References
  -  D. Fatta, A. Papadopoulos, M. Loizidou, A study on the landfill
    leachate and its impact on the groundwater quality of the
    greater area, Environ. Geochem. Health, 21 (1999) 175–190. 
 
  -  S. Mor, A. Vischher, K. Ravindra, R.P. Dahiya, A. Chandra,
    C.O. Van, Induction of enhanced methane oxidation in compost:
    temperature and moisture response, Waste Manage., 26 (2006)
    381–388. 
 
  -  I. Javed, F. Mateen, U. Rafique, N. Tabassum, K.S. Balkhair,
    M.A. Ashraf, Synthesis of zeolite from marble powder waste:
    a greener approach and its application for the removal of
    inorganic metals from wastewater, Desal. Wat. Treat., 57 (2016)
    10422–10431. 
 
  -  F. Mateen, I. Javed, U. Rafique, N. Tabassum, M. Sarfraz,
    S.Z. Safi, I. Yusoff, M.A. Ashraf, New method for the adsorption
    of organic pollutants using natural zeolite incinerator ash (ZIA)
    and its application as an environmentally friendly and costeffective
    adsorbent, Desal. Wat. Treat., 57 (2016) 6230–6238 
 
  -  CAP, Waste Not Asia, Malaysia Country Report, Consumers
    Association of Penang, Taipei, Taiwan, Unpublished, 2001. 
 
  -  J. Lu, B. Eichenberger, R. Stearns, Leachate from Municipal
    Landfills: Production and Management, Noyes Publication,
    Park Ridge, N.J., 1985. 
 
  -  S.R. Qasim, W. Chiang, Sanitary Landfill Leachate: Generation,
    Control and Treatment, Technomic Publication, Texas, 1994. 
 
  -  P.-J. He, Z. Xiao, L.-M. Shao, J.-Y. Yu, D.-J. Lee, In situ
    distributions and characteristics of heavy metals in full-scale
    landfill layers, J. Hazard. Mater., 137 (2006) 1385–1394. 
 
  -  Department of Local Government, The Technical Guideline for
    Sanitary Landfill: Design and Operation, Ministry of Housing
    and Local Government Malaysia, 2006. 
 
  -  S.G. Cheong, Geology of the Northwestern Kuala Lumpur
    Area, Selangor with some aspects of soil science and
    geohydrology, Unpublished BSc. (Hons). Thesis, Universiti
    Malaya, 1976, pp. 61. 
 
  -  NAHRIM, Desktop study on Groundwater Contamination at
    Landfill sites in Selangor, National Hydraulic Research Institute
    of Malaysia Report, 2009. 
 
  -  A. Rasheed, F. Farooq, U. Rafique, S. Nasreen, M.A. Ashraf,
    Analysis of sorption efficiency of activated carbon for removal
    of anthracene and pyrene for wastewater treatment, Desal. Wat.
    Treat., 3 (2015) 23–33. 
 
  -  A.L. Chuah, The geology and petrology of the NorthEastern
    Kuala Lumpur Area, Selangor, Peninsular Malaysia,
    Unpublished BSc (Hons). Thesis, Universiti Malaya,
    1973, pp. 66. 
 
  -  T. Lekshamanan, Geochemistry of cave water in Batu Caves,
    Selangor, Unpublished BSc (Hons). Thesis, Universiti Malaya,
    2003, pp. 8–11. 
 
  -  C.P. Lee, M.S. Leman, K. Hasan, B.M. Nasib, R. Karim,
    Stratigraphic Lexicon of Malaysia, Geological Society of
    Malaysia, Kuala Lumpur, 2004, pp. 162. 
 
  -  B.K. Tan, Geological and Geotechnical Problems of Urban
    Centres in Malaysia, In: Proceedings of LANDPLAN II
    Symposium, Kuala Lumpur, April 1984, Association of
    Geoscientists for International Development, Kuala Lumpur,
    1986, pp. 10–14. 
 
  -  O.B. Ibrahim, H.T. Fang, Piled foundation in limestone
    formation, In: Proceedings of the 8th Southeast Asian
    Geotechnical Conference, Kuala Lumpur, 11–15 March, 1985, 1.
    Organising Committee, Kuala Lumpur, 1985, pp. P4/45–P4/52. 
 
