Apisit Songsasen

 

อภิสิฏฐ์ ศงสะเสน

Staff ID D2064
Position Associate Professor in Inorgnic Chemistry
Room Chemistry Building, Room 507
Phone +662-562-5555 ext 2212
Fax +662-579-3955
Email fsciass@ku.ac.th

Education Qualifications

  • B.Sc. (Biochemistry), 1985, Chulalongkorn University, Bangkok, Thailand
  • M.Sc. (Chemistry), 1989, Kasetsart University, Bangkok, Thailand
  • Ph.D. (Inorganic Chemistry), 1998, University of Bristol, Bristol, England
 


Research Interests

  • Coordination Chemistry of precious metals complexes with Thiazolyazo dye.
  • Photocatalytic degradation of pollutants based on the doped TiO2 catalysts.
  • Environmental monitoring and modeling of pollutants in aquatic environments.
  • Utilization of bamboo charcoal.

Honors and Awards

  • Member of GESAMP (The joint group of experts on the scientific aspects of Marine environmental protection) working group 37 supported by UNIDO (United Nations Industrial development Organization). (Started October 2007)External Examiner for the M.Res course of the Department of Civil Engineering, University of Strathclyde, UK. (September, 2007, 2008)Chairpersons, The 3rd Asian Pacific International Conference on Pollutants Analysis and Control, 12th - 15th December 2005, Organized by Faculty of Science, Kasetsart University and The International Association of Environmental Analytical Chemistry (IAEAC)International Advisory Panel of School of Chemistry, University of Bristol, UK.Member of the Scientific committee of 4th ASTM Symposium on Contaminated Sediments: Sustainable Management and Remediation, 30th June – 2nd July 2009, Trinity College, Dublin, Ireland.
 


  1. The ecological complexity of the Thai-Laos Mekong River: II. Metals and polyaromatic hydrocarbons (PAHs) monitoring, modelling and environmental fate

    Keenan, H.E., Bangkedphol, S., Sakultantimetha, A., Songsasen, A.

    Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

    Volume 45, Issue 13, 2010, Pages 1674-1680

    DOI: 10.1080/10934529.2010.513208

    Abstract

    The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. It is hypothesized that pollution may be adversely affecting the water and sediment quality, which threatens the short and long-term use of this major river system. This directly impacts on the health and population of the aquatic life and ultimately human health and the economy for both countries is affected. The quality of the river can be assessed from various chemical and physical parameters, such as PAHs and metals content of both the water and the sediment. The introduction of Environmental Quality Standards (EQS) allows comparison of the values obtained with the guidelines. Furthermore the modelling program EPISUITE was used to determine the environmental partitioning of pollutants within the different environmental compartments. Using the data produced for PAHs and metals the experimental model was compared to the default model. This involved experimentally measuring the log Koc for Mekong sediments and from this determining the log Kow. High availability in sediment of pollutants may lead to greater biomagnification in bethnic fish, which may then be hazardous for human consumption even if it is safe for the species that is accumulating pollutants. The potential for this is shown by the calculated accumulation in biota Cbio values exceeding both the Chronic value (ChrV) and Lethal Concentration 50 (LC50) for fish in the Mekong River. When compared to the EQS guidelines the amount of some PAHs, cadmium and lead in sediment were above the lowest effect level but below the severe effect level. Copyright © Taylor & Francis Group, LLC.


  2. The ecological complexity of the Thai-Laos Mekong River: III. Health status of Mekong catfish and cyprinids, evidence of bioaccumulative effects

    Phanwichien, K., Pradermwong, A., Keenan, H.E., Masawang, K., Lauhachinda, N., Songsasen, A., Sakultantimetha, A., Bangkedphol, S., Gaines, A.F.

    Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

    Volume 45, Issue 13, 2010, Pages 1681-1688

    DOI: 10.1080/10934529.2010.513219

    Abstract

    Histopathology of fish organs was used as biomarkers of toxicity from environmental pollutants. A total of 117 fishes comprising of 52 cyprinids and 65 catfishes were randomly collected from the Mekong River from 5 stations: Chiang Rai, Loei, Nongkhai, Nakhon Phanom and Ubonratchathani. The health of the fish collected in December and April, winter and summer respectively, was evaluated. All fish from the 5 stations developed pathologic lesions with the same characteristics in their livers, kidneys and spleen. In the liver, there was vacuolation of hepatocytes, accumulation of brownish-green granules in the cytoplasm of hepatocytes, necrosis of hepatocytes, granuloma formation and angiogenesis. Kidney lesions consisted of glomerular degeneration, necrosis and focal hyperplasia of renal tubules. In the spleen, there were haemorrhage, melanomacrophage centre infiltration and necrosis of the red pulp and white pulp. The pathologic severity of the catfish was found to be more severe than in the cyprinids and the catfish collected in summer were less healthy than the catfish collected in the winter. These histopathological appearances might arise from the fish feeding on the benthos and thereby accumulating toxic pollutants in their organs. The activities of the serum enzymes, Glutamic Oxalacetic Transaminase (GOT) and Glutamic Pyruvic Transaminase (GPT), were markedly increased, indicating detoxification activity. The highest activity of GOT found in the cyprinids from Chiang Rai 365.30 U/L whereas in the catfish from Nakhon Phanom the activity was 300.73 U/L. The highest GPT activity found in the cyprinids from Nakhon Phanom was 203.23 U/L where as in the catfish from the same station was GPT 389.77 U/L. According to the results from this study, catfish collected from Chiang Rai, Nakhon Phanom and Ubonratchathani showed more severe pathological changes than catfish from the other stations. Fish organs and river water were analysed for Polyaromatic Hydrocarbons (PAHs) and metals. The fish organs showed bioaccumulation of these toxic pollutants. BioConcentration Factors (BCFs) were calculated. Therefore an attempt is made to correlate these findings to the Mekong study in general. Copyright © Taylor & Francis Group, LLC.


  3. The ecological complexity of the Thai-Laos Mekong River: I. Geology, seasonal variation and human impact assessment on river quality

    Udomchoke, V., Sunthornranun, P., Songsasen, A., Phanwichien, K., Jiwapornkupt, P., Homchan, U., Lauhachinda, N., Sakultantimetha, A., Bangkedphol, S., Torrance, K., Gibson, M.D., Gaines, A.F., Booth, P.H., Keenan, H.E.

    Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

    Volume 45, Issue 13, 2010, Pages 1661-1673

    DOI: 10.1080/10934529.2010.513207

    Abstract

    The objective of this study is to assess the variation of pollution in the Thai-Laos Mekong associated with seasonal dynamics concomitant with the natural geological features and human activities that impact on the adverse quality of the river. The complex ecology of the 1500 km stretch of the Thai-LaosMekong River has been studied in this paper to understand the relationship with the geomorphology, with the sub-tropical monsoonal climate and the impact of human activity. Sub-surface geology controls the nature and extent of the drainage basin and of the river channel. The volume flow of the river varies naturally and dynamically in phase with the rainfall; traditional models based on steady state hydraulics are inappropriate. Continuous erosion of the river banks and bed generates a sediment load of impure silt, mica, quartz and clay minerals that inhibits light penetration and limits the primary productivity of the river. The river separates two countries at different stages of development; it flows through or close to eight non-industrial conurbations (Populations 350,000-2,000,000) but is otherwise sparsely populated. The river is used for subsistence agriculture, village transport, fishing including aquaculture and as a source of domestic water. Hydroelectricity is generated from the Laos tributaries. The river is a depository for partially treated urban waste and untreated village waste, hence populations of E.coli bacteria sometimes render the water unsuitable for drinking unless treated with the highest value of 240/100ml found at station 7 during the summer season of 2003. Furthermore the river is polluted by trace metals, notably cadmium and mercury, and by Polycyclic Aromatic Hydrocarbons (PAHs), which are particularly concentrated in the sediments. Previous work has shown that cadmium and mercury exceed the Probable Effect Level (PEL) values of Canadian Environmental Quality Guidelines and that the PAH concentrations were also greater than the Interim Sediment Quality Guidelines (ISQG). Consequently the fish stock, a vital source of protein for the local human population maybe seriously affected. As conflict between the demands of human activities will be exacerbated by the continuing development of the basin; monitoring must be continued and a better model of the river's ecology is needed to predict the impact of development. Copyright © Taylor & Francis Group, LLC.


