中国大气酸沉降与土壤酸化问题

On Acid Atmospheric Deposition and Soil Acidification in China

我国对大气酸沉降的研究起自７０年代末．以酸雨研究占主导地位。我国酸雨现象区域性、发展性强，在地理上以南方酸性土壤地区为主，在成分上以硫酸盐型酸雨为主；无论是酸度还是频率，酸雨都是极严重的生态环境问题。酸沉降已对农、林生态系统生产产生了严重的破坏效应，但其累积性的环境化学反馈却未引起人们的足够重视。我国酸雨地区以强酸性富铝土壤为主，对大气酸沉降有较大的敏感性。应用β指标还表明，酸沉降可使南方主要土壤因酸化而在３０—６０年内降低ｐＨ一个单位。近年来对酸沉降诱发的土壤酸化研究以模拟降水的土柱试验为主，从ｐＨ下降、盐基淋出、Ａｌ及重金属移动等方面来提示出酸沉降可能对土壤产生的化学影响。但作为过程化学研究，其案例监测研究的报道尚很少。对于南方严重的酸雨现象，应加强实地动态监测和过程分析，注重Ａｌ化学及其对环境的反馈，将酸沉降对生态系统的破坏提高到生态毒理机制上。

The research on acid atmospheric deposition in China initiated in the late1970's and focused on acid rain phenomena. The acid deposition was highly regionalizedand strongly developing. Geographically, acid deposition occurred mostly in South China where acid soils dominsted. Chemically, the acid precipitation was predominated bysulphate. The 'acid deposition had been one of the most serious eec-environmental problems in both view points of the acidity and the frequency. The agricultural and forestryimpacts had been entensively revealed while the accumulating feedbacks of the environmental chemistry had not been given much attention. Most of the soils in the regions affected by the acid atmospheric deposition were sensitive to the deposition. Analysis ofthe β1 values indicated that the PH value of the dominant soils in South China might dropby 2 unit within a duration of 30-60 years under the deposition. The research into thesoil acidification accelerated by the deposition had been conducted largely by soil columnexperiment with simulated leaching and depicted possible chemical effects such as PHdrop, base leaching, Al and heavy metal mobilization. However, few researches on theprocess chemistry, field monitoring and case studies had been reported. It is suggestedthat field dynamic monitoring and analysis of deposition-acidification process chemistryshould be encouraged focusing on Al chemistry and the eco-toxicology.