Following is provided as a guide, it is not possible to recommend sampling methods for all waste types. Appropriate sampling depends on how consistent any tested property is throughout a batch of waste. It is the waste generator’s responsibility to ensure that the sampling and analytical methods used are appropriate for the contaminants they are testing for. Australian Enviro Services specialise in asbestos removal in Sydney and contaminated site remediation.
Where the property being tested for is highly consistent throughout the waste, sampling is relatively straightforward and useful guidance can be found in the following Australian Standards:
- AS 1199.0–2003: Sampling Procedures for Inspection by Attributes – Introduction to the ISO2859 Attribute Sampling System (Australian Standard 2003b)
- AS 1141.0–1999: Methods for Sampling and Testing Aggregates (Australian Standard 1999a) is useful for sampling wastes such as aggregates, foundry sand, furnace slag or mining waste.
It is more difficult to accurately sample waste that consists of many different types of waste materials or has chemical contaminants that are not distributed evenly throughout the batch. In such situations, keeping different waste types separate, or separating portions of waste that contain high levels of contaminants from the rest, can be of great benefit.
If unsure of the appropriate sampling or analytical methods for a particular waste, waste generators are strongly encouraged to seek expert help, either from a laboratory that specialises in waste analysis or an appropriately qualified person specialising in such waste management issues, or both. Since most incorrect chemical assessments of waste are due to poor sampling, it is essential that the sampling regime and analytical method used ensure the results are representative of all components and their variability in the waste.
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Precision in chemical analyses
It is important that the test methods and instruments used in analysing a waste are capable of measuring the concentration of each chemical contaminant with enough confidence to assure correct classification.
It is recommended that the upper limit of the combined confidence interval of sampling and analysis (at a probability of 95%) is used for comparison with the maximum values specified in Tables 1 and 2 (Part 1: Classifying waste (December 2009). This approach should give the assessor confidence that a correct classification has been made.
Who can do the chemical analysis and leaching tests?
It is strongly recommended that analytical laboratories accredited by the National Association of Testing Authorities (NATA) are used to perform these analyses and tests. If accredited laboratories are not available locally, contact DECCW’s Waste Management Section for advice.
Frequency of testing
There may be situations in which frequent testing of the waste for an initial period establishes that the characteristics of the waste are consistent enough to give the waste generator confidence to reduce the frequency of testing. On the other hand, some waste streams may show such large variations in properties that every load of waste would need to be tested before classification.It is the responsibility of the waste generator to ensure that frequency of testing provides representative samples for all contaminants in that waste.
Source: Department of Environment, Climate Change & Water NSW
Waste Classification Guidelines Part 1: Classifying Waste
If you need remediation of a contaminated site, contact Australian Enviro Services.