Browsing by Author "Szymczak, R"

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    Application of environmental isotopes of hydrogen (3H), Carbon (13C & 14C) and oxygen (16O/18O) in studies of groundwater-streamflow interactions
    (International Atomic Energy Agency, 2004-10-25) Stone, DJM; Jacobsen, GE; Hughes, CE; Szymczak, R
    A current major effort in Australian water management is the conjunctive management of hydraulically connected Groundwater and Surface water systems, to provide the maximum benefit to water stakeholders. In particular Australia has a legislative limit on the amount of surface water that can be utilised in a particular catchment, but that is not the case for Groundwater, leading to tension amongst users in connected systems. Valley and Murray-Darling Basin, NSW. Streamflow was sampled using a plastic bailer while groundwaters were withdrawn with the use of a Grundfos MP1 environmental sampling pump. They were analysed for stable isotopes ({sup 2}H/H, {sup 18}O/{sup 16}O) ratios, tritium ({sup 3}H), radiocarbon ({sup 14}C) and major and minor chemical species. Rainwaters were collected and analysed for stable isotopes only. Previous tritium in precipitation data were also utilised. Ion Chromatography was used for the analysis of the anions while either ICP-MS or ICP-AES was used for cations. The tritium analysis was carried out by standard procedures of electrolytic concentration and liquid scintillation counting. Analysis of the water samples for deuterium was conducted by CSIRO, Isotope Analysis laboratory using the zinc reduction method and a VG Isogas mass spectrometer (error; {+-} 0.8 per mille). Radiocarbon in groundwaters are measured using accelerator mass spectrometry (AMS). The water samples are filtered to 45 {mu}m prior to CO{sub 2} collection. Dissolved inorganic carbon (DIC) is separated by acidifying the water samples with 85% phosphoric acid, the resulting CO{sub 2} is collected by sparging with He for 15 mins and cryogenic trapping. The CO{sub 2} is purified by heating overnight to 600 deg. C in the presence of Ag wire. Graphite targets are then prepared by the reduction of the CO{sub 2} using H{sub 2} with an Fe catalyst at 600 deg. C. The resulting graphite/iron mix is measured in the ANTARES 10MV Tandem Accelerator. The determination of oxygen-18 was conducted at the University of Wollongong using the CO{sub 2} gas equilibration method, purified using a Micromass Multiprep Unit and measured on a Micromass Prism III (error; {+-} 0.1 per mille). A plot of tritium activity versus borehole location and depth, indicates that the Brogo River (Bega Valley, NSW) is not recharging the adjacent alluvium since the tritium is much lower than in the streamwater. The Bega river however is recharging the adjacent alluvium, both above and below its confluence with the Brogo river, since tritium values are similar in stream and alluvium. Isotopes such as the stable and radioactive isotopes of water and carbon are particularly appropriate for the study of these connected water systems, providing a clear method of determining the source of groundwater, and hence the extent of mixing of nearby surface water (such as the local river), and the time frame for the mixing process. In particular the stable isotopes 2-H, 18-O, and 13-C provide a robust end-member analysis for the hydrographic separation of regional groundwater and any amount of river water which was replenished at a remote location; while the radioactive isotopes 3-H and 14-C are used to confirm the presence in groundwater of (isotopically modern) surface water, but also accurately determine the apparent rate of mixing at particular distances from the river. © The Authors
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    Application of environmental isotopes of hydrogen (3H), Carbon (13C & 14C) and oxygen (16O/18O) in studies of groundwater-streamflow interactions
    (International Atomic Energy Agency, 2006) Stone, DJM; Jacobsen, GE; Hughes, CE; Szymczak, R
    A current major effort in Australian water management is the conjunctive management of hydraulically connected Groundwater and Surface water systems, to provide the maximum benefit to water stakeholders. In particular Australia has a legislative limit on the amount of surface water that can be utilised in a particular catchment, but that is not the case for Groundwater, leading to tension amongst users in connected systems. Valley and Murray-Darling Basin, NSW. Streamflow was sampled using a plastic bailer while groundwaters were withdrawn with the use of a Grundfos MP1 environmental sampling pump. They were analysed for stable isotopes ({sup 2}H/H, {sup 18}O/{sup 16}O) ratios, tritium ({sup 3}H), radiocarbon ({sup 14}C) and major and minor chemical species. Rainwaters were collected and analysed for stable isotopes only. Previous tritium in precipitation data were also utilised. Ion Chromatography was used for the analysis of the anions while either ICP-MS or ICP-AES was used for cations. The tritium analysis was carried out by standard procedures of electrolytic concentration and liquid scintillation counting. Analysis of the water samples for deuterium was conducted by CSIRO, Isotope Analysis laboratory using the zinc reduction method and a VG Isogas mass spectrometer (error; {+-} 0.8 per mille). Radiocarbon in groundwaters are measured using accelerator mass spectrometry (AMS). The water samples are filtered to 45 {mu}m prior to CO{sub 2} collection. Dissolved inorganic carbon (DIC) is separated by acidifying the water samples with 85% phosphoric acid, the resulting CO{sub 2} is collected by sparging with He for 15 mins and cryogenic trapping. The CO{sub 2} is purified by heating overnight to 600 deg. C in the presence of Ag wire. Graphite targets are then prepared by the reduction of the CO{sub 2} using H{sub 2} with an Fe catalyst at 600 deg. C. The resulting graphite/iron mix is measured in the ANTARES 10MV Tandem Accelerator. The determination of oxygen-18 was conducted at the University of Wollongong using the CO{sub 2} gas equilibration method, purified using a Micromass Multiprep Unit and measured on a Micromass Prism III (error; {+-} 0.1 per mille). A plot of tritium activity versus borehole location and depth, indicates that the Brogo River (Bega Valley, NSW) is not recharging the adjacent alluvium since the tritium is much lower