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, rai...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.展开更多
文摘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.