  4. Enhancement of tributyltin degradation under natural light by N-doped TiO2 photocatalyst

    Bangkedphol, S., Keenan, H.E., Davidson, C.M., Sakultantimetha, A., Sirisaksoontorn, W., Songsasen, A.

    Journal of Hazardous Materials

    Volume 184, Issue 1-3, 2010, Pages 533-537

    DOI: 10.1016/j.jhazmat.2010.08.068

    Abstract

    Photo-degradation of tributyltin (TBT) has been enhanced by TiO2 nanoparticles doped with nitrogen (N-doped TiO2). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600°C. X-ray diffraction results showed that N-doped TiO2 remained amorphous at 300°C. At 400°C the anatase phase occurred then transformed to the rutile phase at 600°C. The crystallite size calculated from Scherrer's equation was in the range of 16-51nm which depended on the calcination temperature. N-doped TiO2 calcined at 400°C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3h under natural light when compared with undoped TiO2 and commercial photocatalyst, P25-TiO2 which gave 14.8 and 18% conversion, respectively. © 2010 Elsevier B.V.


  5. Acceleration of tributyltin biodegradation by sediment microorganisms under optimized environmental conditions

    Sakultantimetha, A., Keenan, H.E., Beattie, T.K., Aspray, T.J., Bangkedphol, S., Songsasen, A.

    International Biodeterioration and Biodegradation

    Volume 64, Issue 6, 2010, Pages 467-473

    DOI: 10.1016/j.ibiod.2010.05.007

    Abstract

    The capability of a sediment culture (SED) and bacterial isolate Enterobacter cloacae strain TISTR1971 (B3) to degrade tributyltin (TBT) were optimized by biostimulation; respiration conditions, pH of the media and ambient temperature were studied for more efficient treatment process. Three respiration conditions were investigated; aerobic with/without aeration and anaerobic with 0.1 g NO3 - L-1. Among the three conditions, only aeration which provided excess dissolved oxygen, extensively improved the degradation, giving half-lives of 4.08 and 3.16 days for SED and B3, respectively. Variations in the pH of the media (pH 6, 7 and 7.5) moderately affected the degradation rate, mainly at the early stage of log phase. Appropriate pH increased bioavailability by altering Kd and Kow values, and characteristic of TBT. The shortest half-life for SED was 3.53 days at pH 7.5, and 3.10 days for B3 at pH 7. The study of ambient temperature indicated strong uncertainty of degradation from seasonal variation. The half-lives were minimised at 37 °C (3.22 days) for SED and at 28 °C (3.12 days) for B3. Significant variation was shown between 10 and 28 °C, but slightly increased at the higher temperature. This suggests appropriate temperature control at 28 °C for industrial scale treatment. Investigation of these factors together for the optimum conditions lead to modification of the environment, the consequence of which was more efficient biodegradation of TBT in contaminated sediment and water. © 2010 Elsevier Ltd.


  6. The partition behavior of tributyltin and prediction of environmental fate, persistence and toxicity in aquatic environments

    Bangkedphol, S., Keenan, H.E., Davidson, C., Sakultantimetha, A., Songsasen, A.

