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1.
Biometals ; 36(5): 943-960, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-36749495

RESUMO

Potentially toxic constituents in traditional medicines remain a concern due to health risks posed to consumers. Thirty-six traditional medicines (TM) consisting of 14 Indian Ayurvedic Medicines, 11 Chinese Traditional Medicines and eleven Ghanaian Traditional Medicines were evaluated using Total Reflection X-ray Fluorescence Spectrometer (T-XRF) after microwave assisted acid digestion. Physiologically Based Extraction Test (PBET) was used to obtain bioaccessible elemental concentrations. Merck XVI multi-element standard were used to evaluate the accuracy of the analytical method. The concentrations of the elements were quantified in (mg kg-1): Cr (0.01-698), Mn (0.01-1140), Fe (15-73300), Ni (1-1340), Cu (3-8160), Zn (0.01-224). The greatest bioaccessible concentrations of arsenic was 0.80 mg kg-1 and 0.44 mg kg-1 in the gastric and intestinal phases respectively. In order to evaluate the human health risks from ingesting these TM, the Acceptable Daily Intake (ADI) was calculated for each medicine based on element-specific bioaccessibility-adjusted concentrations and results compared with the United States Environmental Protection Agency (USEPA) Reference Dose (RfD) limits. The Acceptable Daily Intake (ADI) values for risks were within the USEPA RfD. Hazard quotients (HQ) of TM were < 1, meaning elemental concentrations do not pose non-carcinogenic risks to adult consumers. In summary the methods applied in the study gives a new insight on human health risks of potentially toxic and essential micronutrients elements in TM.


Assuntos
Arsênio , Metais Pesados , Oligoelementos , Estados Unidos , Adulto , Humanos , Micronutrientes , Gana , Arsênio/toxicidade , Oligoelementos/análise , Medição de Risco/métodos
2.
Chemosphere ; 286(Pt 3): 131899, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426292

RESUMO

Characterizing the distribution of biota in response to contaminants is a critical element of site risk assessments. In this study we investigated the spatial distributions of biota and soil chemistry data in surface soil from Sunny Corner, a legacy base metal sulfide mine, Australia. Our results showed that copper (Cu), zinc (Zn), arsenic (As) and lead (Pb) in the surface soil exceeded Australian national soil quality guidelines and posed risks to the environment. Environmental (e)DNA metabarcoding of prokaryote and eukaryote composition confirmed the suggestion of environmental risk posed by these elements collectively explaining 72.9 % and 60.5 % of the total variation in the composition of soil prokaryotes and eukaryotes, respectively. Prokaryotic taxa from the phyla Gemmatimonadetes, Verrucomicrobia and Deinococcus-Thermus showed similar spatial patterns to As and Pb, and were positively correlated. Eukaryotic taxa from the phylum Chlorophyta had similar positive correlations with As and Pb in the soil. In contrast, Amoebozoa and Cercozoa, were sensitive to metals and metalloids, having higher relative abundances in soils with lower concentrations of contaminants. Our study shows that metabarcoding is a promising ecological approach for rapid, large scale assessment of contaminated and potentially impacted sites.


Assuntos
DNA Ambiental , Metais Pesados , Poluentes do Solo , Austrália , Biota , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise
3.
J Hazard Mater ; 419: 126483, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34216969

RESUMO

Mining and processing metalliferous ores can degrade the environment well beyond the footprint of the mine, particularly where on-site containment and post-mining remediation has been insufficient to prevent releases of solid and aqueous mine wastes. In this study, we investigated the potential of sediment and water chemistry coupled with environmental (e)DNA metabarcoding to evaluate discrete and cumulative ecological impacts of two legacy base metal (copper (Cu), zinc (Zn), lead (Pb)) mines (Peelwood and Cordillera) which discharge metals via ephemeral tributaries into perennial Peelwood Creek. Although the two mine streams exceeded Australian guidelines for sediment and freshwater quality for Cu, Zn and Pb, Peelwood Creek had relatively low sediment and water metal concentrations, suggesting a low potential for environmental toxicity. Although sediment and water chemistry defined the extent of biological impacts, metabarcoding showed that Peelwood and Cordillera mines had discrete impacts and Peelwood mine was the main source of contamination of Peelwood Creek. Metabarcoding showed that prokaryotes can be good indicators of metal contamination whereas eukaryotes did not reflect contamination impacts in Peelwood Creek. Metabarcoding results showed that benthic communities downstream of Cordillera mine were less impacted than those below Peelwood mine, suggesting that Peelwood mine should be considered for further remediation.


