29 results on '"Krikowa, F."'
Search Results
2. Fitness of two bivalves Saccostrea glomerata and Ostrea angasi exposed to a metal contamination gradient in Lake Macquarie, NSW Australia: Integrating subcellular, energy metabolism and embryo development responses
- Author
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Bartlett, J., primary, Maher, W., additional, Ubrihien, R., additional, Krikowa, F., additional, Edge, K., additional, Potts, J., additional, and Taylor, A., additional
- Published
- 2020
- Full Text
- View/download PDF
3. Arsenic concentrations and speciation in Australian and imported rice and commercial rice products
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Maher, William, Duncan, Elliott, Martin, Hayden, Snell, Peter, Krikowa, F, Jagtap, Rajani, Foster, Simon, Ezaz, Tariq, Ellwood, Michael, Maher, William, Duncan, Elliott, Martin, Hayden, Snell, Peter, Krikowa, F, Jagtap, Rajani, Foster, Simon, Ezaz, Tariq, and Ellwood, Michael
- Abstract
Arsenic concentrations and speciation measurements were determined for six varieties of Australian-grown rice (n = 130), imported rice (n = 53) and rice products (n = 56) from supermarkets. Total As, inorganic As and dimethylarsinic acid (DMA) concentrations in Australian rice ranged from 16 to 630 µg As kg−1 (mean ± s.d.: 220 ± 122 µg kg−1), 16 to 250 µg As kg−1 (92 ± 52 µg As kg−1) and <5 to 432 µg As kg−1 (125 ± 109 µg As kg−1), respectively. Total As, inorganic As and DMA concentrations in imported rice ranged between 31 and 376 µg As kg−1 (130 ± 98 µg kg−1), 17 and 198 µg As kg−1 (73 ± 40 µg As kg−1) and <5 and 327 µg As kg−1 (84 ± 92 µg As kg−1) respectively. Few samples exceeded the guidelines for inorganic As in polished rice. In rice products, total As, inorganic As and DMA concentrations ranged between 21 and 480 µg As kg−1 (160 ± 110 µg As kg−1), 20 and 255 µg As kg−1 (92 ± 78 µg As kg−1) and <5 and 340 µg As kg−1 (65 ± 69 µg As kg−1) respectively. Sixteen samples exceeded the 100 µg kg−1 maximum for inorganic As concentration in rice foods for infants and young children. Ingestion of multiple serves of some rice products poses a potential risk. Environmental chemistry gaps, on processes influencing As occurrence in rice, are discussed.
- Published
- 2018
4. Antimony measurements in environmental matrices: Seven considerations
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Maher, William, Krikowa, F, Foster, Simon, Ellwood, Michael, Bennett, William, Maher, William, Krikowa, F, Foster, Simon, Ellwood, Michael, and Bennett, William
- Abstract
The development of robust methods for determining the concentration and speciation of antimony (Sb) in natural samples is essential to understanding its distribution and cycling in nature. Here we discuss our experiences with a variety of approaches for measuring the content and speciation of Sb in environmental matrices. Total Sb concentration measurements in waters require digestion with HNO3–HCl to release Sb from particulate material and may require a preconcentration step to remove Sb from saline matrices or to obtain the required sensitivity. Plant analyses require the use of HNO3–HBF4 or HNO3–HF while sediments require the use of HNO3–HCl to solubilise Sb and prevent adsorption to silicates. Methods for Sb speciation should be fit for purpose. Volatile Sb species can be measured successfully using SPME-GCMS, waters via hydride generation-trapping ICPMS and sediment extracts using HPLC-ICPMS. Extraction of Sb from sediments and plants presents a challenge; however, the use of citrate is adequate for extraction of Sb from sediments predominately containing Sb associated with Fe–Mn oxyhydroxide phases. We have been unable to successfully quantify organic Sb species in plants because of the oxidation of Sb(III) to Sb(V) and the formation of artefact Sb species. The analysis of solid samples using X-ray absorption spectroscopy should be considered as it has been shown to discriminate between Sb(III) and Sb(V) as well as Sb minerals, oxides and adsorbed Sb species.