than in the streamwater. The Bega river however is recharging the adjacent alluvium, both above and below its confluence with the Brogo river, since tritium values are similar in stream and alluvium. Isotopes such as the stable and radioactive isotopes of water and carbon are particularly appropriate for the study of these connected water systems, providing a clear method of determining the source of groundwater, and hence the extent of mixing of nearby surface water (such as the local river), and the time frame for the mixing process. In particular the stable isotopes 2-H, 18-O, and 13-C provide a robust end-member analysis for the hydrographic separation of regional groundwater and any amount of river water which was replenished at a remote location; while the radioactive isotopes 3-H and 14-C are used to confirm the presence in groundwater of (isotopically modern) surface water, but also accurately determine the apparent rate of mixing at particular distances from the river. © The Authors
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    Application of neutron activatable tracers (NATs) for cohesive sediment transport studies in contaminated estuaries
    (International Atomic Energy Agency, 2004-10-29) Hollins, SE; Szymczak, R; Airey, PL; Peirson, WL; Payne, TE
    ANSTO and the University of NSW Water Research Laboratory (WRL) are investigating the migration of contaminants associated with cohesive sediments in Homebush Bay, Sydney. The study area is a highly urbanised and industrialised catchment with a long history of contamination [1]. Until 1890, when an ocean outfall was commissioned, domestic and industrial waste was discharged directly into Sydney Harbour [2]. Heavy metals and other hydrophobic pollutants have a distinct tendency towards solid phase partitioning. This means that the majority of heavy metals in the estuary are linked to particulates rather than occurring in the dissolved phase. Hence, in order to assess the impacts of the pollution and develop a scientific basis for remediation it is necessary to understand processes that resuspend and disperse the contaminated sediments. The study approach involved the evaluation of the numerical model of the processes using activatable tracer techniques [3]. An ideal tracer binds to the material of interest with high integrity and is detected with high sensitivity and selectivity. Tracers can be used to study sediment transport over extended periods and are therefore ideally suited to observing the impact of extreme weather events on sediment mobilisation by monitoring the distribution of the label before and after the event. The tracer must not only adhere to the cohesive sediment with high integrity but must be detectable with high efficiency, high sensitivity and relatively low cost. Identification of the optimum activatable tracer involved an assessment of the nuclear (Table I) and sorption properties. The implementation of the tracer study involved (a) labelling sediment from the study area with indium-115 in the laboratory and equilibrating for 3 weeks; (b) choosing a site where bathymetric surveys indicated significant recent accretion; (c) injection of the labelled sediment into an accurately located site in Homebush Bay (Fig. 1); (d) undertaking three surveys over the subsequent months; (e) analysis of samples via irradiation in the Fast Access Neutron facility in ANSTO’s research reactor, HIFAR and gamma counting on a High Purity Germanium detector3; and (f) data processing, where the tracer concentrations were contoured using the Surfer© routine and interpreted in terms of advective and dispersive transport using a Gaussian approximation (Fig. 2). Information on vertical transport was obtained by coring. These results are being used to evaluate a three-dimensional finite element model of the study area [4]. Estimates have been made of the aerial dispersion coefficients, of the surficial mixing due to bioturbation and of advective transport. This paper will focus on the optimum choice of the tracer for cohesive sediment transport studies and some early results.
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    A combined multidisciplinary kinetic modeling approach for determination of coastal ecosystem contaminant fluxes
    (Goldschmidt, 2006-08-26) Szymczak, R; Twining, JR; Hollins, SE; Mazumder, D; Creighton, NM
    The historical operation of manufacturing, chemical and other industries in the Sydney Harbour catchment over many decades has left a legacy of high chemical contamination in the surrounding catchment. These contaminants are now seriously impacting on incident commercial fisheries and public utilisation of estuarine resources. Elucidation of environmental processes is the key to effective ecosystem management, however few tools are available to predict their inter-relationships, rates and directions. This work seeks to combine GIS, contaminant transport, ecological, and bioaccumulation models to improve the accuracy and specificity of a probabilistic ecological risk assessment strategy. This study has four components: (1) determination of chemical linkages between high trophic order species and different habitats resources using stable isotopic analyses of carbon and nitrogen. These studies identify trophic cascades forming the basis for selection of biota for contaminant transfer experiments; (2) short-term (weeks – months) chronology and geochemistry of sediment cores and traps in Homebush Bay to determine rates of sedimentation and resuspension (using environmental/cosmogenic 7-Be). Models derived from these studies provide the contaminants levels against which risk is assessed; (3) biokinetic studies using proxy radiotracer isotopes (eg. 75-Se & 109-Cd for analogous stable metals) of the uptake and trophic transfer of contaminants by specific estaurine biota. Here we identify the rates and extent to which contaminants accumulated and transferred to predators/seafoods; and (4) application of a probabilistic ecological risk assessment model (AQUARISK) set to criteria determined by stakeholder consensus. Here we report initial results of the distribution of natural isotopes and redistribution of artificial isotopes injected into ecological compartments to determine the key trophic linkages, contaminant pathways and their rates in temperate estuarine systems of Sydney Harbour & Botany Bay (Australia).
