某场地环境调查项目中个别点位土壤的pH值偏低，但其他检测指标均正常。通过进一步分析场地历史资料，对土壤和地下水中挥发性有机物和半挥发性有机物进行全扫描检测，对硫酸根、硝酸根、氯离子等阴离子含量进行补充检测，探讨了pH值异常的原因。结果表明，导致pH偏低的污染物质主要分布于包气带的局部土壤中，场地历史上硫磺存储不当泄露进入土壤，在硫氧化细菌的作用下转化生成硫酸，可能是导致土壤pH偏低的主要原因；在场地开发建设过程中，极强酸性土壤可能对人体健康、岩土结构、建筑材料、植物生长等产生负面影响，需针对潜在风险采取防范措施。
In a site environmental survey project, the pH values of several individual points of soil are low, while the other indicators tested are normal. To analyze the causes of abnormal pH value, historical data of the site is further investigated, the volatile organic compounds and semi-volatile organic compounds in the soil and groundwater are fully scanned, and the contents of sulfuric acid root, nitrate and chloride ion are tested. The results show that the pollutants causing low pH are mainly distributed in the aerated zone soil. Improper sulfur storage in the history may bring about the leaking of sulfur into the soil, and that can be converted into sulfuric acid under the action of sulfur-oxidizing bacteria, which may be the main reason for the low pH value of the soil. In the process of site development and construction, extremely acidic soil may have negative impacts on human health, geotechnical structure, building materials and plant growth, so it is necessary to take preventive measures against potential risks.