Assuntos
DNA Ambiental , Metais Pesados , Poluentes Químicos da Água , Austrália , Monitoramento Ambiental , Metais Pesados/análise , Metais Pesados/toxicidade , Mineração , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
4.
Environ Int ; 155: 106582, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33940394

RESUMO

We launched the VegeSafe program in 2013 to assist Australians concerned about exposure to contaminants in their soils and gardens. VegeSafe analyses garden soils provided by citizens for trace metals at our laboratory at little to no cost, with easy-to-follow guidance on any intervention required. The response was overwhelming-Australians submitted 17,256 soils from 3,609 homes, and in turn VegeSafe researchers now have unparalleled household-scale data, providing new insights into urban trace metal contamination. The results are sobering, with 35% of homes, particularly those that are older, painted and located in inner cities having soils above the Australian residential guideline (300 mg/kg) for the neurotoxic trace metal lead (Pb). Exposure pathway, blood Pb concentration and vegetable uptake modelling showed the communities in these locations were most at risk. VegeSafe is transformative: 94% of participants better understood contaminants, 83% felt safer in their home environment and 40% undertook remedial action based on their results. The two-way nature of this program enables education of citizens about environmental contaminants, advances public health, and delivers impactful science.


Assuntos
Ciência do Cidadão , Metais Pesados , Poluentes do Solo , Austrália , Cidades , Monitoramento Ambiental , Jardins , Humanos , Metais Pesados/análise , Solo , Poluentes do Solo/análise
5.
J Hazard Mater ; 416: 125794, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-33862483

RESUMO

Acid Rock Drainage (ARD) from legacy mines can negatively impact the biota in sediments and waters for tens of kilometers downstream. Here we used environmental (e)DNA metabarcoding to assess the impacts of metal contaminants on biota in sediment and water downstream of a legacy base metal sulfide mine in southeastern Australia, as exemplar of similar mines elsewhere. Concentrations of metals in water were below Australian water quality guideline values at 20 km downstream for copper (Cu), 40 km downstream for zinc (Zn) and 10 km downstream for lead (Pb). Sediment metal concentrations were below national guideline concentrations at 10 km downstream for Cu, 60 km downstream for Zn and 20 km downstream for Pb. In contrast, metabarcoding showed that biological communities from sediment samples at 10 km and 20 km downstream were similar to sites close to the mine and thus indicative of being impacted, despite metal concentrations being relatively low. As we illustrate, when combined with sediment and water chemistry, metabarcoding can provide more ecological robust perspective on the downstream effects of legacy mines, capturing the sensitivities of a diverse range of organisms.


Assuntos
DNA Ambiental , Metais Pesados , Poluentes Químicos da Água , Austrália , Monitoramento Ambiental , Sedimentos Geológicos , Metais Pesados/análise , Metais Pesados/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
6.
Chemosphere ; 269: 128675, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33657749

