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Appendix D: Sample Containers and Holding Times

Sample containers

Plastic jars are suitable for samples where only inorganic parameters are to be analysed. Glass jars should always be used when organic parameters are needed. Glass jars with Teflon-lined lids must be used for volatile organics.

Holding times

All tests should preferably be carried out as soon as practicable after sampling. Table A7 provides guideline sample holding times based on the Australian standards (AS 4482.1 and 4482.2). These holding times should be used with caution, because the integrity of the sample will depend not only on the length of time the sample has been stored, but also on the conditions of sample handling and storage.

There is no scientifically based study determining maximum holding times for different analyses, and the interpretation of results from samples that have been held in storage for any length of time must take into account the effects this may have had on the results. The effects of storage on sample integrity will be based on the concentration of analyte in the sample, reactions with other compounds that may be present, degradation by microbiological factors, etc. Analytes such as metals and semi-volatile organics (including PCBs, organochlorine pesticides and polycyclic aromatic hydrocarbons) are persistent in the environment and are not likely to change after sampling. The time before analysis is determined as much by the cost of holding samples in storage for extended periods as by the possibility of loss of analyte.

Table A7: Guideline sample holding times for soils
Analyte Holding time
Metals other than mercury and hexavalent chromium 6 months
Mercury 1 month
Hexavalent chromium (Cr VI) 1 month
Cyanide 1 week
Semivolatiles 2 weeks
Volatiles

3 days before extraction

1 week for analysis