- Published
- 2018
5. History of Metal Contamination in Lake Illawarra, NSW, Australia
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Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Batley, Graeme, Taylor, Anne, Krikowa, F, Chariton, Anthony, Zawadzki, Atun, Heijnis, Hendrik, Gruber, Bernd, Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Batley, Graeme, Taylor, Anne, Krikowa, F, Chariton, Anthony, Zawadzki, Atun, Heijnis, Hendrik, and Gruber, Bernd
- Published
- 2015
6. Measurement of arsenic species in environmental, biological fluids and food samples by HPLC-ICPMS and HPLC-HG-AFS
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Maher, William, Ellwood, Michael, Krikowa, F, Raber, George, Foster, Simon, Maher, William, Ellwood, Michael, Krikowa, F, Raber, George, and Foster, Simon
- Abstract
The importance of measuring arsenic (As) species has been appreciated for a long time mainly because of the wide spread knowledge of arsenic's toxicity and its use as a poison. Increasingly health, environmental and food regulations have been written around As species rather than total concentrations. Knowledge of As speciation is important as the chemical form of As controls its bioavailability, toxicity, mobility and therapeutic benefits. Arsenic is present as inorganic (arsenate, arsenite, thioarsenates), complexed (arsenic glutathionines and phytochelatins), low molecular weight (monomethylarsonate, dimethylarsenate, arsenobetaine, arsenocholine etc.) and high molecular weight (arsenic hydrocarbons and arsenic phospholipids) species. In this review we cover the intergrity of As species during collection, storage, sample preparation and measurement by HPLC-ICPMS and HPLC-HG-AFS. It is essential to ensure that As species, especially in waters and sediments, are not artefacts of the preservation or extraction procedure. Most samples can be stored frozen (-20 °C), but the stability of water and sediment samples is matrix dependent and depends on preservation technique applied. Arsenic cannot be extracted from samples using a single set of conditions but must be optimised for each sample type. Methanol-water mixtures with microwave heating are commonly used to extract polar As species from tissues while As-lipids required a non-polar solvent. Dilute acid can be used to increase the efficiencies of extraction of hard to extract tissue As species. Freeze drying is suitable for the drying of biotic material while sediments should not be dried before analysis. Extraction efficiencies are critically dependent on particle size. Polar As species have a wide variety of ionic characteristics thus complimentary chromatographic approaches utilising ion-exchange or reverse phase columns with modifiers are needed to separate all the As species. Arsenic-lipids require the use of a
- Published
- 2015
7. Use of a multi-proxy method to support the restoration of estuaries receiving inputs from industry
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Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Batley, Graeme, Taylor, Anne, Krikowa, F, Chariton, Anthony, Zawadzki, Atun, Heijnis, Hendrik, Gruber, Bernd, Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Batley, Graeme, Taylor, Anne, Krikowa, F, Chariton, Anthony, Zawadzki, Atun, Heijnis, Hendrik, and Gruber, Bernd
- Abstract
In New South Wales (NSW), Australia, the availability of water from estuarine lakes combined with the use of coal as an energy source has resulted in coal-fired power stations on the margins of coastal lakes. The purpose of this study was to use a multi-proxy method to evaluate the extent and trends of historical metal inputs from a coal-fired power station to sediments in Lake Budgewoi. Metal concentrations in 15-cm sediment cores showed a uniform depth profile. The highest concentrations of zinc and copper were found close to the Munmorah Power Station outlet, while arsenic and lead were found in the deposition basin of sediments. Background values for metal concentrations of Zn < 80 mg/kg, As < 15 mg/kg, Se < 1 mg/kg, Cu < 16 mg/kg, Cd < 0.8 mg/kg and Pb < 20 mg/kg were used as the baseline for future studies in this lake. The history of sediment metal concentrations is consistent with power station activities in the lake. Maximum metal concentrations found in sediments of Lake Budgewoi were Zn 122 mg/kg, Cu 45 mg/kg, As 10 mg/kg, Se 1.8 mg/kg, Cd 0.2 mg/kg and Pb 41 mg/kg. The ratio of these values to the national interim sediment quality guidelines are Pb 0.8, Cu 0.7, Zn 0.6, As 0.5 and Cd 0.1. Although concentrations were below guideline values, the multi-proxy method applied in this study was sensitive enough to detect metal concentration changes over the 45 years of power station operation. The results of this study provide environmental regulators with a baseline of the past and current situation of power station metal contamination, and in the future will provide insights into how long it takes the environment to revert to background metal concentrations
- Published
- 2015
8. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand
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Hug, K, Maher, WA, Stott, MB, Krikowa, F, Foster, S, Moreau, JW, Hug, K, Maher, WA, Stott, MB, Krikowa, F, Foster, S, and Moreau, JW
- Abstract
Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with increased
- Published
- 2014
9. Recent history of sediment metal contamination in Lack Macquarie, Australia, and an assessment of ash handling procedure effectiveness in mitigating metal contamination from coal-fired power stations
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Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Gruber, Bernd, Batley, Graeme, Taylor, Anne, Chariton, Anthony, Krikowa, F, Zawadzki, Atun, Heijnis, Hendrik, Schneider Guilhon, Larissa, Maher, William, Potts, Jaimie, Gruber, Bernd, Batley, Graeme, Taylor, Anne, Chariton, Anthony, Krikowa, F, Zawadzki, Atun, and Heijnis, Hendrik
- Published
- 2014
10. Overview of hyphenated techniques using an ICP-MS detector with an emphasis on extraction techniques for measurements of metalloids by HPLC-ICPMS
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Maher, William, Krikowa, F, Ellwood, Michael, Foster, Simon, Jagtap, Rajani, Raber, George, Maher, William, Krikowa, F, Ellwood, Michael, Foster, Simon, Jagtap, Rajani, and Raber, George
- Abstract
In this review we present an overview of hyphenated techniques using an ICPMS detector with an emphasis on extraction techniques for the measurement of metalloids by high pressure liquid chromatography-inductively plasma mass spectrometry (HPLC-ICPMS). Five modes of using hyphenated ICPMS systems; HPLC-ICPMS, HPLC-hydride generation-ICPMS, Cryogenic trapping ICPMS, in-situ Cryogenic trapping ICPMS and Gas Chromatography-ICPMS are described together with their application for the measurement of arsenic, selenium, mercury and antimony species. Two classes of metalloid species are described; "Easy to extract species," stable species existing as discrete molecules or relatively weakly bound to cellular constituents, and Hard to extract species," unstable species that dissociate on extraction and species incorporated within cellular constituents such as proteins. Measurements described include, arsenic species: arsenobetaine, arsenoribosides, arsenic bound to lipids and phytochelatins and other minor arsenic species including thioarsenic species. Selenium species: selenocysteine and selenomethionine, Se-methyl selenomethionine, Se-methyl selenocysteine, y-glutamyl-Se-methylselenocysteine, dimethylselenide and dimethyldiselenide. Mercury species: inorganic Hg and methyl Hg. Antimony species: antimonite and antimonate. Germanium species: inorganic. Extraction methods are discussed in terms of their extraction efficiencies, stability of species and artifact formation.
