HR: 0800h
AN: H51B-0439    [Abstracts]
TI: GROUND AND SURFACE WATER QUALITY OF TSUNAMI AFFECTED SOUTHWESTERN COASTAL AREA OF SRI LANKA
AU: * Jayawardana, D
EM: taranga23@yahoo.com, s069215@matsu.shimane-u.ac.jp
AF: Department of Geoscience, Shimane University 1060 Nishikawatsu, Matsue, 690-8504, Japan
AU: * Jayawardana, D
EM: taranga23@yahoo.com, s069215@matsu.shimane-u.ac.jp
AF: Department of Geology, Peradeniya University, Peradeniya, 20400, Sri Lanka
AU: Ishiga, H
EM: ishiga@riko.shimane-u.ac.jp
AF: Department of Geoscience, Shimane University 1060 Nishikawatsu, Matsue, 690-8504, Japan
AU: Pitawala, H
EM: apitawala@pdn.ac.lk
AF: Department of Geology, Peradeniya University, Peradeniya, 20400, Sri Lanka
AB: The major tsunami of December 2004 hit many South Asian countries bordering the Bay of Bengal and severely devastated the coastal region of Sri Lanka. In the coastal areas of south western Sri Lanka the majority of the population, relies on groundwater for their domestic and agricultural activities, predominantly through traditional private shallow open-dug wells. The study area is located 100 km south of the capital city of Colombo, and was greatly affected by flood waves. The coastal plain is characterized by shallow natural lagoons. Analyses of major parameters (NO₃^-, PO₄^3-, F^-, NH₄⁺, Fe, As, pH, chemical oxygen demand (COD) and electric conductivity) in 40 randomly selected dug wells and surface lagoon water samples were made using field pack test method. Lagoon water parameters (pH, conductivity, dissolved oxygen (DO), total dissolved solid (TDS) oxidation reduction potential (ORP) and salinity) were tested at 18 different locations at varying depths. Soil and tsunami sediment samples where analyzed using XRF for major oxides and trace elements. Results showed that some wells were contaminated with NO₃^- and many wells had higher COD and salinity. Lagoon water parameters showed High salinity and low DO. ORP of the lagoon water showed reduced conditions occurred even in shallow water depth with more negative values for lagoon sediment samples. The XRF analyses showed that high concentrations of Cl, Br and I in lagoon sediments. The results show that dug-wells can be further contaminated with lagoon water, Water from mash lands and by tsunami sediments. Halogen compounds in lagoon sediments are also released in to the groundwater and increase salinity. Contamination is highly dependent on local and regional flow conditions of the groundwater. Key words: Sri Lanka, tsunami, groundwater, dug-wells
DE: 1830 Groundwater/surface water interaction
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: 2007 Fall Meeting