Evaluation and mapping of relative sensitivity of the terrestrial ecosystems to acidic deposition in Fujian

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).

The buffering effects of aquatic sediments against acidic deposition

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.

Effect of acidic deposition on productivity of forest ecosystem and estimation of its economic losses in southern suburbs of Chongqing, China

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.

Acid deposition critical loads modeling for the simulation of sulfur exceedance and reduction in Guangdong, China

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.

Influence of acid deposition on atmospheric corrosion of zinc

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.

Effects of acid deposition on forests in south China

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.

Chance-constrained programming (CCP)abatement of SO_2 emission for acid deposition control in Liuzhou City

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.

Solid components and acid buffering capacity of soils in South China

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.

Influence of Vertical Eddy Diffusivity Parameterization on Daily and Monthly Mean Concentrations of O3 and NOy

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.

Effects of simulated acid rain on cation releasing in soils of South China

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.

The Coexisting Clinopyroxene-Garnet Acidometer and Acidity Facies of Skarn Deposits

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.

Effects of microplastic polystyrene,simulated acid rain and arbuscular mycorrhizal fungi on Trifolium repens growth and soil microbial community composition

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.

Simulated N and S deposition affected soil chemistry and understory plant communities in a boreal forest in western Canada

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.

A NEW DRY DEPOSITION VELOCITY PATTERN AND ITS PRACTICAL APPLICATION IN HIGH RESOLUTION REGIONAL ACID DEPOSITION MODEL

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.

Mapping Critical Loads of Acid Deposition for Soils in China

A method described is to produce critical load maps of acid deposition for soils in China. Critical loads were assigned to the most sensitive soil in each 0.1°×0.1° grid square of China based on the Skokloster classification [1] and adjusted for temperature and land use. The map shows that soils with small critical load (<0.5keq·ha -1 ·a -1 ) i.e., highly sensitive to acid deposition, dominate in the south and northeast China. As a result of the adjustment, much of the acid sensitive area in the south estimated by the Skokloster method is lost. This reflects the decreased sensitivity as a result of agricultural activities and increased weathering rate in response to high temperature. Based on the 0.1°×0.1° map, a series of percentile critical load maps at 1°×1° scale were compiled for integrated assessments, as well as a critical load map using the minimum critical load for each grid. Comparison of critical loads with sulphur deposition in 1995 led to the critical load exceedance maps for sulphur deposition, which show that high exceedance areas do not correlate well with the low critical load areas, and almost one fourth of the land area, mainly in the southeast, is subject to the risk of acidification.

NUMERICAL MODELING OF AIR POLLUTANT AND RAINFALL EFFECT ON ACID WET DEPOSITION

It is helpful to go deep into understanding the acid rainfall through studying the relation of two centers between acid deposition and rainfall and the relation of intensity between them.We adopt a three-dimensional Eulerian regional acid deposition model,or NCAR-RADM,to calculate regional chemical concentrations and dry and wet depositions of acids.The temporally and spatially varied meteorological field is provided by a mesoscale meteorological model,vertion 4.We calculate dry and wet depositions of acids in eight kinds of different rainfall distributions.The results show that the wet depositions of acids near pollutant source is very sensitive to rainfall intensity in initial stage.The distribution of acid wet deposition will tend to that of rainfall intensity when rainfall intensity is small in source.And it will tend to that of initial pollutant concentration when rainfall intensity is large in source.

Therapeutic potential of ethyl acetate fraction of Tephrosia purpurea Linn.leaves in a rat model of gout

Objective: The present study is to determine the potential treatment effects of ethyl acetate fraction of Tephrosia purpurea Linn. leaves(EATP) against gout.Methods: Gout in experimental rats was induced with potassium oxonate at the dose of 250 mg/kg(intraperitoneal injection) for 7 consecutive days;EATP was administered 1 h after administration of the potassium oxonate on each day of experiment. Potassium oxonate was discontinued on the 8 th day;thereafter allopurinol(10 mg/kg, p.o.) and EATP(200 and 400 mg/kg, p.o.) were continued until day 14. The uric acid level was measured from serum and urine during the experiment. Other biochemical parameters were assessed, including blood and urine creatinine, erythrocyte sedimentation rate, and total protein. Blood urea nitrogen, serum aspartate aminotransferase serum alanine aminotransferase and alkaline phosphatase were also measured. The blood was analyzed for levels of malondialdehyde and the antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase.Histopathological and radiological changes in the ankle of rats were observed after completion of the experiment.Results: EATP was able to decrease serum uric acid and creatinine level;it also reduced inflammation,oxidative stress and lysosomal enzyme level, which has a role in acute inflammation. EATP increased uric acid excretion through urine due to its uricosuric effect.Conclusion: EATP lowered the serum uric acid level and increased the urine uric acid level through excretion, which is useful in the treatment of gout. Hence the EATP was found to be helpful in the treatment of gout.

Role of forests in headwater control with changing environment and society

Forest practices in headwater catchments are related to environmental and social contexts.The aim of this study is to analyse the changing protective functions of forests in the upper plain of the Jizera Mts.(North Bohemia,Czech Republic)since the second half of the 19th century.With time,forests have gradually changed from native stands to spruce plantations(Picea abies),introducing exotic conifers(more resistant to air pollution),and,recently,back to more diverse mixed stands.The priority in pro-tective forest functions there shifted from flood protection to integrated control of water resources(quantity and quality).In the 1980s,forest-water interactions were degraded by consequences of extreme acid atmospheric deposition,forest die-back,and extensive clear-cut.In the Jizerka catchment,first signs of recovery were observed in the early 1990s.but.stream waters there are still affected by prolonged acidification.While reconstruction of stream water chemistry at Jizerka follows the drop of the acid deposition in some 5 years,the revival of stream biota takes 10-15 years.In 2071-2100,the pro-jected climate change shows rising annual air temperatures by 3.0-4.6℃,decreasing water yield by 65-123 mm,60%drop in'minimum residual discharge',and 20-30%rise in peak-flows.However,these projected environmental changes cannot substantially decline the high potential in water resource recharge,or,start reverse processes in recent recovery from acidification and radically affect the exis-tence of planned mixed forests in the upper plain of the Jizera Mts.