The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Cyril Feidt - One of the best experts on this subject based on the ideXlab platform.
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Relative Bioavailability of Tropical Volcanic Soil-Bound Chlordecone in Piglets
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Cécile Bouveret, Catherine Jondreville, Guido Rychen, Sylvain Lerch, Cyril FeidtAbstract:The application of chlordecone (CLD), a chlorinated polycyclic ketone pesticide, until 1993 in the French West Indies has resulted in long-term pollution of agricultural Soils (10% of them exceed 1 mg kg(-1)). The aim of this study was to assess the impact of two tropical Volcanic Soils, an andosol and a nitisol, on CLD availability in piglets, using the relative bioavailability (RBA) approach For both Soils and relative to an oil matrix, RBA was close to 100%, indicating that CLD was not retained in the Soil matrices during the piglet digestive process. Additionally, after a 14 day exposure period, liver and subcutaneous fat CLD concentrations exceeded the maximum residue limit (10 mu g kg(-1) of fresh matter and 100 mu g kg(-1) of fat for liver and subcutaneous fat, respectively) beyond a CLD ingestion of 2.1 and 6.8 mu g CLD kg(-1) of body weight per day, respectively. Thus, rearing practices in CLD-contaminated areas should avoid involuntary Soil ingestion by farm animals.
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Relative bioavailability of tropical Volcanic Soil-bound chlordecone in laying hens (Gallus domesticus).
Environmental science and pollution research international, 2012Co-Authors: Catherine Jondreville, Cécile Bouveret, Magalie Lesueur-jannoyer, Guido Rychen, Cyril FeidtAbstract:The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of Soils and of food chains. CLD may be transferred into eggs of hens reared outdoors, through polluted Soil ingestion. Tropical Volcanic Soils display variable capacities of pollutant retention: CLD is less available and more persistent in andosol than in nitisol. The impact of Soil type on CLD bioavailability to hens was tested through a relative bioavailability study. The deposition of CLD in egg yolk and in abdominal fat was measured in 42 individually housed laying hens fed with diets containing graded levels of CLD from polluted andosol, nitisol, or spiked oil during 23 days. Within each ingested matrix, the concentration of CLD in yolk and in abdominal fat linearly increased with the amount of ingested CLD (P 0.1), indicating that CLD was equally bioavailable to laying hens, irrespective of the matrix. This suggests that the hen's gastrointestinal tract efficiently extracts CLD from the two tropical Volcanic Soils, regardless of their retention capacity. Thus, hens reared on polluted Soils with CLD may lay contaminated eggs.
Seiichi Miura - One of the best experts on this subject based on the ideXlab platform.
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influence of freeze thaw action on hydraulic behavior of unsaturated Volcanic coarse grained Soils
Soils and Foundations, 2016Co-Authors: Tatsuya Ishikawa, Tetsuya Tokoro, Seiichi MiuraAbstract:Abstract The aim of this study is to evaluate the effects of freeze–thaw action on the water retention–permeability characteristics of Volcanic coarse-grained Soils under unsaturated conditions in order to examine the hydraulic behavior of Volcanic Soil during the snow-melting season. In this study, a series of water retention, permeability, and slaking tests on three types of crushable Volcanic coarse-grained Soils, differing in their degrees of particle crushability, were performed under various degrees of saturation and freeze–thaw histories, while comparing the test results with those of non-crushable sand. Based on the experimental results, the effects of freeze–thaw action on the water retentivity, permeability, and particle breakage were examined. The test results indicated that freeze–thaw action has a strong influence on the hydraulic behavior of crushable Volcanic coarse-grained Soils under unsaturated conditions, even if the Soil is a non-frost-susceptible geomaterial.
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cyclic deformation strength evaluation of compacted Volcanic Soil subjected to freeze thaw sequence
Soils and Foundations, 2015Co-Authors: Satoshi Matsumura, Seiichi Miura, Shoji Yokohama, Shima KawamuraAbstract:Abstract The aim of this paper was to clarify the effect of freeze-thawing on the cyclic shear behavior of a crushable Volcanic Soil that is widely deposited in Hokkaido, Japan. Using a traxial apparatus, which was newly developed to simulate freeze–thaw cycles and cyclic loading, a series of cyclic triaxial tests was performed on compacted Volcanic Soils subjected to freeze–thaw cycles. The experimental results showed that freeze-thawing leads to a significant decrease in the liquefaction strength of densely-compacted Volcanic Soils. The decrement in liquefaction strength depended strongly on the behavior of the excess pore water pressure during cyclic loading. In addition, according to the variation in cyclic deformation behavior induced by the freeze–thaw sequence, it was anticipated that the freeze-thawing would be related to the change in the Soil fabric of the specimens. However, the specimens compacted at a lower dry density seemed to be inconsistent with the above; i.e., the liquefaction strength became almost the same regardless of whether or not the specimens were exposed to the freeze-thaw sequence. Thus, it was concluded that the freeze-thaw sequence can degrade the dynamic properties of Volcanic Soil, but that such influences ought to be incorporated into a correlation with the dry density.
