Proclamation

Literature sources

Advantages

Composite sampling reduces analytical costs

[18] [19] [20] [21]

Composite sampling provides a better estimate of the mean concentration of the samples

[22] [23]

It helps in identifying the units with the highest level of constituents of interest

[24] [25] [26]

When a benchmark is set for appropriately adjusted composition levels, Composite sampling can help detect major variations in composition due to the increased number of samples.

[27] [28]

Disadvantages

Some information is lost when individual samples are mixed with each other. Dilution can occur. This loss of information is a concern when one has to determine the threshold of a constituent in the samples.

[29] [30]

Composite sampling is not suitable in cases where activity levels are close to analytical detection limits.

[26] [31]

For non-homogenous composite samples the spatial variability or temporal information is lost.

[20] [32]

Composite sampling should not be used when the integrity of individual samples alters due to physical mixing such as loss of volatile components.

[25] [33]

Surrogate ratios cannot be established using composite sampling

[34] [35]

Composite sampling guidelines

If there is a large variation in compositions caused by the heterogeneous nature of some contaminant, the researcher needs to account for potential large errors.

[36] [37]

Composite sampling is very helpful in reducing analysis costs for cases where the size of pattern sampling is smaller than the spacing between statistically necessary random sampling areas.

[29] [38]

In order to make the composite samples, the individual samples must be of equivalent volume/weight. The individual samples must be homogenized properly to make a composite sample.

[39] [40]

The user must develop a strategy to re-test the individual samples, in case the threshold value set for a composite level is reached. This will make it possible to retrieve the potentially lost information during the compositing the samples

[41] [42]

The users must define the threshold and modify the investigation level for the composite samples. Moreover, the user must account for the dilution factor when calculating the final results.

[43] [44] [45]