P. T. S. Wong

National Water Research Institute, Fountain Valley, California, United States

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Publications (58)267.49 Total impact

  • E. A. H. Smith · C. I. Mayfield · P. T. S. Wong
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    ABSTRACT: Partial dissolution of the inorganic (apatite) fraction of flesh-free fish (Perca sp.) cheek-bone material, added to P-free (<0.001 μg∙ml−1 total P) nutrient media as bone chips with a particle-size distribution of <250 μm, supported considerable populations of algae and bacteria at slightly alkaline pH levels and relatively low slurry densities (1–1000 μg∙ml−1). Bacteria and algae rapidly colonized the apatitic bone material and produced extracellular material in response to growth on bone surfaces. Acidic filtrates from bacterial cultures, aerobically or anaerobically cultivated in apatite media, readily solubilized bone material as indicated by increases in soluble ortho-PO43− concentrations after short exposure periods. Water extraction of bone apatite crystals showed that fish bones are sparingly soluble in lake water. Microbially mediated dissolution of bone material by acid end-products of bacterial metabolism would therefore greatly increase the rate of bone dissolution in nature. Regeneration of allochthonous-P from fish-bone dissolution may contribute significantly to the P-cycle of many aquatic ecosystems. Key words: biologic apatite, calcium phosphate, fish bone carbonate hydroxyapatite, dahllite
    No preview · Article · Apr 2011
  • E. A. Smith · C. I. Mayfield · P. T. S. Wong
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    ABSTRACT: Phosphorus-free nutrients were added to three epilimnetic (pH 7.8) 40-ℓ tanks. Apatite crystals (30–100 μm) were added at loading rates of 30, 2, and 0 mg∙day−1. After a 60-day incubation at 20 °C, levels of particulate organic carbon, particulate nitrogen, and particulate organic phosphorus in Tank 1 increased from 0.42, 0.090, and 0.015 to 6.10, 0.820, and 0.430 μg∙ml−1, respectively. This increase was due to the proliferation of algae, bacteria, and zooplankton and did not occur in the tank with only P-free nutrients. Algae and bacteria grew extensively on the surfaces of apatite crystals causing crystals to aggregate. Zooplankton increases followed those in algae and bacteria, and grazing was restricted to the areas around the apatite crystals. Results suggest that the contribution of soluble ortho-PO43− from apatite to the P-cycle of aquatic environments would be more important under oligotrophic conditions than in areas receiving high loadings of anthropogenic-PO43−, particularly where high erosion increases apatite loadings. Key words: apatite, calcium phosphate, hydroxyapatite, fluorapatite, algae, biogeochemistry, freshwater communities
    No preview · Article · Apr 2011
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    P. T. S. Wong · Y. K. Chau · P. L. Luxon
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    ABSTRACT: Recommended levels of a number of metals for Great Lakes Water Quality Objectives were found to be very toxic to freshwater algae when these metals were present simultaneously in lake water and culture medium. The diatom tested was more sensitive to metal toxicity than the blue-green and green algae. Key words: metals, Water Quality Objectives, toxicity, algae, diatom, primary productivity
    Preview · Article · Apr 2011
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    M. E. Starodub · P. T. S. Wong · C. I. Mayfield · Y. K. Chau
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    ABSTRACT: The effect of complexation and pH on heavy metal (Cu, Zn, Pb) toxicity to a freshwater green alga, Scenedesmus quadricauda, was investigated. Extracellular ligands produced by S. quadricauda were capable of binding heavy metals and reducing their single and combined toxicities. Apparent complexing capacities and the ability of the sediment humics and artificial complexing agents such as ethylenediaminetetraacetic acid (EDTA), citric acid, and glycolic acid to ameliorate Cu, Zn, or Pb toxicity were also assessed. The toxicity of metals to algal growth was enhanced at acidic pH. Combined toxicity of these metals was significantly greater at pH 4.5 than at pH 8.5 or pH 6.5. Synergistic effects (between Cu, Zn, and Pb) towards algal growth increased at low pH. Specific heavy metals, their respective concentrations, the presence of complexing ligands, and pH influence both individual and combined heavy metal toxicities.