  -  A.F.A. Bakar, I. Yusoff, T.F. Ng, M.A. Ashraf, Cumulative
    impacts of dissolved ionic metals on the chemical characteristics
    of river water affected by alkaline mine drainage from the Kuala
    Lipis gold mine, Pahang, Malaysia, Chem. Ecol., 13 (2014)
    22–33. 
 
  -  K. Parveen, U. Rafique, S.Z. Safi, M.A. Ashraf, A novel method
    for synthesis of functionalized hybrids and their application for
    wastewater treatment, Desal. Wat. Treat., 2 (2015) 33–45. 
 
  -  M.A. Ashraf, I. Yusoff, I. Yusof, Y. Alias, Study of contaminant
    transport at an open tipping waste disposal site, Environ. Sci.
    Pollut. Res., 20 (2013a) 4689–4710. 
 
  -  M.A. Ashraf, I. Yusoff, M.A. Rehman, Y. Alias, Removal of Cd
    (II) onto Raphanus sativus peels biomass: equilibrium, kinetics
    and thermodynamics, Desal. Wat. Treat., 51 (2013) 4402–4412. 
 
  -  I. Yusoff, Y. Alias, M. Yusof, M.A. Ashraf, Assessment of
    pollutants migration at Ampar Tenang landfill site, Selangor,
    Malaysia, Science Asia, 39 (2013) 392–409. 
 
  -  M. Ahmad, S. Aqib, K.S. Balkhair, S. Batool, N.K.A. Bakar,
    M.A. Ashraf, Study of modern nano enhanced techniques for
    removal of dyes and water, J. Nanomater., 864914 (2014) 1–20. 
 
  -  O. Umi Kalsum, Pencemaran Air dan Tanah di Tapak Pelupusan
    Sisa di Negeri Selangor, Unpublished MSc Thesis, Universiti
    Kebangsaan Malaysia, 2009, 114 p. (in Malay). 
 
  -  C.S. Hutchinson, D.N.K. Tan, Geology of Peninsular Malaysia,
    University of Malaya & Geological Society of Malaysia, Kuala
    Lumpur, 2009. 
 
  -  Ministry of Health, National Guidelines for Raw Drinking
    Water Quality. Engineering Services Division, Ministry of
    Health Malaysia, Putrajaya, 2000. 
 
  -  E.A. Suna, T.T. Onay, In situ heavy metal attenuation in landfills
    under methanogenic conditions, J. Hazard. Mater., 99 (2003)
    159–175. 
 
  -  Survey of – MTAC, Arsenic removal in Column Water treatment,
    PDF Acrobat by SDWilson, yzc_northernlat2011_presentation_
    marymcdougall.pdf. 
 
  -  M.R. Taha, W.Z. Wan Yaacob, A.R. Samsudin, J. Yaakob,
    Groundwater quality at two landfill sites in Selangor, Malaysia,
    Bull. Geol. Soc. Malaysia, 57 (2011) 13–18. 
 
  -  USEPA, Characterization of Products Containing Lead and
    Cadmium in Municipal Solid Waste in the United States, 1970
    to 2000, EPA/530-SW-89-015C, Washington, DC, January, 1989. 
 
  -  A.C. Waltham, P.G. Fookes, Engineering classification of karst
    ground condition, Q. J. Eng. Geol. Hydroge., 36 (2003) 101–118. 
 
  -  W.Y. Wan Zuhairi, Heavy metal sorption capabilities of some
    soil samples from active landfill sites in Selangor, Bull. Geol.
    Soc. Malaysia, 46 (2003) 295–297. 
 
  -  X. Xu, B. Gao, W. Wang, Q. Yue, Y. Wang, S. Ni, Adsorption
    of phosphate from aqueous solutions onto modified wheat
    residue: characteristics, kinetic and column studies, Colloids
    Surf. B Biointerfaces, 70 (2009) 46–52. 
 