- Published
- 2012
11. Sponges as sentinels: patterns of spatial and intra-individual variation in trace metal concentration
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De Mestre, C, Maher, W, Roberts, D, Broad, Allison, Krikowa, F, Davis, Andrew R, De Mestre, C, Maher, W, Roberts, D, Broad, Allison, Krikowa, F, and Davis, Andrew R
- Abstract
If sponges are to be effective biomonitors we require a better understanding of the spatial scales over which metals vary in these organisms. We determined how concentration of Cd, Zn, Cu, Pb, Hg and Se varied over four spatial scales for two common estuarine sponge species in the Sydney region. We examined variability with a fully nested sampling design; between coastal lakes, within coastal lakes, between sponges and within sponges. Calculation of variance components confirmed that 'within-sponge' variation in Cd, Zn, Cu, Pb and Se concentrations were low (1-14%) relative to the two largest spatial scales (49-98%) examined. In contrast, Hg concentrations exhibited marked variability 'between-sponges' and were below detection at one location. There was little evidence that sponge size was a good predictor of metal concentration. Taken together, these outcomes confirm that fragments of these sponges could be successfully transplanted and therefore show promise as biomonitors of metal contamination.
- Published
- 2012
12. Bioaccumulation of antimony and arsenic in a highly contaminated stream adjacent to the Hillgrove Mine, NSW, Australia
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Telford, Kristy, Maher, William, Krikowa, F, Foster, Simon, Ellwood, Michael, Ashley, P.M., Lockwood, Peter V, Wilson, Susan C, Telford, Kristy, Maher, William, Krikowa, F, Foster, Simon, Ellwood, Michael, Ashley, P.M., Lockwood, Peter V, and Wilson, Susan C
- Abstract
Bioaccumulation and uptake of antimony (Sb) were investigated in a highly contaminated stream, Bakers Creek, running adjacent to mining and processing of Sb-As ores at Hillgrove Mine, NSW, Australia. Comparisons with arsenic (As) were included owing to its co-occurrence at high concentrations. Mean metalloid creek rhizome sediment concentrations were 777 115g g-1 Sb and 60 6g g-1 As, with water concentrations at 381 23g L-1 Sb and 46 2g L-1 As. Antimony and As were significantly elevated in aquatic autotrophs (96-212g g-1 Sb and 32-245g g-1 As) but Sb had a lower uptake efficiency. Both metalloids were elevated in all macroinvertebrates sampled (94-316g g-1 Sb and 1.8-62g g-1 As) except Sb in gastropods. Metalloids were detected in upper trophic levels although biomagnification was not evident. Metalloid transfer to riparian vegetation leaves from roots and rhizome soil was low but rhizome soil to leaf As concentration ratios were up to 2-3 times greater than Sb concentration ratios. Direct exposure to the rhizosphere sediments and soils, water ingestion and consumption of aquatic autotrophs appear to be the major routes of Sb and As uptake for the fauna of Bakers Creek.
- Published
- 2009
13. Selenium in sediments, pore waters and benthic infauna of Lake Macquarie, New South Wales, Australia
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Barford, John Patrick, Reible, D.D., Gomes, V.G., Jeswani, H.K., Roach, A.C., Krikowa, F., Maher, W.A., Peters, G.M., Barford, John Patrick, Reible, D.D., Gomes, V.G., Jeswani, H.K., Roach, A.C., Krikowa, F., Maher, W.A., and Peters, G.M.
- Abstract
Measurements of selenium in sediments and benthic infauna of Lake Macquarie, an estuary on the east coast of Australia, indicate that sediments are a significant source of selenium in the lake's food web. Analysis of surficial sediment samples indicated higher selenium concentrations near what are believed to be the main industrial sources of selenium to the lake: a smelter and a power station. Sediment cores taken from sediments in Mannering Bay, near a power station at Vales Point, contained an average of 12 times more selenium in surficial sections than sediment cores from Nord's Wharf, a part of the lake remote from direct inputs of selenium. The highest selenium concentration found in Mannering Bay sediments (17.2 μg/g) was 69 times the apparent background concentration at Nord's Wharf (0.25 μg/g). Pore water concentrations in Mannering Bay were also high, up to 5 μg/l compared to those at Nord's Wharf which were below detection limits (0.2 μg/l). Selenium concentrations in muscle tissues of three benthic-feeding fish species (Mugil cephalus, Platycephalus fuscus, Acanthopagrus australis) were significantly correlated (p < 0.05) with surficial sediment selenium concentration. Selenium concentrations in polychaetes and molluscs of Mannering Bay were up to 58 times higher than those from Nord's Wharf. Two benthic organisms, the eunicid polychaete Marphysa sanguinea and the bivalve mollusc Spisula trigonella, were maintained at different densities in selenium-spiked sediments. Both animals accumulated selenium from the spiked sediment, confirming that bioaccumulation from contaminated sediments occurs. Collectively, these data suggest that benthic food webs are important sources of selenium to the fish of Lake Macquarie.
