The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Claire J Horwell - One of the best experts on this subject based on the ideXlab platform.
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particulate matter produced during commercial sugarcane harvesting and processing a respiratory Health Hazard
Atmospheric Environment, 2017Co-Authors: Claire J Horwell, Jennifer Le S Blond, Susan R Woskie, B J WilliamsonAbstract:Emissions from sugarcane burning are known to impact on the respiratory Health of sugar estate workers and local populations. Despite this, there have been few studies on occupational and ambient exposures and risks from airborne particulate matter (PM) associated with field burning and ash re-suspension. From workplace monitoring on sugarcane estates in two different South American countries in 2010 and 2011, median concentrations of airborne PM10 (particulate matter nominally <10 μm in diameter) were found to be statistically much higher during pre-harvest sugarcane burning (1807 μg m−3) than during either sugarcane cutting after burning (∼123 μg m−3) or in the sugarcane processing factory (∼175 μg m−3). Median PM10 measurements in ambient scenarios, for example in the sugarcane fields before the burning or during 24 h measurements in neighboring villages (bordering the sugarcane plantation), were much lower, between 18 and 37 μg m−3. From the analysis of size-selective samples of airborne PM10, collected during sugarcane field burning, cutting and ambient periods, almost all (∼96 wt %) fell within the ‘respirable’ fraction (<4 μm aerodynamic diameter), with a mass median aerodynamic diameter (MMAD) of 1.1 μm. Residual ash from field and bagasse burning, characterised using Scanning Electron Microscopy (SEM) with X-ray elemental analysis, was found to contain carbonaceous and silicate-dominated particles in the PM0.5 and PM0.5-2.5 size ranges and fibres from <10 to over 50 μm in length. Only a small proportion of the field burning ash (average 0.6 vol %) and bagasse ash (average 1.3 vol %) was in the respirable fraction. However, from grinding experiments, which simulate disaggregation as a result of disturbance during harvest or bagasse ash removal, the ash was fragile and easily broken down into thoracic particulate (<10 μm aerodynamic diameter) and, in some instances, created respirable-sized PM. From exposure calculations, the 8 h time weighted average (TWA) concentrations of PM10, during the different measurement scenarios, were found to be below occupational exposure limits (OELs; 5000 μg m−3 for respirable PM). Ambient PM10 exposure of residents surrounding the sugarcane plantations was found to be below the WHO air quality guideline (50 μg m−3 as a 24 h mean). The relative risk calculated for ‘all cause’ mortality from exposure of nearby residents to PM10 generated by sugarcane burning was found to be 3%. The concentrations of PM10 produced during the processing of sugarcane were high (up to 21.5 mg m−3), which is concerning given that re-suspended particles of ash in the fields and processing plant have been previously shown to contain potentially toxic cristobalite. PM produced during sugarcane burning, and during extended periods of local exposure to the smoke and re-suspended ash, therefore, should be considered as both a potential acute and chronic respiratory Health Hazard. This issue will become increasingly important with the forecasted rise in sugarcane production for biofuels.