    Full-text · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
  • P. T. S. Wong · Y. K. Chau · J. L. Yaromich · O. Kramar
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    ABSTRACT: A freshwater green alga, Ankistrodesmus falcatus, exposed to solutions of trialkyllead, dialkyllead, and inorganic lead (II) compounds (1 mg/L) for 24 h accumulated these compounds with concentration factors of about 100, 2000, and 20 000, respectively. Incubation of this alga with trimethyllead and dimethyllead species over a long period (28 d) revealed the ability of the organism to metabolize these compounds. The metabolic processes for trimethyllead followed a dealkylation sequence with the formation of dimethyllead and lead (II) compounds. The alga not ony accumulated dimethyllead, but also contained significant amounts of trimethyllead and lead (II) compounds. Neither chemical disproportionation reactions nor photodecomposition could account for the quantities produced.
    No preview · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
  • P. T. S. Wong · Y. K. Chau · O. Kramar · G. A. Bengert
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    ABSTRACT: The effects of a number of inorganic and organic tin compounds on pure cultures of green and blue-green algae and natural phytoplankton in lake water were tested. Organic tin compounds were generally more inhibitory to primary production and reproduction of the algae than inorganic tin compounds. The toxicity of organotin compounds varied considerably with the number and nature of the organic groups attached to tin, with trialkyl tin compounds being the most toxic forms. Within a given alkyl tin compound series, the longer the carbon chain, the higher the toxicity. A direct relationship between toxicity and partition coefficients of trialkyl tin compounds was observed. Other tin compounds had no such direct relationship.Key words: algae, tin, toxicity, partition coefficients
    No preview · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
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    R. J. Maguire · P. T. S. Wong · J. S. Rhamey
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    ABSTRACT: Tributyltin pesticides are increasingly widespread, but their environmental persistence is poorly known. The accumulation and metabolism of tri-n-butyltin cation (Bu3Sn+) by a green alga, Ankistrodesmus falcatus, was determined at 20 °C over a 4-wk period; about 50% of the original Bu3Sn+ was converted to di-n-butyltin (Bu2Sn2+) and small quantities of butyltin (BuSn3+) and inorganic tin. An apparent algal bioconcentration factor of 3 × 104 was estimated for Bu3Sn+.
    Preview · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
  • P. T. S. Wong · R. J. Maguire · Y. K. Chau · O. Kramar
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    ABSTRACT: Uptake of Sn by Ankistrodesmus falcatus occurred very rapidly. The alga accumulated 2.3 and 4.1 mg Sn/g dry weight of cells after 2 and 60 min of incubation, respectively, in the presence of 46 μgSn/L of medium. Increasing Sn concentrations in the medium resulted in a steady increase in the Sn concentrations in the cells. At 6 mg of Sn and 3 mg of dry weight of cells in 1 L of medium, the cells had accumulated 100 mg Sn/g dry weight of cells, representing 10% of the dry cell mass. The uptake of Sn from the medium and the release of Sn from the cells were not affected by other metals (Pb, As, Zn, Cd, Hg, Sb, and Cu). Addition of EDTA, however, caused an immediate and rapid release of 60% of Sn from the cells. Heat-killed cells took up Sn faster and to a higher level than living nonheated cells. About 85% of Sn taken up by the cells was recovered in the cellular polysaccharide fraction and 15% in the protein fraction, while the lipid and the small molecular weight metabolites accounted for 0.2% of the total Sn.
    No preview · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
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    ABSTRACT: Isolates from four genera of freshwater green algae were capable of methylating sodium arsenite in lake water and Bold's basal medium. Analysis of the liquid phase of the methylation flasks revealed the presence of methylarsonic acid, dimethylarsinic acid, and trimethylarsine oxide. Volatile arsine and methylarsines were not detected in the headspace gases presumably because of the inability of the algae to reduce completely the methylated–arsenic species. Although the algae varied with respect to their methylating abilities, the levels of methylated–arsenic compounds were always significantly higher when the algae were grown in lake water. This may have been due to the lower phosphate concentration in the lake water. We suggest that arsenic methylation by green algae constitutes an additional source for the formation and cycling of organo-arsenic compounds in freshwater ecosystems.
