An effective method for determining the optimal sampling scale based on the purposes of soil pollution investigations and the factors influencing the pollutants.

There is a lack of a systematic method for determining the optimal sampling scale based on the purposes of soil pollution investigations (purpose) and the factors influencing of pollutants, which could affect the accuracy of determining pollution scope of the pollution. Therefore, in this study, both the purpose and the influencing factors were considered to determine the optimal sampling scale. The conclusions were obtained through geostatistical and spatial analysis. (1) The optimal sampling scale should account for 3% of the range of the pollutants, which can identify pollution information and minimize sampling costs. (2) The optimal sampling scale should be set to 3% of the range of the main factor influencing the pollutants in the absence of prior pollution information. (3) The greater the influences of the factors on the pollutants, the closer the optimal sampling scale calculated according to the influencing factors will be to that calculated based on the purpose. (4) The method of determination based on both the purpose and the influencing factors was concluded to be rational and reliable based on validation and advantage analysis. These results provide a method for soil pollution investigation that can minimize costs and improve the representativeness of the sample sites.