Abstract

The wet deposition has three components, rainfall, snowfall and sea spray. The chemical agents of these components are: Na⁺, K⁺, Ca²⁺, Mg²⁺, Al³⁺, Mn⁴⁺, Fe³⁺, SO₄ ^2-, NO₃ ^-, NH₄ ⁺, Cl^-, apart from the trace metals profile. These chemical modifiers, when deposited on the earth's surface, either in the dry or wet form (rained out from aerosols) beyond the acitical load on the solid earth, geochemical perturbation onsets, affecting the physical structures, soils, surface waters, vegetation, soil mocrobes, aquacultures and ultimately the human life. It thus becomes essential that each country, to her best capability, makes this study in a holistic way so that a total database is developed for national, regional and international use, in the context of UN Commission for Sustainable Development, for which each number state has a country program.

In this presentation, it is attempted to focus on the wet deposition processes of chemical agents from the atmosphere on the terrestrial environment, including precipitation/rain water and sea spray. In Bangladesh perspective, with agrarian economy, what would be the possible impact of these depositions on soil, surface water and the physical structures would be highlighted, keeping in view the overall situation in Asia in this regard.