RESUMO

Metal contaminants in Antarctic soils are typically found around research stations which are concentrated in ice-free coastal areas. The risk of these contaminants to the Antarctic environment is not well understood, given Antarctica's unique organisms and climate. This study assessed the use of diffusive gradients in thin-films (DGT), a passive sampler that measures fluxes of labile metals from soils to porewaters, in Antarctic soils. DGT-labile measurements were compared to three chemical extractants of increasing strength including high-purity water, dilute acid (1 M HCl), and concentrated acids (3:1 v/v HNO3:HCl), to understand differences in contaminant geochemistry that may affect environmental risk. One site had high lead concentrations measured with dilute (114 ± 4 mg kg-1) and concentrated (150 ± 10 mg kg-1) acids, while DGT-labile concentrations were below the method detection limit (0.5 µg L-1), indicating that the lead species has low solubility or lability. Another site had low concentrations of zinc measured by dilute (36.2 ± 0.5 mg kg-1) or concentrated (76 ± 6 mg kg-1) acid extracts, but had high DGT-labile concentrations (350 ± 80 µg L-1). This reflects an active source of zinc supplied from soil to pore water over time. Copper was found to be acid extractable, water-soluble, and DGT-labile, with DGT-labile concentrations of up to 12 µg L-1. Despite the soil and metal-specific geochemical differences, any of the extracts could be used with statistical clustering techniques to identify differences in sites with elevated metal concentrations. This study shows that the DGT-method can identify contaminated sites comparably to chemical extracts but provides environmentally relevant measurements of metal contaminant lability in Antarctic soils.


Assuntos
Poluentes do Solo , Solo , Regiões Antárticas , Monitoramento Ambiental , Poluentes do Solo/análise , Zinco/análise
7.
Environ Pollut ; 274: 116537, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33529902

RESUMO

Most legacy mines contributed to contamination of the environment before and after cessation of mining. Contamination from waste rock, slag and tailings can introduce large concentrations of metals and metalloids to the surface soil and downstream sediments. Since ants are able to accumulate metals in their bodies, we investigated the possibility of using the elemental compositions of ants as indicators of metals at legacy mines developed on ores rich in copper (Cu), zinc (Zn), arsenic (As), silver (Ag) and lead (Pb). Our results showed the concentrations of manganese (Mn) and Cu in ants were not significantly different between mine and reference samples and only Zn was significantly different between contaminated and reference areas. Crematogaster spp. and Notoncus spp. from reference areas accumulated larger concentrations of metals in their bodies compared to ants from the mine. Ants accumulated metals in different parts of their bodies. The abdomen was the main site for accumulation of Mn, iron (Fe) and Zn. Mandibles were only associated with accumulation of Zn. Copper and Pb showed no area of preferential accumulation and traces were detected in the whole body of the ants. Ants from five genera had similar regions for metal accumulation. The exoskeleton did not contribute to accumulation of metals; instead all metals were stored in internal organs. Not all genera were suitable for use as indicators; only Iridomyrmex spp. and Ochetellus spp. accumulated larger amount of metals in mine samples compared to reference samples.


Assuntos
Formigas , Metais Pesados , Poluentes do Solo , Animais , Monitoramento Ambiental , Metais Pesados/análise , Mineração , Poluentes do Solo/análise
8.
Vet Med Sci ; 7(1): 240-250, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32776458

RESUMO

The carcass of a critically endangered, juvenile female grey nurse shark (Carcharias taurus, Rafinesque 1810) was recovered from a south-eastern Australian beach and subjected to necropsy. The 1.98-m-long shark exhibited advanced cachexia with its total weight (19.0 kg) and liver weight (0.37 kg) reduced by 60% and 89%, respectively, compared with a healthy individual of the same length. Marked tissue decomposition was evident preventing histopathology and identification of a definitive cause of death. At necropsy, the abdominal organs were abnormally displaced and showed marked reductions in size compared with a healthy individual of the same size. Importantly, a hook-shaped enterolith (HSE), with a rough surface and cream in colour, was found within the spiral valve of the intestine and is to the authors' knowledge, the first description of such in any marine animal. X-ray diffractometry showed that the HSE comprised the minerals monohydrocalcite (Ca[CO3].H2O; ~70 wt%) and struvite (Mg [NH4 ] [PO4 ]. [H2 O]6 ; ~30 wt%). A CT scan showed concentric lamellate concretions around a 7/o offset J-hook that formed the nidus of the HSE. Nylon fishing line attached to the hook exited the HSE and was evident in the abdominal cavity through a perforation in the intestinal wall where the posterior intestinal artery merges. The most parsimonious reconstruction of events leading to enterolithiasis and secondary cachexia in this shark was the consumption of a hooked fish and subsequent hook migration causing perforations of the cardiac stomach wall followed by the thin, muscular wall of the apposed, sub-adjacent intestine.


