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Title: Simultaneous assessment of deposition effects of base cations, sulfur, and nitrogen using an extended critical load function for acidification

Abstract

Base cations (BC) play an important role to prevent soil acidification. In certain acid sensitive areas, such as China, BC deposition is high and a considerable fraction is of anthropogenic origin. BC deposition might decrease in the future with the implementation of air pollution control measures. The effect of changes in BC deposition, however, has seldom been considered in critical load calculations based on the steady-state mass balance (SSMB) method. In order to better quantify the importance of the BC deposition for acid deposition mitigation policy, an extension of the SSMB method for critical load calculation for soil acidification is presented. The BC deposition is taken into account as a variable along with sulfur (S) and nitrogen (N) deposition, creating an S-N-BC critical load function. As a case study, critical loads of S and N for the Tie Shan Ping catchment in Chongqing in southwest China under variable BC deposition were calculated. Results indicate that abatement of BC deposition has significant impact on the critical loads of S and N. A 75% reduction in BC of assumed anthropogenic origin decreases the critical loads of acids by 58%. The current deposition does not exceed the critical loads, but if BC depositionmore » from anthropogenic sources was controlled, then the exceedance would be considerable. Uncertainty analysis show that the size of the BC deposition of natural origin is the single parameter contributing the most to the steady-state S and N critical load. The extended critical load function can be used by policy makers to set more reasonable acidity control strategies in the future. The method also highlights for policymakers the 'competition' between emission control of particulate matter driven by human health targets and potential increase of net acid load from such measures. 38 refs., 4 figs., 1 tab.« less

Authors:
; ; ; ;  [1]
  1. Tsinghua University, Beijing (China). Department of Environmental Science and Engineering
Publication Date:
OSTI Identifier:
20885831
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 41; Journal Issue: 6; Other Information: iduan@tsinghua.edu.cn
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; CHINA; ACIDIFICATION; CATIONS; SOILS; DEPOSITION; COAL; COMBUSTION; AIR POLLUTION CONTROL; MATHEMATICAL MODELS; INPUT-OUTPUT ANALYSIS; SULFUR; NITROGEN

