reservoir sites, the Langat and as well as in the highly urbanized Klang Semenyih Dams, located the upstream of the Valley, industries, and agricultural areas Langat River catchments. In addition, the (Nordin et al. 1999). The river also provides development of new townships such as recreational sites and habitats for fish and Bandar Baru Nilai and the expansion of other aquatic wildlife. However, recent existing towns and villages such as Kajang, development activities in the basin threaten Dengkil, and Semenyih have contributed to water quality in the river and have the poten- increasing population density with concomi- tial to disrupt its ability to supply water tant urbanization and industrialization, requirements. In addition, pollution by which have the potential to cause complex industries, manufacturers, commercial oper- environmental problems. ations, and animal farms along the river have The Langat River currently plays a the potential to aggravate the drop in water crucial role in water supply, fishing, waste quality (DOE 1998; Mazlin et al. 2000). The disposal, agriculture, and industry. However, objectives of the present study were to

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FIGURE 1 Locations of five sampling stations along the Langat River determine water-quality conditions in the except for station 3, which is a discharge point Langat River upstream and downstream of from UKM before joining the river. the Universiti Kebangsaan Malaysia (UKM) campus and to determine pollution levels of Sampling Methodology the Langat River based on Water Quality Index (WQI) and Interim National Water Study of the development of water-quality Quality Standards (INWQS) classifications. criteria and standards for Malaysia, initiated by the Department of Environment (DOE) in Study Area 1986, has recommended a set of Interim National Water Quality Standards (INWQS) The study area of the Langat River is located for individual water-quality parameters. The between latitudes 2°40’152” N and 3°16’ INWQS and the WQI define six classes of 15“ N and between longitudes 101°19’20” E water quality (I, IIA, IIB, III, IV, and V) and and 102°01’10” E (see Figure 1). Sampling identify the highest sustainable beneficial uses stations in the study area were divided into five, for each class (DOE 1994). Five sampling based on different activities along the Langat stations were set up in the study area. Two River. All stations were located along the river bottle samples were collected from each

The Arab World Geographer/Le Géographe du monde arabe 12, no 3-4 (2009) Water-Quality Assessment of the Langat River 191 station. Biochemical oxygen demand (BOD) season. During the wet season, pH values samples were collected in black bottles, water ranged from 5.55 to 6.39, for a mean of 6.05 samples for other purposes were collected in (see Figure 2b). Overall, stations showed clear bottles, and all samples were stored in normal distribution during the two sampling iced cooler boxes and processed immediately periods. According to Rump and Christ in the lab (see APHA 1998). Temperature, (1988), a pH range of 6.5–8.0 is considered conductivity, pH, and dissolved oxygen (DO) normal for a freshwater ecosystem, while were analyzed in situ. Other parameters— the best pH range for phytoplankton growth

BOD, total suspended solids (total suspended is between 6 and 8.5 (Mason 1992). Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 solids), total dissolved solids, oil and grease, According to the INWQS for Malaysia, the ammonia nitrogen (NH3-N), nitrates (NO3-), pH values for the Langat River fall into sulfate (SO4), phosphate (PO4), and Class I. The lowest pH value was recorded at E. coli—were analyzed in the laboratory. All station 1 during second sampling. samples were analyzed according to the Hach and American Public Health Association Conductivity (APHA) methods. The DOE-WQI and INWQS classifications were used to classify Conductivity values during first sampling the results and according to DOE (1998) meth- (wet season) ranged from 104 s/cm to ods. Six water-quality parameters—DO, pH, 158 s/cm, with an average value of BOD, chemical oxygen demand (COD), TSS, 131.2 s/cm, while during the second and NH3-N—were used for WQI calculations sampling (dry season), conductivity values (UKM-DOE 2000). ranged from 77 s/cm to 114 s/cm, for an average value of 103.10 s/cm (see Figure Result and Discussions 2c). These values are considered in the low range; it is most probable that certain miner- Temperature als in the water were settling down. According to the INWQS, conductivity The results of temperature measurements for values below 1 000 s/cm are classified under the two sampling periods show that Class I and suitable to support aquatic life. sampling temperatures ranged from 27.29°C The lowest values were recorded at station 3 to 29.23°C, with a mean value of 28.21°C, in (104 s/cm and 77 s/cm); the highest value November (wet season) and from 26.16°C to was recorded at station 5 (158 s/cm), repre- 27.56°C, with a mean value of 27.19°C, in senting higher levels of dissolved salts in the February (dry season), suitable for aquatic water that may have been due to the organisms (see Figure 2a). The temperature discharge from nearby settlements. range at the sampling sites appears to indi- Conductivity values were lower at second cate normal readings for the two seasons. sampling than at first sampling, showing the The temperature was lowest at station 1, effect of less rain, which is to decrease the because sampling was conducted in the early concentration of salt minerals. morning, and increased at station 5. In the tropical climate, the temperature normally Dissolved Oxygen (DO) increases (during the sampling day) from morning to afternoon. During the first sampling period, DO values ranged from 3.72 to 6.05 mg/L, for an aver- pH age of 4.25 mg/L; at second sampling, DO values ranged from 2.27 to 3.44 mg/L, for an pH value at first sampling ranged from 6.7 to average of 2.89 mg/L (see Figure 2d). The 7.35 (mean: 6.87), recorded during the dry highest DO value was recorded at station 3

