Arsenic speciation analysis was conducted on fish samples （sardine and anchovy） collected from six areas along the Greek coastline, i.e. Artemisium Straits, Thermaikos Gulf, Amvrakikos Gulf, Strymonian Gulf, Thracia...Arsenic speciation analysis was conducted on fish samples （sardine and anchovy） collected from six areas along the Greek coastline, i.e. Artemisium Straits, Thermaikos Gulf, Amvrakikos Gulf, Strymonian Gulf, Thracian Sea, and Elefsina Gulf. Total arsenic levels ranging from 11.8 to 62.6 mg As/kg dry weight were determined. Arsenobetaine, a non-toxic form of arsenic, was found to be the main arsenic species, present at 8.6 to 58.8 mg As/kg dry weight, accounting for 67--95% of the total arsenic. Also detected in all fish samples was dimethylarsinic acid, although at considerably lower concentrations, ranging from 0.072-3.956 mg As/kg dry weight. Monomethylarsonic acid was detected at low levels in all anchovy samples, and only in sardines from one area. Finally, inorganic arsenic in the form of arsenate was detected only in fish at one area, indicating the possible effect of an environmental parameter on its presence at detectable amounts. Statistical analysis revealed the environmental variables, such as salinity, total organic carbon and nitrogen, ammonium, phosphate, total phosphorus, dissolved oxygen and pressure index, are potentially correlated to As species concentrations. Furthermore, based on factor analysis, the biological parameters, such as fish weight, lipids, protein and ash content, that are correlated to As species concentrations of fish were also identified. The interrelationship of arsenobetaine and dimethylarsinic acid concentrations within each fish species was evaluated.展开更多
Dust storms in arid and desert areas affect radiation budget,air quality,visibility,enzymatic activities,agricultural products and human health.Due to increased drought and land use changes in recent years,the frequen...Dust storms in arid and desert areas affect radiation budget,air quality,visibility,enzymatic activities,agricultural products and human health.Due to increased drought and land use changes in recent years,the frequency of dust storms occurrence in Iran has been increased.This study aims to identify dust source areas in the Sistan watershed(Iran-Afghanistan borders)-an important regional source for dust storms in southwestern Asia,using remote sensing(RS)and bivariate statistical models.Furthermore,this study determines the relative importance of factors controlling dust emissions using frequency ratio(FR)and weights of evidence(WOE)models and interpretability of predictive models using game theory.For this purpose,we identified 211 dust sources in the study area and generated a dust source distribution map-inventory map-by dust source potential index based on RS data.In addition,spatial maps of topographic factors affecting dust source areas including soil,lithology,slope,Normalized difference vegetation index(NDVI),geomorphology and land use were prepared.The performance of two models(WOE and FR)was evaluated using the area under curve(AUC)of the receiver operating characteristic curve.The results showed that soil,geomorphology and slope exhibited the greatest influence in the dust source areas.The 55.3%(according to FR)and 62.6%(according to WOE)of the total area were classified as high and very high potential dust sources,while both models displayed acceptable accuracy with subsurface levels of 0.704 for FR and 0.751 for WOE,although they predict different fractions of dust potential classes.Based on Shapley additive explanations(SHAP),three factors,i.e.,soil,slope and NDVI have the highest impact on the model's output.Overall,combination of statistic-based predictive models(or data mining models),RS and game theory techniques can provide accurate maps of dust source areas in arid and semi-arid regions,which can be helpful for mitigation of negative effects of dust storms.展开更多
Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predict...Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predictions of future dust concentration.However,these issues still remain relatively poorly known in Central Asia(CA).The extensive loess deposits on the CA pediments provide a promising archive to explore atmospheric dust dynamics and climatic conditions in the past and their association with loess formation.This study investigates the granulometric and magnetic properties of a loess section(named Osh section)in the Fergana Valley,which provides a sensitive record of atmospheric dust dynamics since 30 ka based on radiometric(AMS ^(14)C)dating.The frequency-dependent magnetic susceptibility(χfd)and the mean grain size are used to reconstruct the broadscale effective moisture and summer atmospheric dynamics pattern in CA,respectively.The results show that the precession forcing exerts a huge influence on the wind-regime variabilities in CA,but with different physical processes under the impact of the Northern Hemisphere ice sheet(NHIS)before and after 15 ka.The origin of the sedimentation rate variations in the Osh loess is also linked to the NHIS-modulated changes of the atmospheric circulation patterns.Either the strengthened westerlies or the increased surface roughness from higher vegetation cover in loess-deposition areas have significantly accelerated the loess accumulation.As a result,these complicated influence factors of sedimentation rate change in the Osh loess section,especially during the Holocene epoch,may hamper accessibility of the authentic dust emission flux and atmospheric dust concentration in CA.展开更多
基金supported by the Greek National Fisheries Data Collection ProgramSpecial Account for Research–University of Crete for the funding of a Type B research grant
文摘Arsenic speciation analysis was conducted on fish samples （sardine and anchovy） collected from six areas along the Greek coastline, i.e. Artemisium Straits, Thermaikos Gulf, Amvrakikos Gulf, Strymonian Gulf, Thracian Sea, and Elefsina Gulf. Total arsenic levels ranging from 11.8 to 62.6 mg As/kg dry weight were determined. Arsenobetaine, a non-toxic form of arsenic, was found to be the main arsenic species, present at 8.6 to 58.8 mg As/kg dry weight, accounting for 67--95% of the total arsenic. Also detected in all fish samples was dimethylarsinic acid, although at considerably lower concentrations, ranging from 0.072-3.956 mg As/kg dry weight. Monomethylarsonic acid was detected at low levels in all anchovy samples, and only in sardines from one area. Finally, inorganic arsenic in the form of arsenate was detected only in fish at one area, indicating the possible effect of an environmental parameter on its presence at detectable amounts. Statistical analysis revealed the environmental variables, such as salinity, total organic carbon and nitrogen, ammonium, phosphate, total phosphorus, dissolved oxygen and pressure index, are potentially correlated to As species concentrations. Furthermore, based on factor analysis, the biological parameters, such as fish weight, lipids, protein and ash content, that are correlated to As species concentrations of fish were also identified. The interrelationship of arsenobetaine and dimethylarsinic acid concentrations within each fish species was evaluated.
