17th Philippine Chemistry Congress
May 23-25, 2001
Cagayan de Oro City

ABSTRACTS: ENVIRONMENTAL CHEMISTRY

TS2 E1

DISSOLVED RARE EARTH ELEMENTS IN THE SOUTH CHINA SEA: GEOCHEMICAL CHARACTERIZATION OF THE WATER MASSES

Dia Sotto Alibo¹and Yoshiyuki Nozaki²

¹University of San Carlos, Cebu City

²University of Tokyo, Tokyo, Japan

We have measured the vertical profiles of dissolved rare earth elements (REEs) and yttrium in the South China Sea together with conductivity-temperature-depth and hydrographic measurements to compare with those in the western North Pacific and the Sulu Sea. Although the South China Sea is rapidly flushed by the Pacific through the Luzon Strait with a sill depth of ~2500 m (Broecker et al., 1986), a unique REE pattern is developed within the sea. The most striking difference exists in the dissolved Ce profiles. Dissolved Ce generally decreases from high values (6-9 pmol/kg) at the surface to a minimum of ~3 pmol/kg at around 300-500 m where the North Pacific Intermediate Water penetrates. In deepwaters of the North Pacific and the Sulu Sea it remains at a relatively low and nearly constant concentration level of ~5 pmol/kg throughout the water column, whereas in the South China Sea, it gradually increases with depth to a minimum of 12.9 pmol/kg at ~2500 m, resembling the "nutrient-like" profiles of other strictly trivalent REEs, and then sharply drops to a constant value of ~6 pmol/kg in the bottom water below 2900 m. Some lighter REEs like Pr, Nd, and Gd, though to a much lesser extent, also show similar concentration breaks at the sill depth, but the other hydrographic properties like dissolved oxygen, nutrients, pH, and alkalinity do not. Therefore dissolved REEs may best be utilized to characterize the water masses.

Two major sources for dissolved REEs in the South China Sea are fluvial and coastal input to the surface ocean and a bottom release into the deep water during the passage over the Luzon Strait. Redox chemistry including reduction of Ce(IV) to Ce(III) in the pore water of hemipelagic sediments and subsequent release of dissolved Ce(III) to the overlying deep water may be involved in the latter. The middle REE-enriched patterns with a significant Gd depression relative to that of the North. Pacific Deep Water are characteristic of the South China Sea and prevail throughout the water column by physical circulation. Since the bottom water of the basin is also fed by the North Pacific, the dissolved CE(III) must be oxidized through bacterial mediation and removed from the bottom water presumably by scavenging near/at the sediment-water interface along the slopes of the basin.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TS2 E2

 

EFFECT OF TITANIUM (IV) OXIDE ON THE N, P, K AND Zn CONTENT OF MALIGAYA PADDY SOIL AND RICE PLANT (Oryza sativa Linn.) AT DIFFERENT GROWTH STAGES

Rodel M. Bulatao¹, Germenegildo Gines², Tomas D. Gajete³,

David P. Peñaloza Jr.¹ and Danila Paragas¹

¹Department of Chemistry, College of Arts and Sciences

Central Luzon State University, Muñoz Science City, Nueva Ecija

²Agronomy Department, Philippine Rice Research Institute

Maligaya, Muñoz Science City, Nueva Ecija

³Farm Resources Division, Research Office

Central Luzon State University, Muñoz Science City, Nueva Ecija

TiO₂ suspension was proven in several studies to be effective in the photodegradation of organics leading to the formation of less toxic or nontoxic products. The effect of this semiconductor to both soil and plant macro- and micronutrients when applied in the soil to eliminate pesticide residues was evaluated in this study. TiO₂ was mixed with the fertilizers (organic and inorganic) and applied as basal or topdress. The pH and organic matter content of Maligaya paddy soil was determined. The available and exchangeable N, P, K and Zn levels of the soil and rice plant at different growth stages (0, 7, 14, 28, 48, 56, 84 and 92 days after transplanting (DAT)) were determined. The effect of TiO₂ on the agronomic properties of rice plants such plant height, number of productive tiller, leaf area index, dry matter yield and grain yield were also investigated.