    Chemosphere

    Volume 77, Issue 10, 2009, Pages 1326-1332

    DOI: 10.1016/j.chemosphere.2009.09.046

    Abstract

    Tributyltin (TBT) is one of the most toxic anthropogenic compounds introduced into the aquatic environment. It has a relatively high affinity for particulate matter, providing a direct and potentially persistence route of entry into benthic sediments. To understand TBT behavior, computational programs are an exceptionally helpful tool for modeling and prediction. EPISuite program was used for evaluation of the prediction data including fate, persistence and toxicity from the partition coefficient values. Without experimental data, the model is useful for prediction but is essentially a default model. A site specific assessment is possible by measuring the partition coefficients and entering the experimental values obtained into the model. This paper describes the results of a study undertaken to determine the partition coefficients and the effect of various parameters on such partition coefficients. The octanol-water partition coefficient (Kow) was determined by the OECD shake-flask method, with the logarithm values obtained ranging from 3.9 to 4.9 depending on salinity. The sediment-water partition coefficient (Kd) was determined by ASTM method of generating Freundlich adsorption isotherms, the obtained values ranged from 88 to 4909 L kg-1 depending on sediment properties, salinity, pH, and temperature. The experimental partition coefficient Kow and Koc (calculated from Kd) were used as input data into the prediction program to provide accurate values for the natural samples in situ. The experimental prediction showed lower toxicity than the default model, but represent actual toxicity and accumulation at the natural site. Moreover, the environmental fate was significantly different when the experimental values and the default values were compared. Crown Copyright © 2009.


  7. Pigments and anti-cholesterol agent production by monascus kaoliang KB9 and its color mutants in rice solid cultures

    Chayawat, J., Jareonkitmongkol, S., Songsasen, A., Yongsmith, B.

    Kasetsart Journal - Natural Science

    Volume 43, Issue 4, 2009, Pages 696-702

    DOI:

    Abstract

    A comparative study of four Monascus strains, (a red-pigment-producing Monascus kaoliang KB9 strain and its three color mutants of red, yellow and white) on various agar media revealed different colony and pigment characteristics. Three agar media: MYS, GYP and PDA gave clear cultural characteristics. Upon varying medium formulas, the wild type and the red mutant showed red pigmentation, while the yellow and white mutants showed deep orange and white pigmentation, respectively. All strains were grown on rice solid culture and examined for the production of pigment and anti-cholesterol agent using a spectrophotometer and a modified HPLC method, respectively. The results showed that the wild-type strain (KB9) and its red mutant (KB 10M16) could produce substantial amounts of anti-cholesterol agent compared with the yellow and white mutants (KB20M10.2 and KB20M1). Due to its good growth and production of the greatest amount of anti-cholesterol agent, the wild-type KB9 strain was selected for a study on the optimization of anti-cholesterol agent fermentation. Under favorable conditions of 64% relative humidity at room temperature (28-30°C) for 5 weeks incubation, production of the anti-cholesterol agent and red pigment was high, with 17,892 mg/kg and 4,640 Unit (OD500) and 4,834 Unit (OD400) per gram dried weight, respectively.


  8. Development and application of an analytical method for the determination of partition coefficients of tributyltin in the forth and clyde canal, Glasgow, Scotland

    Bangkedphol, S., Keenan, H.E., Davidson, C., Sakultantimetha, A., Dyer, M., Songsasen, A.

    Journal of ASTM International

    Volume 6, Issue 7, 2009, Pages -

    DOI: 10.1520/JAI102119

    Abstract

    Tributyltin (TBT) was widely used in the past as a blocide for boats. This has led to widespread environmental contamination. Most analytical methods are based on high resolution techniques with complicated sample preparation. For this study, a simple application of an analytical method was developed using HPLC/UV. The developed method was studied to determine TBT, dibutyltin, and monobutyltin in sediment and water samples. The separation was performed in isocratic mode on a cyanopropyl column with a mobile phase of hexane containing 5 % tetrahydrofuran and 0.03 % acetic acid. This method was confirmed using standard GC-MS techniques and verified by statistical paired t-test method. Under the experimental conditions used, the limit of detection of TBT and DBT were 0.70 and 0.50 ppm, respectively. An optimized extraction method for butyltins in water and sediment samples was developed by using hexane containing 0.05 %-0.5 % tropolone, and 0.2 % sodium chloride in water at pH1.7. The quantitative extraction of butyltin compounds in a certified reference material (BCR-646) and naturally contaminated samples was achieved with recoveries ranging from 95 % to 108 % and precision of 0.02 %-1.00 % relative standard deviation. This developed method was used to determine the contamination level of butyltins in environmental samples collected from the Forth and Clyde canal, Scotland, United Kingdom. The values obtained exceeded the Environmental Quality Standard values. Partition coefficients are major parameters influencing the behavior of pollutants, therefore the methodology developed was used to determine experimentally the partition coefficients Koc, K d, and Kow. The comparison between values obtained experimentally and computational default model values (EPI Suite V 3.20) showed disparity. In terms of bioaccumulation, the implications of this finding may lead to greater biomagnification in the food chain. Copyright © 2009 by ASTM International.


