INTRODUCTION
Consequence with the heavy expanding use of fi~ssihl e1 during this century h the
industrial countries markedly created the problem of acid rain in many areas as tile
cumulative loaditig of acid deposition. Iu Thailand where coal consumption for ligtutebase
power plmt has becolne the recognition for the increment of acid rain problem, the
certain concern is iilfluenced by its rapid growing of ecoilolny and the power deina~idf iorn
iudusl~iasi ector. y~leid te consumpti011 for power plant generation is expect to be 34.0
Mtons 111 2000 [I] md the unabated sulfiu dioxide emission in Thailand is anticipated at
2.25 Mtolis in 2000 [2]. The report fiom Thailand Developmeat Research Iustitute has
forcasted fbr the sub dioxide and nitrogen oxide £?om the Mae Moh power plant (the
p ower plant of Thailand) approximately 1.6 Mtons and 0.23 Mtons, respectively, by
the year 20 11 [3]. It is potentially addressed that Thailand is iikely to confiont the serious
acid rain problems in the near hture according to the anticipation of sufir dioxide
elnissiou I1 the next decade. The acid deposition can damage uot ody the terrestrial aild
fiesh water ecosystem but also the soil and its ecosystem which play as the accumulated
basin where short and long term effect of acid rain could happen. Damage to this
resources in Europe and North America have been recognized and political strategy to
mitigate against hrther damage was established. In order to reduced the adverse effect, as
happen in Europe md North America, the research involved in the impact of sulfur
dioxide on the ecosystem need to take into account. As soil ecosystem is the primaiy
source to uptake acid deposition, the impact of sulfur dioxide both direct and indirect
effect could bring the severe damage in the near hture pa~icularlyi n the northern part of
llailand where main power plant are located. Thus this research focused on the effects of
simulated acid rain oil the metal and nutrient mobility and the important microorgallisms
chauge iu the noithem forest soil of Thailand iu order to observed the preliminary change
when acid rain occurred.