Determination of soil remediation target values and remediation practices based on olfactory effects: a case study of a saccharin chemical plant in Shanghai

Due to the lack of relevant technical standards and specifications, systematic method support and practical verification are still insufficient for soil odor identification, evaluation, and restoration management. Taking a saccharin chemical plant site as an example, we demonstrate the rationality of odor control target setting and the effectiveness of restoration techniques by identifying odor substances, setting soil restoration target values based on olfactory effects, and conducting soil odor restoration. Through production process analysis and sampling testing, the substances causing odor in the soil of the plot were identified, mainly including toluene, 2-chlorotoluene, 4-chlorotoluene, and ammonia nitrogen. Based on the odor threshold values of pollutants in the air and the soil volatilization factor model, the soil restoration target values based on olfactory effects were derived, and the corresponding restoration target values for toluene, 2-chlorotoluene, 4-chlorotoluene, and ammonia nitrogen were calculated as 162.14, 492.28, 492.28, and 164.00 mg/kg. By using thermal desorption technology with a heating temperature of 250 ℃ and a heating time of 30 minutes, the concentration of odor substances could be reduced to below the restoration target value, and the corresponding odor intensity test result was grade 2, indicating that it had reached an acceptable odor level. The results of this study can provide methodological support and empirical reference for soil odor identification, evaluation, and restoration.