Based on the semi-quantitative approach, four environmental factors of sites (i.e. bedrock lithology, soil type, land use, and rainfall) were categorized, weighted and combined to determine and assess the relative sen...Based on the semi-quantitative approach, four environmental factors of sites (i.e. bedrock lithology, soil type, land use, and rainfall) were categorized, weighted and combined to determine and assess the relative sensitivity of the terrestrial ecosystems to acidic deposition in Fujian Province. Then the factors have been digitized and combined to assign an overall value for each mesh square (16.77 km×18.39 km) by using the geographic information system (GIS) The results indicated that the most sensitive area in Fujian was mainly located in the southeast, and the least: ensitive area was distributed sporadically in the east along the coast. Due to slow weathering rate of siliceous rocks, acid to weakly acid reactions of the soils, along with the greater percent of coniferous forests, more than 80 percent of the total area exhibits higher sensitivity classes (4–7).展开更多
Acidic deposition,which is mainly caused by atmospheric pollution,is one of the global environmental problems.Thinning is an effective management to improve the tree productivity,reduce the wildfire risk and maintain ...Acidic deposition,which is mainly caused by atmospheric pollution,is one of the global environmental problems.Thinning is an effective management to improve the tree productivity,reduce the wildfire risk and maintain a healthy forest.Since thinning may reduce the effect of acidic deposition,the effect of thinning on acidic deposition was estimated.The biomass,soil properties,pH value of runoff and groundwater in both unthinned and thinned Chinese fir plantations were measured and compared over a 5-year period(2-6 years after thinning).The results indicated that acidic deposition in the Huitong State Ecosystem Research Station was serious,and it got worse with time.Forest thinning resulted in a huge change in biomass and soil properties.During the 5-year monitoring period,biomasses of understory and litter,plant species richness,coverage of undergrowth plant layer were significantly higher in thinned site than in unthinned site.Moreover,higher soil fertility as well as lower amounts of runoff and groundwater were found in thinned site.It was suggested that thinning could improve the structure of forest,leading to restoring the effluent(runoff and groundwater) pH to the normal value.展开更多
The cation exchange and the chemical weathering are two important processes for sedi-ments to buffer the acidification of surface water. In this paper, for sediments these two processeshave been studied. The relations...The cation exchange and the chemical weathering are two important processes for sedi-ments to buffer the acidification of surface water. In this paper, for sediments these two processeshave been studied. The relationship between BFC of sediments and ANC of the surface waters andthe weathering characteristics of sediments were discussed. The buffering effect and mechanism of sedi-ments against acidic deposition have also been studied. The results show that BFC of sediments arepositively correlative to ANC of the surface waters. the chemical weathering rate of sediments can beexpressed as R=k×[H ̄ +] ̄m.展开更多
In accordance with principles and methods of ecology, the effects of acidic deposition on productivity and volume increment of masson pine and Cinnamomum campora forest which are widely distributed in southern sub...In accordance with principles and methods of ecology, the effects of acidic deposition on productivity and volume increment of masson pine and Cinnamomum campora forest which are widely distributed in southern suburbs of Chongqing, China were studied. Based on the field data and measurements, a multivariable stepwise regression model was established to analyze the effects of multiple environmental factors on the productivity of the forest ecosystems. This model was used to assess the volume and economic losses of these two forest ecosystems caused by acidic deposition. The result showed that, among the environmental factors, pH value of precipitation, soil depth, soil organic contents and slope are the dominant ones influencing the growth of masson pine forest. It was also shown that the acidic deposition has no clear relation to the growth of C.Campora forest, so development of such broad leaved forest is suitable in the area.展开更多
The current acid deposition critical loads in Guangdong, China were calculated using the PROFILE model with a 3 km × 3 km resolution. Calculations were carded out for critical loads of potential acidity, actual a...The current acid deposition critical loads in Guangdong, China were calculated using the PROFILE model with a 3 km × 3 km resolution. Calculations were carded out for critical loads of potential acidity, actual acidity, sulfur and nitrogen, with values in extents of 0-3.5, 0-14.0, 0-26.0 and 0-3.5 kmol/(hrnE.year), respectively. These values were comparable to previously reported results and reflected the influences of vegetation and soil characteristics on the soil acid buffering capacity. Simulations of SO2 emission and sulfur deposition in this study showed that sulfur deposition core areas mirrored SO2 emission centers. The prediction of sulfur deposition after 20% and 40% reduction of SO2 emission suggested that the reduction of area sources contributed greatly to the decrease of sulfur deposition. Thus, abatement of area source emissions could be the primary way to mitigate sulfur deposition in Guangdong to meet both the provincial and national regulations of air pollution control.展开更多
