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UPV Theses and Dissertations

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    Assessment of heavy metal traces (Copper and lead) in the soft tissue of Oysters Crassostrea virginica
    Balboa, Dexter G. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2010-04-05)
    The bivalve mollusk Crassostrea virginica is abundant in Brgy. Calaparan, Arevalo and Brgy. Bacong, Dumangas; and are widely consumed by the residence as food. Bioaccumulation of Copper and Lead in the soft tissues of C. virginica from Brgy. Calaparan, Arevalo and Brgy. Bacong, Dumangas were measured and checked if they are still within the permissible levels of Copper and Lead in food based on Median International Standards for metals compiled by the Food and Agricultural Organization of the United Nations. Metal concentrations (μg/g) were determined using Flame Atomic Absorption Spectrophotometer. Mean concentrations of the heavy metals in C. virginica from Calaparan, Arevalo- Cu 27.829, Pb 1.2133; Bacong, Dumangas- Cu 57.834, Pb 0.1338. These levels of Copper and Lead in oyster tissue from both sites are within the the range of Median International Standards for metals and are safe for human consumption. Statistical analysis through one- way ANOVA (F > Fcrit, showed significant difference between sites (Fcrit = 18.51282) for Copper (F value, 215.06569) but not for Lead (F value, 2.25151). The study also provided further solid evidence that bivalve like Crassostrea virginica can recover and concentrate environmentally derived and anthropogenic traces of heavy metals.
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    Molluscicidal effect of quicklime, CaO on golden snail (Pomacea canaliculata)
    Baibado, Joewel Tarra (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1998-03)
    The golden snail (Pomacea canaliculata) is presently a major pest of rice in lowland and rainfed areas through out the Philippines . The problem of golden snail infestation in rice farming system includes damage to the rice plants, rice yield losses, additional expense, side effects of chemicals and destructive effect on native snails . The study was conducted to evaluate the molluscicidal effect of calcium oxide for the control of golden snails in farmlands and to determine the 96hour LC50 in order to know the lethal concentration of calcium oxide to golden snails. Calcium oxide was found to have a molluscicidal activity on golden snails The golden snails were exposed to different concentrations namely. 100 ppm. 200 ppm. 300 ppm .400 ppm. and 500 ppm Remarkable lethal effects of calcium oxide (p<0.05) has been found in 4(H) and 500 ppm concentrations which has reached 60-100 % after the 96 hour treatment. The 96-hour LC50 within the 95% confidence interval was 322.02 ppm as computed Calcium oxide is safe on rice when used as a molluscicide It performs dual function as fertilizer/soil stabilizer and molluscide. These dual effects are very significant because it means big savings on the part of the rice farmers. Considering the prevalence of this pest, farmers spend much on molluscicides and their application. With calcium oxide, the farmer has a molluscicide and soil stabilizer in one application.