Phosphorus(P)is an essential nutrient for many organisms in the ocean,which plays a central role in the stability of ecosystems and the evolution of the environment.The distribution,occurrence and source-sink process ...Phosphorus(P)is an essential nutrient for many organisms in the ocean,which plays a central role in the stability of ecosystems and the evolution of the environment.The distribution,occurrence and source-sink process of P in offshore waters are highly influenced by mariculture activities.P transformation in water-sediment system is the key process in P cycling,however,the mechanism is poorly documented in the coastal sea which is influenced by human activities.Based on the comprehensive surveys in the adjacent waters outside Rushan Bay in May,July and August 2014 and February 2015,the form and transformation of P in the suspended particulate matter(SPM)and surface sediment were analyzed.The results showed that contents of total P,authigenic P and organic P of SPM increased with the increase in distance from the shoreline off Rushan Bay,and the detrital-P decreased.The partition coefficient of P between water and SPM was related to the chemical activity of different forms of P,and a higher reactivity of inorganic P associated with SPM was observed.Hypoxia induced by mariculture changes the distribution and morphological composition of P in SPM and sediment in this typical aquaculture area,which can result in a conversion of sink to source of P in the sediment,thereby having a significant impact on the regional nutrient budget and associated with eutrophication.展开更多
Background:Understanding how species diversify is a long-standing question in biology.The allopatric speciation model is a classic hypothesis to explain the speciation process.This model supposes that there is no gene...Background:Understanding how species diversify is a long-standing question in biology.The allopatric speciation model is a classic hypothesis to explain the speciation process.This model supposes that there is no gene flow during the divergence process of geographically isolated populations.On the contrary,the speciation with gene flow model supposes that gene flow does occur during the speciation process.Whether allopatric species have gene flow during the speciation process is still an open question.Methods:We used the genetic information from 31 loci of 24 Chinese Bamboo Partridges(Bambusicola thoracicus)and 23 Taiwan Bamboo Partridges(B.sonorivox)to infer the gene flow model of the two species,using the approxi-mate Bayesian computation(ABC)model.The ecological niche model was used to infer the paleo-distribution during the glacial period.We also tested whether the two species had a conserved ecological niche by means of a back-ground similarity test.Results:The genetic data suggested that the post-divergence gene flow between the two species was terminated before the mid-Pleistocene.Furthermore,our ecological niche modeling suggested that their ecological niches were highly conserved,and that they shared an overlapping potential distribution range in the last glacial maximum.Conclusions:The allopatric speciation model cannot explain the speciation process of the two Bamboo Partridges.The results of this study supported a scenario in which speciation with gene flow occurring between the allopatric species and have contributed to our understanding of the speciation process.展开更多
This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including th...This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.展开更多
A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-...A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy to investigate the influence of copper element distribution and speciation on the color of porcelain. In black-colored region, copper accumulates at the interface between the body and glaze layers with metallic copper particles as the main speciation. In contrast, Cu is irregularly distributed in the red-colored region with multi-valence speciation. The differences in Cu distribution and speciation in black- and red-colored regions indicate that they are the main factors influencing the different colors of copper-red underglaze porcelain.展开更多
The black soldier fly larvae(BSFL)(Hermetia illucens)are a good candidate for poultry and livestock manure treatment.The harvested insect bodies and feces can be used as animal feed and organic fertilizer.However,heav...The black soldier fly larvae(BSFL)(Hermetia illucens)are a good candidate for poultry and livestock manure treatment.The harvested insect bodies and feces can be used as animal feed and organic fertilizer.However,heavy metals have a negative impact on the transformation process of the manure by BSFL.Here we evaluated the effects of Cd,Cr and As in pig manure on the growth of BSFL,as well as the mobility and changes in speciation of the metals during the transformation process.The results showed that As significantly reduced the weight of BSFL,but Cr and Cd had no significant effects on BSFL growth.The bioaccumulation factors(BAFs)at various concentrations of Cd(2.8–3.7)were significantly higher than those of Cr(0.44–0.62)and As(0.43–0.45).The heavy metals in pig manure were mainly transferred to BSFL feces,and the distribution percentages of Cd,Cr and As in the BSFL feces were 52.6–62.0%,90.3–94.2%and 93.0–93.3%,respectively.Cd concentrations in BSFL feces were significantly lower than those in the pig manure,while there were no significant differences in the concentrations of Cr and As between BSFL feces and pig manure(except for the treatment with the addition of 150 mg Cr kg^(–1)).The metal speciation(weak acid soluble,reducible,oxidizable and residual fractions)in BSFL feces obviously changed when compared with pig manure.In BSFL feces,the reducible proportion of Cr decreased while the oxidizable proportion increased.Cd mainly existed in the weak acid soluble and reducible states in pig manure and BSFL feces.For As,the proportions of weak acid soluble and reducible states decreased in BSFL feces.After the BSFL transformation process,the bioavailable fraction of Cr decreased by 17.3–23.1%,but those of Cd and As did not change significantly,except for As in the CK group.These findings contribute to our understanding of the roles of BSFL during the biotransformation process of livestock manure as well as the safe utilization of transformed products.展开更多
