Document Type : Original Research Article


1 Department of Environmental Science, Padmakanya Multiple Campus, Tribhuvan University, Kathmandu, Nepal

2 Department of Mathematics and Statistics, Padmakanya Multiple Campus, Tribhuvan University, Kathmandu, Nepal

3 Department of Botany, Bhaktapur Multiple Campus, Tribhuvan University, Bhaktapur, Nepal

4 Department of Chemistry, Amrit Campus, Tribhuvan University, Kathmandu, Nepal

5 Department of Chemistry, Padmakanya Multiple Campus, Tribhuvan University, Kathmandu, Nepal

6 Department of Environmental Science, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal


Ever-increasing population, rapid urbanization, and industrialization have critically deteriorated the urban soil quality. This study was conducted to assess the ecological risk of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) in four different land-use urban soils viz, commercial area (CA), heavy traffic ring roadside (HT), residential area (RA), and agricultural farm (AF) of Kathmandu District, Nepal. For this purpose, concentrations of the five heavy metals (HMs) were determined by using a flame atomic absorption spectrophotometer (FAAS), in a total of 31 soil samples collected from all four land uses. Pollution indices such as contamination factor (CF), degree of contamination (CD), pollution load index (PLI), geo-accumulation index (I-geo), ecological risk factor (ER), and potential ecological risk (PER) were used to assess the ecological risk posed by the HMs. The overall mean concentrations for Cd, Cr, Cu, Ni, and Pb were 0.98, 137.1, 79.80, 100.00, and 72.3 mg/kg, respectively, and were found 2-4 times greater than the background values. The statistical analysis revealed a poor correlation of the HMs against pH and total organic carbon (TOC) suggesting little influence on HMs contamination. Results also showed the highest concentrations of the HMs in HT soils among the land use types. Ecological risk assessment revealed CF (0.42-5.06) and CD (7.83-15.72) values as indicators for low to considerable, and moderate to considerable risks respectively, in soils of all land uses under the present investigation. Whereas the PLI values (1.12-2.96) corresponded to the polluted urban soils, the Igeo values (0.08-1.02) indicated an unpolluted to the moderately polluted class of soil contamination in all the land-uses. Likewise, the ER (0.91- 114.90) and PER (113.97-170.14) values pointed out that all the land use urban soils were exposed to a class of low to considerable, and moderate to considerable risks, respectively. Among the HMs, Cd, and Pb posed a comparatively high ecological risk for soils of all land uses and the estimated indices indicated HT as the most vulnerable land use suggesting immediate control measures.

Graphical Abstract

Contamination and Ecological Risk Assessment of Heavy Metals in Different Land Use Urban Soils of Kathmandu District, Nepal