The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the alu...The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the aluminum toxicity on pine seedlings, and the long-term soil acidification model (LTSAM) and a terrestrial biogeochemistry model (CENTURY) are used to simulate the influences of acid deposition on pine forest ecosystems. The indoor experiment results of aluminum toxicishow that aluminum ions in solution limit plant growth and acid deposition enhances this effect by facilitating the release of aluminum ions from the soil. Pine seedling bio- mass and root elongation decrease as the aluminum concentration increases. The results of model simulations show that the soil chemis- try varies significantly with different changes in acid deposition. When the acid deposition increases, the pH value in the soil solution decreases and the soil A13+ concentration increases. The increased acid deposition also has negative impacts on the forest ecosystem, i.e., decreases plant biomass, net primary productivity (NPP) and net C02 uptake. As a result, the soil organic carbon (SOC) decreases be- cause of the limited supply of decomposition material. Thus acid deposition need be reduced to help protect the forest ecosystems.展开更多
Site exposure tests both open and sheltered have been carried out in acid deposition area in Southwest China. Results from six sites show that acid deposition exerts a great influence on atmospheric corrosion of Zn, a...Site exposure tests both open and sheltered have been carried out in acid deposition area in Southwest China. Results from six sites show that acid deposition exerts a great influence on atmospheric corrosion of Zn, and it is more serious in wet condition. Basically, Zn corrosion is directly proportional to time of exposure. While SO2 is the main pollutant of the atmosphere environment, Zn corrosion has a linear relationship to SO2 depositing rate and a hyperbolic to rain pH value.Observations by SEM, EDAX and X-ray diffraction show that under sheltered exposure condition, the corrosion products of Zn in heavy acid deposition area principally are sulphates.Based on the corrosion rates measured, the working life of galvanized steel can be predicated.展开更多
Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. T...Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. The results showed that contribution rates of acid deposition to forest volume loss in seven provinces of south China vary from 24 5% to 37 91%; the volume loss rates range from 7% to 20%. Total volume losses per year are 1 0145×10 6 m 3, of which Zhejiang Province is the greatest, totalling 3 841×10 5 m 3, while Anhui Province is the least, amounting to 1 59×10 4 m 3.展开更多
A deterministic linear programming model which optimizes the abatement of each SO2 emission source, is extended into a CCP form by introducing equations of probabilistic constrained through the incorporation of uncert...A deterministic linear programming model which optimizes the abatement of each SO2 emission source, is extended into a CCP form by introducing equations of probabilistic constrained through the incorporation of uncertainty in the source-receptor-specific transfer coefficients. Based on the calculation of SO2 and sulfate average residence time for Liuzhou City, a sulfur deposition model has been developed and the distribution of transfer coefficients have been found to be approximately log-normal. Sulfur removal minimization of the model shows that the abatement of emission sources in the city is more effective, while control cost optimization provides the lowest cost programmes for source abatement at each allowable deposition limit under varied environmental risk levels. Finally a practicable programme is recommended.展开更多
Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 th...Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42", NO3, NH4+ and H+. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42" and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H+ concentrations traveled over local EGU (Electric Generating Unit) emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service.展开更多
INTRODUCTION Soil acidification due to acid deposition has been one of the major environmental prob-lems concerned by soil scientists and ecologists for the recent 20 years(van Breemen,1990).Soil acidification with a ...INTRODUCTION Soil acidification due to acid deposition has been one of the major environmental prob-lems concerned by soil scientists and ecologists for the recent 20 years(van Breemen,1990).Soil acidification with a marked pH decrease of forest soils within various time intervals hasbeen reported in Germany,Sweden,the Netherlands,Australia and the United展开更多