The soils treated with TiO₂ had higher pH and lower organic matter content at different growth stages of the rice plant. All the agronomic properties of the rice plant were affected by TiO₂. Moreover, TiO₂ treated soils contained lower concentrations of available and exchangeable N, P, K and Zn. On the other hand, higher concentration of N, P, K and Zn in the rice plant grown in TiO₂ treated soil was observed. Based on the results of this study, TiO₂ has the ability of enhancing the solubility of the macro- and micronutrients in soil, hence, increasing N, P, K and Zn availability to the rice plant.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TS2 E3

 

OXIDATIVE DEGRADATION OF HUMIC SUBSTANCES FROM MANILA BAY SEDIMENTS BY THERMOCHEMOLYSIS WITH TETRAMETHYLAMMONIUM HYDROXIDE (TMAH)

Aurea N. Miranda¹, Robert Helleur², Elma C. Llaguno³ and Teofilo A. Abrajano Jr.⁴

¹Institute of Chemistry, University of the Philippines, Los Baños, Laguna

²Environmental Science Program, Memorial University of Newfoundland

St. John's Newfoundland, Canada

³Institute of Chemistry, University of the Philippines, Diliman

⁴Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute

New York, USA

Tetramethylarnmonium hydroxide (TMAH) thermochemolysis with GC-MS was employed to characterize the organic matter and their humic and fulvic acid fractions (HA and FA) in the sediments of East and West Manila Bay. The TMAH degradation products of the sediment and HA and FA samples were correlated with probable precursors to determine the relative contributions of autochthonous and allochthonous inputs.

The contribution of allochthonous materials was found to be higher in FA than in HA since the FA’s in general produced the greater number and the higher yields of lignin derived compounds. The HA’s on the other hand, were found to be mainly autochthonous in origin based on the number as well as the relative amounts of fatty acids found in their degradation products.

The TMAH thermochemolysates of the HA and FA samples indicate the humic substances in East Bay sediments are of mixed origin while those in the West Bay sediments are mainly derived from autochthonous sources.

The sediments yielded more varied types of TMAH degradation products than their respective HA and FA fractions. Hydrocarbons such as alkylbenzenes, alkylnaphthalenes and aliphatics were found in sediments but not in HA and FA, indicating the exclusion effect of the extraction procedure used in isolating the humic and fulvic acids.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TS2 E4

 

FARMING PRACTICES ADOPTED BY FARMERS: ITS IMPLICATION TO PESTICIDE RESIDUE CONTENT AND QUALITY OF KEY COMMERCIAL CROPS IN REGION III

Mhara Mallari¹, Lourella Bautista¹, Arlene Francisco¹, Vernon Santiago¹, Resly Peralta¹,

David P. Peñaloza Jr.¹, Aurea DC. Roxas² and Danila Paragas¹

¹Department of Chemistry, College of Arts and Sciences

Central Luzon State University, Muñoz Science City, Nueva Ecija

²Pest Management Division, Research Office

Central Luzon State University, Muñoz, Nueva Ecija

This study aimed to monitor the possibility of pesticide accumulation in key commercial crops in Region III as affected by the frequency and kind of pesticides applied.

Pesticide residue analyses in crops such as rice, onion, garlic, ampalaya, eggplant and string beans were done using the Rapid Field Kit technique for organochlorine (OC), organophosphorous (OP), pyrethroid and carbamate.

Results revealed that probability of pesticide contamination is higher in agriculture crops where farmers used to apply pesticides three or five days before harvest. This is very true in vegetables where chemicals were applied few days before harvest.

While the type of pesticides used by most of the farmers surveyed were claimed to be less persistent like the OP’s and the carbamates, they may still persist in the crops where they were applied as well as in the soil for a longer time if misused or carelessly applied. OP's and carbamates have relatively short half-lives compared to OC’s.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP1

 

LEAD UPTAKE OF WATERCRESS (NastuRTIUM officialis)

Melchor Bahod, Magdaletia D. Pandosen and Louisa P. Pladio

Benguet State University, La Trinidad, Benguet

Nasturtium officialis commonly known as watercress is a creeping perennial of the mustard family popular as a salad vegetable. It grows best in cold, running, water and is cultivated in streams or prepared ditches. The plant has smooth, fleshy stems bearing round, pinnate leaves, small, white, clustered flowers and many seeded pods. It is a water-loving herb that ranges from 15-30 cm in height.

Some plants like the water hyacinth, can concentrate heavy metals in their tissues. Studies have shown that some plants contain simple peptides known as phytochelatin which is responsible for metal detoxification. Watercress has the same habitat requirements as the water hyacinth. This study was conducted to determine the potential of watercress to absorb and accumulate heavy metals, lead in particular. Lead is prevalent on polluted water and watercress was observed to grow well in polluted waters.

In this study, watercress cuttings were grown under controlled laboratory conditions, on prepared plastic trays watered with different concentration levels of Pb(NO₃)₂ solution: 0, 20, and 40 ppm. The growth and yield of watercress as affected by lead nitrate concentration was evaluated. The lead content of the harvested watercress shoots (edible part), the roots, and the soil used were analyzed using Atomic Absorption Spectrophotometry (AAS).