  9. Isolation of tributyltin-degrading bacteria citrobacter braakii and enterobacter cloacae from butyltin-polluted sediment

    Sakultantimetha, A., Keenan, H.E., Dyer, M., Beattie, T.K., Bangkedphol, S., Songsasen, A.

    Journal of ASTM International

    Volume 6, Issue 6, 2009, Pages -

    DOI: 10.1520/JAI102120

    Abstract

    Tributyltin compound (TBT) released into the aquatic environment is generally degraded by bacteria in water and sediment. The isolation of TBT-degrading bacteria from TBT polluted sediment leads to the indication of specific potential TBT degraders. Two new strains of bacteria designated as B2 and B3 were successfully isolated using glycerol medium containing tributyltin chloride (TBTC) at 130 μW from contaminated sediment collected from Bowling Basin in Glasgow. The observed degradation after 14 days of the microcosm from the sediment and the isolated bacteria were investigated at an initial concentration of 1 μM TBTC. It was found that TBT was degraded by the bacterial strains B2 and B3 at 8.3 and 16.9%, respectively. The results indicate that B2 and B3 are effective as TBT degraders. EC50 of B2 and B3 in water were 88.73 and 112.53 μM TBTC, which were significantly higher than the concentration of TBT measured at the basin, suggesting a low effect of TBT on the growth and activity of bacteria. After identification using API 20E and 16S sequencing, the bacterial isolate strain B2 is Citrobacter braakii and B3 is Enterobacter cloacae. Therefore, this study has discovered two species of high resistance TBT dégrader which have never been previously studied or isolated based upon TBT degradation ability. Copyright © 2009 by ASTM International.


  10. Development of a low-cost method of analysis for the qualitative and quantitative analysis of butyltins in environmental samples

    Bangkedphol, S., Keenan, H.E., Davidson, C., Sakultantimetha, A., Songsasen, A.

    Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

    Volume 43, Issue 14, 2008, Pages 1744-1751

    DOI: 10.1080/10934520802330453

    Abstract

    Most analytical methods for butyltins are based on high resolution techniques with complicated sample preparation. For this study, a simple application of an analytical method was developed using High Performance Liquid Chromatography (HPLC) with UV detection. The developed method was studied to determine tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) in sediment and water samples. The separation was performed in isocratic mode on an ultra cyanopropyl column with a mobile phase of hexane containing 5% THF and 0.03% acetic acid. This method was confirmed using standard GC/MS techniques and verified by statistical paired t-test method. Under the experimental conditions used, the limit of detection (LOD) of TBT and DBT were 0.70 and 0.50 μg/mL, respectively. The optimised extraction method for butyltins in water and sediment samples involved using hexane containing 0.05-0.5% tropolone and 0.2% sodium chloride in water at pH 1.7. The quantitative extraction of butyltin compounds in a certified reference material (BCR-646) and naturally contaminated samples was achieved with recoveries ranging from 95 to 108% and at %RSD 0.02-1.00%. This HPLC method and optimum extraction conditions were used to determine the contamination level of butyltins in environmental samples collected from the Forth and Clyde canal, Scotland, UK. The values obtained severely exceeded the Environmental Quality Standard (EQS) values. Although high resolution methods are utilised extensively for this type of research, the developed method is cheaper in both terms of equipment and running costs, faster in analysis time and has comparable detection limits to the alternative methods. This is advantageous not just as a confirmatory technique but also to enable further research in this field. Copyright © Taylor & Francis Group, LLC.


  11. Using low-cost iron byproducts from automotive manufacturing to remediate DDT

    Satapanajaru, T., Anurakpongsatorn, P., Songsasen, A., Boparai, H., Park, J.