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INFLUENCE OF FREEZE-THAW ACTION ON DEFORMATION-STRENGTH CHARACTERISTICS AND PARTICLE CRUSHABILITY OF Volcanic COARSE-GRAINED SoilS
Soils and Foundations, 2011Co-Authors: Tatsuya Ishikawa, Seiichi MiuraAbstract:ABSTRACT The objective of this study is to evaluate the effect of freeze-thaw action on the deformation-strength characteristics of crushable Volcanic coarse-grained Soils, wherein significant particle breakage occurs even under relatively low stress levels and saturated conditions. A series of monotonic triaxial compression tests was performed for Volcanic coarse-grained Soils under various freeze-thaw histories. On the basis of the test results, we examined the above-mentioned effect and the relationship between the degree of particle breakage and the freeze-thaw history. The results indicate that the degree of particle breakage under consolidation and shear increased with freeze-thaw action; and consequently, the strength and the stiffness of the Soils decreased with an increase in the number of freeze-thaw cycles. Moreover, to examine the influence of freeze-thaw action on the single-particle hardness of Volcanic coarse-grained Soils, single-particle crushing tests were conducted. The test results revealed that Volcanic Soil particles become more fragile after being exposed to freeze-thaw action, and as a result, the degree of particle breakage increases. These results indicate that the freeze-thaw action has a strong influence on the deformation-strength characteristics of crushable Volcanic Soils in terms of an increase in particle breakage, even if the Soils lack frost-heave characteristics.
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effect of freeze thaw sequence on deformation properties of crushable Volcanic Soil
Doboku Gakkai Ronbunshuu C, 2009Co-Authors: Masahiko Yamaki, Seiichi Miura, Shoji YokohamaAbstract:北海道のような寒冷地では気温変動による地盤の凍結融解現象が生じる．その影響を定量化することは寒冷地地盤の力学的安定性を見極めるために重要となる．本研究では，北海道に分布する破砕性が顕著な火山性粗粒土を用いて，人工的に凍結融解履歴を繰返し与えた供試体を作製し，凍結融解履歴が破砕性火山灰土の微小ひずみレベルにおける変形特性に及ぼす影響を調べた．一連の試験結果から，凍結融解履歴は破砕性火山灰土の変形特性に無視できない影響を与えること，初期せん断剛性率G0の顕著な低下を引き起こすことがわかった．その主な原因は凍結融解履歴を繰返し与えることで誘発される粒子の破砕による細粒分の増加であることが示された．また凍結融解履歴により，間隙構造に変化が生じることが示された．
Cécile Bouveret - One of the best experts on this subject based on the ideXlab platform.
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Relative Bioavailability of Tropical Volcanic Soil-Bound Chlordecone in Piglets
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Cécile Bouveret, Catherine Jondreville, Guido Rychen, Sylvain Lerch, Cyril FeidtAbstract:The application of chlordecone (CLD), a chlorinated polycyclic ketone pesticide, until 1993 in the French West Indies has resulted in long-term pollution of agricultural Soils (10% of them exceed 1 mg kg(-1)). The aim of this study was to assess the impact of two tropical Volcanic Soils, an andosol and a nitisol, on CLD availability in piglets, using the relative bioavailability (RBA) approach For both Soils and relative to an oil matrix, RBA was close to 100%, indicating that CLD was not retained in the Soil matrices during the piglet digestive process. Additionally, after a 14 day exposure period, liver and subcutaneous fat CLD concentrations exceeded the maximum residue limit (10 mu g kg(-1) of fresh matter and 100 mu g kg(-1) of fat for liver and subcutaneous fat, respectively) beyond a CLD ingestion of 2.1 and 6.8 mu g CLD kg(-1) of body weight per day, respectively. Thus, rearing practices in CLD-contaminated areas should avoid involuntary Soil ingestion by farm animals.
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Relative bioavailability of tropical Volcanic Soil-bound chlordecone in laying hens (Gallus domesticus).
Environmental science and pollution research international, 2012Co-Authors: Catherine Jondreville, Cécile Bouveret, Magalie Lesueur-jannoyer, Guido Rychen, Cyril FeidtAbstract:The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of Soils and of food chains. CLD may be transferred into eggs of hens reared outdoors, through polluted Soil ingestion. Tropical Volcanic Soils display variable capacities of pollutant retention: CLD is less available and more persistent in andosol than in nitisol. The impact of Soil type on CLD bioavailability to hens was tested through a relative bioavailability study. The deposition of CLD in egg yolk and in abdominal fat was measured in 42 individually housed laying hens fed with diets containing graded levels of CLD from polluted andosol, nitisol, or spiked oil during 23 days. Within each ingested matrix, the concentration of CLD in yolk and in abdominal fat linearly increased with the amount of ingested CLD (P 0.1), indicating that CLD was equally bioavailable to laying hens, irrespective of the matrix. This suggests that the hen's gastrointestinal tract efficiently extracts CLD from the two tropical Volcanic Soils, regardless of their retention capacity. Thus, hens reared on polluted Soils with CLD may lay contaminated eggs.
Catherine Jondreville - One of the best experts on this subject based on the ideXlab platform.