- Published
- 1999
14. Elevated selenium concentrations in Seronorm Trace Elements Serum (Level 2)
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Townsend, AT, Featherstone, AM, Chery, C, Vanhaecke, F, Kirby, J, Krikowa, F, Maher, W, Jacobson, GA, Peterson, GM, Townsend, AT, Featherstone, AM, Chery, C, Vanhaecke, F, Kirby, J, Krikowa, F, Maher, W, Jacobson, GA, and Peterson, GM
- Abstract
Selenium is an essential trace element in humans, the majority of it occurring in selenoproteins. These proteins have several known physiologic functions; they are important antioxidants, maintain normal thyroid function, and are thought to play a role in inhibiting tumor growth. There has been considerable interest in studying selenoproteins in serum because the selenium concentrations reported for many populations are less than those required for optimum activity of selenoenzymes. This may have both long- and short-term consequences for human health.
15. Measurement of trace elements in marine environmental samples using solution ICP-MS. Current and future applications
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Maher, W, Krikowa, F, Kirby, J, Townsend, AT, Snitch, P, Maher, W, Krikowa, F, Kirby, J, Townsend, AT, and Snitch, P
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The strengths and weaknesses of using inductively coupled plasma mass spectrometer (ICPMS) measurements of samples in solution for marine environmental analyses using real world examples is discussed. ICPMS can detect nanogram per litre concentrations of trace elements but suffers from polyatomic interferences generated from the sample matrix. Most of the routine trace elements measured in marine biological tissue and sediment digests, with the notable exceptions of iron, chromium, vanadium, and selenium, are not subject to severe interferences. Low recoveries of trace elements from sediments are due to the inability of extraction acids to remove trace elements such as chromium and nickel from sediment matrices. The use of ICPMS offers the advantage that elements such as phosphorus, which previously required elaborate digestion procedures and a colorimetric determination, can be rapidly determined using nitric acid digestion alone. The use of flow injection coupled with ICPMS allows on-line preconcentration of trace metals and metalloids using chelation by ion-exchange resins or hydride generation and trapping as well as separation from matrix elements. Thus, the routine determination of trace elements and inorganic and methylated arsenic, antimony, mercury, and germanium species in open-ocean waters is possible. The coupling of HPLC and GC to ICPMS allows the measurement of metal and metalloid species in biological and sediment extracts. However, extraction of unaltered species from matrices presents a challenge. Many of the species found in the environmental samples are not known and analytical standards are not available. The concurrent use of HPLC-MS is needed to confirm these species.
16. The effects of different arsenic species in relation to straighthead disease in rice
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H. P. Martin, P. Snell, Elliott G. Duncan, William Maher, Frank Krikowa, Michael J. Ellwood, Martin, HP, Maher, W, Ellwood, M, Duncan, E, Snell, P, Krikowa, F, and 7th International Congress and Exhibition Arsenic in the Environment, 2018 Beijing, China 1-6 July 2018
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Veterinary medicine ,chemistry ,food chains ,arsenic ,chemistry.chemical_element ,food and beverages ,DMA concentrations ,Disease ,Biology ,Arsenic - Abstract
The effects of inorganic arsenic on plants, the mechanisms involved in the uptake and transport of arsenic and how inorganic arsenic enters food chains are well documented. Regulatory limits have been established to control the inorganic arsenic concentrations in certain foods including rice. There is, however, a knowledge gap with respect to dimethylarsenic concentrations. In this study rice was grown hydroponically and exposed to varying DMA concentrations. High levels of DMA were detrimental to rice plants whereby plants showed symptoms consistent with Straighthead disease, a disease that results in dramatic yield losses. Refereed/Peer-reviewed
- Published
- 2018
17. A weight-of-evidence approach for identifying potential sources of untreated sewage inputs into a complex urbanized catchment.
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Codello A, McLellan SL, Steinberg P, Potts J, Scanes P, Ferguson A, Hose GC, Griffith M, Roguet A, Lydon KA, Maher WA, Krikowa F, and Chariton A
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- Escherichia coli, Feces, Humans, Rivers, Water Microbiology, Environmental Monitoring, Sewage
- Abstract
The Hawkesbury-Nepean River (HNR) is the largest catchment in the Sydney region and is undergoing unprecedented population growth. The HNR system receives a mix of anthropogenic inputs such as treated sewage, stormwater and agricultural runoff. Combined, these can diminish the ecological system health and pose potential concerns to human health. Of particular concern are inputs of untreated sewage, that can occur due to a range of different reasons including illegal point source discharges, failure of the sewerage network, and overloading of wastewater treatment plants during storm events. Here, we present findings of an intensive assessment across the HNR catchment where we used a weight-of-evidence (WOE) approach to identify untreated sewage contamination in surface waters against the background of treated effluent and diffuse inputs during post high flow conditions. Total nitrogen and phosphorus concentrations were used to assess treated effluent and diffuse inputs, and microbial analysis, including both culture-based traditional methods for E. coli and enterococci and qPCR analysis of Bacteroides and Lachnospiraceae, were used to assess raw sewage contamination. Despite a background of diffuse inputs from recent high flow events and the influence of treated wastewater, we found no gradient of faecal contamination along the HNR system or its tributaries. We observed two sites with evidence of untreated sewage contamination, where the human markers Bacteroides and Lachnospiraceae qPCR copy numbers were high. The biological and chemical approaches suggested these latter two hotspots originate from an industrial runoff source and possibly from a dry weather sewage leak. Our findings demonstrate the potential of a WOE approach in the assessment of human faecal signal in an urban river that can also pinpoint small sources of contamination as a strategy that can reshape the way monitoring is performed and the chemical end-points chosen to provide pertinent information on the potential risks to aquatic system health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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18. Dimethylarsenate (DMA) exposure influences germination rates, arsenic uptake and arsenic species formation in wheat.
