Incremental Sampling Methodology (ISM) is increasingly used across the environmental industry to evaluate soil contaminants. Unlike traditional discrete sampling, ISM collects numerous soil increments that are combined, processed, and subsampled to produce more representative measurements of contaminant concentrations within a defined area.
By integrating both field sampling practices and laboratory processing, ISM can provide statistically valid mean contaminant concentrations within a defined volume of media. When implemented correctly, this approach can significantly reduce the variability often associated with traditional discrete sampling.
Because ISM relies on close coordination between field collection and laboratory processing, early communication between the environmental consultant and the laboratory is essential to ensure that project objectives, decision units, and processing requirements are clearly defined. Merit Laboratories’ standard laboratory processing procedure utilizes the 2D Japanese slab cake subsampling methodology to support representative subsampling of ISM composites.
Merit Laboratories has supported ISM projects since 2010, beginning with arsenic evaluations at historic apple orchards. With more than 15 years of experience, Merit follows ISM guidance published by the Interstate Technology and Regulatory Council (ITRC) and the Michigan Department of Environment, Great Lakes, and Energy (EGLE).
The ITRC describes ISM as a structured composite sampling and processing protocol designed to reduce data variability and provide a reasonably unbiased estimate of mean contaminant concentrations in soil. An ISM sample represents a defined soil volume, referred to as a decision unit. Each ISM sample typically consists of 30 to 100 increments, which are combined, processed, and subsampled according to established protocols. ISM is also referred to as Multi-Incremental Sampling (MIS).
Merit Laboratories is a leading environmental testing laboratory analyzing air, soil, wastewater, groundwater, drinking water, and other environmental matrices for a wide range of analytical parameters. Merit is also designated as a Small Business Enterprise (SBE) and Woman-Owned Business Enterprise (WBE).