Ca （II） speciation and effect of Gd （III） speciation on Ca （II） speciation in human blood plasma were studied by computer simulation. [CaHCO3]+ is a predominant compound species of Ca （II）. Gd （III） can comp...Ca （II） speciation and effect of Gd （III） speciation on Ca （II） speciation in human blood plasma were studied by computer simulation. [CaHCO3]+ is a predominant compound species of Ca （II）. Gd （III） can compete with Ca （II） for biological molecules. The presence of Gd （III） results in a increase of concentration of free Ca （II） and a decrease of concentration of Ca （II） compounds.展开更多
In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infi...In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.展开更多
Multiple acute and chronic toxicity of arsenic species and its mobilisation from geological deposits into ground and drinking water resources is one of the greatest threats to human health. Arsenic speciation analy-si...Multiple acute and chronic toxicity of arsenic species and its mobilisation from geological deposits into ground and drinking water resources is one of the greatest threats to human health. Arsenic speciation analy-sis, mostly done by liquid chromatography, is a challenging task which requires an intense high quality work with respect to extraction, preservation, separation, detection and validation. A growing number of As-spe-cies and low regulatory limits (10 μg/L) may require more than one speciation method preferably performed by species specific procedures and detectors. Beside As-fractionation for special application there are many selective speciation methods based on high performance separation techniques like capillary electrophoreses, gas and liquid chromatography. Both, fractionation and speciation methods are reviewed. However, the focus is on scopes and limits of ion chromatographic separations, the most frequently used methods. Based on IC-principles the methods applied are critically discussed and recommendations given which should result in more robust and reliable As-speciation.展开更多
A better knowledge of aerosol properties is of great significance for elucidating the complex mechanisms behind frequently occurring haze pollution events.In this study,we examine the temporal and spatial variations i...A better knowledge of aerosol properties is of great significance for elucidating the complex mechanisms behind frequently occurring haze pollution events.In this study,we examine the temporal and spatial variations in both PM_(1)and its major chemical constituents using three-year field measurements that were collected in six representative regions in China between 2012 and 2014.Our results show that both PM_(1)and its chemical compositions varied significantly in space and time,with high PM_(1)loadings mainly observed in the winter.By comparing chemical constituents between clean and polluted episodes,we find that the elevated PM_(1)mass concentration during pollution events should be largely attributable to significant increases in organic matter(OM)and inorganic aerosols like sulfate,nitrate,and ammonium(SNA),indicative of the critical role of primary emissions and secondary aerosols in elevating PM_(1)pollution levels.The ratios of PM_(1)/PM2.5 are found to be generally high in Shanghai and Guangzhou,while relatively low ratios are seen in Xi’an and Chengdu,indicating anthropogenic emissions were more likely to accumulate in forms of finer particles.With respect to the relative importance of chemical components and meteorological factors quantified via statistical modeling practices,we find that primary emissions and secondary aerosols were the two leading factors contributing to PM_(1)variations,though meteorological factors also played important roles in regulating the dispersion of atmospheric PM.展开更多
The evolution of metal species during sludge composting in aerobic reactor has been widely investigated,but little is known in large scale.In this study,the transformations of heavy metals speciation(Zn,Cu,Pb and Cd)i...The evolution of metal species during sludge composting in aerobic reactor has been widely investigated,but little is known in large scale.In this study,the transformations of heavy metals speciation(Zn,Cu,Pb and Cd)in the process of sludge composting were studied in a bunker.Physico-chemical parameters,such as pH,moisture content(MC),organic matter(OM),humic acids(HA)and fulvic acids(FA)contents,were determined to evaluate their impacts on the redistribution of Zn,Cu,Pb and Cd in sludge compost.During the composting process,the contents of Cu,Pb,Zn and Cd in oxidizable and residual forms increased,whereas the contents of the exchangeable Cu,Pb,Zn and Cd decreased,with a slight increase in the total heavy metal contents.The contents of Cu,Zn and Cd in carbonate form and the reducible Cu,Zn and Pb falled;however,the content of Pb in carbonate formed and the reducible Cd increased.The results indicated