Analysis of the mechanism of sulfuric acid discharge from wetland soils in tropical and sub arctic area and the control method of sulfuric acid discharge.

为了估算黄铁矿氧化后硫酸污染的影响范围，在9月（旱季）和3月（雨季）对印度尼西亚加里曼丹中部泥炭沼泽森林中两条河流的地表水化学进行了间隔1.0 ~ 3.0 km的调查。从运河排放到世邦高河和卡哈延河干流的水的pH值比干流水的pH值要低，这意味着从运河向干流输送硫酸。硫酸盐离子/氯离子浓度比值作为估算硫酸黄铁矿对河流水化学贡献的参数，表明黄铁矿氧化产生的硫酸负荷出现在两条河流上游150 km处的河口处。雨季河流干流及人工渠排入干流的水酸度和硫酸盐/氯离子比均高于旱季。这意味着从泥炭沼泽森林向湖泊系统排放的硫铁矿在雨季（高水位）比干季（低水位）要高得多。雨季运河内的水呈高酸性（pH = 2.0-3.0）。泥炭地开发后黄铁矿氧化不仅引起土壤酸化，而且引起湖泊生态系统酸化。在德国东部褐煤矿区也发现了同样的硫酸污染。在德国东部湿地系统中，铁和S与还原性有机物（如泥炭）的氧化还原反应控制着铁和S的氧化还原状态及其产生的质子动力学。热带地区的高酸性淡水可能与泥炭沉积有关。

In order to estimate the range of area that is affected by the sulfuric acid pollution after pyrite oxidation, surface water chemistry of two rivers in peat swamp forests in Central Kalimantan, Indonesia was surveyed at 1.0-3.0 km intervals in September (dry season) and March (rainy season). Water discharged from canals into the main stream of the Sebangau River and the Kahayan River showed lower pH compared to the mainstream water of the rivers, implying sulfuric acid loading from the canal to the main stream of the rivers. The ratio of concentrations of sulfate ion/chloride ion, which was used as a parameter for estimating the contribution of pyritic sulfate to the river water chemistry, showed that the sulfuric acid loading from pyrite oxidation appeared from the river mouth up to 150 km upstream in both the rivers. Water of the mainstream of the rivers as well as water discharged from artificial canals into the mainstream in the rainy season showed much higher acidity and a higher ratio of sulfate ion/chloride ion than those in the dry season. This implies that the discharge of pyritic sulfate from peat swamp forests to the limnological system is much higher in the rainy (high water table) season than the dry (low water table) season. Water in the canal in the rainy season was found to be highly acidic (pH = 2.0-3.0). Pyrite oxidation after peatland development causes not only acidification of soil but also acidification of the limnological ecosystem. The same sulfuric acid pollution was found in brown coal mining area in eastern Germany. Redox reaction of Fe and S associated with reduced organic materials (e.g. peat) controls the redox status of Fe and S and the consequent proton dynamics in wetland system in eastern Germany. Highly acidic fresh water in the tropical area could be associated with peat deposition.