This paper aims to use hyperspectral data to detect the spectral change caused by acid stress to a native forest type in the Three Gorges region of China. For this purpose, a ground-based hyperspectral experiment was ...This paper aims to use hyperspectral data to detect the spectral change caused by acid stress to a native forest type in the Three Gorges region of China. For this purpose, a ground-based hyperspectral experiment was conducted at the Three Gorges region to detect acid deposition that caused Masson pine (Pinus massoniana) forest degra-dation. Continuum removal method was used to isolate wavebands more responsive to stress in wavelengths 450-750nm. The differences in chlorophyll concentrations and needle thickness caused by acidic stress are found to be explicable to the different spectral reflectance patterns in the visible and near-infrared wavelengths. Two new chlorotic indices were utilized to explain the stress-caused leaf chlorosis. The comparison of simulated vegetation indices and principal component analysis (PCA) results suggests that it would be possible to monitor acid rain stress effect on forest ecosystem from some wider spectral regions.展开更多
The effects of soil solid components on soil sensitivity to acid deposition by sequential extraction method were studied. A multiple regression equation of soil sensitivity was set up on the basis of stepwise regressi...The effects of soil solid components on soil sensitivity to acid deposition by sequential extraction method were studied. A multiple regression equation of soil sensitivity was set up on the basis of stepwise regression analysis. The results showed that organic matter expressed dual effects that were decided by soil original pH value and exchangeable cation composition on acid buffering reactions. The hydrolysis of activated oxides was a very important proton buffering reaction when in low pH situation. The crystalline oxides also played a role in the buffering reactions, but the role was restricted by the rate of activation of oxides. Meanwhile, the results by stepwise analysis showed that factors that had significant effect on soil acid buffering capacity were content of montmorillite, soil original pH value, Al 0, Mn 0 and CEC in decreasing order. Finally, sixteen soils were classified into four types of sensitive with single index cluster and multiple fuzzy cluster analysis respectively.展开更多
Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all...Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all reactive nitrogen species, i.e., NOy=NO+NO2+HNO3+PAN. Simulations indicate that great changes in the vertical diffusivity usually occur within the planetary boundary layer (PBL). Daily and monthly mean concentrations of NOy are much more sensitive to changes in the vertical diffusivity than those of ozone and ozone and NOy levels only at or in (relatively) clean sites and areas, where long-range transport plays a crucial role, display roughly equivalent sensitivity. The results strongly suggest that a widely-accepted parameterization scheme be selected and the refinement of the model's vertical resolution in the PBL be required, even for regional and long-term studies, and ozone only being examined in an effort to judge the model's performance be unreliable, and NOy be included for model evaluations.展开更多
This paper deals with the release of base cations and Al^3+ at the treatment with simulated acid rain (SAR) in main soil types collected from South China. Results showed that the amounts of base cations increased obvi...This paper deals with the release of base cations and Al^3+ at the treatment with simulated acid rain (SAR) in main soil types collected from South China. Results showed that the amounts of base cations increased obviously when the pH value of simulated acid rain was lower than 30 or 35. Compared with the leaching of K^+ and Na^+, the leaching of Ca^2+ and Mg^2+ was affected by the pH value of SAR. Only when the amounts of base cations leached from soils exceeded the cation exchange capacity, the pH value of leaching solutions decreased sharply and the amounts of released Al^3+ increased. The H^+ buffering mechanisms, which were affected not only by the pH values of SAR, but also by the types and solid components of soils, were proposed for the main soils studied.展开更多
This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Cou...This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Countries. We performed field exposure tests of carbon steel, zinc and copper at an urban site Guanyinqiao and a rural site Tieshanping inChongqing, then used grey relational analysis, based on the database of the whole corrosion project, to determine the order of the effect of environmental factors on corrosion rates of tested metals, and established dose-response functions for these three metals. The results showed that the two crucial agents of acidic environment, SO2 and H+, were common factors that contributed most to the corrosion of the tested metals. The established dose-response functions for outdoor carbon steel and zinc are proved applicable to use in Chongqing, but the function for copper needs further modifying. We employed these dose- response functions and general environmental data to elaborate the maps of corrosion rate respectively of carbon steel and zinc by geological information system (GIS) technique which help to identify areas of high corrosion damage risk. An acceptable annual average SO2 level of 21 μg/m3 for carbon steel and that of 61 μg/m3 for zinc are also put forward to control the air pollution impact on atmospheric corrosion in Chongqing urban areas.展开更多