that heavy metals(Zn,Cu,Pb and Cd)in sewage sludge could be passivated during composting process.The heavy metals speciation in the compost correlated with the physico-chemical parameters.In addition,linear regression analysis indicated that the content of mobile Pb could predict the total content of Pb.The contents of the residue fraction for Pb,Zn and Cd were decreased,but those for Ni and Cr were increased;the Cu residue fraction was almost constant.The contents of the total mobile fractions(including fractions 1-4)for Zn and Pb were significantly increased,but the increase of those for Cu and Ni were not so remarkable.There were significant degrees of correlation between heavy metal fractions and changes of some selected parameters(for example,pH,composting temperature and OM content).Only the content of the total mobile fractions for Cu could be predictable from its total content.For the prediction of the total mobile fractions of Zn,Ni,Cd and Cr,the R2 value was significantly increased by the inclusion of other variables such as pH,temperature and OM content.展开更多
Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals,many...Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals,many studies have suggested that the bioavailability of trace metals may change according to the conditions of the environment,展开更多
This article presents a review of the analytical relevance of trace metal speciation analysis, which must be considered in environmental and biophysicochemical systems for reliable and efficient assessment and monitor...This article presents a review of the analytical relevance of trace metal speciation analysis, which must be considered in environmental and biophysicochemical systems for reliable and efficient assessment and monitoring of trace metals. Examples are given of methodological approaches used for speciation analysis. An overview of speciation analysis in sediments, aquatic ecosystems and agrosystems is also presented.展开更多
A simple on-line sonodigestion system was successfully used for breakdown organic nickel complexes in environmental waters acidified with diluted nitric acid prior to flow injection total dissolved nickel preconcentra...A simple on-line sonodigestion system was successfully used for breakdown organic nickel complexes in environmental waters acidified with diluted nitric acid prior to flow injection total dissolved nickel preconcentration in a microcolumn containing a chelating resin (Chelite Che with iminodiacetic acid groups) and determination by flame atomic absorption spectrometry. For the determination of the dissolved labile nickel fraction, microcolumns packed with the chelating resin were loaded in-situ with the sample without sample pH modification, and once in the laboratory were inserted in the flow injection device where nickel elution-detection was carried out. The performance of the chelating resin was investigated in order to elucidate its behavior in the presence of dissolved nickel species. The results obtained reveal that the resin, at the experimental employed conditions, retained only dissolved free nickel ions and nickel bound to weak complexes (labile fraction). The figures of merit for determinations in both nickel fractions are given and the obtained values are discussed. The speciation scheme is applied to the analysis of nickel in river and seawater samples collected in Galicia (Northwest, Spain). The results of fractionation showed that Ni are mainly in the dissolved labile fraction in river water, while in seawater samples analyzed was mainly present in the organic fraction.展开更多
A new method was developed in this work to account for inorganic Sb species interconversion during soil sample preparation and subsequent separation steps. The Sb(III) and Sb(V) concentrations at each investigated ste...A new method was developed in this work to account for inorganic Sb species interconversion during soil sample preparation and subsequent separation steps. The Sb(III) and Sb(V) concentrations at each investigated step in the analytical procedure were determined using species specific spikes (121Sb(III) with 81.18% and 123Sb(V) with 74.04% enrichment). The spiking of these enriched isotopes species solutions was done separately before soil sample extraction and before HPLC separation. Simply by subtracting the final concentration of each species done by on-line isotope dilution (ID) from its concentration at different stages of the analytical procedure done by species specific ID, the influence of each step on species transformation can be estimated. After optimization, the extraction procedure for inorganic Sb species 6% Sb(III) (1.3 RSD, n = 3) and 43.2% Sb(V) (2.9% RSD, n = 3) as percent of total Sb were detected in the examined soil sample using online ID. Using the above described methodology we found that there was no reduction of Sb(V) to Sb(III) during sample preparation or species separation. While about 9.3% of extractable Sb (4.6% of total) was converted from Sb(III) to Sb(V) during the extraction step, no conversion during HPLC separation step was observed. By compensating for Sb(III) transformation during the sample preparation step;the extractable Sb(III) and Sb(V) as percent of total Sb yielded 10.6% and 38.7%, respectively.展开更多