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the respiratory Health Hazard of tephra from the 2010 centennial eruption of merapi with implications for occupational mining of deposits
Journal of Volcanology and Geothermal Research, 2013Co-Authors: David E Damby, Claire J Horwell, Peter J. Baxter, Bice Fubini, Pierre Delmelle, Christina Dunster, Ken Donaldson, F Murphy, C Nattrass, S SweeneyAbstract:Ashfall into heavily populated areas during the October–November 2010 eruption of Merapi volcano, Indonesia created anxiety regarding the growing impacts to Health as the eruption escalated and the Hazard zone widened. We made a preliminary assessment of the respiratory Hazards to human Health of the tephra deposits (ashfall, lahar, and PDC surge) from the eruption using a laboratory protocol specifically developed to study the toxic potential of volcanic ash particles. Twenty samples collected from a range of locations were analysed for Health-pertinent mineralogical parameters (grain size, crystalline silica content, morphology, surface area, bulk chemistry, and leachable elements) and bio-reactivity (hydroxyl radical generation, haemolytic potential, oxidative capacity, pro-inflammatory response). The grain size pertinent to respiratory Health was variable, ranging from 1.4–15.6 vol.% sub-4 μm and 3.0–28.9 vol.% sub-10 μm diameter material. No fibre-like particles were observed. Cristobalite was present in all samples, ranging from 1.9–9.5 wt.%, but surface reactivity and in vitro toxicity assays showed low reactivity for all samples tested. The risk of direct exposure to ash from fallout was in any case low due to seasonal rains limiting its re-suspension and the immediate and effective clean-up of communities by local people who supplied the ash to the Indonesian construction industry for use as aggregate. However, mining of the lahar and thick PDC deposits in the valleys draining the volcano is performed on a vast, industrial scale, which could result in high occupational exposure to thousands of sand miners at Merapi during the dry seasons. Further study of the Health Hazard of the mined Merapi deposits is warranted
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Mineralogical analyses and in vitro screening tests for the rapid evaluation of the Health Hazard of volcanic ash at Rabaul volcano, Papua New Guinea
Bulletin of Volcanology, 2010Co-Authors: Jennifer S. Blond, Claire J Horwell, Peter J. Baxter, Sabina A. K. Michnowicz, Maura Tomatis, Bice Fubini, Pierre Delmelle, Christina Dunster, Herman PatiaAbstract:The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory Health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public Health, we investigated the potential Health Hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy - andesitic ash comprised 2.1–6.7 vol.% respirable (sub - 4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre - like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO_4 (gypsum, at
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grain size analysis of volcanic ash for the rapid assessment of respiratory Health Hazard
Journal of Environmental Monitoring, 2007Co-Authors: Claire J HorwellAbstract:Volcanic ash has the potential to cause acute and chronic respiratory diseases if the particles are sufficiently fine to enter the respiratory system. Characterization of the grain-size distribution (GSD) of volcanic ash is, therefore, a critical first step in assessing its Health Hazard. Quantification of Health-relevant size fractions is challenging without state-of-the-art technology, such as the laser diffractometer. Here, several methods for GSD characterization for Health assessment are considered, the potential for low-cost measurements is investigated and the first database of Health-pertinent GSD data is presented for a suite of ash samples from around the world. Methodologies for accurate measurement of the GSD of volcanic ash by laser diffraction are presented by experimental analysis of optimal refractive indices for different magmatic compositions. Techniques for representative sampling of small quantities of ash are also experimentally investigated. GSD results for Health-pertinent fractions for a suite of 63 ash samples show that the fraction of respirable (<4 μm) material ranges from 0–17 vol%, with the variation reflecting factors such as the style of the eruption and the distance from the source. A strong correlation between the amount of <4 and <10 μm material is observed for all ash types. This relationship is stable at all distances from the volcano and with all eruption styles and can be applied to volcanic plume and ash fallout models. A weaker relationship between the <4 and <63 μm fractions provides a novel means of estimating the quantity of respirable material from data obtained by sieving.
Herman Patia - One of the best experts on this subject based on the ideXlab platform.
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Mineralogical analyses and in vitro screening tests for the rapid evaluation of the Health Hazard of volcanic ash at Rabaul volcano, Papua New Guinea
Bulletin of Volcanology, 2010Co-Authors: Jennifer S. Blond, Claire J Horwell, Peter J. Baxter, Sabina A. K. Michnowicz, Maura Tomatis, Bice Fubini, Pierre Delmelle, Christina Dunster, Herman PatiaAbstract:The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory Health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public Health, we investigated the potential Health Hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy - andesitic ash comprised 2.1–6.7 vol.% respirable (sub - 4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre - like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO_4 (gypsum, at
Christina Dunster - One of the best experts on this subject based on the ideXlab platform.
