Browsing by Author "Wijenayaka, W.N.C."

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    Groundwater Contamination around in Paddy Terrace in Badulla; special focus on nutrients and tracer element mobility
    (Uva Wellassa University of Sri Lanka, 2015) Wijenayaka, W.N.C.; Jayawardhana, D.T.
    Groundwater is the water located beneath the earth's surface in soil pore spaces and in the fractures of rock formations[4]. Pollution of groundwater due to contaminated soil and fertilizer/pesticide is hurt animals, plants or humans and it may cause serious health problems, such as, hepatitis, blue baby syndrome, kidney disease, etc (Dissanayake et al., 1984). Paddy terrace is artificial replacement of nutrients in damage land. Due to erosion, nutrients were removed from top soil. Therefore, farmers are needed to apply especially N, P, and K fertilizer in artificial replacement. As a result of artificial nutrients added, groundwater can be highly contaminated around paddy terraces. Previous researchers investigated the sediment and nutrient (N, P, and K) movement behavior in terraced paddy fields system and groundwater contamination around paddy terraces has not been conducted in Sri Lanka. Thus, this research aims at identifying the excess nutrients and tracer elements with the excess pesticides/fertilizers from terrace paddy farming on groundwater and surface water. Also, it is attempted to identify mobility of them to groundwater and surface water during the different stages of the paddy cultivation. A total number of 80 water samples were collected from Rabukpotha area in Badulla, Sri Lanka, at frequent intervals during February to early July 2014, which coincides with the Maha season. The sampling was carried out in two stages of the intermediate period. Before and after cultivation two sample sets were collected and sample sets were renamed as A and B, respectively.
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    Groundwater Contamination Around Paddy Terraces in Badulla; Special Focus on Nutrients and Tracer Element Mobility
    (Uva Wellassa University of Sri Lanka, 2014) Wijenayaka, W.N.C.
    Groundwater can become contaminated when rain water or surface water contact with contaminated soil while infiltrated into the ground and can also contaminated when fertilizer/pesticide soak down through the soil or rock into groundwater. Nutrient and tracer element mobility and magnitude of groundwater contamination due to pesticide/fertilizer use in paddy terrace in Badulla, Sri Lanka was studied during January to May 2014. The study area is located in latitude and longitude of 6.98°, 81.05° and paddy terraces are in Rabukpotha area. Forty water samples were collected both well and surface waters from each two different stages of paddy cultivation, such as before cultivation and after fertization. Eighty water samples were analyzed for 24 chemical parameters (temperature, pH, Eh, turbidity, NO3, POi- , , CO1- , HCO3, Cl-, NH4, Na, K, Mg, Ca, Cu, Pb, Zn, Mn, Fe, Rb, Li, Sr, Cs). The average pH, turbidity conductivity and ORP were present 7.5, 4.47, 0.90 and -22.80 respectively. The water was under reducing environment in several locations. The results could be concluded that the application of N, P, K fertilizers in paddy terraces has a direct impact on the concentration of elements in groundwater. Excessive application of fertilizers to soils contributes to contamination of groundwater around paddy terraces. Some of the elements are (CL, Fe,NO3, Mn, NH 4, Zn, Sr) leach to groundwater with highly usage of artificial fertilizer. Samples which are collected from near the paddy terrace present higher nutrients and tracer elements concentration beyond others. There is significant different between before and after cultivation. With the terrace arrangement, tracer elements and nutrients are enriched in low land areas as compared with other areas. Fe and Zn have moderate positive relationship. After the cultivation, Fe concentration is higher than Zn concentration. Fe is high mobilizing than Zn. Higher Cu concentration is found after cultivation. Cu is leached slightly faster than Zn.