On the basis of geological studies of skarn deposits in China and by using thermodynamic models of thesolid solution, the coexisting clinopyroxene-garnet pair in skarn deposits has been analysed and a coexistingclinop...On the basis of geological studies of skarn deposits in China and by using thermodynamic models of thesolid solution, the coexisting clinopyroxene-garnet pair in skarn deposits has been analysed and a coexistingclinopyroxene-garnet acidometer developed. They can be used to estimate the medium condition under whichthe skarn was formed. The research on the acidity for the formation of various metallic skarn deposits in Chinasuggests that skarns endowed with dissimilar types of mineralization and occurring in diverse environments dif-fer in the acidity conditions for their formation and in the trend of acidity variation of ore-bearing fluid. This,coupled with the study of oxygen fugacity of coexisting minerals, makes it possible to establish the oxygenfugacity-acidity facies of skarn deposits, which reflect the close genetic relationship between the metallizationand the formation of skarn.展开更多
Microplastic pollution is a global and ubiquitous environmental problem in the oceans as well as in the terrestrial environment.We examined the fate of microplastic polystyrene(MPS)beads in experimental soil in the pr...Microplastic pollution is a global and ubiquitous environmental problem in the oceans as well as in the terrestrial environment.We examined the fate of microplastic polystyrene(MPS)beads in experimental soil in the presence and absence of symbiotic arbuscular mycorrhizal fungi(AMF)and simulated acid rain(SAR)to determine whether the combinations of these three factors altered the growth of white clover Trifolium repens.We found that MPS,SAR,or AMF added singly to soil did not alter T.repens growth or yields.In contrast,MPS and AMF together significantly reduced shoot biomass,while SAR and MPS together significantly reduced soil available phosphorus independent of AMF presence.Microplastic polystyrene,AMF,and SAR together significantly reduced soil NO_(3)^(-)-N.Arbuscular mycorrhizal fungi added singly also enriched the beneficial soil bacteria(genus Solirubrobacter),while MPS combined with AMF significantly enriched the potential plant pathogenic fungus Spiromastix.Arbuscular mycorrhizal fungi inoculation with MPS increased the abundance of soil hydrocarbon degraders independent of the presence of SAR.In addition,the abundance of soil nitrate reducers was increased by MPS,especially in the presence of AMF and SAR.Moreover,SAR alone increased the abundance of soil pathogens within the fungal community including antibiotic producers.These findings indicate that the coexistence of MPS,SAR,and AMF may exacerbate the adverse effects of MPS on soil and plant health.展开更多
Aims We conducted a simulated nitrogen(N)and sulfur(S)deposition experi-ment from 2006 to 2012 to answer the following questions:(i)does chronic N and S deposition decrease cation concentrations in the soil and foliag...Aims We conducted a simulated nitrogen(N)and sulfur(S)deposition experi-ment from 2006 to 2012 to answer the following questions:(i)does chronic N and S deposition decrease cation concentrations in the soil and foliage of understory plant species,and(ii)does chronic N and S deposition decrease plant diversity and alter species composition of the understory plant community in a boreal forest in western Canada where intensifying industrial activities are increasing N and S deposition?Methods Our field site was a mixedwood boreal forest stand located~100 km southeast of Fort McMurray,Alberta,Canada.the experiment involved a 2×2 factorial design,with two levels each of N(0 and 30 kg N ha−1 yr−1;applied as NH4NO3)and S addition(0 and 30 kg S ha−1 yr−1;applied as Na2SO4).Four blocks were established in July 2006,each with four plots of 20×20 m randomly assigned to the treatments.Soil and understory vegetation were sampled and cover(%)of individual species of herb(height≤0.5 m)and shrub(height 0.5-1 m)layers was determined in August 2012.Important Findings Seven years after the treatments began,N addition increased dissolved organic carbon and N in the mineral soil(P<0.05),whereas S add-ition decreased exchangeable cations(P<0.05)in the forest floor.In the shrub layer,species evenness,and overall diversity were decreased by N addition(P<0.05)due to increases in abundance of nitrophil-ous species and S addition(P<0.01)due to decreased cation con-centrations in soils.total shrub cover decreased with S addition(P<0.10).Nitrogen and S addition affected neither species richness nor evenness in the herb layer.However,permutational multivariate ana-lysis of variance and non-metric multidimensional scaling analyses(based on plant cover)indicated that the effect of N and S addition on understory plant species composition in the both shrub and herb layers was species-specific.Addition of N decreased foliar phosphorus and potassium concentrations in some species,suggesting potential risk of N-meditated nutrient imbalance in those species.Our results indicate that long-term elevated levels of N and S deposition can negatively impact plant nutrition and decrease the diversity of the understory plant community in boreal forests in northern Alberta,Canada.However,considering that the current N and S deposition rates in northern Alberta are much lower than the rates used in this study,N and S deposition should not negatively affect plant diversity in the near future.展开更多
