Hyperlink 17: Particle Size Selection

Particle size selection must be addressed during project planning. Selecting the target soil particle size is driven by the project decision(s) to be made on the data. Certain decisions may call for the analysis to be performed on bulk soil. Generally, bulk soil refers to all particle sizes <2 mm. This means preparing the soil such that the ratios of all particles <2 mm in the sample reflect the same ratios as in the field. Then, that same ratio must be achieved for the subsample that will be analyzed. Other project decisions may require targeting a different particle size. For example, exposure assumptions may require knowing the concentration of dust-sized particle (see Short Sheet: RTW Recommendations for Sampling and Analysis of Soil at Lead Sites [USEPA 2000c]). That constrains a sample to those particles sizes that represent dust, and sizes larger than that must be removed from the sample. Sample preparation procedures cannot be selected until the target particle size has been identified by upfront systematic project planning.