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    Environmental monitoring at the Australian Nuclear Science & Technology Organisation (ANSTO)
    (International Atomic Energy Agency, 2006) Ferris, JM; Harrison, JJ; Hoffmann, EL; Payne, TE; Szymczak, R
    The Australian Nuclear Science and Technology Organisation (ANSTO) operates several facilities, including Australia’s only research reactor, HIFAR, carrying out production of radiopharmaceuticals and research in nuclear science and technology. ANSTO is an agency of the Commonwealth of Australia. Most ANSTO facilities are at the Lucas Heights Science and Technology Centre (LHSTC), surrounded by a 1.6 km buffer zone, about 40 km southwest of Sydney. ANSTO also operates the National Medical Cyclotron (NMC), located on the grounds of Royal Prince Alfred Hospital in Camberdown, Sydney, which produces shortlived radioisotopes for medical investigations. ANSTO is committed to undertaking its activities in a manner that protects human health and the environment and is consistent with national and international standards and our activities are regulated by the Australian Radiation Protection and Nuclear Safety Agency [1] under the Australian Radiation Protection and Nuclear Safety Act (1998). ANSTO has a comprehensive monitoring programme for the main pathways for potential exposure from routine and accidental releases for radioactivity. Annually, approximately 6000 samples are taken and some 10,000 analyses are performed. ANSTO monitors the amounts of airborne emissions, the radioactive and non-radioactive contaminants released to the sewer and subsequently to local coastal waters, the quality of stormwater leaving the site, the quality of groundwater and soils and sediment in the general vicinity. The principal sources of potential radiation exposure to members of the general public from routine ANSTO operations at the LHSTC and National Medical Cyclotron are from airborne emissions and low- level liquid effluent discharges. The effective dose rate to a hypothetical individual potentially exposed to radiation in routine airborne discharges from the LHSTC during the 2002-03 fiscal year was less than 0.006 mSv/year, based on stack discharge data and concurrent meteorological information. This effective dose is well below the ALARA objective of 0.02 mSv/year and less than 1% of the public dose rate limit of 1 mSv/year for long term exposure that is recommended by the Australian Occupational Health and Safety Commission. It is also less than 1% of the natural background annual dose in Australia of about 1.5 mSv/year [2]. Thermoluminescent dosimeters placed around the LHSTC and at some local residences also demonstrate that the external gamma radiation levels at residential locations in the vicinity of the LHSTC were at normal background levels and not noticeably affected by ANSTO operations. ANSTO operations at the LHSTC and the NMC make only a very small addition to the background radiation dose, even for the comparatively few members of the public identified as potentially exposed to radionuclides entering the environment from the ANSTO sites. The results of the monitoring programme are published annually in documents within the series Environmental and Effluent Monitoring at ANSTO Sites [3 and references therein], copies of which are available in the local Sutherland Shire Central Library and on request from the ANSTO Communications Manager. The environmental and effluent monitoring programme at ANSTO is very much a team effort and acknowledgment goes to all associated staff for their valuable contributions.
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    Environmental monitoring at the Australian Nuclear Science & Technology Organisation (ANSTO)
    (International Atomic Energy Agency, 2004-10-24) Ferris, JM; Harrison, JJ; Hoffmann, EL; Payne, TE; Szymczak, R
    The Australian Nuclear Science and Technology Organisation (ANSTO) operates several facilities, including Australia’s only research reactor, HIFAR, carrying out production of radiopharmaceuticals and research in nuclear science and technology. ANSTO is an agency of the Commonwealth of Australia. Most ANSTO facilities are at the Lucas Heights Science and Technology Centre (LHSTC), surrounded by a 1.6 km buffer zone, about 40 km southwest of Sydney. ANSTO also operates the National Medical Cyclotron (NMC), located on the grounds of Royal Prince Alfred Hospital in Camberdown, Sydney, which produces shortlived radioisotopes for medical investigations. ANSTO is committed to undertaking its activities in a manner that protects human health and the environment and is consistent with national and international standards and our activities are regulated by the Australian Radiation Protection and Nuclear Safety Agency [1] under the Australian Radiation Protection and Nuclear Safety Act (1998). ANSTO has a comprehensive monitoring programme for the main pathways for potential exposure from routine and accidental releases for radioactivity. Annually, approximately 6000 samples are taken and some 10,000 analyses are performed. ANSTO monitors the amounts of airborne emissions, the radioactive and non-radioactive contaminants released to the sewer and subsequently to local coastal waters, the quality of stormwater leaving the site, the quality of groundwater and soils and sediment in the general vicinity. The principal sources of potential radiation exposure to members of the general public from routine ANSTO operations at the LHSTC and National Medical Cyclotron are from airborne emissions and low- level liquid effluent discharges. The effective dose rate to a hypothetical individual potentially exposed to radiation in routine airborne discharges from the LHSTC during the 2002-03 fiscal year was less than 0.006 mSv/year, based on stack discharge data and concurrent meteorological information. This effective dose is well below the ALARA objective of 0.02 mSv/year and less than 1% of the public dose rate limit of 1 mSv/year for long term exposure that is recommended by the Australian Occupational Health and Safety Commission. It is also less than 1% of the natural background annual dose in Australia of about 1.5 mSv/year [2]. Thermoluminescent dosimeters placed around the LHSTC and at some local residences also demonstrate that the external gamma radiation levels at residential locations in the vicinity of the LHSTC were at normal background levels and not noticeably affected by ANSTO operations. ANSTO operations at the LHSTC and the NMC make only a very small addition to the background radiation dose, even for the comparatively few members of the public identified as potentially exposed to radionuclides entering the environment from the ANSTO sites. The results of the monitoring programme are published annually in documents within the series Environmental and Effluent Monitoring at ANSTO Sites [3 and references therein], copies of which are available in the local Sutherland Shire Central Library and on request from the ANSTO Communications Manager. The environmental and effluent monitoring programme at ANSTO is very much a team effort and acknowledgment goes to all associated staff for their valuable contributions.