Assuntos
Caquexia/diagnóstico , Cálculos/complicações , Doenças dos Peixes/diagnóstico , Tubarões , Animais , Caquexia/etiologia , Caquexia/patologia , Cálculos/diagnóstico , Cálculos/etiologia , Cálculos/patologia , Feminino , Doenças dos Peixes/etiologia , Doenças dos Peixes/patologia , New South Wales
9.
Environ Pollut ; 273: 115742, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33545618

RESUMO

Environmental impacts associated with mining can be important even after cessation of ore extraction, particularly where sites are abandoned and unremediated. Acid Mine Drainage (AMD) is a common concern in such legacy mines where sulfide ores were extracted. AMD can introduce large concentrations of heavy metals to aquatic systems and contaminate the environment for many kilometres downstream of old mines. Understanding the pattern and history of contamination from legacy mines can help environmental managers make better management decisions. Meta-analysis is a statistical tool that can help determine the significance of changes in metal contamination over the years since cessation of mining. Here we use meta-analysis to examine metal contamination at and downstream of Sunny Corner silver (Ag)-lead (Pb)-zinc (Zn) mine in eastern Australia. Copper (Cu), Zn and Pb concentrations in water increased from 1978 to 2018 within 2 km downstream of the main mine adit, whereas for stream sediment, only Zn concentrations increased significantly over the same period. In contrast, Pb concentrations in surface soil decreased over the years from 2000 to 2018.

10.
PLoS One ; 14(5): e0210231, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31063495

RESUMO

Human driven changes such as increases in oceanic CO2, global warming, petroleum hydrocarbons and heavy metals may negatively affect the ability of marine calcifiers to build their skeletons/shells, especially in polar regions. We examine spatio-temporal variability of skeletal Mg-calcite in shallow water Antarctic marine invertebrates using bryozoan and spirorbids as models in a recruitment experiment of settlement tiles in East Antarctica. Mineralogies were determined for 754 specimens belonging to six bryozoan species (four cheilostome and two cyclostome species) and two spirorbid species from around Casey Station. Intra- and interspecific variability in wt% MgCO3 in calcite among most species was the largest source of variation overall. Therefore, the skeletal Mg-calcite in these taxa seem to be mainly biologically controlled. However, significant spatial variability was also found in wt% MgCO3 in calcite, possibly reflecting local environment variation from sources such as freshwater input and contaminated sediments. Species with high-Mg calcite skeletons (e.g. Beania erecta) could be particularly sensitive to multiple stressors under predictions for near-future global ocean chemistry changes such as increasing temperature, ocean acidification and pollution.


Assuntos
Organismos Aquáticos/metabolismo , Carbonato de Cálcio/metabolismo , Magnésio/metabolismo , Esqueleto/metabolismo , Regiões Antárticas , Geografia , Análise Espaço-Temporal
11.
Environ Pollut ; 237: 851-857, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29150255

RESUMO

Contamination of soils by metals and metalloids is an important environmental problem in many residential and industrial sites around the world. Lead is a common contaminant, which enters the soil through mining, industrial activities and waste disposal. A range of technologies can be used to remediate soil lead, however most remediation technologies adversely affect the environment and particularly soil biota. We have assessed the efficacy of vermiremediation (the use of earthworms for remediation) to reduce water extractable lead concentrations in soil. Earthworms were introduced to a sandy soil spiked with the common lead minerals cotunnite (PbCl2), cerussite (PbCO3), massicot (PbO) or galena (PbS) at 1000 mg (Pb) kg-1. Lead concentrations in pore water extracted during the experiment were not significantly different in contaminated soil with and without worms. However, concentrations of lead in water from a deionised water extraction (washing) of contaminated soil were significantly lower in soil with earthworms than in soil without. Earthworms accumulated on average (±1 standard deviation) 276 ± 118, 235 ± 66, 241 ± 58 and 40 ± 30 mg kg-1 (dry weight of earthworms) of lead in their bodies, in PbCl2, PbCO3, PbO and PbS-dosed soils, respectively. During the experiment, earthworms lost weight in all contaminated soils, except those containing PbS.