Citation Formats

Yu Zhao, Lei Duan, Thorjorn Larssen, Lanhua Hu, and Jiming Hao. Simultaneous assessment of deposition effects of base cations, sulfur, and nitrogen using an extended critical load function for acidification. United States: N. p., 2007. Web. doi:10.1021/es060380+.
Yu Zhao, Lei Duan, Thorjorn Larssen, Lanhua Hu, & Jiming Hao. Simultaneous assessment of deposition effects of base cations, sulfur, and nitrogen using an extended critical load function for acidification. United States. doi:10.1021/es060380+.
Yu Zhao, Lei Duan, Thorjorn Larssen, Lanhua Hu, and Jiming Hao. Thu . "Simultaneous assessment of deposition effects of base cations, sulfur, and nitrogen using an extended critical load function for acidification". United States. doi:10.1021/es060380+.
@article{osti_20885831,
title = {Simultaneous assessment of deposition effects of base cations, sulfur, and nitrogen using an extended critical load function for acidification},
author = {Yu Zhao and Lei Duan and Thorjorn Larssen and Lanhua Hu and Jiming Hao},
abstractNote = {Base cations (BC) play an important role to prevent soil acidification. In certain acid sensitive areas, such as China, BC deposition is high and a considerable fraction is of anthropogenic origin. BC deposition might decrease in the future with the implementation of air pollution control measures. The effect of changes in BC deposition, however, has seldom been considered in critical load calculations based on the steady-state mass balance (SSMB) method. In order to better quantify the importance of the BC deposition for acid deposition mitigation policy, an extension of the SSMB method for critical load calculation for soil acidification is presented. The BC deposition is taken into account as a variable along with sulfur (S) and nitrogen (N) deposition, creating an S-N-BC critical load function. As a case study, critical loads of S and N for the Tie Shan Ping catchment in Chongqing in southwest China under variable BC deposition were calculated. Results indicate that abatement of BC deposition has significant impact on the critical loads of S and N. A 75% reduction in BC of assumed anthropogenic origin decreases the critical loads of acids by 58%. The current deposition does not exceed the critical loads, but if BC deposition from anthropogenic sources was controlled, then the exceedance would be considerable. Uncertainty analysis show that the size of the BC deposition of natural origin is the single parameter contributing the most to the steady-state S and N critical load. The extended critical load function can be used by policy makers to set more reasonable acidity control strategies in the future. The method also highlights for policymakers the 'competition' between emission control of particulate matter driven by human health targets and potential increase of net acid load from such measures. 38 refs., 4 figs., 1 tab.},
doi = {10.1021/es060380+},
journal = {Environmental Science and Technology},
number = 6,
volume = 41,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • Effects of reduced deposition of N, S, and C{sub B} on nutrient pools, fluxes, soil, and soil solution chemistry were simulated for two Appalachian forest ecosystems using the nutrient cycling model. In the extremely acidic, N- and S-saturated red spruce [Picea rubens (Sarg.)] forest (Nolan Divide), reducing C{sub B} deposition by 50% reduced C{sub B} leaching by {approximately}40% during the 24-yr simulation period. This was due solely to the effects of C{sub B} deposition on the soil exchanger rather than effects on soil solution. Reducing S and N by 50% caused immediate reductions in total anion and cation leaching atmore » Nolan Divide, but the effects on soil solution C{sub B} diminished and C{sub B} leaching was reduced by only 17% over the simulation period. Reducing S and N deposition had a greater effect on soil solution aluminum (Al) and molar Ca/Al ratio than reducing base cation deposition at Nolan Divide. In the moderately acidic, N- and S-accumulating mixed deciduous forest at Coweeta, reduced C{sub B} deposition by 50% caused a very slight reduction in C{sub B} leaching as a result of slightly reduced base saturation and increased soil sulfate adsorption. The effects on reducing S and N deposition by 50% on C{sub B} leaching were greater than those of reduced C{sub B} deposition. The system continued to accumulate both S and N even at reduced deposition at Coweeta, although growth and vegetation uptake were slightly reduced because of increased N deficiency. Base saturation remained well above the Al buffering range at all times at Coweeta and Al was an unimportant component of soil solutions in all scenarios.« less
  • This research presents the risk analysis of acid forming compounds input using critical loads (CL) values of sulfur, nitrogen, and acidity under the computer calculations for terrestrial and freshwater ecosystems of Northern Eurasia. The Cl values are used to set goals for future deposition rates of acidifying and eutrophication compounds so that the environment is protected. CL values for various ecosystems are determined using EM GIS approach. The most influential sources, such as nitrogen, sulfur and base cations uptake by vegetation, surface and groundwater leaching from terrestrial to freshwater ecosystems are described for the whole territory under study regarding uncertaintymore » analysis and the level of corresponding risk assessment. This may be explained by many factors of which the most important are: the estimation of plant uptake is carried out on the basis of data on the biogeochemical cycling of various elements, for which adequate quantitative characterization for all ecosystems under study is either absent or insufficient; reliable information on the quantitative assessment of the ratio between perennial plant biomes increase and dead matter is absent for the required level of spatial and temporal resolution; reliable data on surface and underground runoff in various ecosystems are rare; the influence of hydrothermic factors on the above mentioned processes has not been quantitatively determined at required level of model resolution.« less
  • The main objectives of this study were to identify the regions in Fennoscandia where the critical loads of sulfur (S) and acidifying nitrogen (N) for lakes are exceeded and to investigate the consequences for deposition reductions, with special emphasis on the possible trade-offs between S and N deposition in order to achieve nonexceedance. In the steady-state model for calculating critical loads and their exceedances, all relevant processes acting as sinks for N and S are considered. The critical loads of N and S are interrelated (defining the so-called critical load function), and therefore a single critical load for one pollutantmore » cannot be defined without making assumptions about the other. Comparing the present N and S deposition with the critical function for each lake allows determination of the percentage of lakes in the different regions of Fennoscandia where: (1) S reductions alone can achieve nonexceedance. (2) N reductions alone are sufficient, and (3) both N and S reductions are required but to a certain degree interchangeable. Secondly, deposition reduction requirements were assessed by fixing the N deposition to the present level, in this way analyzing the reductions required for S, and by computing the percentage of lakes exceeded in Finland, Norway and Sweden for every possible percent deposition reduction in S and N, in this way showing the (relative) effectiveness of reducing S and/or N deposition. The results showed clear regional patterns in the S and N reduction requirements. In practically the whole of Finland and the northern parts of Scandinavia man-made acidification of surface waters could be avoided by reducing S deposition alone. In the southern parts of Sweden some reductions in N deposition are clearly needed in addition to those for S. In southern Norway strong reductions are required for both N and S deposition. 55 refs., 5 figs.« less
  • Southern Switzerland with its mainly acidic bedrock is potentially very sensitive to the effects of atmospheric proton input. In addition, this region suffers from relatively high acid deposition originating from the greater Milano area. The soil solution composition at different depths of a cryptopodzolic soil was monitored over a 10 year period with samples collected fortnightly. On the basis of the concept of critical loads of acidity, the molar ratio of base nutrient cations (BC) to aluminum was used as the parameter to assess acidification. Despite characteristic seasonal short-term variations of BC and Al, which could be attributed qualitatively tomore » specific soil chemical processes, statistically significant trends over the entire observation period were observed. In all horizons a depletion of BC concentrations indicated an impoverishment of the nutrient status of the vegetation. Aluminum decreased in the upper soil, whereas a significant increase was observed at the lowest soil depth. The BC/Al ratio decreased significantly in all mineral soil horizons, indicating rapid soil acidification. Considering the constant decrease of acid deposition at the site during the observation period with values significantly below calculated critical loads, the observed acidification is attribute to a memory effect of the high acid loads between 1965 and 1985.« less
  • Methods are discussed for describing patterns of current wet and dry deposition under various scenarios. It is proposed that total deposition data across an area of interest are the most relevant in the context of critical loads of acidic deposition, and that the total (i.e., wet plus dry) deposition will vary greatly with the location, the season, and the characteristics of individual subregions. Wet and dry deposition are proposed to differ in such fundamental ways that they must be considered separately. Both wet and dry deposition rates are controlled by the presence of the chemical species in question in themore » air (at altitudes of typically several kilometers in the case of wet deposition, and in air near the surface for dry). The great differences in the processes involved lead to the conclusion that it is better to measure wet and dry deposition separately and combine these quantifications to produce [open quotes]total deposition[close quotes] estimates than to attempt to derive total deposition directly. A number of options for making estimates of total deposition to be used in critical loads assessment scenarios are discussed for wet deposition (buckets and source receptor models) and for dry deposition (throughfall, micrometerology, surrogate surfaces and collection vessels, inference from concentrations, dry-wet ratios, and source-receptor models). 19 refs., 2 figs., 2 tabs.« less