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    Evaluating trophic linkages in mangrove-based food webs using stable isotopes of carbon and nitrogen
    (Rosenstiel School of Marine and Atmospheric Science University of Miami, 2006-04-19) Mazumder, D; Szymczak, R; Saintilan, N; Williams, RJ
    An understanding of the energy flow pathways and trophic linkages in estuarine food webs is essential for managing estuaries and their ecosystems sustainably. These pathways are complex, given the dynamics in physico-chemical processes, variety and area of habitats. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) were measured for a variety of fish, invertebrate, and crustacean species collected from saltmarsh and mangrove habitats in Botany Bay and Homebush Bay, NSW, Australia. The work is on-going, however, initial observations indicate specific prey-predator linkages evident within a complex trophic structure. Results also advocate the role of certain non-commercial estuarine species as important conduits of energy and nutrition to higher trophic-order commercially valuable species, linking these with specific estuarine habitats. This work seeks to model the source of energy and nutrition in mangrove and saltmarsh-based food webs and to determine the chemical linkages between high trophic order species and different habitat resources. © The Authors.
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    Evaluating trophic linkages in mangrove-based food webs using stable isotopes of carbon and nitrogen
    (Ingenta, 2006-04-19) Mazumder, D; Szymczak, R; Saintilan, N; Williams, RJ
    An understanding of the energy flow pathways and trophic linkages in estuarine food webs is essential for managing estuaries and their ecosystems sustainably. These pathways are complex, given the dynamics in physico-chemical processes, variety and area of habitats. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) were measured for a variety of fish, invertebrate, and crustacean species collected from saltmarsh and mangrove habitats in Botany Bay and Homebush Bay, NSW, Australia. The work is on-going, however, initial observations indicate specific prey-predator linkages evident within a complex trophic structure. Results also advocate the role of certain non-commercial estuarine species as important conduits of energy and nutrition to higher trophic order commercially valuable species, linking these with specific estuarine habitats. This work seeks to model the source of energy and nutrition in mangrove and saltmarsh-based food webs and to determine the chemical linkages between high trophic order species and different habitat resources. © 2007 Rosenstiel School of Marine and Atmospheric Science
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    ISO 9001 accreditation in an R&D environment - is it possible?
    (International Atomic Energy Agency, 2006) Szymczak, R; Henderson-Sellers, A; Lowson, RT; Chisari, R
    The Australian Nuclear Science and Technology Organisation (ANSTO) is Australia's national nuclear organisation and its centre of Australian nuclear expertise. ANSTO is in the process of replacing its 1950’s, 15 MW, high flux (up to 1015 n cm-2 s-1) reactor with a new reactor which will allow it to continue its cutting edge nuclear science and radiopharmaceutical production well into the 21st century. A ministerial requirement for licensing the facility is ISO 9001 accreditation of its quality management system. The accreditation process has been staggered at ANSTO. Individual divisions are attaining ISO 9001 accreditation separately, leading up to site-wide accreditation of an overarching ANSTO Business Management System. ANSTO Environment is the largest multidisciplinary environmental research group in Australia and the largest R & D unit at ANSTO, comprising around 150 biologists, chemists, engineers, geophysicists, meteorologists, microbiologists, oceanographers, physicists, and technicians (Fig. 1). ANSTO Environment operates and maintains a wide range of advanced nuclear and analytical facilities including three particle accelerators, a 10 MV Tandem accelerator, a 3 MV Van de Graaff accelerator and a newly acquired 2MV HVEE tandetron; a high current 50 kV Metal Vapour Vacuum Arc Ion Implantation (MEVVA) Facility; a Secondary Ion Mass Spectrometer (SIMS); and many other laboratory and field-based facilities. The objective of ANSTO Environment is to carry out a problem-focused, balanced program of strategic and applied research and development, using its nuclear science-based core expertise and closely-related techniques, to: · assist the Commonwealth Government to further its national and international initiatives, and to protect and conserve the natural environment through sustainable development; · assist industry in advancing Australia's competitive position in the world economy; · ensure that environmental monitoring of nuclear facilities is effective in assuring operational adherence to sound environmental protection principles. “Make everything as simple as possible, but not simpler” Albert Einstein In February 2000 ANSTO Environment successfully acquired ISO 9001:2000 accreditation of its quality management system and was amongst the first organisations to adopt the new 2000 revision of the international ISO 9001 standard. The new standard allows a much more flexible and less prescriptive format for quality management systems however, in the absence of examples of accreditation in the R & D area, presented a challenge in concept, definition of process, buy-in by staff and subsequent maintenance of the successful certification. The ANSTO Environment Manual of Good Management Practice [1] outlines our identity, our vision, our core values, our responsibilities, our operational processes and our commitment to continual improvement via internal and external review. This paper is a description and discussion of the elements, concepts and process for achieving staff buy-in in the face of initial opposition. This included identifying those necessary elements of a good management system, rejection of pejorative dogma associated with ‘Quality’ and ownership of the process by all the staff.
