酸性硫酸盐土中硫的形态含量分布和酸化特征

对广东省台山市南部滨海平原酸性硫酸盐土(以下简称ASS)S的形态、含量、分布和酸化特征的研究表明,ASS全硫含量高达0.615%,比咸田高2～6倍,比砂泥田高3～9倍;其硫以无机硫为主,占全硫的82.3%～90.4%,其中,黄铁矿硫的含量最高,占全硫的30.3%～46.2%,黄铁矿硫在剖面中的分布与全硫含量同步。ASS硫含量的空间变异和剖面内部的分异十分显着。ASS发育过程中,适合黄铁矿累积的环境及其持续时间与地形地貌(山)的关系十分密切。ASS的主要致酸物质是黄铁矿的氧化,酸化的ASS的pH一般在5.5以下,最低达2.83.ASS可氧化总酸度一般比实际总酸度高2～3倍,潜在的环境风险极.

Characteristics of sulfur forms content distribution and its acidification of acid sulfate soils

Characteristics of sulfur forms, content, distribution and its acidification of Acid Sulfate Soils (ASS) in the southern coastal regions of Taishan city, Guangdong, are studied. The results show that the sulfur content of ASS is very high, 2 to 6 times than coastal saline soil, 3 to 9 times than paddy soil. The sulfate of ASS is mainly in inorganic forms, it covers 82.3% to 90.4% of the total sulfur in the soil. Among them, pyrite is the highest form; it covers 30.3% to 46.2% of the total sulfur in the soil. The distribution of pyrite in profile is corresponding with the total sulfur. The difference of sulfur content in the profile and between the soils is significant. The sulfur is very high in the place where near the hill. This means the suitable sulfur accumulation place is near the hill. Acidity of ASS is come from pyrite oxidation. The acidification cause pH value drops to 5.5, even to 2.83. The potential acidity of ASS is 2 to 3 time high than the actual acidity, the potential environmental risk of ASS is great.