College of Arts and Sciences

This study investigated the residual level of polycyclic aromatic hydrocarbons (PAH) in sediments and shellfishes from some heavily impacted areas of Southern Guimaras, Central Philippines two years after the M/T Solar I oil spill. Chemical analysis revealed that the PAH is still within detectable level in some heavily impacted areas of TINMAR and Luzaran in Southern Guimaras, although there was a significant decrease in total PAH of coastal sediments from (3 -25 ppm) one year after the oil spill to (1 ppb -17 ppm) two years. However, the total PAH in mangrove surface sediments of TINMAR is relatively lower (<0.16 ppm -0.8 ppm) and remained almost at the same level two years after the oil spill. On the other hand, the shellfishes recorded a more dramatic decrease in PAH from (9.7-18.7 ppm) one year after the oil spill to (1 ppb -2.4 ppm) two years after.

AbstrAct. Curative and preventive protocols were developed against vibriosis using Guava (Psidium guajava Linn) leaves. Cytotoxicity test on guava leaves proved that it is non-toxic with an LC 50 of 1985 ppm. Treatment using 198.5 ppm of powdered guava leaves (10% of LC 50 ) had reduced the Vibrio count in water from 1.0 x 10 6 CFU/mL to an average of 5.9 x 10 4 CFU/mL at 48 th hour relative to the negative control (1.5 x 10 5 CFU/mL). The efficacy of powdered guava leaf treatment against Vibrio harveyi is comparable to the positive control, chloramphenicol (4.0 x 10 4 CFU/mL).

Third-hand tobacco smoke was evaluated through chemical analysis of polycyclic aromatic hydrocarbons (PAHs) adsorbed on different fabrics (cotton, silk, polyester and acetate) by ultrasonic extraction with n-hexane and subsequently analyzed using gas chromatography-mass spectroscopy. The total PAHs concentration adsorbed on the different fabrics ranged from 63-119 μg g -1 tobacco (dry weight) with the lowest level of total PAHs observed in silk and the highest level in polyester. Total naphthalene and alkyl napthalene concentration ranged from 50 to 100 μg g -1 tobacco, with silk having adsorbed the lowest level of naphthalene and the highest level observed in polyester. On the other hand, acetate adsorbed the highest level of benzo(a)pyrene (0.038 μg g -1 ). A positive correlation was observed between the fabric's chemical structure and the adsorption behavior of PAHs. PAH compounds exhibited high adsorption to less polar fabrics like acetate and polyester, while silk has lower affinity to PAHs due to the presence of polar amino acid side chains.

Sorbent materials were prepared from two lignocellulosic materials, banana peelings (BP) and rice husks (RH). Scanning Electron Microscopy (SEM) studies revealed that sorbent from BP has a rough surface with structures of no definite shape and size, while RH sorbents showed smooth surface with regular patterns of structures. Fourier Transfrom Infrared (FT-IR) studies also revealed that both sorbents are rich in -OH, -C=O, -CH2 groups and traces of -C-O stretches. Batch sorption experiments were conducted to assess the surfactants, phenols, and nutrient (N and P) removal potential of the prepared sorbent materials under two initial pH conditions (6 and 9) for both surface and effluent water, and two salinity conditions (3 and 33 ppt) for surface water only. In general, both BP and RH derived sorbent materials showed potential in removing surfactants and phenols from surface waters. Removal of surfactants and phenols was observed to be significantly affected by salinity but not by the initial pH level. Sorption of the surfactants to the BP sorbents was observed to be favorable at slightly acidic pH of 6 and high salinity water (33 ppt). Phenol removal by BP and the RH-derived sorbents was not significantly affected by pH changes within the range of common environmental water levels. In contrast, the removal of phenol by both sorbent materials was significantly reduced at higher salinity concentration regardless of the pH level. Lastly, results suggest that the sorbent materials evaluated in this study showed minimal or no potential application as sorbents for reducing nutrient (N and P) concentrations in both surface and effluent waters.