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    ISO 9001 accreditation in an R&D environment - is it possible?
    (International Atomic Energy Agency, 2004-10-24) Szymczak, R; Henderson-Sellers, A; Lowson, RT; Chisari, R
    The Australian Nuclear Science and Technology Organisation (ANSTO) is Australia's national nuclear organisation and its centre of Australian nuclear expertise. ANSTO is in the process of replacing its 1950’s, 15 MW, high flux (up to 1015 n cm-2 s-1) reactor with a new reactor which will allow it to continue its cutting edge nuclear science and radiopharmaceutical production well into the 21st century. A ministerial requirement for licensing the facility is ISO 9001 accreditation of its quality management system. The accreditation process has been staggered at ANSTO. Individual divisions are attaining ISO 9001 accreditation separately, leading up to site-wide accreditation of an overarching ANSTO Business Management System. ANSTO Environment is the largest multidisciplinary environmental research group in Australia and the largest R & D unit at ANSTO, comprising around 150 biologists, chemists, engineers, geophysicists, meteorologists, microbiologists, oceanographers, physicists, and technicians (Fig. 1). ANSTO Environment operates and maintains a wide range of advanced nuclear and analytical facilities including three particle accelerators, a 10 MV Tandem accelerator, a 3 MV Van de Graaff accelerator and a newly acquired 2MV HVEE tandetron; a high current 50 kV Metal Vapour Vacuum Arc Ion Implantation (MEVVA) Facility; a Secondary Ion Mass Spectrometer (SIMS); and many other laboratory and field-based facilities. The objective of ANSTO Environment is to carry out a problem-focused, balanced program of strategic and applied research and development, using its nuclear science-based core expertise and closely-related techniques, to: assist the Commonwealth Government to further its national and international initiatives, and to protect and conserve the natural environment through sustainable development; · assist industry in advancing Australia's competitive position in the world economy; · ensure that environmental monitoring of nuclear facilities is effective in assuring operational adherence to sound environmental protection principles. “Make everything as simple as possible, but not simpler” Albert Einstein In February 2000 ANSTO Environment successfully acquired ISO 9001:2000 accreditation of its quality management system and was amongst the first organisations to adopt the new 2000 revision of the international ISO 9001 standard. The new standard allows a much more flexible and less prescriptive format for quality management systems however, in the absence of examples of accreditation in the R & D area, presented a challenge in concept, definition of process, buy-in by staff and subsequent maintenance of the successful certification. The ANSTO Environment Manual of Good Management Practice [1] outlines our identity, our vision, our core values, our responsibilities, our operational processes and our commitment to continual improvement via internal and external review. This paper is a description and discussion of the elements, concepts and process for achieving staff buy-in in the face of initial opposition. This included identifying those necessary elements of a good management system, rejection of pejorative dogma associated with ‘Quality’ and ownership of the process by all the staff.