Statistical analyses using ANOVA showed that the growth and yield of watercress watered with solutions of lead nitrate were significantly reduced compared to those grown on the control, plain water. The plants grown on lead nitrate solution produced thinner stems with narrow leaf margins and severe curling and browning of the roots were also observed. Compared to the robust, dense and dark green plants observed on the control plants, the plants treated with lead nitrate were less dense and chlorotic.

Analysis showed that the roots have higher lead content compared to the harvested watercress shoots. The lead content of the harvested watercress shoots was found to be below the safe limit. The lead uptake of watercress is insignificant compared to water hyacinth. Based on these results, Nosturtium officialis (watercress) is not a good lead detoxifier because it is a poor absorber of lead.

 

 

 

 

 

 

 

 

 

 

 

EP2

 

CYTOTOXICITY AND GENOTOXICITY STUDIES ON MANILA BAY WATERS

Myrna Nicol Ogoc ^1,2, Irene M. Villaseñor² and Titos A. O. Quibuyen²

¹University of Eastern Philippines, Catarman, Northern Samar

²Institute of Chemistry, University of the Philippines, Diliman

Water samples from Parañaque, Las Pinas, Pasay, Divisoria, North and South Harbors, Navotas and Malabon areas were collected. Their mutagenic potentials were determined using the Micronueleus test, an in vivo assay. The samples collected from Navotas and Malabon areas exhibited the highest mutagenic activity compared to other sites.

Samples were again collected from six (6) sampling points in Malabon and Navotas river tributaries. The samples were then extracted with hexane. The mutagenicity potential of Malabon and Navotas river tributaries using aqueous sample extracts were higher as compared to the organic extracts and the negative control.

Total metal AAS analysis from aqueous samples revealed the following: Zinc was detected at the range from 0.03 to 0.06 mg/L; Chromium at 0.05 mg/L; Copper at 0.04-0.05; Lead at < 0.05 mg/L; and Cadmium and Mercury at 0.003 to 0.00005 mg/L. The chloride concentration observed along the sites of Navotas and Malabon rivers ranged from 5300 to7700 mg/L.

The mutagenic waters were then subjected to cytotoxicity tests using the brine shrimp assay.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP3

 

MONITORING OF HEAVY METALS IN WASTEWATER OF AN INDUSTRIAL ELECTRONIC PLANT

Marc Lawrence J. Romero¹ and Elmer-Rico E. Mojica²

¹Laboratory Analyst, First Sumiden Circuits, Inc, Diezmo, Cabuyao, Laguna

²Institute of Chemistry, College of Arts and Sciences

University of the Philippines Los Baños, Laguna

The concentration level of different heavy metals in wastewater of an industrial electronic plant was monitored for the whole year of 2000. Sampling was done at least once a month in the sedimentation tank and twice a month in the sewerage tank.

For the sedimentation tank, five heavy metals were monitored. The heavy metals concentration were observed to be in the range of 0.02 to 0.676 ppm for iron, 0.02 to 0.427 ppm for nickel, 0.068 to 1.632 ppm for copper and 0.01 to 1.747 ppm for lead. The concentration for chromium was found to be way below the 0.02 ppm.

The heavy metals coming from the sewerage tank were also monitored. The level of concentration of the different metals were observed to be in the range of 0.002 to 0.722 ppm for zinc, 0.01 to 0.04 ppm for chromium, 0.01 to 0.18 ppm for lead, 0.005 to 1.277 ppm for copper, 0.003 to 0.16 ppm for nickel and 0.003 to 0.01 for cadmium.

Statistical analysis of the data showed significant changes in the concentration of the metals with time in the sedimentary tank while no significant changes occurred in the sewerage tank. The results of statistical analysis on the two different laboratories that performed the analysis are not significantly different with the exception of that of copper. Analysis also showed that the concentration of the heavy metals in the sedimentation and sewerage tank is significantly different.

