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ISSN 1811-0231 / ISEIS Publication Series Number P002
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Paper EIA04-045, Volume 2 (2004), Pages 439-455 = complimentary
Assessment of Target Loads for Acid Deposition with Static and Dynamic Model
S. D. Xie*, L. Qi and M. Hou
Department of Environmental Sciences, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing 100871, China. *Corresponding author: sdxie@pku.edu.cn.
Abstract
Although the determination of target loads for acid deposition is significantly affected by policy, economy, technology and time, it is based on the tolerant capaclity of ecosystems to acid deposition. Considering these factors, a method is put forward to determine the target loads for a given ecosystem or region by Steady-State Mass Balance approach (SSMB) combined Dynamic Acidification Model. The first step is to define the protection objective, and to calculate the critical load for this objective with SSMB. And then a value to the target load based on the critical load is set considering the factors mentioned above. And the response of ecosystem to this load was simulated using the dynamic model, in order to estimate the recovering process and time needed for the harmed ecosystem. A method was applied to assess target loads of Liuzhou, China. The results indicate that the critical loads of sulfur deposition for all types of soil species in Liuzhou area range from 0.50 to 1.80 keq ha-2 yr-1. If 95% soil is to be protected from being harmed, the critical load should be 0.70 keq ha-2 yr-1. The red earth and the yellow red earth in this area would recover slowly in the period 2045 until to the 1985’s level in 2065, if the sulfur deposition was set to be 6 g m-2 yr-1 in 2005, 3 g m-2 yr-1 in 2010 and 1.2 g m-2 yr-1 which equalls the critical load level in 2015.
Keywords: Acid deposition, Acidification model, Critical loads, Red earth, Target loads