The antibacterial properties of the microalgae Chaetoceros calcitrans were assessed. Samples of C. calcitrans were first extracted in methanol, and then in different organic solvents of increasing polarity, n-hexane (n-Hex), dichloromethane (DCM) and ethyl acetate (EA) by liquid-liquid extraction. Solvent extracts were screened for antibacterial activity against four species of bacteria: Gram positive, Staphylococcus aureus and Bacillus subtilis; and Gram negative, Escherichia coli and Vibrio harveyi, with Amoxicillin as positive control, N-Hex extract, with significantly lower antibacterial activity than Amoxicillin, showed significantly higher activity than DCM and EA extracts, and least in methanolic extract. High antibacterial activity of n-Hex extract against all the microorganisms indicates that the bioactive components could be non-polar since the activity decreased as the solvent became more polar like methanol, and finally lost in aqueous extract. Results also showed that t...

This study was conducted to compare lipid extraction from wet paste-like Tetraselmis sp. using isopropanol:hexane, absolute ethanol and chloroform:methanol at different ultrasonic extraction times. The best solvent system and ultrasonic extraction time is chloroform:methanol (1:1) at 50 minutes, respectively. Soaking effect (before and after extraction) gave a higher crude lipid (0.65 % -28 %) recovery than those that were not. Ultrasonic extraction of Tetraselmis sp. gave higher crude lipid yield (15.3 %) than the Folch method (11.78 %). Qualitative analysis of fatty acid profile using different solvents showed no significant difference. Fatty acid present in Tetraselmis sp. is predominantly C16 (Palmitic acid) with significant amount of C18:0 (Stearic acid), C18:1 n-9 (Oleic acid), C18:2 n-6 (Linoleic acid) and C18:3 n-3 (α-Linolenic acid) and C20:5 n-3 (Eicosapentanoic acid). Fatty acid profile is not dependent on extraction solvent but crude lipid yield varies with the solvent s...

This study was conducted to compare lipid extraction from wet paste-like Tetraselmis sp. using isopropanol:hexane, absolute ethanol and chloroform:methanol at different ultrasonic extraction times. The best solvent system and ultrasonic extraction time is chloroform:methanol (1:1) at 50 minutes, respectively. Soaking effect (before and after extraction) gave a higher crude lipid (0.65 % -28 %) recovery than those that were not. Ultrasonic extraction of Tetraselmis sp. gave higher crude lipid yield (15.3 %) than the Folch method (11.78 %). Qualitative analysis of fatty acid profile using different solvents showed no significant difference. Fatty acid present in Tetraselmis sp. is predominantly C16 (Palmitic acid) with significant amount of C18:0 (Stearic acid), C18:1 n-9 (Oleic acid), C18:2 n-6 (Linoleic acid) and C18:3 n-3 (α-Linolenic acid) and C20:5 n-3 (Eicosapentanoic acid). Fatty acid profile is not dependent on extraction solvent but crude lipid yield varies with the solvent system.

AbstrAct. This study characterizes the community structure and spatio-temporal distributions of meiofaunal assemblages in a seagrass bed dominated by Thalassia hemprichii in Southern Guimaras. Two transects were laid parallel on the shore at the low water mark and at the 1-meter depth. Five sampling points 10 meters apart from each other were sampled in each transect. Meiofauna were sampled using a core cylinder with an inner diameter of 2 cm and pushed to a depth of 10 cm. Surveys were conducted once yearly within the southwest monsoon months of August-September from 2005 to 2007. Forty-six taxa were identified, with the harpacticoids copepods as the numerically dominant group with an overall mean density of 119367.8 ind./m-2 , followed by the nematodes. High meiofaunal densities were observed in 2007 (388853.5 ind./m-2) while a relatively lower density was observed in 2006 (156051.0 ind./m-2) which could be attributed to the physical disturbance (i.e., storm) in those months. No significant difference was found in the species composition and no decrease in the abundance of sensitive taxa such as harpacticoid was observed.