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the respiratory Health Hazard of tephra from the 2010 centennial eruption of merapi with implications for occupational mining of deposits
Journal of Volcanology and Geothermal Research, 2013Co-Authors: David E Damby, Claire J Horwell, Peter J. Baxter, Bice Fubini, Pierre Delmelle, Christina Dunster, Ken Donaldson, F Murphy, C Nattrass, S SweeneyAbstract:Ashfall into heavily populated areas during the October–November 2010 eruption of Merapi volcano, Indonesia created anxiety regarding the growing impacts to Health as the eruption escalated and the Hazard zone widened. We made a preliminary assessment of the respiratory Hazards to human Health of the tephra deposits (ashfall, lahar, and PDC surge) from the eruption using a laboratory protocol specifically developed to study the toxic potential of volcanic ash particles. Twenty samples collected from a range of locations were analysed for Health-pertinent mineralogical parameters (grain size, crystalline silica content, morphology, surface area, bulk chemistry, and leachable elements) and bio-reactivity (hydroxyl radical generation, haemolytic potential, oxidative capacity, pro-inflammatory response). The grain size pertinent to respiratory Health was variable, ranging from 1.4–15.6 vol.% sub-4 μm and 3.0–28.9 vol.% sub-10 μm diameter material. No fibre-like particles were observed. Cristobalite was present in all samples, ranging from 1.9–9.5 wt.%, but surface reactivity and in vitro toxicity assays showed low reactivity for all samples tested. The risk of direct exposure to ash from fallout was in any case low due to seasonal rains limiting its re-suspension and the immediate and effective clean-up of communities by local people who supplied the ash to the Indonesian construction industry for use as aggregate. However, mining of the lahar and thick PDC deposits in the valleys draining the volcano is performed on a vast, industrial scale, which could result in high occupational exposure to thousands of sand miners at Merapi during the dry seasons. Further study of the Health Hazard of the mined Merapi deposits is warranted
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Mineralogical analyses and in vitro screening tests for the rapid evaluation of the Health Hazard of volcanic ash at Rabaul volcano, Papua New Guinea
Bulletin of Volcanology, 2010Co-Authors: Jennifer S. Blond, Claire J Horwell, Peter J. Baxter, Sabina A. K. Michnowicz, Maura Tomatis, Bice Fubini, Pierre Delmelle, Christina Dunster, Herman PatiaAbstract:The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory Health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public Health, we investigated the potential Health Hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy - andesitic ash comprised 2.1–6.7 vol.% respirable (sub - 4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre - like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO_4 (gypsum, at
Peter J. Baxter - One of the best experts on this subject based on the ideXlab platform.
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the respiratory Health Hazard of tephra from the 2010 centennial eruption of merapi with implications for occupational mining of deposits
Journal of Volcanology and Geothermal Research, 2013Co-Authors: David E Damby, Claire J Horwell, Peter J. Baxter, Bice Fubini, Pierre Delmelle, Christina Dunster, Ken Donaldson, F Murphy, C Nattrass, S SweeneyAbstract:Ashfall into heavily populated areas during the October–November 2010 eruption of Merapi volcano, Indonesia created anxiety regarding the growing impacts to Health as the eruption escalated and the Hazard zone widened. We made a preliminary assessment of the respiratory Hazards to human Health of the tephra deposits (ashfall, lahar, and PDC surge) from the eruption using a laboratory protocol specifically developed to study the toxic potential of volcanic ash particles. Twenty samples collected from a range of locations were analysed for Health-pertinent mineralogical parameters (grain size, crystalline silica content, morphology, surface area, bulk chemistry, and leachable elements) and bio-reactivity (hydroxyl radical generation, haemolytic potential, oxidative capacity, pro-inflammatory response). The grain size pertinent to respiratory Health was variable, ranging from 1.4–15.6 vol.% sub-4 μm and 3.0–28.9 vol.% sub-10 μm diameter material. No fibre-like particles were observed. Cristobalite was present in all samples, ranging from 1.9–9.5 wt.%, but surface reactivity and in vitro toxicity assays showed low reactivity for all samples tested. The risk of direct exposure to ash from fallout was in any case low due to seasonal rains limiting its re-suspension and the immediate and effective clean-up of communities by local people who supplied the ash to the Indonesian construction industry for use as aggregate. However, mining of the lahar and thick PDC deposits in the valleys draining the volcano is performed on a vast, industrial scale, which could result in high occupational exposure to thousands of sand miners at Merapi during the dry seasons. Further study of the Health Hazard of the mined Merapi deposits is warranted