    Water, Air, and Soil Pollution

    Volume 175, Issue 1-4, 2006, Pages 361-374

    DOI: 10.1007/s11270-006-9143-9

    Abstract

    Water, soil and sediment contaminated with DDT poses a threat to the environment and human health. Previous studies have shown that zerovalent iron (ZVI) can effectively remediate water contaminated with pesticides like DDT, metolachlor, alachlor. Because the type of iron can significantly influence the efficiency and expense of ZVI technology, finding a cheaper and easily available iron source is one way of making this technology more affordable for field application. This study determined the effects of iron source, solution pH, and presence of Fe or Al salts on the destruction of DDT. Batch experiments demonstrated successful removal of DDT (>95% in 30 d) in aqueous solutions by three different iron sources with the following order of removal rates: untreated iron byproduct (1.524 d-1) > commercial ZVI (0.277 d-1) > surface-cleaned iron byproduct (0.157 d-1). DDT removal rate was greatest with the untreated iron byproduct because of its high carbon content resulted in high DDT adsorption. DDT destruction rate by surface-cleaned iron byproduct increased as the pH decreased from 9 to 3. Lowering solution pH removes Fe (III) passivating layers from the ZVI and makes it free for reductive transformations. By treating DDT aqueous solutions with surface-cleaned iron byproduct, the destruction kinetics of DDT were enhanced when Fe(II), Fe(III) or Al(III) salts were added, with the following order of destruction kinetics: Al(III) sulfate > Fe(III) sulfate > Fe(II) sulfate. Cost analysis showed that the cost for one kg of surface-cleaned iron byproduct was $12.33, which is less expensive than the commercial ZVI. Therefore, using surface-cleaned iron byproduct may be a viable alternative for remediating DDT-contaminated environments. © Springer 2006.


  12. Environmental monitoring of the sediment pollution along the Thai:Laos Mekong

    Keenan, H.E., Dyer, M., Songsasen, A., Bangkedphol, S., Homchan, U.

    Journal of ASTM International

    Volume 3, Issue 7, 2006, Pages -

    DOI:

    Abstract

    The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. However historic pollution is adversely affecting the water and sediment quality that threatens the short- and long-term supply/use of this major river system. This can have a major impact on the health and population of the marine life and ultimately adversely affect human health and the economy for both countries. As a first stage in the assessment of the scale and extent of the pollution problem, an in-depth program of sampling and analysis has been carried out for both water and sediments for three seasons since 2000. A range of water quality parameters were measured from ten sampling stations. These included the PolyAromatic Hydrocarbons (PAHs) initially measured as chrysene equivalents, then as individual compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3,cd)pyrene. A range of heavy metals were measured including chromium, cadmium, mercury, copper, zinc, lead, and titanium. This paper presents the results of the field study to date and provides a preliminary evaluation of the extent of the pollution and potential for bioaccumulation within the local food chain. Copyright © 2006 by ASTM International.


  13. Environmental monitoring of the sediment pollution along the Thai:Laos Mekong

    Keenan, H.E., Dyer, M., Songsasen, A., Bangkedphol, S., Homchan, U.

    ASTM Special Technical Publication

    Volume , Issue 1482, 2006, Pages 3-10

    DOI:

    Abstract

    The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. However historic pollution is adversely affecting the water and sediment quality that threatens the short- and long-term supply/use of this major river system. This can have a major impact on the health and population of the marine life and ultimately adversely affect human health and the economy for both countries. As a first stage In the assessment of the scale and extent of the pollution problem, an in-depth program of sampling and analysis has been carried out for both water and sediments for three seasons since 2000. A range of water quality parameters ware measured from ten sampling stations. These included the PolyAromatic Hydrocarbons (PAHs) Initially measured as chrysene equivalents, then as individual compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3,cd)pyrene. A range of heavy metals were measured including chromium, cadmium, mercury, copper, zinc, lead, and titanium. This paper presents the results of the field study to date and provides a preliminary evaluation of the extent of the pollution and potential for bioaccumulation within the local food chain. Copyright © 2006 by ASTM International.