Assuntos
Chumbo/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Animais , Biota , Carbonatos/toxicidade , Metaloides , Minerais , Oligoquetos/efeitos dos fármacos , Solo , Poluentes do Solo/análise , Sulfetos/toxicidade , Testes de Toxicidade , Água
12.
PLoS One ; 12(6): e0179029, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28582427

RESUMO

The Talbragar Fish Bed is one of Australia's most important Jurassic deposits for freshwater fishes, land plants and aquatic and terrestrial insects. The site has yielded many well preserved fossils, which has led to the formal description of numerous new species and higher taxa. The excellent preservation of many fossils has allowed detailed anatomical studies, e.g. of the early teleost fish Cavenderichthys talbragarensis (Woodward, 1895). Here we report on the fluorescent characteristics and mineral composition of a range of Talbragar fossils. Most specimens fluoresce under ultraviolet, blue and green light. Elemental and mineralogical analyses revealed that the Talbragar fossils consist predominantly of quartz (SiO2), a mineral that is likely to account for the observed fluorescence, with trace kaolinite (Al2Si2O5(OH)4) in some of the fish fossils. Rock matrices are predominantly composed of quartz and goethite (FeO(OH)). Closer inspection of a plant leaf (Pentoxylon australicum White, 1981) establishes fluorescence as a useful tool for the visualisation of anatomical details that are difficult to see under normal light conditions.


Assuntos
Peixes/anatomia & histologia , Fósseis , Insetos/anatomia & histologia , Folhas de Planta/anatomia & histologia , Plantas/anatomia & histologia , Animais , Austrália , Evolução Biológica , História Antiga , Insetos/química , Compostos de Ferro/análise , Compostos de Ferro/química , Compostos de Ferro/história , Caulim/análise , Caulim/química , Caulim/história , Medições Luminescentes , Metais Pesados/análise , Metais Pesados/química , Metais Pesados/história , Minerais/análise , Minerais/química , Minerais/história , Folhas de Planta/química , Plantas/química , Quartzo/análise , Quartzo/química , Quartzo/história , Espectrometria de Fluorescência
13.
Appl Spectrosc ; 70(5): 840-51, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27044848

RESUMO

Transportable energy dispersive X-ray fluorescence (XRF) spectrometers allow the elemental composition of coins to be measured at collections, enhancing security while maximizing access to historically important material. We assessed 10 silver coins, using five XRF spectrometers. We found no systematic differences between analyses using Mo- and Rh-anode tubes, and no substantial advantage using He flush over air for elements heavier than Ti. Higher voltage X-ray tubes enhanced analytical precision. Understanding patina composition made a numerical correction possible, allowing an approximation of the underlying coin metal with good results for metals including Cu, Ag, Au, Pb, and Bi.

14.
Appl Spectrosc ; 69(7): 815-22, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26037330

RESUMO

This study investigates X-ray intensity and dispersion around handheld X-ray fluorescence (XRF) instruments during the measurement of a range of sample matrices to establish radiation exposure risk during operation. Four handheld XRF instruments representing three manufacturers were used on four smooth, flat-lying materials of contrasting matrix composition. Dose rates were measured at 10, 20, 30, and 40 cm intervals every 30° around the instrument at 0 and 45° from the horizontal, as well as vertically from the instrument screen. The analysis of polyethylene recorded dose rates 156 times higher (on average) than steel measurements and 34 times higher than both quartz sand and quartz sandstone. A worst-case exposure scenario was assumed where a user analyses a polyethylene material at arms reach for 1 h each working day for one year. This scenario resulted in an effective body dose of 73.5 µSv, equivalent to three to four chest X-rays (20 µSv) a year, 20 times lower than the average annual background radiation exposure in Australia and well below the annual exposure limit of 1 mSv for non-radiation workers. This study finds the advantages of using handheld XRF spectrometers far outweighs the risk of low radiation exposure linked to X-ray scattering from samples.