    No preview · Article · Apr 2011 · Canadian Journal of Fisheries and Aquatic Sciences
  • U. Borgmann · Y. K. Chau · P. T. S. Wong · M. Brown · J. Yaromich
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    ABSTRACT: The relationship between bioaccumulation and toxicity of tributyltin in Hyalella azteca was determined for future use in identifying freshwater sites of TBT induced toxicity in the field. Hyalella accumulated waterborne TBT rapidly, reaching equilibrium within 1 week. Short exposure times are, therefore, sufficient to measure TBT availability in laboratory or field exposures. Accumulation was not affected significantly by body size for animals between 0.1 and 0.6 mg dry weight, eliminating the need for a body size correction factor. Young amphipods were more sensitive to TBT than adults when both were exposed for 1 week. The 4-wk LC50 initiated with 0–1-week-old young was 4.8 nM. TBT accumulation was approximately proportional to TBT in water, and the 4-week LC50 expressed on a body concentration basis was 110 nmole/g dry weight. Accumulation of TBT by adult Hyalella to concentrations of about 100 nmole/g or more during short term (1-wk) exposures to environmental samples would suggest chronic TBT-induced toxicity is present at those sites.
    No preview · Article · Jul 1996 · Journal of Aquatic Ecosystem Stress and Recovery
  • P. T. S. Wong · D. M. Whittle · Y. K. Chau · M. Brown
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    ABSTRACT: Severn Sound is a heavily used recreational and beating area in the southeast corner of Georgian Bay, Lake Huron, Canada. Because of the concern over the possible release of tributyltin species (TBT) from antifouling paints on boat hulls and marinas, surveys were carried out in 1989 and 1992 to determine the presence of this species and its degradation products dibutyltin (DBT) and monobutyltin (MBT) in this area. Many fish (pike and young–of–the–year spottail shiners) and sediment samples collected in 1989 contained detectable levels of TBT. A maximum concentration of TBT was recorded in northern pike in the spring to be 240 ng Sn g−1. Maximum levels occurred in marinas during the beginning of the boating season and significantly reduced during the summer and early autumn, although the maximum value of TBT in sediment (392 ng Sn g−1) was observed in the summer of 1989. The seasonal variation of TBT levels was further substantiated in the subsequent 1992 study, in which sediments from three areas in a marina were sampled at monthly intervals from May to October. TBT levels were much higher in May and then generally decreased with time. Mussels (Elliptio complanta) caged in the marina for three months also contained TBT. DBT was frequently detected in the sediments but less frequently in fish and mussels. MBT was generally below detection limits. Plants (macrophytes and cladophora) contained very small amounts of butyltin compounds.
    No preview · Article · Jul 1994 · Applied Organometallic Chemistry
  • P. T. S. Wong · Y. K. Chau · N. Ali · D. M. Whittle
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    ABSTRACT: Sediment and water samples were taken from five sites in Thunder Bay, one upstream (control) and four downstream locations from a bleached kraft pulp mill. Biochemical effects were examined by estimating the carbohydrate content and enzymatic activities of alkaline phosphatase, cellulase, and dehydrogenase in the sediment. Genotoxicity and toxicity of sediment and water were assessed by the SOS Chromotest, although liver microsomal samples were not used to screen for progenotoxic substances. Sediment and water samples were also analyzed for resin and fatty acids, which indicate the degree of effluent contamination. Significant differences in enzyme activity and carbohydrate content were found between sites. Genotoxic values were obtained for downstream water samples for most of the sampling months, however, the sediment only showed genotoxic activity in the July and October samples. The study showed that there are substances causing genotoxic and biochemical effects in the Kaministiquia River, Ontario. © 1994 by John Wiley & Sons, Inc..
