Soil samples stored in sealed vials have been shown to undergo significant biodegradation over time periods greater than 48 hours. Holding time guidelines for VOCs are given in SW846, Method 5035A, Appendix A, Table “Recommended VOC Sample Preservation Techniques and Holding Times.” The holding time for preserved soil samples should be interpreted as 14 days from the time of sample collection (stored at 4±2o C). Due to potential biodegradation, samples stored in sealed containers, but not chemically preserved, should not be stored for more than 48 hours prior to analysis or chemical preservation. .