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    Nuclear and isotopic techniques for improved management of contaminants impacting aquaculture and fisheries activities
    (Asian Fisheries Society, 2007-11) Szymczak, R; Twining, JR; Hollins, SE; Mazumder, D
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    Nuclear and isotopic techniques underpinning probabilistic ecological risk analysis in coastal marine systems
    (American Geophysical Union, 2006-02-20) Szymczak, R; Twining, JR; Hollins, SE; Hughes, CE; Mazumder, D; Alquezar, R
    The historical operation of manufacturing, chemical and other industries in the Sydney Harbour catchment over many decades has left a legacy of high chemical contamination in the surrounding catchment, such that a recent report describes Port Jackson as one of the most contaminated harbours in the world (Birch & Taylor, 2005). The legacy in Homebush Bay is amongst the worst in the harbour and presents a considerable management problem. Elucidation of environmental processes is the key to effective ecosystem management, however few tools are available to determine their inter-relationships, rates and directions. This study has four components: (1) determination of linkages between high trophic order species and different habitats resources using stable isotopic analyses of carbon and nitrogen. These studies identify trophic cascades forming the basis for selection of biota for contaminant transfer experiments; (2) short-term (weeks - months) chronology and geochemistry of sediment cores and traps in Homebush Bay to determine rates of sedimentation and resuspension (using environmental/cosmogenic 7Be). Models derived from these studies provide the contaminants levels against which risk is assessed; (3) biokinetic studies using proxy radiotracer isotopes (eg. 75Se & 109Cd for analogous stable metals) of the uptake and trophic transfer of contaminants by specific estuarine biota. Here we identify the rates and extent to which contaminants accumulated and transferred to predators/seafoods; and (4) application of a probabilistic ecological risk assessment model (AQUARISK) set to criteria determined by stakeholder consensus. In this study we analysed the distribution of natural isotopes and redistribution of artificial isotopes injected into ecological compartments to determine the key trophic linkages and contaminant pathways in an estuarine system and contribute to improving the accuracy and specificity of a probabilistic ecological risk assessment strategy. © Author(s) (2006)
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    Po-210 and Pb-210 concentration factors for zooplankton and faecal pellets in the oligotrophic South-West Pacific
    (International Atomic Energy Agency, 2004-10-24) Jeffree, RA; Szymczak, R; Peck, GA
    In a previous study on zooplankton sampled from very low productivity waters of French Polynesia [1], their Po-210 concentrations were found to be unexpectedly elevated, compared to values measured in marine zooplankton from various other geographical regions of the world. For the French Polynesian samples their Po-210 concentrations also increased appreciably as their biomass declined. A simple conceptual and mathematical model, that incorporated the established role of zooplankton faecal pellets in the removal of Po-210 and particle-reactive radionuclides and stable metals from the water column, could capture the shape of this empirical relationship between Po-210 concentration and their biomass and also explained the biomass-related mechanism that increases Po-210 concentrations in zooplankton [2]. Similarly, a field investigation in the Timor Sea showed that a range of particle-reactive elements showed elevated water concentrations as particle removal rates, as inferred from Th-234: U-238 disequilibria, reduced in the euphotic zone [3]. However, in these previous studies simultaneous in situ measurements of a range of parameters valuable in assessment of the role of zooplankton in the biogeochemical cycling of particle-reactive elements like Po-210 and Pb-210 were not made. Here we report preliminary results of a field study, that was undertaken in the oligotrophic waters of the South-West Pacific between New Caledonia and Fiji, where we simultaneously measured a) zooplankton biomass and their faecal pellet production rates, b) Po-210 and its progenitor Pb-210 in water, zooplankton and their faecal pellets and c) particle flux rates using U-238:Th-234 disequilibria, to further assess the role of zooplankton in Po-210 and Pb-210 biogeochemistry in the euphotic zone of oligotrophic systems [4]. Zooplankton sampled from the oceanic region of the South-West Pacific between Fiji and New Caledonia had biomasses ranging from 0.1 to 7.1 mgDW/m3, with a median value of 3.6 and mean of 2.65 mgDW/m3. Their faecal pellet production rates were measured on board and varied between 1.82.10-4-3.78.10-3 g dry faecal pellet. g dry zooplankton-1. hour-1, median ). Their measured Po-210 and Pb-210 concentrations were 830-2655 Bq.KgDW-1 and 44-617Bq. KgDW-1, respectively. Po-210 and Pb-210 concentrations in zooplankton varied between 565-1736 Bq.Kg dry weight-1 and 47-551 Bq.Kg dry weight-1, respectively. Po-210 concentration factors that only varied between 1.3 –3.3. 105 were elevated compared to the IAEA recommended value of 3.104 based on previous values [5]. Similarly, Pb-210 concentration factors ranging from 0.9-9.1. 104, were considerably elevated compared to the IAEA recommended value of 1.103 [5], indicating the presence of a further concentrating mechanism. Our results for Po-210 and Pb-210 show a consistency with published values [5,6] in that the concentration factor for Po-210 is elevated relative to Pb-210, but contrast with previous reported values in both being elevated by about an order of magnitude. Their comparably elevated concentrations in faecal pellets suggest that enhanced concentrations in zooplankton are a reflection of the heightened concentrations in their dietary phytoplankton.