    No preview · Article · Feb 1994 · Environmental Toxicology and Water Quality
  • Y. K. Chau · P. T. S. Wong
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    ABSTRACT: Recent developments in the techniques of speciation and determination of organometallic compounds in the environment are reviewed. There is an increasing trend in the use of high performance liquid chromatography as separation tool, and in the use of plasma-excited atomic emission spectrometry as detector. New techniques have been reported to overcome the historically difficult interface of HPLC to furnace AAS. There are also new techniques in the derivatization of ionic organometallic species for gas chromatography. Tandem analytical systems are getting more and more sophisticated, so are the sensitivity and specificity.
    No preview · Article · Aug 1991 · Fresenius Journal of Analytical Chemistry
  • Y. K. Chau · P. T. S. Wong · G. A. Bengert
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    ABSTRACT: A simple, fast, and sensitive, isocratic high-performance liquid chromatography technique was developed for the determination of adenine nucleotides (ATP, ADP, AMP) in biological tissues. In conjunction with this technique, a new method of dissolving biological samples and extraction of nucelotides was introduced, using a tissue solubilizer, TMAH (tetramethylammonium hydroxide). The adenine nucleotides were separated on a C-18 column, eluted isocratically with a solvent system consisting of 0.15 M potassium dihydrogen phosphate and disodium hydrogen phosphate, and water at a 60:40 ratio, using an ultra-violet detector at 254 nm. The HPLC technique has sensitivity in the picomol level and is suitable for nucleotide pool and adenylate energy charge calculations. There was no interference from other nucleotides such as the cyclic AMP's, adenine and adenosine. Guanosine diphosphate and guanosine triphosphate gave peaks in the chromatograms but did not interfere.
    No preview · Article · May 1991 · International Journal of Environmental Analytical Chemistry
  • P. T. S. Wong · Y. K. Chau
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    ABSTRACT: Studies with natural phytoplankton from Lake Ontario as well as with pure cultures of two green and one diatom freshwater algal species revealed that the International Joint Commission water quality objective of 30 μg Zn/L was toxic to primary productivity and cell multiplication. The toxicity of Zn varied with its anionic forms, with nitrate being the most toxic, followed by chloride, sulphate, and acetate. Experiments with radioactive 65Zn indicated that Zn was rapidly taken up by the algae, and incorporated mainly into polysaccharide and nucleic acid fractions. These results indicate that an objective for Zn of 30 μg/L is too high to protect algae in the Great Lakes. Based on our results and other published data, a new objective of 10 μg Zn/L has been recommended to the International Joint Commission.
    No preview · Article · May 1990 · Environmental Toxicology and Water Quality
  • P T S Wong · Y K Chau · J Yaromich · P Hodson · M Whittle
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    ABSTRACT: Analyses of fish and other environmental samples (clams, macrophytes, sediments and waters) from areas upstream and downstream from two alkyllead manufactures beside the St Lawrence and St Clair Rivers, Ontario, show a clear indication of elevated alkyllead levels in samples near the industries. Most species of fish contained alkyllead compounds with tetraethyllead and triethyllead as the predominant forms. Most fish from the contaminated areas contained 50–75% of total lead as alkylleads. Carp, yellow perch and white sucker were generally the most contaminated species while pike, alewife and rock bass were the least contaminated. Average alkyllead levels varied from year to year but declined steadily after 1981. For example, the geometric mean of alkyllead compounds in carp from the St Lawrence River decreased from 4207 μg kg−1 in 1981 to 2000 μg kg−1 in 1982 and to 49 μg kg−1 in 1987, reflecting the reduction of alkylleads in the effluents and the closure of one of the manufactures in 1985. Alkyllead levels were consistently lower in muscle and carcass samples in comparison with whole fish containing fatty intestines. However, muscle levels were generally equal to carcass levels. The concentrations of alkyllead compounds were generally low in clams, macrophytes, sediments and waters except from the immediate vicinity of the manufactures' final effluent discharges.
    No preview · Article · Jan 1989 · Applied Organometallic Chemistry
  • Y K Chau · P T S Wong · G A Bengert · J Wasslen
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    ABSTRACT: The bioconcentration of alkyllead compounds from water and from contaminated sediments by freshwater mussels (Elliptio complanata) has been investigated. Higher levels of trimethyllead than triethyllead species are accumulated for the same exposure period. In-vivo transformation of the trialkyllead species by a series of dealkylation reactions giving dialkyllead and inorganic lead(II) species appears to take place. Rates of accumulation are higher for the more contaminated sediments.