Main Subjects

[1] R.A. Wuana, F.E. Okieimen, Heavy metals in contaminated soils: a review of sources, chemistry, risks and best available strategies for remediation. International Scholarly Research Notices, 2011.
[2] G.M. Pierzynski, J.T. Sims, G.F. Vance, Soils and Environmental Quality, 2nd edition, CRC Press, London, UK (2000).
[3] S. Khan, Q. Cao, Y.M. Zheng, Y.Z. Huang, Y.G. Zhu, Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China. Environmental Pollution, 152 (2008) 686-692.
[4] M.K. Zhang, Z.Y. Liu, H. Wang, Use of single extraction methods to predict bioavailability of heavy metals in polluted soils to rice. Communications in Soil Science and Plant Analysis, 41 (2010) 820-831.
[5] C.S.C. Wong, X.D. Li, G. Zhang, S.H. Qi, X.Z. Peng, Atmospheric deposition of heavy metals in the Pearl River Delta, China. Atmospheric Environment, 37 (2003) 767-776.
[6] M. Lei, Y. Zhang, S. Khan, P.F. Qin, B.H. Liao, Pollution, fractionation and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils from a Pb/Zn mining area. Environmental Monitoring and Assessment, 168 (2010) 215– 222.
[7] M.J. McLaughlin, B.A. Zarcinas, D.P. Stevens, N. Cook, Soil testing for heavy metals. Communications in Soil Science and Plant Analysis, 31 (2000) 1661-1700.
[8] W. Ling, Q. Shen, Y. Gao, X. Gu, Z. Yang, Use of bentonite to control the release of copper from contaminated soils. Soil Research, 45 (2007) 618-623.
[9] I. Suciu, C. Cosma, M. Todică, S.D. Bolboacă, L. Jäntschi, Analysis of soil heavy metal pollution and pattern in Central Transylvania. International Journal of Molecular Sciences, 9 (2008) 434-453.
[10] M. Arora, B. Kiran, S. Rani, A. Rani, B. Kaur, N. Mittal, Heavy metal accumulation in vegetables irrigated with water from different sources. Food chemistry, 111 (2008) 811-815.
[11] H. Chen, Y. Teng, S. Lu, Y. Wang, J. Wang, Contamination features and health risk of soil heavy metals in China. Science of the Total Environment, 512 (2015) 143-153.
[12] M.A. Kashem, B.R. Singh, K. Shigenao, Mobility and distribution of cadmium, nickel and zinc in contaminated soil profiles from Bangladesh. Nutrient Cycling in Agroecosystems, 77 (2007) 187–198.
[13] M.S. Islamd, A.M. Idris, A.R.M.T. Islam, K. Phoungthong, M.M. Ali, M.H. Kabir, Geochemical variation and contamination level of potentially toxic elements in land-uses urban soils. International Journal of Environmental Analytical Chemistry, (2021) 1-18.
[14] R. Proshad, M.S. Islam, T. Kormoker, Assessment of heavy metals with ecological risk of soils in the industrial vicinity of Tangail district, Bangladesh. International Journal of Advanced Geosciences, 6 (2018) 108-116.
[15] S. Huang, L. Wang, Y. Zhao, Ecological risk assessment from the perspective of soil heavy metal accumulations in Xiamen city, China. International Journal of Sustainable Development & World Ecology, 25 (2018) 411-419.
[16] M.R. Mehr, B. Keshavarzi, F. Moore, R. Sharifi, A. Lahijanzadeh, M. Kermani, Distribution, source identification and health risk assessment of soil heavy metals in urban areas of Isfahan province, Iran. Journal of African Earth Sciences, 132 (2017) 16-26.
[17] P. Sharma, Urbanization and development. Population monograph of Nepal, Central Bureau of Statistics: Kathmandu, Nepal. 1 (2003) 375.
[18] R.B. Thapa, Y. Murayama, Examining spatiotemporal urbanization patterns in Kathmandu Valley, Nepal: Remote sensing and spatial metrics approaches. Remote Sensing, 1 (2009) 534-556.
[19] B. Das, P.V. Bhave, S.P. Puppala, R.M. Byanju, A global perspective of vehicular emission control policy and practices: an interface with Kathmandu valley case, Nepal. Journal of Institute of Science and Technology, 23 (2018) 76-80.
[20] I.C. Yadav, N.L.  Devi, V.K. Singh, J. Li, G. Zhang, Spatial distribution, source analysis, and health risk assessment of heavy metals contamination in house dust and surface soil from four major cities of Nepal. Chemosphere, 218 (2019) 1100-1113.
[21] R.K. Trivedy, P.K. Goel, Chemical and Biological Methods for Water Pollution Studies, Environmental Publications, Oriental Printing Press, Aligarh (1986).
[22] A. Walkley, C.A. Black, An examination of Degtja reff methods for determining soil organic matter and a proposed modification of the chromic and titration method. Soil Science, 37 (1934) 29–38.
[23] A. Christoforidis, N. Stamatis, Heavy metal contamination in street dust and roadside soil along the major national road in Kavala's region, Greece. Geoderma, 151 (2009) 257-263.
[24] B. Welz, Atomic Absorption Spectrometry. VCH Verlagsgesellschaft mbh, Germany (1985).