The Arab World Geographer/Le Géographe du monde arabe 12, no 3-4 (2009) 192 Gasim, Jamil, Rahim and Toriman in November (first sampling period). The stations along the Langat River meet the results were classified as Class III, meaning WQI-recommended threshold level for the that the water is suitable for agricultural support of aquatic life (Class I). activities only (DOE 1998). Meanwhile, the presence of large quantities of organic Ammonia-Nitrogen (NH3-N) matter, domestic and industrial wastes, and increased density of zooplankton may have Analysis of water samples collected for this caused a general reduction in DO values study during the wet and dry seasons reveal Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 (Law 1980; Offiong and Edet 1998; that NH3-N values ranged from 0.41 to Kailasam and Sivakami 2004). In addition, 2.31 mg/L during the first sampling period, the shallowness of the river could be another and from 0.38 to 2.56 mg/L during the contributing factor in the decrease in second sampling (see Figure 3c). The aver- dissolved oxygen. age value of NH3-N was 1.59 mg/L in November (wet season) and 2.03 mg/L in Biological Oxygen Demand (BOD) February (dry season). Ammonia-nitrogen values were higher during the second BOD values for the first sampling period sampling period, as there was no rain that ranged from 2.24 to 4.2 mg/L, an average of could stimulate microorganism activity in 3.39 mg/L; during the second sampling the water (Elmund, Allen, and Rice 1999). period, BOD values ranged from 0.84 to However, the INWQS recommends a maxi- 2.45 mg/L, for an average of 1.44 mg/L (see mum NH3-N threshold level of 0.3 mg/L for Figure 3a). When BOD values for the two the support of aquatic life in Malaysian sampling periods were compared, values rivers. The main source of ammonia in were found to be higher for the first Langat River is probably residential efflu- sampling. The highest BOD value ents and surrounding discharge. According (4.20 mg/L) was recorded during the wet to INWQS, therefore, those stations where season at station 3, and the lowest values exceeded the threshold value of 0.3 (0.84 mg/L) during the dry season at station mg/L fall into Class V for ammonia-nitrogen 4. Based on INWQS, BOD values in this concentration, indciating that the aquatic study are classified between Class I and ecosystem of the Langat River is severely Class IIB, suitable only for recreational use polluted with NH3-N. with body contact. Nitrates (NO3-) Chemical Oxygen Demand (COD) Values of NO3- during the first sampling COD values during the first sampling period period ranged from 1.3 to 10.04 mg/L, for an ranged from 5.5 to 15.5 mg/L, or 11.0 mg/L average of 5.75 mg/L; during the second on average; during the second sampling sampling, values ranged from 2.75 to period, values ranged from 14.5 to 25 mg/L, 6.55 mg/L, an average of 5.22 mg/L (see for an average of 21.20 mg/L (see Figure Figure 3d). The lowest NO3- value was 3b). The lowest COD value was recorded at 1.30 mg/L, recorded at station 3, and the station 3 (5.5 mg/L) during the first sampling highest value was recorded at station 4 period, and the highest at station 5 (25 mg/L) (10.05 mg/L). The main sources of this during the second sampling period. COD pollutant may be fertilizers used on planta- concentration was higher during the second tions and/or untreated human waste (Gasim sampling period; this result was identified et al. 2002). The INWQS threshold level of with a higher concentration of inorganic nitrate for Malaysian rivers to support the matter in the river. COD levels at these aquatic life is 10 mg/L. The nitrate levels

The Arab World Geographer/Le Géographe du monde arabe 12, no 3-4 (2009) Water-Quality Assessment of the Langat River 193 pH Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021