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Duncan EG, Maher WA, Foster SD, Krikowa F, O'Sullivan CA, and Roper MM
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- Arsenic analysis, Arsenic chemistry, Cacodylic Acid metabolism, Cacodylic Acid pharmacokinetics, Edible Grain toxicity, Global Health, Herbicides, Oryza, Plant Structures chemistry, Plant Structures metabolism, Silicon Dioxide analysis, Soil Pollutants analysis, Soil Pollutants toxicity, Triticum growth & development, Arsenic pharmacokinetics, Cacodylic Acid pharmacology, Germination drug effects, Triticum metabolism
- Abstract
The contamination of cereals with arsenic (As) is a global health and agronomic concern. This study compared the physiological response, As uptake and As speciation in the grains and above ground tissues of 20 wheat cultivars exposed to 5 mg As kg
-1 soil as either arsenate (AsV ) or dimethylarsenate (DMA) under glasshouse conditions. Germination rates for the majority of cultivars exceeded 80% for the majority of cultivars when exposed to AsV , but fell significantly to 20-40% when exposed to DMA. For a number of cultivars, grain yields were 20-50% lower when plants were exposed to DMA compared to AsV . Grain As concentrations were between 0.6 and 1.6 μg As g-1 grain across the twenty cultivars when exposed to AsV , whereas grain As concentrations were much higher (2.2-4.6 μg As g-1 grain) when exposed to DMA. When plants were exposed to AsV , 100% of the As present in the grain was found as inorganic As while in plants exposed to DMA, 70-90% of As was present as DMA with the remainder found as inorganic As. DMA is believed to be incorporated by plants via silica (Si) acid channels and assessment of grain Si concentrations demonstrated that up to 40% less Si was accumulated in grains when plants were exposed to DMA. The decreased germination rates and grain yields in the presence of DMA is similar to the symptoms described for straight head disease in rice, which has been linked to DMA exposure. The results presented here indicate some analogous processes occur in wheat to those described in rice. We hypothesise that exposure to DMA may have inhibited Si-metabolism and translocation which resulted in both developmental impairment and possibly an increased susceptibility to soil pathogens., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2017
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19. The response of Isidorella newcombi to copper exposure: Using an integrated biological framework to interpret transcriptomic responses from RNA-seq analysis.
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Ubrihien RP, Ezaz T, Taylor AM, Stevens MM, Krikowa F, Foster S, and Maher WA
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- Animals, Copper metabolism, Gene Expression Profiling, Gene Expression Regulation drug effects, Genetic Association Studies, Intracellular Membranes drug effects, Intracellular Membranes metabolism, Lysosomes drug effects, Lysosomes metabolism, Molecular Sequence Annotation, Snails metabolism, Transcriptome drug effects, Water Pollutants, Chemical toxicity, Copper toxicity, Environmental Exposure analysis, Sequence Analysis, RNA methods, Snails drug effects, Snails genetics, Transcriptome genetics
- Abstract
This study describes the transcriptomic response of the Australian endemic freshwater gastropod Isidorella newcombi exposed to 80±1μg/L of copper for 3days. Analysis of copper tissue concentration, lysosomal membrane destabilisation and RNA-seq were conducted. Copper tissue concentrations confirmed that copper was bioaccumulated by the snails. Increased lysosomal membrane destabilisation in the copper-exposed snails indicated that the snails were stressed as a result of the exposure. Both copper tissue concentrations and lysosomal destabilisation were significantly greater in snails exposed to copper. In order to interpret the RNA-seq data from an ecotoxicological perspective an integrated biological response model was developed that grouped transcriptomic responses into those associated with copper transport and storage, survival mechanisms and cell death. A conceptual model of expected transcriptomic changes resulting from the copper exposure was developed as a basis to assess transcriptomic responses. Transcriptomic changes were evident at all the three levels of the integrated biological response model. Despite lacking statistical significance, increased expression of the gene encoding copper transporting ATPase provided an indication of increased internal transport of copper. Increased expression of genes associated with endocytosis are associated with increased transport of copper to the lysosome for storage in a detoxified form. Survival mechanisms included metabolic depression and processes associated with cellular repair and recycling. There was transcriptomic evidence of increased cell death by apoptosis in the copper-exposed organisms. Increased apoptosis is supported by the increase in lysosomal membrane destabilisation in the copper-exposed snails. Transcriptomic changes relating to apoptosis, phagocytosis, protein degradation and the lysosome were evident and these processes can be linked to the degradation of post-apoptotic debris. The study identified contaminant specific transcriptomic markers as well as markers of general stress. From an ecotoxicological perspective, the use of a framework to group transcriptomic responses into those associated with copper transport, survival and cell death assisted with the complex process of interpretation of RNA-seq data. The broad adoption of such a framework in ecotoxicology studies would assist in comparison between studies and the identification of reliable transcriptomic markers of contaminant exposure and response., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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20. History of human impact on Lake Kutubu, Papua New Guinea: The geochemical signatures of oil and gas mining activities in sediments.