[25] L. Hakanson, An ecological risk index for aquatic pollution control. A sedimentological approach. Water Research, 14 (1980) 975-1001.
[26] K.K. Turekian, K.H. Wedepohl, Distribution of the elements in some major units of the earth's crust. Geological Society of America Bulletin, 72 (1961) 175-192.
[27] T.T. Duong, B.K. Lee, Determining contamination level of heavy metals in road dust from busy traffic areas with different characteristics. Journal of Environmental Management, 92 (2011) 554-562.
[28] L. Madrid, E. Dı́az-Barrientos, F. Madrid, Distribution of heavy metal contents of 494 urban soils in parks of Seville. Chemosphere, 49 (2002) 1301-1308.
[29] D.L. Tomlinson, J.G.  Wilson, C.R. Harris, D.W. Jeffrey, Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index. Helgoländer meeresuntersuchungen, 33 (1980) 566-575.
[30] A. Moller, H.W. Müller, A. Abdullah, G. Abdelgawad, J. Utermann, Urban soil pollution in Damascus, Syria: concentrations and patterns of heavy metals in the soils of the Damascus Ghouta. Geoderma, 124 (2005) 63-71.
[31] W. Guo, X. Liu, Z. Liu, G. Li, Pollution and potential ecological risk evaluation of heavy metals in the sediments around Dongjiang Harbor, Tianjin. Procedia Environmental Sciences, 2 (2010) 729-736.
[32] S. Islam, K. Ahmed, S. Masunaga, Potential ecological risk of hazardous elements in different land-use urban soils of Bangladesh. Science of the Total Environment, 512 (2015a) 94-102.
[33] W. Luo, Y. Lu, J.P. Giesy, T. Wang, Y. Shi, G. Wang, Y. Xing, Effects of land use on concentrations of metals in surface soils and ecological risk around Guanting Reservoir, China. Environmental Geochemistry and Health, 29 (2007) 459-471.
[34] D.H. Yaalon, Soils in the Mediterranean region: what makes them different?. Catena, 28 (1997) 157-169.
[35] S. Ahmad, E.N. Siddiqui, S. Khalid, Studies on certain physico chemical properties of soil of two fresh water ponds of Darbhanga. Environmental Pollution, 31 (1996) 31-39.
[36] M. Stone, J. Marsalek, Trace metal composition and speciation in street sediment: Sault Ste. Marie, Canada. Water, Air, and Soil Pollution, 87 (1996) 149-169.
[37] H.M.D.V. Herath, H.M.T.G.A. Pitawala, J. Gunathilake, T.Y.S. Dalugoda, Heavy metal contamination in road deposited sediments in Colombo urban area. Proceedings to 29th Technical Sessions of Geological Society of Sri Lanka, (2013) 127-130.
[38] J.A. Baldock, P.N. Nelson, Soil organic matter, CRC press (2000).
[39] D.W. Yap, J. Adezrian, J. Khairiah, B.S. Ismail, R. Ahmad-Mahir, The uptake of heavy metals by paddy plants (Oryza sativa) in Kota Marudu, Sabah, Malaysia. Am Eurasian J Agric Environ Sci, 6 (2009) 16-19.
[40] S. Ray, P.S. Khillare, K.H. Kim, R.J. Brown, Distribution, sources, and association of polycyclic aromatic hydrocarbons, black carbon, and total organic carbon in size-segregated soil samples along a background–urban–rural transect. Environmental Engineering Science, 29 (2012) 1008-1019.
[41] S. Li, Z. Jia, Heavy metals in soils from a representative rapidly developing megacity (SW China): Levels, source identification and apportionment. Catena, 163 (2018) 414-423.
[42] L.Q. Ma, F. Tan, W.G. Harris, Concentrations and distributions of eleven metals in Florida soils. Journal of Environmental Quality, 26 (1997) 769-775.
[43] S.M. Al-Shayeb, Heavy metal content of roadside soils along ring road in Riyadh (Saudi Arabia). Asian Journal of Chemistry, 13 (2001) 407.
[44] E. Sabzevari, S. Sobhanardakani, Analysis of Selected Heavy Metals in Indoor Dust Collected from City of Khorramabad, Iran: A Case Study. Jundishapur Journal of Health Science, 10 (2018) e67382. https//
[45] A. Ghani, A. Ghani, Effect of chromium toxicity on growth, chlorophyll and some mineral nutrients of brassica juncea L. Egyptian Academic Journal of Biological Sciences, H. Botany, 2 (2011) 9-15.
[46] C. Johansson, M. Norman, L. Burman, Road traffic emission factors for heavy metals. Atmospheric Environment, 43 (2009) 4681-4688.
[47] J.E. Fergusson, N.D. Kim, Trace elements in street and house dusts: sources and speciation. Science of the Total Environment, 100 (1991) 125-150.
[48] M. Akhter, I. Madany, Heavy metals in street and house dust in Bahrain. Water, air and Soil Pollution, 66 (1993) 111-119.
[49] P. Panagos, C. Ballabio, E. Lugato, A. Jones, P. Borrelli, S. Scarpa, L. Montanarella, Potential sources of anthropogenic copper inputs to European agricultural soils. Sustainability, 10 (2018) 2380.
[50] C.E. Martınez, H.L. Motto, Solubility of lead, zinc and copper added to mineral soils. Environmental Pollution, 107 (2000) 153-158.
