Browsing by Author "Liyandeniya, A.B."

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Acidification and neutralization potentials of rainwater at University of Peradeniya
(Faculty of Graduate Studies, University of Kelaniya, 2015) Kumari, D.M.R.A.; Liyandeniya, A.B.; Priyantha, N.
Constituents present in rainwater affects compositional changes leading to acidification or neutralization, and hence the quantification of constituents in rain water. In this respect, the purpose of the present study was to establish a relationship between acidification and neutralization potential of rainwater particulates via bulk precipitation and ambient air quality via dry deposition. Analysis of 30 samples of bulk deposition and 11 samples of dry deposition collected during the four month period from May to September, 2013 at the University of Peradeniya premises for main ions responsible for acidification and neutralization reveals that Na+, Mg2+, Ca2+, K+, NH4 +, NO3  and SO4 2- were major ions present in the samples, and further, Ca2+ and NH4 + dominated constituents for neutralization of rainwater acidity, while NO3  and SO4 2- led to high level of acidity. The regression analysis between the summation of the concentrations of NO3  and SO4 2− vs. the summation of the concentrations of Ca2+ and NH4 + reveals that there is a significant correlation with r = 0.66 for bulk precipitation although the correlation is not good for dry deposition with r = 0.38. This difference can be attributed to the different deposition rates of particulates present in ambient air. . Regression analysis applied on each variable demonstrates that, Ca2+ can be present as CaSO4 and Ca(NO3)2 and NH4 + can be present as (NH4)2SO4 and NH4NO3. Further analysis of the results of compositional variables indicates that 53.3% of SO4 2 can be explained by Ca2+ and NH4 +in bulk precipitation, among which 47.5% appears as CaSO4 and only 5.8% as (NH4)2SO4. Further, only 19% of the NO3  is explained by both Ca2+ and NH4 + out of which 6% appears as Ca(NO3)2 and 13% as NH4NO3. In dry deposition, 33.5% of SO4 2 and 95.4% NO3  were explained by the above two cationic independent parameters, and 33% of SO4 2 appears as CaSO4 and only about 0.5% as (NH4)2SO4. Among 95.4% of explained NO3 , 39.2% appears as Ca(NO3)2 and 56.2% NH4NO3. The linear regression analysis suggests that, Ca2+ is involved in a higher percentage (62.5%) for the neutralization process, whereas the involvement of NH4 + is at lower level of 37.5%.
Characterization of trace metal concentration (Al, Fe, Mn, Cu, Zn, Pb) of bulk precipitation in Kandy district, Sri Lanka
(Faculty of Graduate Studies, University of Kelaniya, 2015) Liyandeniya, A.B.; Priyantha, N.; Deeyamulla, M.P.; Wickramasinghe, W.G.R.C.
The atmospheric precipitation is an important phenomenon in which pollutants are scavenged from the atmosphere. Wet deposition accounts for rain, fog and snow, while dry deposition is the accumulation and fallout of aerosol particles and gases without dissolution of water. It is very important to have baseline data on the chemical composition of the atmosphere to take regulatory measures to control atmospheric pollution in Sri Lanka. The main objective of this study was thus to determine selected trace metals (Al, Fe, Mn, Cu, Zn, Pb) in bulk precipitation samples collected weekly in three sampling locations, namely the University of Peradeniya premises, Polgolla and Kandy for a period of one year from August 2013 to July 2014. Trace metals were determined in filtered and preserved rainwater (bulk) samples using Graphite Furnace Atomic Absorption Spectrometer, and volume weighted mean values of selected trace metals were subsequently calculated. Kandy municipality showed the highest contamination and followed the sequence of Al > Zn > Fe > Mn > Cu > Pb and volume weighted mean concentrations of above sequence are 53.6 μg L-1, 38.0 μg L-1, 5.8 μg L-1, 5.4 μg L-1, 4.2 μg L-1, <2.0 μg L-1. Polgolla dam site also recorded some trace metal contamination following the sequence, Al > Zn > Fe > Cu > Mn > Pb and volume weighted mean concentrations of above sequence are 51.5 μg L-1, 40.5 μg L-1, 4.8 μg L-1, 2.4 μg L-1, 1.5 μg L-1, <2.0 μg L-1. Despite less industrialization and less traffic congestion, Peradeniya University premises also showed some extent of atmospheric trace metal contamination following sequence of Al > Zn > Cu > Fe > Mn > Pb and volume weighted mean concentrations of above sequence are 46.1 μg L-1, 44.3 μg L-1, 2.6 μg L-1, 1.9 μg L-1, 1.7 μg L-1, <2.0 μg L-1. Principal component analysis (PCA), used to predict possible sources for the above trace metal contaminants, indicates that Mn, Cu and Zn are originated mainly from anthropogenic activities, such as fossil fuel combustion and burning municipal waste. Al and Fe are mainly originated from natural sources as those metals are the major components of alumino-silicate based earth crust.
Chemical characteristics of wet precipitation at Peradeniya in Sri Lanka
(Environ Monit Assess, 2020) Liyandeniya, A.B.; Deeyamulla, M.P.; Abeysundara, S.P.
The purpose of this research was to study chemical characteristics of precipitation in Peradeniya (Latitude 6.973701, Longitude 79.915256), Kandy District in Sri Lanka. This study was conducted during 2012 to 2014, and wet precipitation was analyzed for pH, conductivity, Na+, NH4+, K+, Mg2+, Ca2+, F−, Cl−, NO3−, SO42−, Pb, Cu, Mn, Al, Zn, and Fe for a total of 125 samples. Less than 2% events of acidic precipitation were recorded, and the VWA of the major ionic species present in precipitation samples were in the order of Ca2+ > Na+ > Cl− > NH4+ > SO42− > K+ > NO3− > Mg2+. Neutralization of acidity of precipitation is much more related to CaCO3 than NH3, and the presence of high content of Ca2+ strongly supports this fact. When considering marine contribution, SO42−/Na+, Ca2+/Na+, Mg2+/Na+, and K+/Na+ ratios are higher than the reference value suggesting that contribution of sources other than marine. Concentration of Zn is the highest while that of Mn is the lowest. Principal component analysis identified probable sources for major ionic and elemental sources as both natural and anthropogenic sources such as vehicular emission due to heavy traffic, waste incineration, bio mass burning, brass industry, and construction.