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Schneider L, Haberle SG, Maher WA, Krikowa F, Zawadzki A, and Heijnis H
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- Barium analysis, Humans, Papua New Guinea, Surface Properties, Trace Elements analysis, Environmental Monitoring methods, Geologic Sediments chemistry, Hydraulic Fracking, Lakes chemistry, Oil and Gas Industry, Water Pollutants, Chemical analysis
- Abstract
Lake Kutubu, a large tropical lake in Papua New Guinea, is well known for its ecological importance; however, there have been recent changes to the pristine nature of this lake due to activities associated with the largest oil and gas project in PNG. The aim of this study was to determine the geochemical profile of sediment cores of Lake Kutubu and to comprehend the contamination changes undergone in this lake due to mining activities utilising the hydraulic fracturing method. Sediment core profiles of Na, Mg, Al, Si, P, Ca, Ti, Cr, Fe, Mn, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Ce, Pb and U, grain size and dating analyses were conducted for five sites in the lake. Grain size and dating demonstrated that the northwest side of Lake Kutubu has sediments of allocthonous origin while the southeast sediments are of autochthonous origin. Ba was the element with the largest changes in concentrations since 1990 and the best tracer of mining activities near the lake. Sites KTB 02 and KTB 10 northwest of the lake showed the most distinct changes in element concentrations. Element enrichment factors (EF = 2.8, 4.2 and 3.2 respectively) demonstrated that Mn, Se and Ba have undergone a moderate enrichment in the lake since mining activities started. Ni, Cd and Se concentrations exceed sediment guidelines in some samples. No guideline is available for Ba, and special attention should be given to this element in this lake. This study demonstrated that Lake Kutubu oil/gas extraction activities are significant sources of elements to this lake and highlights the need for studies on the partitioning and speciation of elements to understand organism metal exposure., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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21. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata.
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Schmitz HA, Maher WA, Taylor AM, and Krikowa F
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- Animals, Heavy Metal Poisoning, Lipid Peroxidation drug effects, Lysosomes drug effects, Poisoning, Water Pollutants, Chemical toxicity, Cadmium metabolism, Cadmium toxicity, Geologic Sediments chemistry, Ostreidae drug effects, Ostreidae metabolism, Phytoplankton chemistry
- Abstract
Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93μg/g dry mass) and cadmium-enriched phytoplankton (1.6-3μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9±0.4μg/g and 23±2μg/g respectively compared to controls 0.97±0.05μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9±0.1μg/g compared to controls 1.2±0.1μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4-21μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
22. An evaluation of the use of reptile dermal scutes as a non-invasive method to monitor mercury concentrations in the environment.
- Author
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Schneider L, Eggins S, Maher W, Vogt RC, Krikowa F, Kinsley L, Eggins SM, and Da Silveira R
- Subjects
- Animals, Bone and Bones metabolism, Brazil, Environmental Pollutants pharmacokinetics, Fresh Water, Mass Spectrometry, Mercury pharmacokinetics, Muscle, Skeletal metabolism, Alligators and Crocodiles metabolism, Environmental Monitoring methods, Environmental Pollutants analysis, Epidermis metabolism, Keratins chemistry, Mercury analysis, Turtles metabolism
- Abstract
Reptiles are ideal organisms for the non-invasive monitoring of mercury (Hg) contamination. We have investigated Hg bioaccumulation in tissue layers of reptile dermis as a basis for establishing a standardized collection method for Hg analysis. Tissue samples from freshwater turtle species Podocnemis unifilis and Podocnemis expansa and caiman species Melanosuchus niger and Caiman crocodilus, all from the Amazonian region, were analysed in this study. We first tested the relationships between Hg concentrations in keratin and bone to Hg concentrations in muscle to determine the best predictor of Hg concentration in muscle tissue. We then investigated the potential for measuring Hg concentrations across turtle carapace growth rings as an indicator of longer term changes in Hg concentration in the environment. Hg concentrations were significantly lower in bone (120 ng g(-1) caimans and 1 ng g(-1) turtles) than keratin (3600 ng g(-1) caimans and 2200 ng g(-1) turtles). Keratin was found to be a better predictor of exposure to Hg than muscle and bone tissues for both turtles and caimans and also to be a reliable non-invasive tissue for Hg analysis in turtles. Measurement of Hg in carapace growth rings has significant potential for estimating Hg bioaccumulation by turtles over time, but full quantification awaits development and use of a matrix-matched reference material for laser ablation ICPMS analysis of Hg concentrations in keratin. Realising this potential would make a valuable advance to the study of the history of contamination in mining and industrial sites, which have until now relied on the analysis of Hg concentrations in sediments., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