A new dry deposition velocity pattern (NDDVP) for the study of region-scale dry deposition processes is developed. The mean ratio between NDDVP and 1022 experimental data of dry deposi- tion velocity V_d is 1. 06±...A new dry deposition velocity pattern (NDDVP) for the study of region-scale dry deposition processes is developed. The mean ratio between NDDVP and 1022 experimental data of dry deposi- tion velocity V_d is 1. 06±0.82. The result shows that NDDVP is well consistent with experimental data. Practical cases are forecasted by the high resolution regional acid deposition model (EM3) with both NDDVP and old V_d pattern. The maximum ratio between the central concentrations for SO4 can reach 2.4 only due to different V_d patterns. 3-D distributions of species concentrations and dry depositions forecasted by NDDVP are better than those by the old V_d pattern.展开更多
文摘Based on the semi-quantitative approach, four environmental factors of sites (i.e. bedrock lithology, soil type, land use, and rainfall) were categorized, weighted and combined to determine and assess the relative sensitivity of the terrestrial ecosystems to acidic deposition in Fujian Province. Then the factors have been digitized and combined to assign an overall value for each mesh square (16.77 km×18.39 km) by using the geographic information system (GIS) The results indicated that the most sensitive area in Fujian was mainly located in the southeast, and the least: ensitive area was distributed sporadically in the east along the coast. Due to slow weathering rate of siliceous rocks, acid to weakly acid reactions of the soils, along with the greater percent of coniferous forests, more than 80 percent of the total area exhibits higher sensitivity classes (4–7).
基金Project(41271332)supported by the National Natural Science Foundation of ChinaProject(11JJ2031)supported by the Natural Science Foundation of Hunan Province,China
文摘Acidic deposition,which is mainly caused by atmospheric pollution,is one of the global environmental problems.Thinning is an effective management to improve the tree productivity,reduce the wildfire risk and maintain a healthy forest.Since thinning may reduce the effect of acidic deposition,the effect of thinning on acidic deposition was estimated.The biomass,soil properties,pH value of runoff and groundwater in both unthinned and thinned Chinese fir plantations were measured and compared over a 5-year period(2-6 years after thinning).The results indicated that acidic deposition in the Huitong State Ecosystem Research Station was serious,and it got worse with time.Forest thinning resulted in a huge change in biomass and soil properties.During the 5-year monitoring period,biomasses of understory and litter,plant species richness,coverage of undergrowth plant layer were significantly higher in thinned site than in unthinned site.Moreover,higher soil fertility as well as lower amounts of runoff and groundwater were found in thinned site.It was suggested that thinning could improve the structure of forest,leading to restoring the effluent(runoff and groundwater) pH to the normal value.
文摘The cation exchange and the chemical weathering are two important processes for sedi-ments to buffer the acidification of surface water. In this paper, for sediments these two processeshave been studied. The relationship between BFC of sediments and ANC of the surface waters andthe weathering characteristics of sediments were discussed. The buffering effect and mechanism of sedi-ments against acidic deposition have also been studied. The results show that BFC of sediments arepositively correlative to ANC of the surface waters. the chemical weathering rate of sediments can beexpressed as R=k×[H ̄ +] ̄m.
文摘In accordance with principles and methods of ecology, the effects of acidic deposition on productivity and volume increment of masson pine and Cinnamomum campora forest which are widely distributed in southern suburbs of Chongqing, China were studied. Based on the field data and measurements, a multivariable stepwise regression model was established to analyze the effects of multiple environmental factors on the productivity of the forest ecosystems. This model was used to assess the volume and economic losses of these two forest ecosystems caused by acidic deposition. The result showed that, among the environmental factors, pH value of precipitation, soil depth, soil organic contents and slope are the dominant ones influencing the growth of masson pine forest. It was also shown that the acidic deposition has no clear relation to the growth of C.Campora forest, so development of such broad leaved forest is suitable in the area.