[51] J.A. Markus, A.B. Mcbratney, An urban soil study: heavy metals in Glebe, Australia. Austrian Journal of Soil Research, 34 (1996) 453-465.
[52] T.K. Rout, R.E. Masto, L.C.  Ram, J. George, P.K. Padhy, Assessment of human health risks from heavy metals in outdoor dust samples in a coal mining area. Environmental Geochemistry and Health, 35 (2013) 347-356.
[53] J.Q. Yuen, P.H. Olin, H.S. Lim, S.G. Benner, R.A. Sutherland, A.D. Ziegler, Accumulation of potentially toxic elements in road deposited sediments in residential and light industrial neighborhoods of Singapore. Journal of Environmental Management, 101 (2012) 151-163.
[54] M. Hossain, S. Ullah, S. Ahad, M. Ullah, Transfer of Cadmium from Soil to Vegetable Crops. Bangladesh Journal of Scientific and Industrial Research, 42 (2008) 327–334.
[55] J.U. Ahmad, M. Goni, Heavy metal contamination in water, soil, and vegetables of the industrial areas in Dhaka, Bangladesh. Environmental Monitoring and Assessment, 166 (2010) 347-357.
[56] W. Wilcke, S. Müller, N. Kanchanakool, W. Zech, Urban soil contamination in Bangkok: heavy metal and aluminium partitioning in topsoils. Geoderma, 86 (1998) 211-228.
[57] R. Renner, Arsenic and lead leach out of popular fertilizer. Environmental Science & Technology, 38 (2004) 382A.
[58] M. Chen, L.Q. Ma, W.G. Harris, Baseline concentrations of 15 trace elements in Florida surface soils. Journal of Environmental Quality, 28 (1999) 1173-1181.
[59] J.A. Rodriguez, N. Nanos, J.M. Grau, L. Gil, M. Lopez-Arias, Multiscale analysis of heavy metal contents in Spanish agricultural topsoils. Chemosphere, 70 (2008) 1085-1096.
[60] M. Alamgir, M. Islam, N. Hossain, M.G. Kibria, M.M. Rahman, Assessment of heavy metal contamination in urban soils of Chittagong city, Bangladesh. International Journal of Plant & Soil Science, Chittagong 7 (2015) 362-372.
[61] S. Chonokhuu, C. Batbold, B. Chuluunpurev, E. Battsengel, B. Dorjsuren, B. Byambaa, Contamination and health risk assessment of heavy metals in the soil of major cities in Mongolia. International Journal of Environmental Research and Public Health, 16 (2019) 2552.
[62] J.A. Acosta, A. Faz, K. Kalbitz, B. Jansen, S. Martínez-Martínez, Heavy metal concentrations in particle size fractions from street dust of Murcia (Spain) as the basis for risk assessment. Journal of Environmental Monitoring, 13 (2011) 3087-3096.
[63] G. Shi, Z. Chen, S. Xu, J. Zhang, L. Wang, C. Bi, J. Teng, Potentially toxic metal contamination of urban soils and roadside dust in Shanghai, China. Environmental Pollution, 156 (2008) 251-260.
[64] Y.M. Zheng, T.B. Chen, J.Z. He, Multivariate geostatistical analysis of heavy metals in topsoils from Beijing, China. Journal of Soils and Sediments, 8 (2008) 51-58.
[65] S. Dehghani, F. Moore, B. Keshavarzi, A.H. Beverley, Health risk implications of potentially toxic metals in street dust and surface soil of Tehran, Iran. Ecotoxicology and Environmental Safety, 136 (2017) 92-103.
[66] K. Sonu, I.C. Yadav, A. Kumar, N.L. Devi, Dataset on assessment of heavy metals contamination in multi-environmental samples from Patna, India. Data in brief, 25 (2019) 104079.
[67] J. Nnaji, Assessment of heavy metal contamination of agricultural soils and cassava leaves along Umuahia-Ikot-Ekpene highway, Abia state. Research Journal of Pharmaceutical, Biological and Chemical Sciences, 6 (2015) 301-304.
[68] P. Liu, H.J. Zhao, L.L. Wang, Z.H. Liu, J.L. Wei, Y.Q. Wang, Y.F. Zhang, Analysis of heavy metal sources for vegetable soils from Shandong Province, China. Agricultural Sciences in China, 10 (2011) 109-119.
[69] Y. Du, B. Gao, H. Zhou, X. Ju, H. Hao, S. Yin, Health risk assessment of heavy metals in road dusts in urban parks of Beijing, China. Procedia Environmental Sciences, 18 (2013) 299-309.
[70] M.N. Tijani, S. Onodera, Hydrogeochemical assessment of metals contamination in an urban drainage system: a case study of Osogbo township, SW-Nigeria. Journal of Water Resource and Protection, 1 (2009) 164-173.
[71] R. Proshad, S. Ahmed, M. Rahman, T. Kumar, Apportionment of hazardous elements in agricultural soils around the vicinity of brick kiln in Bangladesh. Journal of Environmental and Analytical Toxicology, 7 (2017) 2161-0525.
[72] M.A. Islam, D. Romić, M.A. Akber, M. Romić, Trace metals accumulation in soil irrigated with polluted water and assessment of human health risk from vegetable consumption in Bangladesh. Environmental Geochemistry and Health, 40 (2018) 59-85.
[73] M.S. Islam, M.K. Ahmed, M. Habibullah-Al-Mamun, M.F. Hoque, Preliminary assessment of heavy metal contamination in surface sediments from a river in Bangladesh. Environmental Earth Sciences, 73 (2015b) 1837-1848.