Mercury(Hg) is a global pollutant and can be accumulated in the food chain, posing exposure risks to humans. In this study, rice plants and corresponding rhizosphere soil samples were collected from a watershed of the...Mercury(Hg) is a global pollutant and can be accumulated in the food chain, posing exposure risks to humans. In this study, rice plants and corresponding rhizosphere soil samples were collected from a watershed of the Wawu River Basin that is heavily impacted by historic Hg mining and retorting activities. Total mercury(THg)and methylmercury(MeHg) in rice grains, as well as other tissues and soil samples, were measured. Five soil Hg fractions, as well as soil parameters, were also determined.The results show that the average concentrations of THg and MeHg in rice grains were 14 ± 7.0 lg kg^(-1) and7.2 ± 4.0 lg kg^(-1). Soil organic-bound(Hg-o) and strong complex-bound(Hg-s) were the main Hg fractions,accounting for 44% of the total. To estimate the Hg–ligand interaction in the soils, soil-N/Hg(R = 0.451, p \ 0.05),-S/Hg(R = 0.372, p \ 0.1), and-OM/Hg ratio(R = 0.320,p \ 0.5) with MeHg_(soil) were observed with significant positive correlations, indicating that the formation of Hg–OM, Hg–N–OM or Hg–S–OM complexes could prevent Hg(II) from methylation in soils. The significant positive correlations of the-N/Hg ratio,-S/Hg ratio and-OM/Hg ratio with MeHg in rice tissues suggested that Hg methylation and MeHg demethylation occurred throughout the rice paddy ecosystem. The estimated MeHg daily intake(EDI) was 0.075 ± 0.041 lg kg^(-1) bw d^(-1) and was lower than the RfD level of 0.1 lg kg^(-1) bw d^(-1) recommended by the US EPA. However, approximately 29% of the hazardous index(HI) of MeHg in grain exceeded 1, posing a potential threat to local populations, particularly pregnant women and children.展开更多
This paper presents a computer model using thermodynamic relationships and mass balance to investigate the speciation of aluminum in acidic natural water equilibria with mineral kaolinite. Factors affecting the distri...This paper presents a computer model using thermodynamic relationships and mass balance to investigate the speciation of aluminum in acidic natural water equilibria with mineral kaolinite. Factors affecting the distribution are discussed. Compared with the case of equilibria with gibbsite, some unique characteristics are discovered. The model is verified by analyzing practical water samples. Effect of errors in thermodynamic data on calculation is evaluated by the Monte Carlo simulation.展开更多
Introduction Coupled techniques such as HPLC–HG–AAS,HPLC–ICP–MS,HPLC–HG–AFS are widely used for arsenic speciation analysis in biosamples,during which pretreatment method usually plays a significant role.
Selenium(Se)has been recognized as a key trace element that is associated with growth of primary producers in oceans.During March and May 2018,surface water(67 samples)was collected and measured by HG-ICP-MS to invest...Selenium(Se)has been recognized as a key trace element that is associated with growth of primary producers in oceans.During March and May 2018,surface water(67 samples)was collected and measured by HG-ICP-MS to investigate the distribution and behavior of selenite[Se(Ⅳ)],selenate[Se(Ⅵ)]and dissolved organic selenides(DOSe)concentrations in the Zhujiang River Estuary(ZRE),South China Sea(SCS)and Malacca Straits(MS).It showed that Se(Ⅳ)(0.14–3.44 nmol/L)was the dominant chemical species in the ZRE,related to intensive manufacture in the watershed;while the major species shifted to DOSe(0.05–0.79 nmol/L)in the MS,associated with the wide coverage of peatland and intensive agriculture activities in the Malaysian Peninsula.The SCS was identified as the northern and southern sections(NSCS and SSCS)based on the variations of surface circulation.The insignificant variation of Se(IV)in the NSCS and SSCS was obtained in March,potentially resulting from the high chemical activity and related preferential assimilation by phytoplankton communities.Contrastively,the lower DOSe concentrations in the SSCS likely resulted from higher primary production and utilization during March.During May,the concentration of Se(Ⅳ)remained low in the NSCS and SSCS,while DOSe concentrations increased notably in the SSCS,likely due to the impact of terrestrial inputs from surface current reversal and subsequent accumulation.On a global scale,DOSe is the dominant Se species in tropical oceans,while Se(Ⅳ)and Se(Ⅵ)are major fractions in high-latitude oceans,resulting from changes in predominated phytoplankton and related biological assimilation.展开更多
Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespre...Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespread species(P.sylvestris and P.densiflora)via hybrid speciation,the conclusion was based on a low number of informative restriction sites.In this study,we analyzed the sequences of four Pinus chloroplast(cp)genomes(P.sylvestris,P.densiflora,P.funebris and P.takahasii)to clarify whether hybrid speciation was involved.The complete cp-genomes of Pinus species ranged in size from 119,865 to 119,890 bp,similar to other Pinus species.Phylogenetic results based on the whole cp-genomes showed P.sylvestris clustered with P.funebris and P.takahasii,which suggested that P.sylvestris was the paternal parent in hybridization events.In an analysis of simple sequence repeats(SSRs),we detected a total of 69 SSRs repeats among the four Pinus cp-genomes;most were A or T bases.In addition,we identified divergent hotspot regions among the four Pinus cp-genomes(trnE-clpP,cemA-ycf4,petD-rpoA,psbD-trnT,and trnN-chlL),in P.sylvestris(psbD-trnT,trnN-chlL,psbB and rps8)and in P.densiflora(trnE-clpP,petD-rpoA,ycf3 intron,psbD-trnT,and trnN-chlL).The genome information found in this study provides new insights into hybrid speciation in P inus and contributes to a better understanding of the phylogenetic relationships within the Pinus genus.展开更多
基金The National Natural Science Foundation of China under contract Nos 41806097,42176048 and 42149902.
