TITLE:
Chemical Composition of Rainwater at Selected Sites on Upolu Island, Samoa
AUTHORS:
T. Imo, P. Amosa, F. Latu, V. Vaurasi, R. Ieremia
KEYWORDS:
Atmosphere, Pollutants, Sources, Concentration, Anions, Cations, Samoa
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.11 No.3,
June
11,
2021
ABSTRACT: The study
involved analysis of rainwater samples at four sites on Upolu Island, Samoa
from November 2019 to April 2020. A total of 48 rainwater samples were analysed
in order to determine the major cations (Na+, Mg2+, Ca2+,
K+) and anions (Cl-, , ) in wet precipitation from the four sites. The
average pH of the rainwater was 6.89, perhaps due to neutralization. Only 50%
of the rain samples had a pH above 5.6. This shows strong inputs of alkaline species
to rainwater samples in some sites. The average pH of samples higher than 5.6
is due to high loadings of sodium ions. The rainwater samples are dominated by
Na+, Ca2+, Mg2+, Cl- and . The principal cations and anions, in decreasing
order, are Na+ > Mg2+ > Ca2+ > K+ and Cl- > > . The correlation study and the comparison of major
ion composition with other sites revealed that rainwater ion composition is
strongly influenced by marine sources rather than anthropogenic and terrestrial
sources.