基金supported by Guangdong Provincial Natural Science Foundation (No. 02-38100-4202003 and 06202438)New Century Excellent Talents Program of Ministry of Education of the People’s Republic of China(No. NCET-04-0790)
文摘The current acid deposition critical loads in Guangdong, China were calculated using the PROFILE model with a 3 km × 3 km resolution. Calculations were carded out for critical loads of potential acidity, actual acidity, sulfur and nitrogen, with values in extents of 0-3.5, 0-14.0, 0-26.0 and 0-3.5 kmol/(hrnE.year), respectively. These values were comparable to previously reported results and reflected the influences of vegetation and soil characteristics on the soil acid buffering capacity. Simulations of SO2 emission and sulfur deposition in this study showed that sulfur deposition core areas mirrored SO2 emission centers. The prediction of sulfur deposition after 20% and 40% reduction of SO2 emission suggested that the reduction of area sources contributed greatly to the decrease of sulfur deposition. Thus, abatement of area source emissions could be the primary way to mitigate sulfur deposition in Guangdong to meet both the provincial and national regulations of air pollution control.
基金Under the auspices of National Basic Research Program of China(No.2010CB951802,2005CB422207)Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-219)National High Technology Research and Development Program of China(No.2009AA122104)
文摘The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the aluminum toxicity on pine seedlings, and the long-term soil acidification model (LTSAM) and a terrestrial biogeochemistry model (CENTURY) are used to simulate the influences of acid deposition on pine forest ecosystems. The indoor experiment results of aluminum toxicishow that aluminum ions in solution limit plant growth and acid deposition enhances this effect by facilitating the release of aluminum ions from the soil. Pine seedling bio- mass and root elongation decrease as the aluminum concentration increases. The results of model simulations show that the soil chemis- try varies significantly with different changes in acid deposition. When the acid deposition increases, the pH value in the soil solution decreases and the soil A13+ concentration increases. The increased acid deposition also has negative impacts on the forest ecosystem, i.e., decreases plant biomass, net primary productivity (NPP) and net C02 uptake. As a result, the soil organic carbon (SOC) decreases be- cause of the limited supply of decomposition material. Thus acid deposition need be reduced to help protect the forest ecosystems.
文摘Site exposure tests both open and sheltered have been carried out in acid deposition area in Southwest China. Results from six sites show that acid deposition exerts a great influence on atmospheric corrosion of Zn, and it is more serious in wet condition. Basically, Zn corrosion is directly proportional to time of exposure. While SO2 is the main pollutant of the atmosphere environment, Zn corrosion has a linear relationship to SO2 depositing rate and a hyperbolic to rain pH value.Observations by SEM, EDAX and X-ray diffraction show that under sheltered exposure condition, the corrosion products of Zn in heavy acid deposition area principally are sulphates.Based on the corrosion rates measured, the working life of galvanized steel can be predicated.
文摘Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. The results showed that contribution rates of acid deposition to forest volume loss in seven provinces of south China vary from 24 5% to 37 91%; the volume loss rates range from 7% to 20%. Total volume losses per year are 1 0145×10 6 m 3, of which Zhejiang Province is the greatest, totalling 3 841×10 5 m 3, while Anhui Province is the least, amounting to 1 59×10 4 m 3.
文摘A deterministic linear programming model which optimizes the abatement of each SO2 emission source, is extended into a CCP form by introducing equations of probabilistic constrained through the incorporation of uncertainty in the source-receptor-specific transfer coefficients. Based on the calculation of SO2 and sulfate average residence time for Liuzhou City, a sulfur deposition model has been developed and the distribution of transfer coefficients have been found to be approximately log-normal. Sulfur removal minimization of the model shows that the abatement of emission sources in the city is more effective, while control cost optimization provides the lowest cost programmes for source abatement at each allowable deposition limit under varied environmental risk levels. Finally a practicable programme is recommended.
文摘Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42", NO3, NH4+ and H+. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42" and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H+ concentrations traveled over local EGU (Electric Generating Unit) emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service.
基金Project supported by the National Natural Science Foundation of China.
文摘INTRODUCTION Soil acidification due to acid deposition has been one of the major environmental prob-lems concerned by soil scientists and ecologists for the recent 20 years(van Breemen,1990).Soil acidification with a marked pH decrease of forest soils within various time intervals hasbeen reported in Germany,Sweden,the Netherlands,Australia and the United
文摘This paper aims to use hyperspectral data to detect the spectral change caused by acid stress to a native forest type in the Three Gorges region of China. For this purpose, a ground-based hyperspectral experiment was conducted at the Three Gorges region to detect acid deposition that caused Masson pine (Pinus massoniana) forest degra-dation. Continuum removal method was used to isolate wavebands more responsive to stress in wavelengths 450-750nm. The differences in chlorophyll concentrations and needle thickness caused by acidic stress are found to be explicable to the different spectral reflectance patterns in the visible and near-infrared wavelengths. Two new chlorotic indices were utilized to explain the stress-caused leaf chlorosis. The comparison of simulated vegetation indices and principal component analysis (PCA) results suggests that it would be possible to monitor acid rain stress effect on forest ecosystem from some wider spectral regions.