文摘Phosphorus(P)is an essential nutrient for many organisms in the ocean,which plays a central role in the stability of ecosystems and the evolution of the environment.The distribution,occurrence and source-sink process of P in offshore waters are highly influenced by mariculture activities.P transformation in water-sediment system is the key process in P cycling,however,the mechanism is poorly documented in the coastal sea which is influenced by human activities.Based on the comprehensive surveys in the adjacent waters outside Rushan Bay in May,July and August 2014 and February 2015,the form and transformation of P in the suspended particulate matter(SPM)and surface sediment were analyzed.The results showed that contents of total P,authigenic P and organic P of SPM increased with the increase in distance from the shoreline off Rushan Bay,and the detrital-P decreased.The partition coefficient of P between water and SPM was related to the chemical activity of different forms of P,and a higher reactivity of inorganic P associated with SPM was observed.Hypoxia induced by mariculture changes the distribution and morphological composition of P in SPM and sediment in this typical aquaculture area,which can result in a conversion of sink to source of P in the sediment,thereby having a significant impact on the regional nutrient budget and associated with eutrophication.
基金This work was supported by the China Postdoctoral Science Foundation(2019M660044)National Natural Science Foundation of China(31872244)Biodiversity Survey,Monitoring and Assessment Project of Ministry of Ecology and Environment,China(2019HB2096001006 to Z.W.Z).
文摘Background:Understanding how species diversify is a long-standing question in biology.The allopatric speciation model is a classic hypothesis to explain the speciation process.This model supposes that there is no gene flow during the divergence process of geographically isolated populations.On the contrary,the speciation with gene flow model supposes that gene flow does occur during the speciation process.Whether allopatric species have gene flow during the speciation process is still an open question.Methods:We used the genetic information from 31 loci of 24 Chinese Bamboo Partridges(Bambusicola thoracicus)and 23 Taiwan Bamboo Partridges(B.sonorivox)to infer the gene flow model of the two species,using the approxi-mate Bayesian computation(ABC)model.The ecological niche model was used to infer the paleo-distribution during the glacial period.We also tested whether the two species had a conserved ecological niche by means of a back-ground similarity test.Results:The genetic data suggested that the post-divergence gene flow between the two species was terminated before the mid-Pleistocene.Furthermore,our ecological niche modeling suggested that their ecological niches were highly conserved,and that they shared an overlapping potential distribution range in the last glacial maximum.Conclusions:The allopatric speciation model cannot explain the speciation process of the two Bamboo Partridges.The results of this study supported a scenario in which speciation with gene flow occurring between the allopatric species and have contributed to our understanding of the speciation process.
基金financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2015ZX07205003)
文摘This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.
基金supported by Natural Science Foundation of China(Nos.51762027 and 11875312)Jiangxi Collaborative Innovation Center of Ceramic Relics Conservation and Imperial Kiln Research
文摘A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy to investigate the influence of copper element distribution and speciation on the color of porcelain. In black-colored region, copper accumulates at the interface between the body and glaze layers with metallic copper particles as the main speciation. In contrast, Cu is irregularly distributed in the red-colored region with multi-valence speciation. The differences in Cu distribution and speciation in black- and red-colored regions indicate that they are the main factors influencing the different colors of copper-red underglaze porcelain.
基金the National Key Research and Development Program of China(2018YFD0500205)the Tianjin Science and Technology Plan Project,China(19ZYYFSN00010 and 18ZXYENC00130)the National Natural Science Foundation of China(21607114)。
文摘The black soldier fly larvae(BSFL)(Hermetia illucens)are a good candidate for poultry and livestock manure treatment.The harvested insect bodies and feces can be used as animal feed and organic fertilizer.However,heavy metals have a negative impact on the transformation process of the manure by BSFL.Here we evaluated the effects of Cd,Cr and As in pig manure on the growth of BSFL,as well as the mobility and changes in speciation of the metals during the transformation process.The results showed that As significantly reduced the weight of BSFL,but Cr and Cd had no significant effects on BSFL growth.The bioaccumulation factors(BAFs)at various concentrations of Cd(2.8–3.7)were significantly higher than those of Cr(0.44–0.62)and As(0.43–0.45).The heavy metals in pig manure were mainly transferred to BSFL feces,and the distribution percentages of Cd,Cr and As in the BSFL feces were 52.6–62.0%,90.3–94.2%and 93.0–93.3%,respectively.Cd concentrations in BSFL feces were significantly lower than those in the pig manure,while there were no significant differences in the concentrations of Cr and As between BSFL feces and pig manure(except for the treatment with the addition of 150 mg Cr kg^(–1)).The metal speciation(weak acid soluble,reducible,oxidizable and residual fractions)in BSFL feces obviously changed when compared with pig manure.In BSFL feces,the reducible proportion of Cr decreased while the oxidizable proportion increased.Cd mainly existed in the weak acid soluble and reducible states in pig manure and BSFL feces.For As,the proportions of weak acid soluble and reducible states decreased in BSFL feces.After the BSFL transformation process,the bioavailable fraction of Cr decreased by 17.3–23.1%,but those of Cd and As did not change significantly,except for As in the CK group.These findings contribute to our understanding of the roles of BSFL during the biotransformation process of livestock manure as well as the safe utilization of transformed products.