  -  R.N. Yong, Y. Phadungchewit, pH influence on selectivity and
    retention of heavy metals in some clay soils, Can. Geotech. J., 30
    (1993) 821–833. 
 
  -  H. Zabidi, M.H. De Freitas, Preferred Direction of Karst in The
    Kuala Lumpur Limestone Formation: A Smart Tunnel Case
    Study, Case Report, Kuala Lumpur, Malaysia, 2010. 
 
  -  E.A.R. Bahaa-Eldin, I. Yusoff, S.A. Rahim, W.Y. Wan Zuhairi,
    M.R. Abdul Ghani, Heavy metal contamination of soil beneath
    a waste disposal site at Dengkil, Selangor, Malaysia, Soil
    Sediment Contam., 17 (2018) 449–466. 
 
  -  Boehme, Susan, M. Panero, Y. Rosenthal, V. Thomas, Pollution
    Prevention and Management Strategies for Cadmium in the
    NY/NJ Harbor Watershed, New York Academy of Sciences,
    New York, 2003. 
 
  -  C.B. Boss, K.J. Fredeen, Concepts, Instrumentation, and
    Techniques in Inductively Coupled Plasma Optical Emission
    Spectroscopy, 2nd ed., Perkin-Elmer Corporation, Norwalk,
    Connecticut, 1999. 
 
  -  J.S. Bull, J.V. Evans, R.M. Wecnsler, Biological technology at the
    treatment of leachate from sanitary landfill, J. Water Res., 17
    (1983) 1473–1481. 
 
  -  Environmental Quality Act, Government of Malaysia, Act 127,
    1974, 33 p. 
 
  -  S.S. Gupta, K.G. Bhattacharyya, Adsorption of Ni (II) on clays,
    J. Colloid Interface Sci., 295 (2006) 21–32. 
 
  -  N.H. Hussin, I. Yusoff, Y. Alias, S. Mohamad, N.Y. Rahim,
    M.A. Ashraf, Ionic liquid as a medium to remove iron and
    other metal ions: a case study of the North Kelantan Aquifer,
    Malaysia, Environ. Earth Sci., 71 (2013) 2105–2113. 
 
  -  N. Jawahar Raj, A. Prabhakaran, Lineaments of Kodaikanal-
    Palani massif, Southern Granulitic Terrain of Tamil Nadu,
    India: a study using SRTM DEM and LANDSAT satellite’s OLI
    sensor’s FCC, Geol. Ecol. Landscape, 2 (2018) 188–202. 
 
  -  A. Barakat, R. Khellouk, A.E. Jazouli, F. Touhami, S. Nadem,
    Monitoring of forest cover dynamics in eastern area of Béni-Mellal Province using ASTER and Sentinel-2A multispectral
  data, Geol. Ecol. Landscape, 2 (2018) 203–215. 
 
  -  H. Uddina, A.B.M. Alaamaa, I.S.M. Zaidul, S.A. Abbasb,
    M. Awang, T.K. Fahim, Current analytical methods for
    amlodipine and its formulations: a review, J. CleanWAS, 1
    (2017) 17–22. 
 
  -  A.I. Gogoba, H.M.M. Peralta, H. Basri, M.M. Nmaya, Inhibitory
    effect of pigment extract from Scenedesmus sp. on food spiked
    with foodborne Staphylococcus aureus, J. CleanWAS, 1 (2017)
    23–25. 
 
  -  A. Wong, Natural treatment technology for cleaning wastewater,
    Water Conserv. Manage., 1 (2017) 7–10. 
 
  -  A.A. Mahzan, A.S. Ramli, A.S.M. Abduh, I. Izhar,
    M.Z.M.Y. Indirakumar, A.A.M. Salih, A.S.A. Jahri, O.Q. Wei,
    Preliminary study of Sg. Serai Hot Spring, Hulu Langat,
    Malaysia, Water Conserv. Manage., 1 (2017) 11–14. 
 
  -  M.M. Hanafiah, A.H. Nadheer, S.T. Ahmed, M.A. Ashraf,
    Removal of chromium from aqueous solutions using a palm
  kernel shell adsorbent, Desal. Wat. Treat. 118 (2018) 172–180.