基金The study was financially supported by the Fund for Support of Researchers and Technologists of Iran(97022330)Panhellenic Infrastructure for Atmospheric Composition and Climate Change(PANACEA,MIS 5021516)+1 种基金Competitiveness,Entrepreneurship and Innovation(NSRF 2014-2020)co-financed by Greece and the European Union(European Regional Development Fund).
文摘Dust storms in arid and desert areas affect radiation budget,air quality,visibility,enzymatic activities,agricultural products and human health.Due to increased drought and land use changes in recent years,the frequency of dust storms occurrence in Iran has been increased.This study aims to identify dust source areas in the Sistan watershed(Iran-Afghanistan borders)-an important regional source for dust storms in southwestern Asia,using remote sensing(RS)and bivariate statistical models.Furthermore,this study determines the relative importance of factors controlling dust emissions using frequency ratio(FR)and weights of evidence(WOE)models and interpretability of predictive models using game theory.For this purpose,we identified 211 dust sources in the study area and generated a dust source distribution map-inventory map-by dust source potential index based on RS data.In addition,spatial maps of topographic factors affecting dust source areas including soil,lithology,slope,Normalized difference vegetation index(NDVI),geomorphology and land use were prepared.The performance of two models(WOE and FR)was evaluated using the area under curve(AUC)of the receiver operating characteristic curve.The results showed that soil,geomorphology and slope exhibited the greatest influence in the dust source areas.The 55.3%(according to FR)and 62.6%(according to WOE)of the total area were classified as high and very high potential dust sources,while both models displayed acceptable accuracy with subsurface levels of 0.704 for FR and 0.751 for WOE,although they predict different fractions of dust potential classes.Based on Shapley additive explanations(SHAP),three factors,i.e.,soil,slope and NDVI have the highest impact on the model's output.Overall,combination of statistic-based predictive models(or data mining models),RS and game theory techniques can provide accurate maps of dust source areas in arid and semi-arid regions,which can be helpful for mitigation of negative effects of dust storms.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant Nos.XDB40000000 and XDB26000000)Natural Science Foundation of China(Grant Nos.41977385 and 41572162)+1 种基金Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0101)State Key Laboratory of Loess and Quaternary Geology(Grant No.SKLLQGPY2006).
文摘Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predictions of future dust concentration.However,these issues still remain relatively poorly known in Central Asia(CA).The extensive loess deposits on the CA pediments provide a promising archive to explore atmospheric dust dynamics and climatic conditions in the past and their association with loess formation.This study investigates the granulometric and magnetic properties of a loess section(named Osh section)in the Fergana Valley,which provides a sensitive record of atmospheric dust dynamics since 30 ka based on radiometric(AMS ^(14)C)dating.The frequency-dependent magnetic susceptibility(χfd)and the mean grain size are used to reconstruct the broadscale effective moisture and summer atmospheric dynamics pattern in CA,respectively.The results show that the precession forcing exerts a huge influence on the wind-regime variabilities in CA,but with different physical processes under the impact of the Northern Hemisphere ice sheet(NHIS)before and after 15 ka.The origin of the sedimentation rate variations in the Osh loess is also linked to the NHIS-modulated changes of the atmospheric circulation patterns.Either the strengthened westerlies or the increased surface roughness from higher vegetation cover in loess-deposition areas have significantly accelerated the loess accumulation.As a result,these complicated influence factors of sedimentation rate change in the Osh loess section,especially during the Holocene epoch,may hamper accessibility of the authentic dust emission flux and atmospheric dust concentration in CA.
