Calculating critical loads of sulfur deposition for 100 surface waters in China using the MAGIC model

Although decades of acid deposition have apparently not resulted in surface water acidification in China, some surface waters may have the potential t rend of being acidified, especially those in southern China. In this paper, a dynamic acidification model--MAGIC was applied to 100 surface waters in southern and northeastern China to evaluate the impact of acid deposition t o surface waters and to determine their critical loads of S deposition, bot h regions having distinguishing soil, geological and acid deposition charac teristics. Results indicate that most surface waters included in this paper are not sensitive to acid deposition, with critical loads of S for these w aters comparatively high. On the other hand, surface waters in southern Chi na, especially those in Fujian, Jiangxi and Guangdong provinces, are more s usceptible to acidification than those in northeastern China, which coincid es with their different patterns of soil, geological and acid deposition co nditions. Among all the waters, a few small ponds, such as those on top of the Jinyun mountain and Emei mountain, are the most sensitive to acid depos ition with critical loads of 1.84 and 3.70 keq(.)ha(-1.)yr(-1), respectivel y. For the considerable ANC remaining in most 100 surface waters, it is not likely that acidification will occur in the near future for these waters.