文摘The effects of soil solid components on soil sensitivity to acid deposition by sequential extraction method were studied. A multiple regression equation of soil sensitivity was set up on the basis of stepwise regression analysis. The results showed that organic matter expressed dual effects that were decided by soil original pH value and exchangeable cation composition on acid buffering reactions. The hydrolysis of activated oxides was a very important proton buffering reaction when in low pH situation. The crystalline oxides also played a role in the buffering reactions, but the role was restricted by the rate of activation of oxides. Meanwhile, the results by stepwise analysis showed that factors that had significant effect on soil acid buffering capacity were content of montmorillite, soil original pH value, Al 0, Mn 0 and CEC in decreasing order. Finally, sixteen soils were classified into four types of sensitive with single index cluster and multiple fuzzy cluster analysis respectively.
基金the National Natural Science Foundation of China (Grant No. 40575068) the National Key Project of Basic Research of China (Grant No. 2005CB422205) the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No. KZCX2-YW-205).
文摘Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all reactive nitrogen species, i.e., NOy=NO+NO2+HNO3+PAN. Simulations indicate that great changes in the vertical diffusivity usually occur within the planetary boundary layer (PBL). Daily and monthly mean concentrations of NOy are much more sensitive to changes in the vertical diffusivity than those of ozone and ozone and NOy levels only at or in (relatively) clean sites and areas, where long-range transport plays a crucial role, display roughly equivalent sensitivity. The results strongly suggest that a widely-accepted parameterization scheme be selected and the refinement of the model's vertical resolution in the PBL be required, even for regional and long-term studies, and ozone only being examined in an effort to judge the model's performance be unreliable, and NOy be included for model evaluations.
文摘This paper deals with the release of base cations and Al^3+ at the treatment with simulated acid rain (SAR) in main soil types collected from South China. Results showed that the amounts of base cations increased obviously when the pH value of simulated acid rain was lower than 30 or 35. Compared with the leaching of K^+ and Na^+, the leaching of Ca^2+ and Mg^2+ was affected by the pH value of SAR. Only when the amounts of base cations leached from soils exceeded the cation exchange capacity, the pH value of leaching solutions decreased sharply and the amounts of released Al^3+ increased. The H^+ buffering mechanisms, which were affected not only by the pH values of SAR, but also by the types and solid components of soils, were proposed for the main soils studied.
基金a corrosion subprogram of the international project Regional Air Pollution in Developing Countries under the contract No. JT73065.
文摘This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Countries. We performed field exposure tests of carbon steel, zinc and copper at an urban site Guanyinqiao and a rural site Tieshanping inChongqing, then used grey relational analysis, based on the database of the whole corrosion project, to determine the order of the effect of environmental factors on corrosion rates of tested metals, and established dose-response functions for these three metals. The results showed that the two crucial agents of acidic environment, SO2 and H+, were common factors that contributed most to the corrosion of the tested metals. The established dose-response functions for outdoor carbon steel and zinc are proved applicable to use in Chongqing, but the function for copper needs further modifying. We employed these dose- response functions and general environmental data to elaborate the maps of corrosion rate respectively of carbon steel and zinc by geological information system (GIS) technique which help to identify areas of high corrosion damage risk. An acceptable annual average SO2 level of 21 μg/m3 for carbon steel and that of 61 μg/m3 for zinc are also put forward to control the air pollution impact on atmospheric corrosion in Chongqing urban areas.
文摘On the basis of geological studies of skarn deposits in China and by using thermodynamic models of thesolid solution, the coexisting clinopyroxene-garnet pair in skarn deposits has been analysed and a coexistingclinopyroxene-garnet acidometer developed. They can be used to estimate the medium condition under whichthe skarn was formed. The research on the acidity for the formation of various metallic skarn deposits in Chinasuggests that skarns endowed with dissimilar types of mineralization and occurring in diverse environments dif-fer in the acidity conditions for their formation and in the trend of acidity variation of ore-bearing fluid. This,coupled with the study of oxygen fugacity of coexisting minerals, makes it possible to establish the oxygenfugacity-acidity facies of skarn deposits, which reflect the close genetic relationship between the metallizationand the formation of skarn.