基金the NSFC for financial support of this work (Project Nos.29890280, 29971029).
文摘Ca （II） speciation and effect of Gd （III） speciation on Ca （II） speciation in human blood plasma were studied by computer simulation. [CaHCO3]+ is a predominant compound species of Ca （II）. Gd （III） can compete with Ca （II） for biological molecules. The presence of Gd （III） results in a increase of concentration of free Ca （II） and a decrease of concentration of Ca （II） compounds.
基金This study was funded by the survey projects initiated by the Ministry of Natural Resources of the People’s Republic of China(1212010741003,1212011220224,and 121201011000150022)China Geological Survey(DD20189220,DD20211317)+2 种基金the public welfare scientific research project launched by the Ministry of Natural Resources of the People’s Republic of China(201111020)the project of 2015 Natural Science Basic Research Plan of Shaanxi Province of China(2015JM4129)the project of 2016 Fundamental Research Funds for the Central Universities of China(an open-end fund)(310829161128).
文摘In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.
文摘Multiple acute and chronic toxicity of arsenic species and its mobilisation from geological deposits into ground and drinking water resources is one of the greatest threats to human health. Arsenic speciation analy-sis, mostly done by liquid chromatography, is a challenging task which requires an intense high quality work with respect to extraction, preservation, separation, detection and validation. A growing number of As-spe-cies and low regulatory limits (10 μg/L) may require more than one speciation method preferably performed by species specific procedures and detectors. Beside As-fractionation for special application there are many selective speciation methods based on high performance separation techniques like capillary electrophoreses, gas and liquid chromatography. Both, fractionation and speciation methods are reviewed. However, the focus is on scopes and limits of ion chromatographic separations, the most frequently used methods. Based on IC-principles the methods applied are critically discussed and recommendations given which should result in more robust and reliable As-speciation.
基金This work was financially supported by National Key R&D Plan(Grant No.2017YFC0210000)National Natural Science Foundation of China(Grant No.41701413)+1 种基金National Key R&D Plan(Grant No.2017YFC0212703)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB05020401).Meteorological data were acquired from the Meteorological Information Comprehensive Analysis and Process System(air temperature,relative humidity,and wind speed),and ERA-Interim reanalysis(boundary layer height)that was provided by the European Centre for Medium-Range Weather Forecasts.
文摘A better knowledge of aerosol properties is of great significance for elucidating the complex mechanisms behind frequently occurring haze pollution events.In this study,we examine the temporal and spatial variations in both PM_(1)and its major chemical constituents using three-year field measurements that were collected in six representative regions in China between 2012 and 2014.Our results show that both PM_(1)and its chemical compositions varied significantly in space and time,with high PM_(1)loadings mainly observed in the winter.By comparing chemical constituents between clean and polluted episodes,we find that the elevated PM_(1)mass concentration during pollution events should be largely attributable to significant increases in organic matter(OM)and inorganic aerosols like sulfate,nitrate,and ammonium(SNA),indicative of the critical role of primary emissions and secondary aerosols in elevating PM_(1)pollution levels.The ratios of PM_(1)/PM2.5 are found to be generally high in Shanghai and Guangzhou,while relatively low ratios are seen in Xi’an and Chengdu,indicating anthropogenic emissions were more likely to accumulate in forms of finer particles.With respect to the relative importance of chemical components and meteorological factors quantified via statistical modeling practices,we find that primary emissions and secondary aerosols were the two leading factors contributing to PM_(1)variations,though meteorological factors also played important roles in regulating the dispersion of atmospheric PM.
基金Supported by the National Natural Science Fund of China(31372351,31272484)。
文摘The evolution of metal species during sludge composting in aerobic reactor has been widely investigated,but little is known in large scale.In this study,the transformations of heavy metals speciation(Zn,Cu,Pb and Cd)in the process of sludge composting were studied in a bunker.Physico-chemical parameters,such as pH,moisture content(MC),organic matter(OM),humic acids(HA)and fulvic acids(FA)contents,were determined to evaluate their impacts on the redistribution of Zn,Cu,Pb and Cd in sludge compost.During the composting process,the contents of Cu,Pb,Zn and Cd in oxidizable and residual forms increased,whereas the contents of the exchangeable Cu,Pb,Zn and Cd decreased,with a slight increase in the total heavy metal contents.The contents of Cu,Zn and Cd in carbonate form and the reducible Cu,Zn and Pb falled;however,the content of Pb in carbonate formed and the reducible Cd increased.The results indicated that heavy metals(Zn,Cu,Pb and Cd)in sewage sludge could be passivated during composting process.The heavy metals speciation in the compost correlated with the physico-chemical parameters.In addition,linear regression analysis indicated that the content of mobile Pb could predict the total content of Pb.The contents of the residue fraction for Pb,Zn and Cd were decreased,but those for Ni and Cr were increased;the Cu residue fraction was almost constant.The contents of the total mobile fractions(including fractions 1-4)for Zn and Pb were significantly increased,but the increase of those for Cu and Ni were not so remarkable.There were significant degrees of correlation between heavy metal fractions and changes of some selected parameters(for example,pH,composting temperature and OM content).Only the content of the total mobile fractions for Cu could be predictable from its total content.For the prediction of the total mobile fractions of Zn,Ni,Cd and Cr,the R2 value was significantly increased by the inclusion of other variables such as pH,temperature and OM content.
