Incremental Sampling Methodology

Poster Presentation

Prepared by H. Behzadi
Accutest Laboratories, 4405 Vineland Road C-15 , Orlando, Florida, 32811, United States


Contact Information: harryb@accutest.com; 407-425-6700


ABSTRACT

By its very nature, soil is a highly heterogeneous solid with many components. Sampling soil for the purpose of obtaining an estimate of the mean contaminant concentration is highly susceptible to sampling errors from a variety of sources. Traditional discrete soil sampling methods don’t always provide the accurate, reproducible, and defensible data needed for effective project planning.

Incremental sampling methodology (ISM) is a structured composite sampling and processing protocol that reduces data variability and provides a reasonably unbiased estimate of mean contaminant concentrations in a volume of soil targeted for sampling.

Variability in measured contaminant concentrations between discrete soil samples is due primarily to the particulate nature of soil and heterogeneity in the distribution of contaminants. The elements of ISM that control data variability are incorporated into (a) the field collection of soil samples and (b) laboratory processing and subsampling procedures. ISM is designed to obtain a single aliquot for analysis that has all constituents in the same proportion as an explicitly defined volume of soil. Properly executed, the methodology provides reasonably unbiased, reproducible estimates of the mean concentration of analytes in the specified volume of soil.

ISM can lower site investigation costs by lowering the number of samples necessary to achieve an acceptable level of statistical confidence. Additionally, remedial efforts can be improved because of more accurate soil delineation.