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    Po-210 and Pb-210 concentration factors for zooplankton and faecal pellets in the oligotrophic South-West Pacific
    (International Atomic Energy Agency, 2006) Jeffree, RA; Szymczak, R; Peck, GA
    In a previous study on zooplankton sampled from very low productivity waters of French Polynesia [1], their Po-210 concentrations were found to be unexpectedly elevated, compared to values measured in marine zooplankton from various other geographical regions of the world. For the French Polynesian samples their Po-210 concentrations also increased appreciably as their biomass declined. A simple conceptual and mathematical model, that incorporated the established role of zooplankton faecal pellets in the removal of Po-210 and particle-reactive radionuclides and stable metals from the water column, could capture the shape of this empirical relationship between Po-210 concentration and their biomass and also explained the biomass-related mechanism that increases Po-210 concentrations in zooplankton [2]. Similarly, a field investigation in the Timor Sea showed that a range of particle-reactive elements showed elevated water concentrations as particle removal rates, as inferred from Th-234: U-238 disequilibria, reduced in the euphotic zone [3]. However, in these previous studies simultaneous in situ measurements of a range of parameters valuable in assessment of the role of zooplankton in the biogeochemical cycling of particle-reactive elements like Po-210 and Pb-210 were not made. Here we report preliminary results of a field study, that was undertaken in the oligotrophic waters of the South-West Pacific between New Caledonia and Fiji, where we simultaneously measured a) zooplankton biomass and their faecal pellet production rates, b) Po-210 and its progenitor Pb-210 in water, zooplankton and their faecal pellets and c) particle flux rates using U-238:Th-234 disequilibria, to further assess the role of zooplankton in Po-210 and Pb-210 biogeochemistry in the euphotic zone of oligotrophic systems [4]. Zooplankton sampled from the oceanic region of the South-West Pacific between Fiji and New Caledonia had biomasses ranging from 0.1 to 7.1 mgDW/m3, with a median value of 3.6 and mean of 2.65 mgDW/m3. Their faecal pellet production rates were measured on board and varied between 1.82.10-4-3.78.10-3 g dry faecal pellet. g dry zooplankton-1. hour-1, median ). Their measured Po-210 and Pb-210 concentrations were 830-2655 Bq.KgDW-1 and 44-617Bq. KgDW-1, respectively. Po-210 and Pb-210 concentrations in zooplankton varied between 565-1736 Bq.Kg dry weight-1 and 47-551 Bq.Kg dry weight-1, respectively. Po-210 concentration factors that only varied between 1.3 –3.3. 105 were elevated compared to the IAEA recommended value of 3.104 based on previous values [5]. Similarly, Pb-210 concentration factors ranging from 0.9-9.1. 104, were considerably elevated compared to the IAEA recommended value of 1.103 [5], indicating the presence of a further concentrating mechanism. Our results for Po-210 and Pb-210 show a consistency with published values [5,6] in that the concentration factor for Po-210 is elevated relative to Pb-210, but contrast with previous reported values in both being elevated by about an order of magnitude. Their comparably elevated concentrations in faecal pellets suggest that enhanced concentrations in zooplankton are a reflection of the heightened concentrations in their dietary phytoplankton.
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    Probabilistic risk assessment and risk mapping of sediment metals in Sydney Harbour embayments.
    (Taylor & Francis, 2008-11) Twining, JR; Creighton, NM; Hollins, SE; Szymczak, R
    Sediment metal concentrations in embayments of Sydney Harbour, acquired from the literature and from samples collected for this study, were used to generate contaminant probability density distributions using AQUARISK. The sediment metal concentrations often exceeded Australia's interim sediment quality guidelines. Similarly, estuarine spiked sediment toxicity test literature provided adverse biotic effects concentration data to generate species sensitivity distributions using AQUARISK. Although the harbor is subject to other inorganic and organic contamination, we have used sediment metals to demonstrate an approach for ecological risk mapping and environmental management prioritization. Sufficient spiked sediment toxicity test data were found for only three metals Cd, Cu, and Zn and some tests were likely to overestimate toxicity. The estimates of the hazardous concentration to 5% of species (the 50th percentile of the 95% species protection level) were 5, 12, and 40 mg/kg DW of total sediment metal for Cd, Cu, and Zn, respectively. These values were generally low when compared with the interim sediment quality guidelines due to the overestimation of toxic effects in the literature data. The parameters for the species sensitivity distributions have been combined with the measured sediment metal concentrations in Homebush Bay to generate risk maps of the estimated species impact for each metal as well as for all three metals collectively assuming proportional additivity. This has demonstrated the utility of comparing contaminants on a consistent scaleecological risk. © 2008, Taylor & Francis Ltd.
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    Tools based on nuclear and isotopic techniques for the management of threatened coastal ecosystems
    (Taylor & Francis, 2009-10) Szymczak, R
    Elucidation of in situ environmental processes is the key to effective ecosystem management. However, due to the complexity of coastal ecosystems, few tools are available to determine the inter-relationships and rates of these events. It is only when all of the important variables are understood and computationally described that effective ecological risk analysis can be accomplished. Model packages already exist which describe and predict specific coastal processes and further refinement of subroutines and user-interfaces has some value; however the truly significant advances lie in synergistic integration of different codes. Predictive ecological risk analysis requires transport models predicting contaminant concentrations under a range of environmental scenarios and bioaccumulation and trophic-transfer models using keystone species (or critical groups) identified by models elucidating trophic structure. In an attempt to elucidate natural processes, or solve environmental problems, stable and radioisotope tracers have a number of advantages over conventional techniques. Stable isotope studies replace visual observations of prey-predator interactions with statistically interpretable chemical data. Radiotracers provide real time kinetic data on uptake and transfer of specific contaminants and environmental transport processes. The unique assemblage and application of these nuclear and isotopic environmental probes will greatly assist in effective ecological risk assessment of present situations and the resource-economic evaluation of proposed management options. The nuclear-based technologies developed from studies undertaken in the Sydney (Australia) environs are transferred to developing countries via the IAEA/Regional Cooperative Agreement (RCA) Project: Improving Regional Capacity for Assessment, Planning and Responding to Aquatic Environmental Emergencies (RAS/8/095). The IAEA Project objectives were to improve the regional capacity for the management of aquatic radiological and environmental risks and to develop capabilities in the RCA countries to assess, plan and respond to pollution events in aquatic environments. Expert missions supported national projects in individual Member States, further developing and transferring skills and technologies. © 2009, Taylor & Francis Ltd.
