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] |