Assuntos
Exposição Ocupacional/análise , Exposição à Radiação/análise , Espectrometria por Raios X/instrumentação , Desenho de Equipamento , Humanos , Risco , Espalhamento de Radiação , Raios X
15.
Environ Sci Pollut Res Int ; 22(14): 10981-1000, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25783163

RESUMO

This paper reviews the environmental problems, impacts and risks associated with the generation and disposal of produced water by the emerging coal seam gas (CSG) industry and how it may be relevant to Australia and similar physical settings. With only limited independent research on the potential environmental impacts of produced water, is it necessary for industry and government policy makers and regulators to draw upon the experiences of related endeavours such as mining and groundwater extraction accepting that the conclusions may not always be directly transferrable. CSG is widely touted in Australia as having the potential to provide significant economic and energy security benefits, yet the environmental and health policies and the planning and regulatory setting are yet to mature and are continuing to evolve amidst ongoing social and environmental concerns and political indecision. In this review, produced water has been defined as water that is brought to the land surface during the process of recovering methane gas from coal seams and includes water sourced from CSG wells as well as flowback water associated with drilling, hydraulic fracturing and gas extraction. A brief overview of produced water generation, its characteristics and environmental issues is provided. A review of past lessons and identification of potential risks, including disposal options, is included to assist in planning and management of this industry.


Assuntos
Resíduos Industriais , Campos de Petróleo e Gás , Eliminação de Resíduos Líquidos/métodos , Austrália , Carvão Mineral , Água Subterrânea , Gás Natural , Poluentes da Água
16.
Environ Pollut ; 175: 168-77, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23428086

RESUMO

Freeze-thaw cycling may influence the chemistry, mineral stability and reaction rate during metal orthophosphate fixation. This study assessed the formation and stability of Cu-, Pb-, and Zn-phosphates in chemically simple laboratory systems during 240 freeze-thaw cycles (120 days) from +10 to -20 °C, using X-ray diffractometry. In single heavy metal systems, chloro- and hydroxy-pyromorphite (Pb(5)(PO(4))(3)(Cl,OH)), sodalite (Na(6)Zn(6)(PO(4))(6)·8H(2)O), chiral zincophosphate (Na(12)(Zn(12)P(12)O(48))·12H(2)O), and copper phosphate hydrate (Cu(3)(PO(4))(2)·3H(2)O) were the primary phosphate minerals that formed, and were typically stable during the experiment. Zinc and Cu-phosphate formation was reduced in multi heavy metal systems, and was substantially lower in abundance than chloropyromorphite. Successful Cu-, Pb- and Zn-phosphate formation can be expected in cold and freezing environments like the polar regions. However, field implementation of orthophosphate fixation needs to consider competing ion effects, concentration of the phosphate source, and the amount of free-water.


Assuntos
Metais Pesados/química , Fosfatos/química , Poluentes do Solo/química , Congelamento , Cinética , Metais Pesados/análise , Minerais/análise , Minerais/química , Modelos Químicos , Fosfatos/análise , Poluentes do Solo/análise , Temperatura
17.
Environ Pollut ; 161: 143-53, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22230079

RESUMO

Low temperatures and frequent soil freeze-thaw in polar environments present challenges for the immobilisation of metals. To address these challenges we investigated the chemical forms of Pb, Zn and Cu in an Antarctic landfill, examined in vitro reaction kinetics of these metals and orthophosphate at 2 and 22 °C for up to 185 days, and subjected the products to freeze-thaw. Reaction products at both temperatures were similar, but the rate of production varied, with Cu-PO(4) phases forming faster, and the Zn- and Pb-PO(4) phases slower at 2 °C. All metal-orthophosphate phases produced were stable during a 2.5 h freeze-thaw cycle to -30 °C. Metal immobilisation using orthophosphate can be successful in polar regions, but treatments will need to consider differing mineral stabilities and reaction rates at low temperatures.