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Relative Bioavailability of Tropical Volcanic Soil-Bound Chlordecone in Piglets
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Cécile Bouveret, Catherine Jondreville, Guido Rychen, Sylvain Lerch, Cyril FeidtAbstract:The application of chlordecone (CLD), a chlorinated polycyclic ketone pesticide, until 1993 in the French West Indies has resulted in long-term pollution of agricultural Soils (10% of them exceed 1 mg kg(-1)). The aim of this study was to assess the impact of two tropical Volcanic Soils, an andosol and a nitisol, on CLD availability in piglets, using the relative bioavailability (RBA) approach For both Soils and relative to an oil matrix, RBA was close to 100%, indicating that CLD was not retained in the Soil matrices during the piglet digestive process. Additionally, after a 14 day exposure period, liver and subcutaneous fat CLD concentrations exceeded the maximum residue limit (10 mu g kg(-1) of fresh matter and 100 mu g kg(-1) of fat for liver and subcutaneous fat, respectively) beyond a CLD ingestion of 2.1 and 6.8 mu g CLD kg(-1) of body weight per day, respectively. Thus, rearing practices in CLD-contaminated areas should avoid involuntary Soil ingestion by farm animals.
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Relative bioavailability of tropical Volcanic Soil-bound chlordecone in laying hens (Gallus domesticus).
Environmental science and pollution research international, 2012Co-Authors: Catherine Jondreville, Cécile Bouveret, Magalie Lesueur-jannoyer, Guido Rychen, Cyril FeidtAbstract:The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of Soils and of food chains. CLD may be transferred into eggs of hens reared outdoors, through polluted Soil ingestion. Tropical Volcanic Soils display variable capacities of pollutant retention: CLD is less available and more persistent in andosol than in nitisol. The impact of Soil type on CLD bioavailability to hens was tested through a relative bioavailability study. The deposition of CLD in egg yolk and in abdominal fat was measured in 42 individually housed laying hens fed with diets containing graded levels of CLD from polluted andosol, nitisol, or spiked oil during 23 days. Within each ingested matrix, the concentration of CLD in yolk and in abdominal fat linearly increased with the amount of ingested CLD (P 0.1), indicating that CLD was equally bioavailable to laying hens, irrespective of the matrix. This suggests that the hen's gastrointestinal tract efficiently extracts CLD from the two tropical Volcanic Soils, regardless of their retention capacity. Thus, hens reared on polluted Soils with CLD may lay contaminated eggs.
Tatsuya Ishikawa - One of the best experts on this subject based on the ideXlab platform.
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influence of freeze thaw action on hydraulic behavior of unsaturated Volcanic coarse grained Soils
Soils and Foundations, 2016Co-Authors: Tatsuya Ishikawa, Tetsuya Tokoro, Seiichi MiuraAbstract:Abstract The aim of this study is to evaluate the effects of freeze–thaw action on the water retention–permeability characteristics of Volcanic coarse-grained Soils under unsaturated conditions in order to examine the hydraulic behavior of Volcanic Soil during the snow-melting season. In this study, a series of water retention, permeability, and slaking tests on three types of crushable Volcanic coarse-grained Soils, differing in their degrees of particle crushability, were performed under various degrees of saturation and freeze–thaw histories, while comparing the test results with those of non-crushable sand. Based on the experimental results, the effects of freeze–thaw action on the water retentivity, permeability, and particle breakage were examined. The test results indicated that freeze–thaw action has a strong influence on the hydraulic behavior of crushable Volcanic coarse-grained Soils under unsaturated conditions, even if the Soil is a non-frost-susceptible geomaterial.
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INFLUENCE OF FREEZE-THAW ACTION ON DEFORMATION-STRENGTH CHARACTERISTICS AND PARTICLE CRUSHABILITY OF Volcanic COARSE-GRAINED SoilS
Soils and Foundations, 2011Co-Authors: Tatsuya Ishikawa, Seiichi MiuraAbstract:ABSTRACT The objective of this study is to evaluate the effect of freeze-thaw action on the deformation-strength characteristics of crushable Volcanic coarse-grained Soils, wherein significant particle breakage occurs even under relatively low stress levels and saturated conditions. A series of monotonic triaxial compression tests was performed for Volcanic coarse-grained Soils under various freeze-thaw histories. On the basis of the test results, we examined the above-mentioned effect and the relationship between the degree of particle breakage and the freeze-thaw history. The results indicate that the degree of particle breakage under consolidation and shear increased with freeze-thaw action; and consequently, the strength and the stiffness of the Soils decreased with an increase in the number of freeze-thaw cycles. Moreover, to examine the influence of freeze-thaw action on the single-particle hardness of Volcanic coarse-grained Soils, single-particle crushing tests were conducted. The test results revealed that Volcanic Soil particles become more fragile after being exposed to freeze-thaw action, and as a result, the degree of particle breakage increases. These results indicate that the freeze-thaw action has a strong influence on the deformation-strength characteristics of crushable Volcanic Soils in terms of an increase in particle breakage, even if the Soils lack frost-heave characteristics.