Station Station

FIGURE 2 Distribution of temperature, pH, conductivity, and DO values in the study area found in this study are below INWQS sampling period and at station 1 (0.29 mg/L) threshold levels (Class III), which suggests during second sampling. The INWQS that the Langat River is generally not badly threshold level for phosphate-phosphorus in polluted by runoff nitrates. Malaysian rivers is 0.10 mg/L. Recorded phosphate-phosphorus levels thus exceeded Phosphate-Phosphorus (PO43-) the INWQS level (Class IV) at all sampling stations studied along the Langat River. PO43- values during the first sampling period ranged from 0.31 to 0.93 mg/L, for an aver- Sulphate (SO42-) age of 0.786 mg/L; during the second sampling period, values ranged from 0.29 to SO42- values during the first sampling period 0.94 mg/L, an average of 0.67 mg/L (see ranged from 1.5 to 39.5 mg/L, for an average Figure 4a). The lowest PO43- values were value of 26.2 mg/L; during the second recorded at station 3 (0.31 mg/L) during first sampling period, values ranged from 13.5 to

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Station Station

FIGURE 3

Distribution of BOD, COD, NH3-N, and NO3- values in the study area

26 mg/L, 22.50 mg/L on average (see Figure Total Suspended Solids (TSS) 4b). The lowest level of SO42- was recorded at station 3 during the first sampling period TSS values during the first sampling period (1.5 mg/L) and again during second ranged from 6.75 to 143.5 mg/L, for an aver- sampling period (13.5 mg/L). The highest age of 89.35 mg/L, and from 11 to level of SO42- was recorded at station 4 73.75 mg/L, for an average of 50.35 mg/L, during the first sampling period (39.5 mg/L) during the second sampling period (see and at station 1 during the second sampling Figure 4c). The lowest value was recorded at period (26.2 mg/L). The levels of sulphate station 3 (6.75 mg/L) and the highest at recorded were considered very low at all station 5 (143.5 mg/L). The TSS levels sampling stations, meaning that sulphate measured at the five stations were classified levels at these stations were within the under INWQS Class IIA–IIB. As noted, TSS normal range based on the INWQS (Class I). values were lower during the second

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Station Station

FIGURE 4

Distribution of PO4, SO42-, TSS, TDS, oil and grease, and E. coli values in the study area

The Arab World Geographer/Le Géographe du monde arabe 12, no 3-4 (2009) 196 Gasim, Jamil, Rahim and Toriman sampling period, because there was less rain ranged from 52 800 to 205 700 and less runoff from areas near the river. count/100 mL, for an average of 130 680 count/100 mL (see Figure 4f). Total Total Dissolved Solids (TDS) coliform concentration for the Langat River, according to INWQS, falls under TDS values ranged from 139 to 179.5 mg/L, Class V. The Langat River exceeded the for an average of 164.7 mg/L, during the INWQS threshold value of 100 count/100 ﬁrst sampling period, and from 86.5 to mL, indicating that TC counts in Langat

122.5 mg/L, for an average of 111.6 mg/L, River were high. This may be due to the Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 during the second (see Figure 4d). The waters that flow into the river in the rainy lowest value of TDS was recorded at station season or to discharges that carry domestic 3 (139 mg/L), and the highest at station 5 and industrial wastes. (179.5 mg/L). TDS values were higher during the first sampling period than during Conclusion the second. A high value of TDS implies that water has a high concentration of sedi- Of the 14 physico-chemical and biological ments, which may come from dissolution of parameters measured, three (NH3-N, PO4, rocks and soils or from land-clearing activ- and E. coli) exceeded the recommended ity (Alloway 1997). Based on INWQS clas- INWQS levels set by the DOE. Based on the sification, TDS values were within the Water Quality Index (WQI), the Langat normal average (TDS < 500 mg/L) and River can be categorized as moderately could be classified as Class I. polluted and within Class III at all sampling stations, with the exception of station 3 Oil and Grease (O&G) during the second sampling period (categorized as Class II). Therefore, in terms of O&G values recorded during the first river pollution, the Langat River is within sampling period ranged from 3.3 to the safety limits for potable water usage. 7.5 μg/L, for an average of 5.6 μg/L; during But its present condition is not ideal for the second sampling, values ranged from supporting a healthy aquatic ecosystem. 4.17 to 18 μg/L, for an average of The main pollution sources in the study area 11.27 μg/L (see Figure 4e). The highest are related to human activities, especially level of oil and grease was recorded at those from non-point sources. station 3 (18 μg/L) in both periods and A paired 2-sample t-test for means showed comes from the many workshops and significant differences among the five restaurants located at station 3. O&G levels stations (p < 0.05) for pH, conductivity, DO, recorded at all stations along the Langat COD, BOD, TDS, and O&G among four of River all exceed the recommended INWQS the five stations (excluding station 3) threshold level (Class I), indicating that the (p < 0.05) for DO, conductivity, COD, BOD, river is most likely not suitable to support and TSS. A two-way analysis of variance healthy aquatic life. (ANOVA) showed significant differences among the five stations (p < 0.05) for NH3- Escherichia coli N and TDS but no significant differences among four of the five stations (excluding Total coliform (TC) values during the first station 3). sampling period ranged from 12 100 to 167 200 count/100 mL, an average of 93 280 count/100 mL; during the second sampling period, total coliform values