基金supported by the National Natural Science Foundation of China(Nos.31971745 and 32171688)Jiangsu Qinglan Project。
文摘Microplastic pollution is a global and ubiquitous environmental problem in the oceans as well as in the terrestrial environment.We examined the fate of microplastic polystyrene(MPS)beads in experimental soil in the presence and absence of symbiotic arbuscular mycorrhizal fungi(AMF)and simulated acid rain(SAR)to determine whether the combinations of these three factors altered the growth of white clover Trifolium repens.We found that MPS,SAR,or AMF added singly to soil did not alter T.repens growth or yields.In contrast,MPS and AMF together significantly reduced shoot biomass,while SAR and MPS together significantly reduced soil available phosphorus independent of AMF presence.Microplastic polystyrene,AMF,and SAR together significantly reduced soil NO_(3)^(-)-N.Arbuscular mycorrhizal fungi added singly also enriched the beneficial soil bacteria(genus Solirubrobacter),while MPS combined with AMF significantly enriched the potential plant pathogenic fungus Spiromastix.Arbuscular mycorrhizal fungi inoculation with MPS increased the abundance of soil hydrocarbon degraders independent of the presence of SAR.In addition,the abundance of soil nitrate reducers was increased by MPS,especially in the presence of AMF and SAR.Moreover,SAR alone increased the abundance of soil pathogens within the fungal community including antibiotic producers.These findings indicate that the coexistence of MPS,SAR,and AMF may exacerbate the adverse effects of MPS on soil and plant health.
文摘Aims We conducted a simulated nitrogen(N)and sulfur(S)deposition experi-ment from 2006 to 2012 to answer the following questions:(i)does chronic N and S deposition decrease cation concentrations in the soil and foliage of understory plant species,and(ii)does chronic N and S deposition decrease plant diversity and alter species composition of the understory plant community in a boreal forest in western Canada where intensifying industrial activities are increasing N and S deposition?Methods Our field site was a mixedwood boreal forest stand located~100 km southeast of Fort McMurray,Alberta,Canada.the experiment involved a 2×2 factorial design,with two levels each of N(0 and 30 kg N ha−1 yr−1;applied as NH4NO3)and S addition(0 and 30 kg S ha−1 yr−1;applied as Na2SO4).Four blocks were established in July 2006,each with four plots of 20×20 m randomly assigned to the treatments.Soil and understory vegetation were sampled and cover(%)of individual species of herb(height≤0.5 m)and shrub(height 0.5-1 m)layers was determined in August 2012.Important Findings Seven years after the treatments began,N addition increased dissolved organic carbon and N in the mineral soil(P<0.05),whereas S add-ition decreased exchangeable cations(P<0.05)in the forest floor.In the shrub layer,species evenness,and overall diversity were decreased by N addition(P<0.05)due to increases in abundance of nitrophil-ous species and S addition(P<0.01)due to decreased cation con-centrations in soils.total shrub cover decreased with S addition(P<0.10).Nitrogen and S addition affected neither species richness nor evenness in the herb layer.However,permutational multivariate ana-lysis of variance and non-metric multidimensional scaling analyses(based on plant cover)indicated that the effect of N and S addition on understory plant species composition in the both shrub and herb layers was species-specific.Addition of N decreased foliar phosphorus and potassium concentrations in some species,suggesting potential risk of N-meditated nutrient imbalance in those species.Our results indicate that long-term elevated levels of N and S deposition can negatively impact plant nutrition and decrease the diversity of the understory plant community in boreal forests in northern Alberta,Canada.However,considering that the current N and S deposition rates in northern Alberta are much lower than the rates used in this study,N and S deposition should not negatively affect plant diversity in the near future.
基金The study is supported by the National Natural Science Foundation of China,LASG and LAPC in IAP, CAS
文摘A new dry deposition velocity pattern (NDDVP) for the study of region-scale dry deposition processes is developed. The mean ratio between NDDVP and 1022 experimental data of dry deposi- tion velocity V_d is 1. 06±0.82. The result shows that NDDVP is well consistent with experimental data. Practical cases are forecasted by the high resolution regional acid deposition model (EM3) with both NDDVP and old V_d pattern. The maximum ratio between the central concentrations for SO4 can reach 2.4 only due to different V_d patterns. 3-D distributions of species concentrations and dry depositions forecasted by NDDVP are better than those by the old V_d pattern.