The values obtained fall within the permissible levels set by the Department of Environment and Natural Resources for industrial water supply class I and II.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP4

 

Fatty Acid and Lipid Class Biogeochemistry of Rapidly Settling Particles During a Spring Bloom in a Cold Ocean Environment

C. S. Ramos¹, T. A. O. Quibuyen¹, C. C. Parrish² and T. A. Abrajano, Jr.³

¹Institute of Chemistry, University of the Philippines, Diliman

²Ocean Sciences Centre, Memorial University of Newfoundland

St. John’s, Newfoundland, Canada

³Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute

Troy, New York, USA

The lipid class, fatty acid molecular assemblage and the compound-specific d ¹³C composition of individual fatty acids were examined as part of a study to elucidate the transfer of primary photosynthate to benthic environments. Lipid classes from rapidly settling particles showed a discrepancy between the fluxes from sediment traps collected at different depths. Comparison of the non-poisoned and poisoned traps indicated a significant contribution from zooplankton (swimmers) in the poisoned traps. Variations of the fatty acid molecular signature agreed with predicted initial predominant taxa during a spring bloom in a cold ocean environment from literature. The shifts in fatty acid isotopic composition, both temporal and with depth, supported the widely held paradigm that growth rates and dissolved inorganic carbon substrate limitations influence d ¹³C.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP5

THE EFFECT OF MERCURY ON RICE CHLOROPLASTS

Fritzie dela Cruz¹ and Titos A. O. Quibuyen²

¹Department of Biology, Ateneo de Naga, Naga City

²Institute of Chemistry, University of the Philippines, Diliman

The effect of Hg on chloroplasts ultrastructure, chlorophyll profile and growth and biomass of rice plants (Oryza sativa L.) was investigated in the surrounding rice fields of a gold mining area and in experimental set-ups using hydroponics culture with 0.9 and 2.9 ppm Hg-treatments. Bioconcentration of Hg in roots and shoots of rice plants growing in the contaminated area exceeded the natural plant content of 0.04 ppm. Hg accumulation in roots (0.282 ppm) was higher than that of the shoots (0.117 ppm), while the total chlorophyll (a + b) contents was significantly reduced (37%) compared to the control. The chloroplasts either had the usual lens shape but appear elongated and smaller in width or had disturbed lens shape. In both forms, the inner membrane system was less developed compared to the plastids from the control site. Increasing concentration of Hg ions in the medium resulted in elevated bioconcentration of Hg in rice plants grown in the hydroponics culture, accompanied by inhibition of both root/shoot growth and root/shoot biomass. Rice plants grown on the nutrient solution with 2.9 ppm Hg showed more pronounced effect of toxicity, as evident from respectively, 73.6%, and 49 % reduction over the control of root/shoot elongation. Reduction in total chlorophyll correlates with Hg concentration in the medium as shown by respectively, 37%, and 61% decline over the control in 0.9 and 2.9 ppm Hg-treatment. 0.9 ppm Hg-treated chloroplasts are either enlarged or elongated, the inner membrane system had lost its ordered distribution, and the number of osmiophilic globules notably increased. The effect of 2.9 ppm Hg-treatment was more pronounced. Chloroplasts occur either in grossly disturbed shape or with ruptured double outer membrane, the inner membrane system is entirely destroyed due to the progressive unstacking of the granal thylakoids, and the number of osmiophilic globules continuously increased. It is suggested that the high affinity, of Hg ions with the sulfo group in sulpholipids destroys existing H-bonds among the carbohydrate moiety, leading to the compression of the macromolecules and eventually disintegration of the membranes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP6

 

N, P, K AND Zn CONTENT OF MALIGAYA PADDY SOIL PLANTED TO RICE (ORyza saTIva Linn.) APPLIED WITH TITANIUM (IV) OXIDE POWDER (PoT ExpeRIMENT)

Marvin F. Adap, Redel L. Guitierez, David P. Peñaloza and Danila S. Paragas

Department of Chemistry, College of Arts and Sciences

Central Luzon State Uiversity, Muñoz Science City, Nueva Ecija

The effect of TiO₂ on the N, P, K and Zn content of Maligaya paddy soil grown to rice (Oryza sativa Linn.) at different growth stages was studied. The available and exchangeable N, P, K and Zn content of Maligaya paddy soil were determined at different collection periods.

Results revealed that the soil pH changed with respect to collection period and a highly significant result among group treatments with and without TiO₂ was obtained. This change in pH may be attributed to the effect of TiO₂. Lower organic matter content was observed in the soil treated with TiO₂. TiO₂ might have enhanced the transformation of organic matter into available form of nutrients readily absorbed by the plants. The NH₄-N concentration had decreased in soil samples treated with TiO₂, thus, suggesting that any organic nitrogen degraded by TiO₂ had increased the available NH₄-N in soil. Available P was also found to have lower concentrations in samples with TiO₂ and this might be due to its increased solubility. Exchangeable K and Zn had also decreased in soils treated with TiO₂.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP7

