Methodology  
 Heavy metals are scavenged during rainfall. Therefore,  atmospheric deposition of the 
   heavy metals during rain is an important marker of precipitation chemistry.
 The rainfall samples were collected at JNU site in Delhi. JNU campus spreads over 4.12 km2 
   with high green cover. The coordinates of the site are 28°54’ N and 77°18’ E. Fig. 1 shows 
   the sampling location in south of Delhi.
 Samples were collected using sampling assembly of bottle and funnel (diameter 20cm) as 
   shown in Fig. 2. Samples were digested using 1ml of 5% nitric acid and preserved at 4°C 
   for analysis. The prepared samples along with the blanks were analysed using ICP-OES. 
   The samples were analysed quantitatively using multielement standard.
           Fig. 1 Sampling location    Fig. 2 Sampling assembly
        Seventh WMO International Workshop on Monsoon (IWM-7), 22-26 March, 2022, IMD, MoES, New Delhi, India
                                                           2
                                Results & Summary
    Fig. 3 Relative abundance of heavy metals      Fig. 4 Matrix showing interactions between heavy 
              during rainfall events                            metals and rainfall depth
                                          Results & Summary
                                                                                             Table 1. Average concentrations 
       It   was  seen  that  Al  showed  the  highest  mean                                              of heavy metals
       concentration  (1059.2  µg/l)  among  analyzed  metals. 
       The concentrations of this lithogenic metal ranged from 
       0 - 5180 µg/l  during July and August.
   Among the heavy metals contributed by anthropogenic 
       sources, Pb (466.9 µg/l), Ni (312.3 µg/l) and Cr (191.5) 
       were  most  abundant  at  the  selected  site  during  all 
       rainfall events.
   Pearson’s  correlation  (r)  showed  good  association 
       between Ni and Cr (r=0.56) indicating common sources 
       such as fuel combustion. Similarly, for crustal elements 
       such as Al and Fe (r = 0.98), Al and Ba (r = 0.93), Ba 
       and Fe (0.91). 
   Negative association between rainfall depth and heavy 
       metals Al (r=-0.59), Ba (r=-0.57), Cr (r=-0.61), Fe (r=-
       0.58),  Mn  (r=-0.56)  and  Zn  (r=-0.53)  indicated  the 
       scavenging effect of rainfall on heavy metals.