Sansfica Young (Sri Lanka)

Email: s089261 @matsu.shimane-u.ac.jp

Thesis title:  Assessment of the environment from the geochemical compositions of Mahawelli river sediments, Sri Lanka.

Supervisor:  Prof. Hiroaki Ishiga (2008-2010).
Local advisor:  Dr. H. M. T. G. A. Pitawala

The Mahaweli River is the longest river(335Km) in Sri Lanka, and it also has the largest drainage basin on the island. It also cuts across the Intermediate and Dry Zones of the country (Fig 1), as well as across two of the main litho-tectonic units, the Highland and Vijayan Complexes (see Fig 2). The river is now used heavily for hydroelectric power generation and for agricultural purposes.

The objective of my research project is to study the geochemical characteristics of sediments in the Mahaweli River, in order to (a) understand the intensity of weathering and erosion; (b) identify the possible sources of the sediments; and (c) assess the effects of anthropogenic activity on the chemistry of the sediments.

The sediment deposition, flow rate and slope of the river, and human impact on natural sedimentation processes within the river were considered when selecting sampling locations. Samples were collected using the hand pit method. All samples were air dried and divided into two duplicates using the cone and quarter method. One duplicate was selected for chemical analysis. The samples were then oven dried at 160℃ and ground to powder prior to analysis by X-ray fluorescence spectrometry for major and trace elements. The mineralogical composition and textural characteristics of the samples will also be studied using X-ray diffractometry and grain size analysis if necessary.