23. History of metal contamination in Lake Illawarra, NSW, Australia.
- Author
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Schneider L, Maher W, Potts J, Batley G, Taylor A, Krikowa F, Chariton A, Zawadzki A, Heijnis H, and Gruber B
- Subjects
- Cesium Radioisotopes, Environmental Monitoring, Geologic Sediments analysis, Lead Radioisotopes, New South Wales, Arsenic analysis, Lakes chemistry, Metals, Heavy analysis, Water Pollutants, Chemical analysis
- Abstract
Lake Illawarra has a long history of sediment contamination, particularly by metals, as a result of past and current industrial operations and land uses within the catchment. In this study, we examined the history of metal contamination in sediments using metal analysis and (210)Pb and (137)Cs dating. The distributions of copper, zinc, arsenic, selenium, cadmium and lead concentrations within sediment cores were in agreement with historical events in the lake, and indicated that metal contamination had been occurring since the start of industrial activities in Port Kembla in the late 1800 s. Most metal contamination, however, has occurred since the 1960s. Sedimentation rates were found to be 0.2 cm year(-1) in Griffins Bay and 0.3 cm year(-1) in the centre of the lake. Inputs from creeks bringing metals from Port Kembla in the northeast of the lake and a copper slag emplacement from a former copper refinery on the Windang Peninsula were the main sources of metal inputs to Lake Illawarra. The metals of highest concern were zinc and copper, which exceeded the Australian and New Zealand sediment quality guideline values at some sites. Results showed that while historical contamination persists, current management practices have resulted in reduced metal concentrations in surface sediments in the depositional zones in the centre of the lake., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
24. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.
- Author
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Hug K, Maher WA, Stott MB, Krikowa F, Foster S, and Moreau JW
- Abstract
Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with increased sequences from Aquificaceae, supports a role for methyltransferase in thermophilic arsenic resistance. Our study highlights microbial contributions to coupled arsenic and sulfur cycling at Champagne Pool, with implications for understanding the evolution of microbial arsenic resistance in sulfidic geothermal systems.
- Published
- 2014
- Full Text
- View/download PDF
25. Bioavailability and toxicity of zinc from contaminated freshwater sediments: linking exposure-dose-response relationships of the freshwater bivalve Hyridella australis to zinc-spiked sediments.
- Author
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Marasinghe Wadige CP, Taylor AM, Maher WA, and Krikowa F
- Subjects
- Animals, Biological Availability, Biomarkers metabolism, Fresh Water, Gills drug effects, Gills metabolism, Hepatopancreas drug effects, Metallothionein metabolism, Water Pollutants, Chemical metabolism, Water Pollutants, Chemical toxicity, Bivalvia drug effects, Environmental Exposure, Geologic Sediments chemistry, Zinc metabolism, Zinc toxicity
- Abstract
To evaluate the use of the freshwater bivalve Hyridella australis as a potential biomonitor for zinc contamination in freshwater sediments, the bioavailability and toxicity of zinc contaminated sediments (low 44 ± 5, medium 526 ± 41, high 961 ± 38 μg/g dry mass) were investigated in laboratory microcosms for 28 days by examining H. australis exposure-dose-response relationships. Zinc concentrations in sediments and surface waters were measured as zinc exposure. Zinc in whole organism soft body tissues and five individual tissues were measured as organism zinc dose. Sub-cellular localisation of zinc in hepatopancreas tissues was investigated to further understand the zinc handling strategies and tolerance of H. australis. Total antioxidant capacity, lipid peroxidation and lysosomal membrane stability were measured in hepatopancreas tissues as zinc induced biomarker responses. Accumulated zinc concentrations in whole body tissues of H. australis reflected the zinc exposure and exhibited exposure dependent zinc accumulation at day 28. Gills accumulated significantly higher zinc concentrations than other tissues, however, no significant differences in zinc accumulation between treatments were detected for any of the individual tissues analysed. Analysis of individual tissue zinc concentrations, therefore, may not offer any advantages for monitoring bioavailable zinc in freshwater environments with this organism. Relationships between tissue zinc and calcium concentration suggest accumulation of zinc by H. australis may have occurred as an analogue of calcium which is a major constituent in shell and granules of unionid bivalves. A high percentage of accumulated zinc in the hepatopancreas tissues was detoxified and stored in metallothionein like proteins and metal rich granules. Of the zinc accumulated in the biologically active metal pool, 59-70% was stored in the lysosome+microsome fraction. At the concentrations tested, increasing zinc exposure resulted in decreasing total antioxidant capacity and measurable increases in the sublethal effects, lipid peroxidation and lysosomal membrane destabilisation, were observed. Based on exposure-dose analysis, H. australis partially regulates zinc uptake and weakly exhibits bioavailability of zinc in freshwater environments, however, exposure-response analysis shows zinc induced toxicological effects, suggesting the potential of this organism as a biomonitor for zinc in heavily contaminated freshwater environments., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
