Incremental Sampling Methodology (ISM) is an increasingly accepted approach for characterizing soil contamination and reducing the uncertainty commonly associated with traditional discrete sampling methods. By collecting and combining multiple increments from a defined area, ISM is designed to provide a more representative estimate of mean contaminant concentrations within a designated decision unit.
Merit Laboratories performs ISM analytical testing for the following contaminant groups:
Metals
Pesticides
PFAS
Polynuclear Aromatic Hydrocarbons (PNAs)
Polychlorinated Biphenyls (PCBs)
Semi-Volatile Organic Compounds (SVOCs)
Volatile Organic Compounds (VOCs)
Unlike discrete sampling, which can be heavily influenced by localized heterogeneity, ISM incorporates structured field collection, sample processing, and subsampling procedures to improve data representativeness and support more defensible decision-making. A typical ISM sample consists of 30 to 100 increments collected systematically or randomly across a defined soil volume and combined into a single composite sample for laboratory analysis.
Because ISM requires the integration of both field and laboratory practices, early coordination between the environmental consultant and the laboratory is critical. Project objectives, decision unit design, sample mass requirements, contaminant analytes, and processing protocols should be established before field mobilization to ensure data quality objectives are achieved.
Merit Laboratories provides environmental analytical services for soil, groundwater, drinking water, wastewater, air, and other environmental matrices. Merit is certified as both a Small Business Enterprise (SBE) and Woman-Owned Business Enterprise (WBE).