The Arab World Geographer/Le Géographe du monde arabe 12, no 3-4 (2009) Water-Quality Assessment of the Langat River 197

Acknowledgements Gasim, M. B., Sulaiman, W. N. A, and Yaziz, M. The authors wish to acknowledge Universiti I. 2002. Land use changes and their impacts Kebangsaan Malaysia for the award of research on water quality in the Semenyih River, grants UKM-OUP-PLW-II-48/2010 and UKM- Selangor, Malaysia. Jurnal Teknologi GUP-ASPL-07-05-141. Thanks are also due to Mineral 9(2):103–11. the Faculty of Science and Technology, UKM, for Kailasam, M., and Sivakami, S. 2004. Effect of the use of research facilities. thermal effluent discharge on benthic fauna off Tuticorin bay, south east coast of India. Indian Journal of Marine Sciences 33:194– Downloaded from http://meridian.allenpress.com/awg/article-pdf/12/3-4/188/1448477/arwg_12_3-4_l511557453vpl178.pdf by guest on 23 September 2021 References 201. Abdullah, H. K., and Jusoh, J. 1997. An Law, F. S. 1980. Sewage pollution in Kelang appraisal of Malaysia’s water resources: River and its estuary. Pertanika 3(1):13–19. Problems and prospects. Penang: Mason, C. F. 1992. Biological indicators of fresh Consumers Association Penang. water pollution, 2nd ed. Singapore: Alloway, B. J. 1997. Soil pollution and land Longman Singapore. contamination. In Pollution: Causes, effects Mazlin, B. M., Hassan, B. B., and Chia, J. P. and control, ed. R. M. Harrison, 319–39. 2000. Pemonitoran kualiti air kolam New York: Springer. pengoksidan kumbahan UKM, Bangi yang American Public Health Association [APHA]. mengalirkan efluen Sungai Langat. In 1998. Standard methods for the examina- Simposium Penyelidikan Ekosistem tion of waters and wastewater, 20th ed. Lembangan Langat I (SPELL I), ed. M. Washington, D.C.: APHA. Nordin and H. Hasan,198–212. UKM Department of Environment [DOE], Malaysia. Bangi: LESTARI. 1986. WQS phase I study: Development of Muhiyuddin, W. M., and Rainis, R. 2002. water criteria and tsandards for Malaysia. Modeling landslide using GIS and RS: A Kuala Lumpur: DOE, Ministry of Science, case study of upper stream of Langat River Technology and Environment. Basin, Malaysia. Proceedings of the inter- ——. 1994. Classification of Malaysian rivers: national conference Environment: Ten Years Final report on development of water qual- After Rio, 284–91. ity and standards for Malaysia (phase IV— Noorazuan, M. H., and Kadaruddin, A. 1999. river classification). Kuala Lumpur: DOE. Sumber dan penggunaan air bersih di ——. 1998. Water pollution control in the Upper Lembangan Saliran Langat, Selangor. Paper Langat River Basin. Kuala Lumpur: DOE. presented at Simposium Penyelidikan Elfithri, R., Mokhtar, M., Harman Shah, A. H., Lembangan Langat, Shah Alam, 5–6 June. and Idrus, S. 2002. Collaborative decision Nordin, M., and Azrina, L. A. 1998. Training and making issues in sustainable water research for measuring and monitoring resources management: A case study on ecosystem health of a large-scale ecosys- Langat basin. Proceedings of the interna- tem: The Langat Basin Selangor, Malaysia. tional conference Environment: Ten Years Ecosystem Health 4(3):188–90. After Rio, 304–14. Nordin, M., et al. 1999. Ecosystem health in Elmund, G. K., Allen, M. J., and Rice, E. W. Malaysia: A case study of the Langat Basin. 1999. Comparison of Eschericha coli, total Paper presented at International Congress coliform and fecal coliform populations as on Ecosystem Health: Managing for indicators of wastewater treatment effi- Ecosystem Health, Sacramento, California, ciency. Water Environment Research 15–20 August. 71:332–39. Offiong, O. E., and Edet, A. E. 1998. Water qual- Fariz, A., and Nordin, M. 2000. Manufacturing ity assessment in Akpabuyo, Cross River industries and ecosystem health: A case of Basin, south-eastern Nigeria. the Langat River. In Simposium Environmental Geology 34:167–74. Penyelidikan Ekosistem Lembangan Langat I (SPELL I), ed. M. Nordin and H. Hasan, 189–97. UKM Bangi: LESTARI.

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