26. Exposure-dose-response relationships of the freshwater bivalve Hyridella australis to cadmium spiked sediments.
- Author
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Marasinghe Wadige CP, Maher WA, Taylor AM, and Krikowa F
- Subjects
- Animals, Bivalvia chemistry, Bivalvia metabolism, Fresh Water, Hepatopancreas chemistry, Hepatopancreas drug effects, Hepatopancreas metabolism, Bivalvia drug effects, Cadmium toxicity, Environmental Exposure, Geologic Sediments chemistry, Water Pollutants, Chemical toxicity
- Abstract
To understand how benthic biota may respond to the additive or antagonistic effects of metal mixtures in the environment it is first necessary to examine their responses to the individual metals. In this context, laboratory controlled single metal-spiked sediment toxicity tests are useful to assess this. The exposure-dose-response relationships of Hyridella australis to cadmium-spiked sediments were, therefore, investigated in laboratory microcosms. H. australis was exposed to individual cadmium spiked sediments (<0.05 (control), 4±0.3 (low) and 15±1 (high) μg/g dry mass) for 28 days. Dose was measured as cadmium accumulation in whole soft body and individual tissues at weekly intervals over the exposure period. Dose was further examined as sub-cellular localisation of cadmium in hepatopancreas tissues. The biological responses in terms of enzymatic and cellular biomarkers were measured in hepatopancreas tissues at day 28. H. australis accumulated cadmium from spiked sediments with an 8-fold (low exposure organisms) and 16-fold (high exposure organisms) increase at day 28 compared to control organisms. The accumulated tissue cadmium concentrations reflected the sediment cadmium exposure at day 28. Cadmium accumulation in high exposure organisms was inversely related to the tissue calcium concentrations. Gills of H. australis showed significantly higher cadmium accumulation than the other tissues. Accumulated cadmium in biologically active and biologically detoxified metal pools was not significantly different in cadmium exposed organisms, which suggests that H. australis has some tolerance to cadmium. The metallothionein like protein fraction played an important role in the sequestration and detoxification of cadmium and the amount sequestered in this fraction increased with increased cadmium exposure. The highest percentage of biologically active cadmium was associated with the lysosome+microsome and mitochondrial fractions. Cadmium concentrations in these two fractions of cadmium exposed organisms were significantly higher with respect to controls. Total antioxidant capacity decreased with increased cadmium exposure and tissue dose. Lipid peroxidation increased and lysosomal membrane stability decreased significantly with increased cadmium exposure and tissue dose. Based on exposure-dose-response analysis in this study, H. australis would be a suitable organism for assessing cadmium sediment exposure and toxicity., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
27. Effects of lead-spiked sediments on freshwater bivalve, Hyridella australis: linking organism metal exposure-dose-response.
- Author
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Marasinghe Wadige CP, Taylor AM, Maher WA, Ubrihien RP, and Krikowa F
- Subjects
- Animals, Calcium analysis, Dose-Response Relationship, Drug, Fresh Water, Lead analysis, Lead metabolism, Magnesium analysis, Regression Analysis, Tissue Distribution, Bivalvia drug effects, Environmental Exposure, Geologic Sediments chemistry, Lead toxicity, Soil Pollutants toxicity
- Abstract
Lead entering aquatic ecosystems adsorbs to sediments and has the potential to cause adverse effects on the health of benthic organisms. To evaluate the freshwater bivalve Hyridella australis as a bioindicator for sediment toxicity, their exposure-dose and response to lead contaminated sediments (< 0.01, 205 ± 9 and 419 ± 16 μg/g dry mass) was investigated in laboratory microcosms using 28 day exposures. Despite high concentrations of lead in the sediments, organisms accumulated low concentrations of lead in their tissues after 28 days of exposure (low treatment: 2.2 ± 0.2 μg/g dry mass, high treatment: 4.2 ± 0.1 μg/g dry mass), however, accumulated lead concentrations in lead exposed organisms were two fold (low treatment) and four fold (high treatment) higher than that of unexposed organisms (1.2 ± 0.3 μg/g dry mass). Accumulation of lead by H. australis may have occurred as analogues of calcium and magnesium. Labial palps accumulated significantly more lead than other tissues. Of the lead accumulated in the hepatopancreas, 83%-91% was detoxified and stored in metal rich granules. The proportions and concentrations of lead in this fraction increased with lead exposure, which suggests that lead detoxification pathway plays an important role in metal tolerance of H. australis. The biologically active lead was mainly present in the mitochondrial fraction which increased with lead exposure. Total antioxidant capacity of H. australis significantly decreased while lipid peroxidation and lysosomal membrane destabilation increased with lead exposure. This study showed a clear lead exposure-dose-response relationship and indicates that H. australis would be a good biomonitor for lead in freshwater ecosystems., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
28. Arsenoriboside degradation in marine systems: the use of bacteria culture incubation experiments as model systems.
- Author
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Duncan EG, Maher WA, Foster SD, Mikac KM, Krikowa F, and Florance A
- Subjects
- Arsenicals analysis, Arsenicals metabolism, Bacteria metabolism, Biodegradation, Environmental, Culture Media, Plants metabolism, Seawater microbiology, Water Pollutants, Chemical analysis, Water Pollutants, Chemical metabolism, Arsenicals chemistry, Seawater chemistry, Water Pollutants, Chemical chemistry
- Abstract
Arsenoribosides (as glycerol; phosphate; sulfate and sulfonate) persisted in all bacteria-inoculated cultures irrespective of the source of bacteria (seawater, macro-algae surface) or the culture media used (DIFCO Marine Broth 2216 or novel blended Hormosira banksii tissue-based). This is unlike observations from traditional macro-algae tissue decomposition studies or in nature. In addition known arsenoriboside degradation products such as dimethylarsenoethanol (DMAE), dimethylarsenate (DMA), methylarsenate (MA) and arsenate - As(V) were not detected in any cultures. Consequently, the use of bacterial culture incubation experiments to explain the fate of arsenoribosides in marine systems appears limited as the processes governing arsenoriboside degradation in these experiments appear to be different to those in macro-algae tissue decomposition studies or in nature., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
29. Increased selenium concentrations in seronorm trace elements serum (level 2).
- Author
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Townsend A, Featherstone A, Chéry CC, Vanhaecke F, Kirby J, Krikowa F, Maher B, Jacobson G, and Peterson G
- Subjects
- Humans, Mass Spectrometry methods, Quality Control, Reference Standards, Selenium standards, Serum, Spectrophotometry, Atomic, Reagent Kits, Diagnostic standards, Selenium blood
- Published
- 2004
- Full Text
- View/download PDF
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