Undergraduate Theses
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Item Geochemical association of Cr, Cu, Ni, and Pb in the sediments of Iloilo River estuaryArban, John Paul B. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2005-04)The geochemical association of Cr, Cu, Ni, and Pb in the sediments of Iloilo River Estuary has been studied using a modified Tessier’s sequential extraction procedure. The results obtained show that most of the metals studied are mostly associated in the residual and organic matter fractions of the sediment samples (Cr: 66.26% - 74.36% in the residual,15.43% - 24.08% in the Fe-Mn oxide fraction, 8.14% - 12.71% in organic matter fraction, and 0.000% - 2.996% in the exchangeable/carbonate fraction; Cu: 39.30% - 46.73% in the residual, 12.00% - 52.18% in the organic fraction, 3.227% - 11.41% in the Fe-Mn fraction, and 0.000% - 17.43% in the exchangeable/carbonate fractions; Ni: 42.75% - 57.02% in the organic matter fraction, 24.93% - 39.33% in the residual, 5.814% - 14.15% in the Fe-Mn fraction, and 5.504% - 13.12% exchangeable/carbonate fraction; and Pb in sample AAA-21: 48.02% in the residual, 38.55% in the organic matter fraction, and 7.33% in the Fe-Mn fraction, and 6.078% in the exchangeable/carbonate fraction). The analysis of the total metal concentrations of the sediment samples taken from Iloilo River are found to be above the reported concentration of uncontaminated sediment except for Pb in sediment sample AAA-21 (Chromium: 102.1 ug/g - 150.5 pg/g; Copper: 62.56 pg/g - 111.7 pg/g; Nickel: 53.40 pg/g - 75.44 pg/g; and Lead in sample AAA-21: 22.21 pg/g). The study shows that about 50% of the total metal concentration in the sediment samples are bioavailable to the aquatic organisms.Item Community structure of a ten-year old naturally, regenerating mangrove stand in Baguingin, Tigbauan, IloiloAnimas, Ruphil May J. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-04)The structure of the mangrove community in Baguingin, Tigbauan was studied using the transect line plot method with seven plots established. Community structure is described in terms of the following parameters: basal area, stems per hectare, relative density, relative frequency, relative dominance, and importance value of the species and the Shannon Index of Diversity. Variations in these parameters are correlated with certain physico-chemical factors-- air and water temperature, soil pH, water salinity, land elevation- and the degree of human influence. Three true mangrove species were found in the area: Excoecaria agallocha, Avicennia marina, and Avicennia alba. A. marina was found to have the highest relative density of 70.8%. relative dominance of 52.35% and importance value of 169.82. A. marina and A. alba have equal relative frequency of 46.67%. Seedlings and saplings of A. marinadominate the area, indicating that the community is a young and regenerating stand. Basal area significantly increased from sea to land ( 53.68 cm2 to 431.66 cm2) and from creek to land ( 8.83 cm2 to 366.54 cm2). Shannon Index of Diversity gave a result of 0. The very low diversity index means that there is uneven distribution of individual trees among the species, and only a few kinds of species were present and are centered around only two genera, Avicennia species and Excoecaria agallocha.