Assuntos
Poluentes Ambientais/química , Metais Pesados/química , Transição de Fase , Fosfatos/química , Regiões Antárticas , Regiões Árticas , Cobre/análise , Cobre/química , Poluentes Ambientais/análise , Chumbo/análise , Chumbo/química , Metais Pesados/análise , Modelos Químicos , Fosfatos/análise , Compostos de Zinco/análise , Compostos de Zinco/química
18.
Environ Pollut ; 159(12): 3496-503, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21907472

RESUMO

Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H(2)PO(4))(2)] or sodium phosphate [Na(3)PO(4)]) reacts with lead (PbSO(4) or PbCl(2)) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 °C to -20 °C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO(4) and Na(3)PO(4) were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate.


Assuntos
Difosfatos/química , Chumbo/química , Minerais/química , Fosfatos/química , Congelamento
19.
Environ Sci Technol ; 42(11): 4088-92, 2008 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-18589970

RESUMO

Potentially toxic substances in electrical and electronic equipment are increasingly regulated, yet there is little guidance regarding appropriate sample preparation and analysis for compliance testing. Printed circuit boards are likely to contain regulated substances. Unfortunately, they are very difficult to break into homogeneous components of a mass allowing ready analysis by X-ray fluorescence (XRF) spectrometry, instrumental neutron activation analysis or dissolution-based techniques such as inductively coupled plasma, yet they must be analyzed despite this heterogeneity. Analysis of unprepared samples of circuit board using microspot, hand-held, benchtop and polarizing XRF spectrometers results in unacceptable analytical precision. Shredding samples to < 0.5 mm improves analytical precision sufficientlyfor RoHS compliance screening. To improve analytical precision further, additional sample preparation by fine shredding or milling is required. Milling for 90 s using a puck and ring mill reduces mean particle size to < 90 microm, which is sufficiently fine for XRF analyses or acid dissolution. Sample loss during milling means that fine shredding is probably an optimal form of sample preparation.


Assuntos
Cádmio/análise , Cromo/análise , Eletrônica , Substâncias Perigosas/análise , Chumbo/análise , Telefone Celular , Espectrometria por Raios X/instrumentação , Espectrometria por Raios X/métodos
20.
J Environ Monit ; 10(1): 60-70, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18175018

RESUMO

The remediation of the Thala Valley landfill, Casey Station, East Antarctica, is part of efforts to clean-up contaminated sites associated with the Australian Antarctic Program. These sites, ranging from abandoned rubbish dumps to fuel spills, are contaminated principally with metals and petroleum hydrocarbons. Remediation success depends on accurate, cost-effective and timely--fit-for-purpose--chemical analysis of soil and water samples from the site, which is required to guide excavation, the in situ or off-site treatment and disposal of contaminated material, and to validate satisfactory remediation. Owing to the remote location of Antarctica, it is necessary to carry out chemical analyses on-site. Waste and soil contaminated with Pb, Zn, Cd, and Cu were excavated from Thala Valley for removal to Australia, treatment and disposal. Analysis of total metal concentrations in soil was performed at Casey Station with a transportable energy dispersive X-ray fluorescence (EDXRF) spectrometer. Soil samples were prepared using a simple size-fractionation method to expedite sample throughput. A method for assessing contaminant mobility in solid waste (toxicity characteristic leaching procedure, TCLP) was also used to characterise soil. Although this was more labour-intensive and time-consuming than the total metals analysis, it was of great utility because leachable metals were often significant determinants in the assessment of contaminated soil. The combined data helped managers during remediation, directing excavation and allowing waste to be classified for treatment and disposal before its return to Australia.


Assuntos
Arsênio/análise , Metais/análise , Poluentes do Solo/análise , Regiões Antárticas , Monitoramento Ambiental , Eliminação de Resíduos , Espectrometria por Raios X , Gerenciamento de Resíduos , Poluentes Químicos da Água/análise
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