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Mineralogical analyses and in vitro screening tests for the rapid evaluation of the Health Hazard of volcanic ash at Rabaul volcano, Papua New Guinea
Bulletin of Volcanology, 2010Co-Authors: Jennifer S. Blond, Claire J Horwell, Peter J. Baxter, Sabina A. K. Michnowicz, Maura Tomatis, Bice Fubini, Pierre Delmelle, Christina Dunster, Herman PatiaAbstract:The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory Health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public Health, we investigated the potential Health Hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy - andesitic ash comprised 2.1–6.7 vol.% respirable (sub - 4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre - like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO_4 (gypsum, at
Bice Fubini - One of the best experts on this subject based on the ideXlab platform.
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the respiratory Health Hazard of tephra from the 2010 centennial eruption of merapi with implications for occupational mining of deposits
Journal of Volcanology and Geothermal Research, 2013Co-Authors: David E Damby, Claire J Horwell, Peter J. Baxter, Bice Fubini, Pierre Delmelle, Christina Dunster, Ken Donaldson, F Murphy, C Nattrass, S SweeneyAbstract:Ashfall into heavily populated areas during the October–November 2010 eruption of Merapi volcano, Indonesia created anxiety regarding the growing impacts to Health as the eruption escalated and the Hazard zone widened. We made a preliminary assessment of the respiratory Hazards to human Health of the tephra deposits (ashfall, lahar, and PDC surge) from the eruption using a laboratory protocol specifically developed to study the toxic potential of volcanic ash particles. Twenty samples collected from a range of locations were analysed for Health-pertinent mineralogical parameters (grain size, crystalline silica content, morphology, surface area, bulk chemistry, and leachable elements) and bio-reactivity (hydroxyl radical generation, haemolytic potential, oxidative capacity, pro-inflammatory response). The grain size pertinent to respiratory Health was variable, ranging from 1.4–15.6 vol.% sub-4 μm and 3.0–28.9 vol.% sub-10 μm diameter material. No fibre-like particles were observed. Cristobalite was present in all samples, ranging from 1.9–9.5 wt.%, but surface reactivity and in vitro toxicity assays showed low reactivity for all samples tested. The risk of direct exposure to ash from fallout was in any case low due to seasonal rains limiting its re-suspension and the immediate and effective clean-up of communities by local people who supplied the ash to the Indonesian construction industry for use as aggregate. However, mining of the lahar and thick PDC deposits in the valleys draining the volcano is performed on a vast, industrial scale, which could result in high occupational exposure to thousands of sand miners at Merapi during the dry seasons. Further study of the Health Hazard of the mined Merapi deposits is warranted
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Mineralogical analyses and in vitro screening tests for the rapid evaluation of the Health Hazard of volcanic ash at Rabaul volcano, Papua New Guinea
Bulletin of Volcanology, 2010Co-Authors: Jennifer S. Blond, Claire J Horwell, Peter J. Baxter, Sabina A. K. Michnowicz, Maura Tomatis, Bice Fubini, Pierre Delmelle, Christina Dunster, Herman PatiaAbstract:The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns regarding how exposure would affect the respiratory Health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public Health, we investigated the potential Health Hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy - andesitic ash comprised 2.1–6.7 vol.% respirable (sub - 4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre - like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO_4 (gypsum, at