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    Trophic importance of a temperate intertidal wetland to resident and itinerant taxa: evidence from multiple stable isotope analyses
    (CSIRO Publishing, 2011-01-18) Mazumder, D; Saintilan, N; Williams, RJ; Szymczak, R
    Juveniles of commercially important fish species congregate in shallow vegetated estuarine habitats during high tides. Considerable debate has centred on whether the significance of these habitats lies in their provision of greater feeding opportunities, or shelter from predation afforded by greater structural complexity. We tested the hypothesis that an inundated mangrove and saltmarsh wetland provided feeding opportunities for itinerant species, and that the contribution of wetland primary producers and grazing herbivores could be identified in their diet, using stable isotopes of carbon and nitrogen. Potential sources of dietary carbon included mangrove, saltmarsh, seagrass, seagrass epiphytic material and benthic organic material. Saltmarsh plants (mostly Sporobolus virginicus and Juncus kraussii) and fine benthic organic material appeared to be the primary sources of dietary carbon for the resident grazing herbivores in the wetlands, based on IsoSource mixing models. During high tide, species of itinerant fish enter the mangrove and, when inundated, the saltmarsh, and feed primarily on crab larvae and copepods. Fine benthic organic matter, seagrass epiphyte, and C3 and C4 plant materials also supplement the diet of some fish. The crab larvae therefore provide a significant source of nutrition and an important link between the intertidal wetlands and the adjacent estuarine ecosystem. The carnivorous fish Acanthopagrus australis, at the highest trophic level, hunted within or adjacent to the mangrove–saltmarsh wetland and fed on several lower-order consumers within the wetland. The present study highlights the significance of mangrove and saltmarsh wetlands as a feeding habitat for resident grazers and itinerant nekton. © 2011, CSIRO Publishing
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    Use of stable isotopes in Sydney catchment process and water quality studies
    (Australian Water Association and Waste Management Association of Australia, 2006-07-30) Hughes, CE; Mazumder, D; Gibson, JJ; Szymczak, R; Cendón, DI; Hollins, SE; Waring, CL
    The use of stable and radioactive isotopes as environmental tracers is becoming more widespread as isotopic analysis techniques become more accessible. ANSTO’s Isotopes for Water Project aims to increase awareness of the potential uses of isotopes in the management of catchments, rivers, reservoirs, aquifers, estuaries and biota. This paper outlines a range of potential applications using a wide range of isotopes (δ18O, δ2H, 14C, δ13C, δ15N, 3H, 7Be, 210Pb, 35S, δ34S, δ18O and Δ17O) in hydrology, hydrogeology, ecology and contaminant geochemistry with examples from the Sydney basin. The studies being undertaken by ANSTO include: • application of stable water isotopes to catchment and reservoir water balance; • age dating of groundwater to underpin sustainability assessment; • tracing the source of contaminants and nutrients such as nitrogen, organic matter and sulfate in catchments and waterways; • quantifying contaminated sediment dynamics and contaminant uptake into biota using shorted-lived radioisotopes; • tracing trophic linkages in aquatic food webs.
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    Variability of stable isotope ratios of glassfish (Ambassis jacksoniensis) from mangrove/saltmarsh environments in Southeast Australia and implications for choosing sample size
    (Taylor & Francis, 2008-04) Mazumder, D; Williams, RJ; Reid, D; Saintilan, N; Szymczak, R
    Stable isotopes offer an accurate and cost-effective way to understand critical pathways of energy, and their use has application where aquatic habitats have been degraded. Isotope ratios can offer insights into appropriate conservation and rehabilitation techniques to manage these valuable resources. To date, the literature shows little attention to spatial and temporal variation in isotope signatures of samples taken from estuarine environments. This study reports on an investigation of sample size by which to determine isotopic signatures within a single species of fish, Ambassis jacksoniensis. Provided are two ways by which to determine how many samples are needed, and the results imply that care may be needed in interpreting previous studies based on small sample size. A minimum of five individuals would appear necessary in some cases. © 2008, Taylor & Francis Ltd.
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    Variability of stable isotope ratios of mangrove glassfish (Ambassis Jacksoniensis) from southeast Australia and the implications for ecosystem studies
    (Ingenta, 2007-05-03) Mazumder, D; Williams, RJ; Szymczak, R; Reid, D; Saintilan, N
    Scientists concerned with organic matter flow and food web structures in aquatic ecosystems are increasingly realizing the potential of stable isotope ratios as natural tracers. Stable isotopes offer an accurate and cost effective way to understanding critical pathways of energy and pollutant transfer. Further, many aquatic habitats have been degraded and isotope ratios offer insights into appropriate conservation and rehabilitation techniques to manage these valuable resources. So far, the literature shows little attention has been paid to spatial and temporal variations in isotope signatures of samples taken from saltmarsh and mangrove environments. This study reports on investigations into the differences in isotopic signatures within a single species, Ambassis jacksoniensis, surveyed from two locations at two different times. The results suggest significant variation in δ13C between different season and location for glassfish, but not for δ15N. The results also suggest that care is needed in interpreting previously published results. © 2007 Rosenstiel School of Marine and Atmospheric Science