ISO 14507:2003 specifies three methods for the pretreatment of soil samples in the laboratory prior to the determination of organic contaminants:

• if volatile organic compounds are to be measured;
• if moderately volatile to non-volatile organic compounds are to be measured, if the result of the subsequent analysis must be accurate and reproducible, and if the sample contains particles larger than 2 mm and/or the contaminant is heterogeneously distributed;
• if non-volatile organic compounds are to be measured and the extraction procedure prescribes a field-moist sample, or if the largest particles of the sample are smaller than 2 mm and the contaminant is homogeneously distributed. This procedure is also applicable if reduced accuracy and repeatability are acceptable.

The pretreatment described in ISO 14507:2003 is used in combination with an extraction procedure in which the contaminant is available for the extraction liquid.

NOTE For the pretreatment of soil samples for the purposes of determining non-volatile inorganic compounds and physico-chemical soil characteristics, see ISO 11464.