    No preview · Article · Jan 1988 · Applied Organometallic Chemistry
  • M.E. Starodub · P.T.S. Wong · C.I. Mayfield
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    ABSTRACT: The toxicity of three metals (Cu, Zn, Pb) individually and in combination in a short term study (photosynthesis) and a long term study (growth) of a freshwater green alga, Scenedesmus quadricauda, was investigated. The relative metal toxicity to S. quadricauda was Cu > Zn ⪢ Pb, which corresponds with their respective electronegativities. This order was observed for both short term and long term studies. Specific individual and multiple heavy metal toxicities differed between short term and long term studies. Primary productivity was more sensitive to low concentrations of individual metals. Interactive effects between Cu, Zn and Pb were also assessed. In general, metal mixtures behaved antagonistically to photosynthesis. Both antagonism and synergism between Cu, Zn and Pb were observed to growth of S. quadricauda, although synergistic effects seemed to predominate.
    No preview · Article · May 1987 · Science of The Total Environment
  • Y K Chau · P T S Wong · C A Mojesky · Arthur J Carty
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    ABSTRACT: Transmethylation reactions between organometals and metal ions in aqueous solutions in biotic and abiotic systems, with and without the presence of sediment, were investigated. It was found that alkyllead compounds can transfer their alkyl groups to Sn(II) and Sn(IV) ions to form various methyltin compounds in biotic and abiotic systems. The presence of sediment enhanced the transmethylation reactions. Methyltin compounds do not transfer their methyl groups of Pb(II). Methylarsenic acids transfer their methyl groups to Sn(II) and Sn(IV) in an abiotic system, but not in a biotic system containing sediment. The strong adsorption of tin onto sediment was the reason for the non-availability of tin ions for methylation. Methylarsenic acids do not transmethylate Pb(II). Other alkyllead compounds, such as ethyllead and butyllead species were also able to transfer their alkyl groups to tin. When both trimethyllead and triethyllead species are present in the same system, only the individual monoalkyl tin species were formed in both the Sn(II) and Sn(IV) solutions. No mixed alkyltin was produced. The findings of this study suggest that alkyllead compounds, if present in the environment, could be potential methylating agents for the formation of other methylmetals, such as methyltins. Methyltin compounds have already been documented to methylate mercuric ions in aqueous solution. Thus the study of transmethylation reactions opens up a new area of research that is essential in predicting the fate of organometals in the environment.
    No preview · Article · Jan 1987 · Applied Organometallic Chemistry
  • R.J. Maguire · R.J. Tkacz · Y.K. Chau · G.A. Bengert · P.T.S. Wong
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    ABSTRACT: Water and sediment samples from 265 locations across Canada were analyzed for butyltin and methyltin species, and inorganic tin. In 10% of the water samples the highly toxic tributyltin species was found at concentrations which could cause growth retardation upon chronic exposure to a sensitive organism, rainbow trout yolk sac fry. High concentrations of tributyltin were found in some sediments (up to 10 mg Sn/kg dry weight), but the biological availability of sediment-associated tributyltin is unknown. Tributyltin was mainly found in areas of heavy boating and shipping traffic, which is consistent with its use as an antifouling agent in some paints for boats, ships and docks. The methyltin species were found much less frequently in water and sediment than tributyltin and its degradation products.
    No preview · Article · Dec 1986 · Chemosphere

Publication Stats

2k Citations
267.49 Total Impact Points


  • 1990-2011
    • National Water Research Institute
      Fountain Valley, California, United States
  • 1984-2011
    • Fisheries and Oceans Canada
      • Great Lakes Laboratory for Fisheries and Aquatic Sciences (GLLFAS)
      Ottawa, Ontario, Canada
  • 1975-2011
    • Environment Canada
      Montréal, Quebec, Canada
  • 1982
    • University of Waterloo
      • Department of Biology
      Ватерлоо, Ontario, Canada
  • 1979
    • McMaster University
      Hamilton, Ontario, Canada