N, P, K AND Zn CONTENT OF UMINGAN SOIL AND RICE PLANT (Oryza sativa Linn.) APPLIED WITH DIFFERENT LOADINGS OF TITANIUM (IV) OXIDE (Pot ExpERIment)

Isagani R. Cajucom¹, Jovino de Dios², David P. Peñaloza Jr.¹ and Danila S. Paragas¹

¹Department of Chemistry, College of Arts and Sciences

Central Luzon State Uni-versity, Muñoz Science City, Nueva Ecija

²Agronomy Department, Philippine Rice Research Institute

Maligaya, Muñoz Science City, Nueva Ecija

Contamination of the environment by pesticide residues arises mainly from their application. Pesticide residues have been detected at the point of application in paddy fields and as a result of spray drift from aerial spraying, runoff from rain, and drainage of paddy water, waterways have also been contaminated. Organochlorine residues were detected from waterways in several Asian countries. Because of their persistent character, toxicity, and bioaccumulative properties, organochlorine pesticides are of particular concerns. Recent studies on the effect of semiconductor powders on the photodecomposition of organochlorine pesticides showed promising results.

Photocatalytic technique using semiconductor powders can be used in the clean-up of pesticides in the rice paddy. Findings also show that TiO₂ contributes to soil fertility particularly in terms of increasing the amount of macro- and micronutrients and facilitates the retention of nutrients in the soil.

This study was conducted primarily to determine the effect of different loadings of TiO₂ on the N, P, K and Zn content of Umingan soil and rice plant at different growth stages (0, 45 and 92 days after transplanting (DAT)). It also aimed to determine the effect of different loadings of TiO₂ on the soil pH, organic matter and moisture content.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP8

INVESTIGATION OF METAL RETENTION CAPACITY OF SILICA BY-PRODUCTS FROM GEOTHERMAL BRINE

Emmanuel S. Ramos, Leonard P. dela Cruz, Leah Buenaflor, John Vincent Misa,

Ma. Conchita Morabe, and Alma Silvestre

Institute of Chemistry, University of the Philippines, Diliman

Silica powder obtained from geothermal brine as by-product of Philippines National Oil Company (PNOC) geothermal plant operation was studied for metal retention capacity. The retention of Cd, Cu, Fe, Hg, K, Pb, and Zn using pH settings established in a previous study was investigated. Atomic Absorption analysis was utilized in determining the amount of metal adsorbed per gram of powder used. A procedure for preparing silica powder out of the geothermal brine is also presented. As a practical application, water samples from various sites containing different metals were extracted of metal content of metal content using the silica by-product.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP9

ON-LINE SOLVENT EXTRACTION OF LEAD AND ZINC IN AIR PARTICULATES

Evelyn Yap, Nathaniel Isidro and Josephine M. Castañares

Department of Chemistry, University of San Carlos, Cebu City

Colored dithizone complex, dithizonates, usually red or purple, are formed when diphenylthiocarbazone in carbon tetrachloride reacts with metals. By controlling the pH, use of buffer and complexing agents, the reaction is made specific to a certain metal. Lead and zinc can be extracted by dithizone at pH 8.5 and 4.0-5.0 respectively. This approach was used for the development of a flow injection technique for the determination of both metals.

Optimized conditions were achieved at 150 m L sample volume, 10 mg/L dithizone solution and 200 cm (Zn) / 300 cm (Pb) reaction coils. Lead and zinc particulate samples ranged from 0.383-0.550 m g/L and 1.15 x 10^-6 m g/L respectively.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EP10

Heavy Metal Remediation of Wastewater Effluents Via N-Acetyl-D-Glucosamine Extract from Cockroach (Periplaneta americana) Shells

Sudat A. Santo, Charlene Mae Soriano, Ma. Rowena Balaoro and Asteria Poblete

Chemsitry Department, Adamson University, Ermita, Manila

Wastewater effluents containng Cu²⁺ and Fe²⁺ ions were subjected to heavy metal remediation. The aqueous wastes were passed separately into columns wherein the extracted crude N-acetyl-D-glucosamine commonly known as chitin, was used instead of resin.

The ability of the chitin to bind metal ions in wastewater was determined through Atomic Absorption Spectroscopy. AAS reading of the concentration of the ions in the effluents showed that Fe²⁺ and Cu²⁺ ions were reduced by 85.95% and 11%, respectively. These results proved that chitin can be feasible cationic resin in ion exchange chromatography.

Properties of the chitin were determined using different parameters such as melting point, nitrogen and ash contents. FT-IR spectroscopy was employed to identify the functional groups present in the crude chitin sample.