Education of the republic of uzbekistan tashkent state technical university named after islam karimov

CIVIL AND ENVIRONMENTAL 
ENGINEERING 
 
DETERMINATION OF CHEMICAL COMPOSITION IN RAIN
WATER AND THEIR IMPACTS
TO THE ENVIRONMENT OF CITY 
 
A.A. Aripov
1*
, S.M. Turabdzhanov
1
, C.T. Aravindkumar
2
, K.U. Aravind
2
,
U.B. Mirzarakhmatov
1
, L.S. Rakhimova
1
1
Tashkent state technical university named after Islam Karimov, Tashkent, 100095, Uzbekistan 
2
Mahatma Gandhi University, Kottayam 686560, Kerala, India 
 
Abstract: 
This study investigated the concentrations of metal ions and other chemical substances 
in samples, sampled from seven sampling regions of Tashkent. The effect of the volume of 
rainfall in the sampling and preceding month, chemical contamination of sampling and sample 
pH was examined.
 
Seven rainwater samples were collected during rainy season between 
February and March 2020 in Tashkent. The mean contents of heavy metals were in decreasing 
order Ni≤Cd≤Co≤V≤Cr≤As≤Cu≤Zn≤Fe≤Mn and they are not exceeded maximum permissible 
concentration (MPC). Sample 1 demonstrate higher level of metal ions such as Cu, Cd, Cr than 
other samples. Sample 2 and 3 were found to be contaminated with Zn and As, the pollution load 
indices suggest that these metals had anthropogenic sources. The other samples were notably 
enriched with Mn, Fe and Co. Presence of NH
4
-
, SO
4
2-
NO
3
 
-
ions as a result of atmospheric 
chemical reactions in studied samples and varied 1.5-3.0 μeq l−l, 54.0-158.0 μeq l−l and 1.0-6.0 
μeq l−l respectively. The quantities of major ions in rainwater were compared with those 
reported in other urban areas. Soluble metal ions such as Na+ and K+ varied 23-204 μeq l−l 
and 4.0-8.0 μeq l−l respectively. pH value showed neutral medium 7.0-7.3 which close to 
distilled water. The rain water at all the places except near the industrial source was not acidic 
and was characterized by the presence of excess cations, particularly Ca. The acid rain near the 
industrial source was associated with excess anions, especially sulphate. This work will continue 
for rather investigation of rain water treatment technologies by using biochar.