J. Shindo et al., EVALUATION OF ESTIMATION METHODS AND BASE DATA UNCERTAINTIES FOR CRITICAL LOADS OF ACID DEPOSITION IN JAPAN, Water, air and soil pollution, 85(4), 1995, pp. 2571-2576
Simplified steady state mass balance model for critical load (CL) esti
mation was applied to a test area in Japan to evaluate applicability o
f the model. Three different criteria for acidification limits (1: [Al
3+]<0.2 eq. m(-3), 2: Al/BC<1.0 mol mol(-1), 3:Al depletion criterion)
were used. Mean values and spatial distribution patterns of CL values
calculated by these criteria were extremely different from each other
. The first criterion produced much higher CL than the second criterio
n in the Japanese condition with high annual precipitation Improvement
s including definition of the criterion were considered necessary. As
quantitative data of the base cation weathering rate (BCw) was lacking
, the rate was specified based on surface geology and the soil type of
each site. To evaluate uncertainty of BCw used for CL calculation, io
n content and particle-size distribution were measured for the soils c
ollected from the test area, and BCw was estimated with PROFILE model
based on these measurements. It appeared that BCw estimates by surface
geology wee adequate as a mean value, but they had uncertainty of abo
ut 50% of the average values due to variability of ion contents within
the same surface geology group.