Risk assessment and source apportionment of wet bulk deposition in three typical sites of Gampaha District, Sri Lanka

Scavenging of pollutants emitted to the atmosphere from natural resources and anthropogenic activities changes the chemical composition of rainwater. However, determination of the extent of atmospheric pollution and identification of pollution sources have not been regularly carried out in Sri Lanka. The objective of this research is therefore to analyze bulk deposition samples collected during a 7-month period from 10 June 2017 to 6 January 2018 in three different locations in Sri Lanka, Katunayake, Gampaha and Lunugama, followed by analysis of rainwater quality parameters including anions and cations using standard methods. These locations differ from each other in geography, industrialization and urbanization. Acid rain was not encountered in any of the three locations during the sampling period according to the pH measurements. The volume-weighted mean ion concentration in the three locations determined by ion chromatography varied as K+ < NH4+ < Mg2+