Study of Physicochemical Parameters of Rainwater: A Case Study of Karachi, Pakistan


The urban centers of developing countries like Karachi city in Pakistan are facing the menace of air pollution and atmospheric wet deposition can be used as a tool for monitoring the quality of air. In this study, rainwater samples from eighteen different towns of Karachi were collected during monsoon season (July to September, 2013) in triplicate and analyzed. Their pH (range 6.2 - 7.9), electrical conductivity (range 0.02 - 0.21 m·S/cm), total dissolved solids (range 32 - 159 mg/l), dissolved oxygen (range 6.3 - 8.2 mg/l) and hardness (23 - 89 mg/l) were immediately monitored within next twenty four hours of sample collections. The samples were then acidified and analyzed for the presence of major cations ammonium, sodium, potassium, magnesium and calcium by flame atomic absorption spectroscopy and flame emission spectroscopy. The anions fluoride, chloride, nitrate, carbonate and sulphate were analyzed by ion chromatography. The results of the analysis were compared with the values provided by WHO guidelines in order to access the quality of water. Most of the rainwater samples were completely free from considerable pollution and meet the WHO standard values. However, in Lyari, Gulshan, Shah Faisal, Landhi, Malir and Gadap town the concentration of Mg2+ and in North Nazimabad, Korangi, Gulshan, Saddar, Lyari, SITE and Keamari town the concentration of N3- is above the WHO standards, indicating their presence from air pollution.

Share and Cite:

Chughtai, M. , Mustafa, S. and Mumtaz, M. (2014) Study of Physicochemical Parameters of Rainwater: A Case Study of Karachi, Pakistan. American Journal of Analytical Chemistry, 5, 235-242. doi: 10.4236/ajac.2014.54029.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Mouli, P.C., Mohan, S.V. and Reddy, S.J. (2005) Rainwater Chemistry at a Regional Representative Urban Site: Influence of Terrestrial Sources on Ionic Composition. Atmospheric Environment, 39, 999-1008.
[2] Fargeli, H. and Aas, W. (2008) Trends of Nitrogen in Air and Precipitation: Model Results and Observations at EMEP Sites in Europe, 1980-2003. Environmental Pollution, 154, 448-461.
[3] Shen, Z., Wang, X., Zhang, R., Ho, K., Cao, J. and Zhang, M. (2011) Chemical Composition of Water Soluble Ions and Carbonate Estimation in Spring Aerosol at a Semi-Arid Site of Tongyu, China. Aerosol and Air Quality Research, 10, 360-368.
[4] Boubel, R.W., Fox, D.L., Turner, D.B. and Stern, A.C. (1994) Fundamentals of Air Pollution. 3rd Edition, Academic Press, Inc., San Diego, 149-152.
[5] Elsom, D. (1987) Atmospheric Pollution: Causes, Effects and Control Policies. Blackwell, Basil.
[6] Al-Momani, F., Gullu, G., Olmez, I., Eler, U., Ortel, E., Sirin, G. and Tuncel, G. (1997) Chemical Composition of Eastern Mediterranean Aerosol and Precipitation: Indications of Long Range Transport. Pure and Applied Chemistry, 69, 41-46.
[7] Granat, L., Suksomsankh, K., Simachaya, S., Tabucanon, M. and Rodhe, H. (1996) Regional Background Acidity and Chemical Composition of Precipitation in Thailand. Atmospheric Environment, 30, 1589-1596.
[8] Possanzini, M., Buttini, P. and Di Palo, V. (1988) Characterization of a Rural Area in Terms of Dry and Wet Deposition. Science of the Total Environment, 74, 111-120.
[9] Kulshrestha, U.C., Kulshrestha, M.J., Sekar, R., Variamani, M., Sarkar, A.K. and Parashar, D.C. (2001) Investigation of Alkaline Nature of Water in India. Water, Air, and Soil Pollution, 130, 1685-1690.
[10] Kelly, T.J., McLaren, S.E. and Kadlecek, J.A. (1989) Seasonal Variations in Atmospheric SOx and NOx Species in the Adirondacks. Atmospheric Environment, 23, 1315-1332.
[11] Bard, S.M. (1999) Global Transport of Anthropogenic Contaminants and the Consequences for the Arctic Marine Ecosystem. Marine Pollution Bulletin, 38, 356-379.
[12] Bierwagen, G., Shedlosky, T.R. and Stanek, K. (2003) Developing and Testing a New Generation of Protective Coatings for Outdoor Bronze Sculpture. Progress in Organic Coatings, 48, 289-296.
[13] Samara, C., Tsitouridou, R. and Balafotis, C.H. (1992) Chemical Composition of Rain in Thessaloniki, Greece, in Relation to Meteorological Conditions. Atmospheric Environment, 26B, 359-367.
[14] Smirnioudi, V.N. and Siskos, P.A. (1992) Chemical Composition of Wet and Dust Deposition in Athens, Greece. Atmospheric Environment, 26B, 483-490.
[15] Raper, D.W. and Lee, D.S. (1996) Wet Deposition at the Sub-20km Scale in a Rural Upland Area of England. Atmospheric Environment, 30, 1193-1207.
[16] Sanusi, A., Wortham, H., Millet, M. and Mirabel, P. (1996) Chemical Composition of Rainwater in Eastern France. Atmospheric Environment, 30, 59-71.
[17] Datar, S.V., Mukhopadhyay, B. and Srivastava, H.N. (1996) Trends in Background Air Pollution Parameter over India. Atmospheric Environment, 30, 3677-3682.
[18] Hasan, A. and Mohib, M. (2003) Urban Slums Reports: The Case of Karachi, Pakistan.
[19] Chughtai, M., Mustafa, S., Mahmood, R. and Mumtaz, M. (2014) Physicochemical Assessment of Rainwater of Karachi, Pakistan. European Academic Research, 1, 4099-4108.
[20] Rao, P.S.P., Momin, G.A., Safai, P.D., Pillai, A.G. and Khemani, L.T. (1995) Rainwater and Throughfall Chemistry in the Silent Valley Forest in South India. Atmospheric Environment, 29, 2025-2029.
[21] Tu, J., Wang, H.S., Zhang, Z.F., Jin, X. and Li, W.Q. (2005) Trends in Chemical Composition of Precipitation in Nanjing, China, during 1992-2003. Atmospheric Research, 73, 283-298.
[22] Zhang, M.Y., Wang, S.J., Wu, F.C., Yuan, X.H. and Zhang, Y. (2007) Chemical Compositions of Wet Precipitation and Anthropogenic Influences at a Developing Urban Site in South Eastern China. Atmospheric Research, 84, 311-322.
[23] World Health Organization (2006) Guidelines for Drinking Water Quality. Vol. 1, Recommendations, Geneva.
[24] Goher, M.E.M. (2002) Chemical Studies on the Precipitation and Dissolution of Some Chemical Element in Lake Qarun. Ph.D. Thesis, Al-Azhar University, Egypt.
[25] Hamhill, L. and Bell, F.G. (1986) Groundwater Resources Development. University Press, Cambridge, 344.
[26] Vijayan, V.S. (1991) Keoladeo National Park Ecology Study. Final Report (1980-1990) BNHS, Bombay.
[27] Kumar, S. (1986) Reactive Scavenging of Pollutants by Rain: A Modelling Approach. Atmospheric Environment, 20, 1015-1024.
[28] Van Egmond, N.D. and Kesseboom, H. (1985) A Numerical Mesoscale Model for Long Term Average NOx and NO2 Concentration. Atmospheric Environment, 19, 587-595.
[29] Ruijgrok, W., Visser, H. and Romer, F.G. (1992) The Scavenging and Wet Deposition of Acidifying Components in Arnhem: 1984-1990. In: Schwartz, S.E. and Slinn, W.G.N., Eds., Precipitation Scavenging and Air-Surface Exchange, Hemisphere Publishing Corp., Washington DC, 471-482.
[30] Meng, Z. and Seinfeld, J.H. (1994) On the Source of the Submicrometer Droplet Mode of Urban and Regional Aerosols. Aerosol Science and Technology, 20, 253-265.
[31] Redington, A.L. and Derwent, R.G. (2002) Calculation of Sulphate and Nitrate Aerosol Concentrations over Europe Using a Lagrangian Dispersion Model. Atmospheric Environment, 36, 425-439.
[32] Pathak, R.K., Wu, W.S. and Wang, T. (2009) Summer Time PM2.5 Ionic Species in Four Major Cities of China: Nitrate Formation in an Ammonia Deficient Atmosphere. Atmospheric Chemistry and Physics, 9, 1711-1722.
[33] Drever, J.I. (1997) The Geochemistry of Natural Waters. 3rd Edition, Prentice Hall, 436.
[34] Back, W. and Hanshaw, B. (1965) Chemical Geohydrology Advances in Hydroscience. Academic Press, New York, 49-109.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.