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RE-EVALUATION OF APPLICABILITY OF AGENCY SAMPLE HOLDING TIMES
Citation:
Schumacher, B A. RE-EVALUATION OF APPLICABILITY OF AGENCY SAMPLE HOLDING TIMES. Presented at Biological Advisory Committee - Research Methods Symposium, Newport, RI, October 14 - 15, 2003.
Impact/Purpose:
The overall objective of this task is to provide the Agency with improved state-of-the-science guidance, strategies, and techniques to more accurately and effectively collect environmental samples. Under this umbrella objective, research is being conducted to: (a) reduce/minimize the loss of VOCs during sample collection, handling, and preservation, (b) collect undisturbed surface sediments so that the effects of recent depositional events (e.g., flooding or dredging) can clearly be delineated as to their influence on the contamination concentrations present downstream (or where the sediments are deposited), and (c) to determine an effective method to effectively and efficiently separate asbestos in soils from the rest of the soil matrix while maintaining the integrity (i.e, no fiber size reduction) of the asbestos fibers.
Description:
The Purpose and Rationale is to:
To assess the validity of currently recognized holding times and to provide a scientific basis for changes tha may be necessary to the current regulations.
While holding times may appear adequate to protect sample integrity and provide sufficient time for laboratory analysis, relevant data is sparse on individually defined holding times and, thus, some of the holding times appear to be arbitrary and/or politically driven.
When holding times are exceeded, even if only by 1 day, the data must be flagged and are often declared invalid or are reported as "estimated", and the data are then called into question, especially if the data are to be used in a court of law.