Author(s)

Rasheda Aktar Samiha¹, Morshad Ahmed¹, Mohammad Shohel^1,2, Abdus Salam^1*

¹Department of Chemistry, Faculty of Science, University of Dhaka, Dhaka, Bangladesh.
²Department of Chemistry, University of Iowa, Iowa City, IA, USA.

A comprehensive analysis on the chemical composition and source apportionment of hailstone samples were conducted in Dhaka, Bangladesh. pH, electrical conductivity (EC), total dissolved solids (TDS), water soluble ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, SO₄^2-, NO₃^-, HCO₃^-) and trace metals (Zn, Fe, Cu, Mn) of hailstone were determined. The result revealed that the average pH, EC, TDS were 6.95 ± 0.54, 356.3 ± 150.6 μS·cm^-1 and 17.5 ± 2.89 mg·L^-1, respectively. The water soluble ions followed the order: Ca²⁺ > Cl^-1 > SO₄^2- > HCO₃^- > Na⁺ > Mg²⁺ > K⁺ > NO₃^-. The concentrations of trace metals ranged in order with Zn > Fe > Cu, while the concentration of Mn was below detection limit. Sodium adsorption ratio (SAR) was 0.20 ± 0.09 meqL^-1 which indicates it is benign to plants and safe for irrigation. The order of neutralization factor (calculated with average concentrations) found in hailstone was NF_Ca(1.16) > NF_Mg (0.36) > NF_K(0.32) which were originated from earth crust. Notable correlation was found in between soil tracers Ca²⁺ and Mg²⁺ (r = 0.87), indicating their common source dust. Enrichment factor analysis revealed that Ca²⁺, Mg²⁺ and K⁺ are mainly from crust, whereas NO₃^- and SO₄^2- are mainly attributable to anthropogenic origins. Further source contribution analysis revealed that anthropogenic actions accounted for 99.2% of total NO₃^- and 89.6% of total SO₄^2-, while 99.2% of total Ca²⁺ and 95% Mg²⁺ were from crustal source.

Hailstone, Water Soluble Ion, Trace Metal, Source Apportionment

Samiha, R. , Ahmed, M. , Shohel, M. and Salam, A. (2018) Chemical Composition and Source Characterization of Hailstones in Dhaka, Bangladesh. Journal of Geoscience and Environment Protection, 6, 71-82. doi: 10.4236/gep.2018.69006.