基金funded by the National Natural Science Foundation of China(grant No.41572329)
文摘Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals,many studies have suggested that the bioavailability of trace metals may change according to the conditions of the environment,
文摘This article presents a review of the analytical relevance of trace metal speciation analysis, which must be considered in environmental and biophysicochemical systems for reliable and efficient assessment and monitoring of trace metals. Examples are given of methodological approaches used for speciation analysis. An overview of speciation analysis in sediments, aquatic ecosystems and agrosystems is also presented.
文摘A simple on-line sonodigestion system was successfully used for breakdown organic nickel complexes in environmental waters acidified with diluted nitric acid prior to flow injection total dissolved nickel preconcentration in a microcolumn containing a chelating resin (Chelite Che with iminodiacetic acid groups) and determination by flame atomic absorption spectrometry. For the determination of the dissolved labile nickel fraction, microcolumns packed with the chelating resin were loaded in-situ with the sample without sample pH modification, and once in the laboratory were inserted in the flow injection device where nickel elution-detection was carried out. The performance of the chelating resin was investigated in order to elucidate its behavior in the presence of dissolved nickel species. The results obtained reveal that the resin, at the experimental employed conditions, retained only dissolved free nickel ions and nickel bound to weak complexes (labile fraction). The figures of merit for determinations in both nickel fractions are given and the obtained values are discussed. The speciation scheme is applied to the analysis of nickel in river and seawater samples collected in Galicia (Northwest, Spain). The results of fractionation showed that Ni are mainly in the dissolved labile fraction in river water, while in seawater samples analyzed was mainly present in the organic fraction.
文摘A new method was developed in this work to account for inorganic Sb species interconversion during soil sample preparation and subsequent separation steps. The Sb(III) and Sb(V) concentrations at each investigated step in the analytical procedure were determined using species specific spikes (121Sb(III) with 81.18% and 123Sb(V) with 74.04% enrichment). The spiking of these enriched isotopes species solutions was done separately before soil sample extraction and before HPLC separation. Simply by subtracting the final concentration of each species done by on-line isotope dilution (ID) from its concentration at different stages of the analytical procedure done by species specific ID, the influence of each step on species transformation can be estimated. After optimization, the extraction procedure for inorganic Sb species 6% Sb(III) (1.3 RSD, n = 3) and 43.2% Sb(V) (2.9% RSD, n = 3) as percent of total Sb were detected in the examined soil sample using online ID. Using the above described methodology we found that there was no reduction of Sb(V) to Sb(III) during sample preparation or species separation. While about 9.3% of extractable Sb (4.6% of total) was converted from Sb(III) to Sb(V) during the extraction step, no conversion during HPLC separation step was observed. By compensating for Sb(III) transformation during the sample preparation step;the extractable Sb(III) and Sb(V) as percent of total Sb yielded 10.6% and 38.7%, respectively.
基金Financial support for this work was provided by the National Natural Science Foundation of China (NSFC: 21767007)the Science and Technological Program of Guizhou (2018-1111)
文摘Mercury(Hg) is a global pollutant and can be accumulated in the food chain, posing exposure risks to humans. In this study, rice plants and corresponding rhizosphere soil samples were collected from a watershed of the Wawu River Basin that is heavily impacted by historic Hg mining and retorting activities. Total mercury(THg)and methylmercury(MeHg) in rice grains, as well as other tissues and soil samples, were measured. Five soil Hg fractions, as well as soil parameters, were also determined.The results show that the average concentrations of THg and MeHg in rice grains were 14 ± 7.0 lg kg^(-1) and7.2 ± 4.0 lg kg^(-1). Soil organic-bound(Hg-o) and strong complex-bound(Hg-s) were the main Hg fractions,accounting for 44% of the total. To estimate the Hg–ligand interaction in the soils, soil-N/Hg(R = 0.451, p \ 0.05),-S/Hg(R = 0.372, p \ 0.1), and-OM/Hg ratio(R = 0.320,p \ 0.5) with MeHg_(soil) were observed with significant positive correlations, indicating that the formation of Hg–OM, Hg–N–OM or Hg–S–OM complexes could prevent Hg(II) from methylation in soils. The significant positive correlations of the-N/Hg ratio,-S/Hg ratio and-OM/Hg ratio with MeHg in rice tissues suggested that Hg methylation and MeHg demethylation occurred throughout the rice paddy ecosystem. The estimated MeHg daily intake(EDI) was 0.075 ± 0.041 lg kg^(-1) bw d^(-1) and was lower than the RfD level of 0.1 lg kg^(-1) bw d^(-1) recommended by the US EPA. However, approximately 29% of the hazardous index(HI) of MeHg in grain exceeded 1, posing a potential threat to local populations, particularly pregnant women and children.
基金the National Natural Science Foundation of China !49831005 ,29777013
文摘This paper presents a computer model using thermodynamic relationships and mass balance to investigate the speciation of aluminum in acidic natural water equilibria with mineral kaolinite. Factors affecting the distribution are discussed. Compared with the case of equilibria with gibbsite, some unique characteristics are discovered. The model is verified by analyzing practical water samples. Effect of errors in thermodynamic data on calculation is evaluated by the Monte Carlo simulation.
基金Financial supports from the State Key Program of National Natural Science of China (Grant 20836009)the Key Pillar Program of Tianjin Municipal Science and Technology (Grant 11ZCKGX02800)+2 种基金the Specialized Research Fund for the Doctoral Program of Chinese Higher Education (Grant 20101208110003)the Tianjin Key Laboratory of Marine Resources and Chemistry in TUST (Grants 201303)the Natural Science Fund of TUST (Grants 20130112)
文摘Introduction Coupled techniques such as HPLC–HG–AAS,HPLC–ICP–MS,HPLC–HG–AFS are widely used for arsenic speciation analysis in biosamples,during which pretreatment method usually plays a significant role.
基金The National Natural Science Foundation of China under contract Nos 41876071,41476065 and 41806096the Biogeochemical Cycle and Biodiversity Regulation Function of Biogenic Elements in the Indo-Pacific Confluence Area under contract No.42090043。
文摘Selenium(Se)has been recognized as a key trace element that is associated with growth of primary producers in oceans.During March and May 2018,surface water(67 samples)was collected and measured by HG-ICP-MS to investigate the distribution and behavior of selenite[Se(Ⅳ)],selenate[Se(Ⅵ)]and dissolved organic selenides(DOSe)concentrations in the Zhujiang River Estuary(ZRE),South China Sea(SCS)and Malacca Straits(MS).It showed that Se(Ⅳ)(0.14–3.44 nmol/L)was the dominant chemical species in the ZRE,related to intensive manufacture in the watershed;while the major species shifted to DOSe(0.05–0.79 nmol/L)in the MS,associated with the wide coverage of peatland and intensive agriculture activities in the Malaysian Peninsula.The SCS was identified as the northern and southern sections(NSCS and SSCS)based on the variations of surface circulation.The insignificant variation of Se(IV)in the NSCS and SSCS was obtained in March,potentially resulting from the high chemical activity and related preferential assimilation by phytoplankton communities.Contrastively,the lower DOSe concentrations in the SSCS likely resulted from higher primary production and utilization during March.During May,the concentration of Se(Ⅳ)remained low in the NSCS and SSCS,while DOSe concentrations increased notably in the SSCS,likely due to the impact of terrestrial inputs from surface current reversal and subsequent accumulation.On a global scale,DOSe is the dominant Se species in tropical oceans,while Se(Ⅳ)and Se(Ⅵ)are major fractions in high-latitude oceans,resulting from changes in predominated phytoplankton and related biological assimilation.
基金funded by Kunyu Mountain National Nature Reserve Administration。
文摘Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespread species(P.sylvestris and P.densiflora)via hybrid speciation,the conclusion was based on a low number of informative restriction sites.In this study,we analyzed the sequences of four Pinus chloroplast(cp)genomes(P.sylvestris,P.densiflora,P.funebris and P.takahasii)to clarify whether hybrid speciation was involved.The complete cp-genomes of Pinus species ranged in size from 119,865 to 119,890 bp,similar to other Pinus species.Phylogenetic results based on the whole cp-genomes showed P.sylvestris clustered with P.funebris and P.takahasii,which suggested that P.sylvestris was the paternal parent in hybridization events.In an analysis of simple sequence repeats(SSRs),we detected a total of 69 SSRs repeats among the four Pinus cp-genomes;most were A or T bases.In addition,we identified divergent hotspot regions among the four Pinus cp-genomes(trnE-clpP,cemA-ycf4,petD-rpoA,psbD-trnT,and trnN-chlL),in P.sylvestris(psbD-trnT,trnN-chlL,psbB and rps8)and in P.densiflora(trnE-clpP,petD-rpoA,ycf3 intron,psbD-trnT,and trnN-chlL).The genome information found in this study provides new insights into hybrid speciation in P inus and contributes to a better understanding of the phylogenetic relationships within the Pinus genus.
