(4) a sample created by combining different fractions (subsamples). Subsamples can be collected at different times or from different locations.
Combined increment samples, or combined replicate samples, or combined samples from replicate trials. Preferred term to bulk sample which is ambiguous. (Horwitz, 1990). See also aggregate sample, primary sample.
a sample collected over time, formed either by continuous sampling or by mixing discrete samples
a series of individual discrete samples taken at selected intervals based on either an increment of flow or time
is a mixture of spot samples taken at different times, or places, from a larger mass of the same material. It is produced by thoroughly mixing the combined spot samples and, if necessary, sub-diving the quantity of the resulting mixture, using approved techniques.
A non-discrete sample composed of more than one specific aliquot collected at various sampling points or times.
A sample that is made up of a number of grab samples that have been thoroughly mixed together.
A combination of individual samples of water or wastewater taken at predetermined intervals to minimize the effect of variability of individual samples.
consists of numerous individual samples of a specified waste stream.
A single sample which is prepared by combining numerous small portions of product material from throughout the lot.
A sample which is made by combining samples from two or more locations. The sample can be of water, soil or another medium.
To have significant meaning, samples for laboratory tests on wastewater should be representative of the wastewater. The best method of sampling is proportional composite sampling over several hours during the day. Composite samples are collected because the flow and characteristics of the wastewater are continually changing. A composite sample will give a representative analysis of the wastewater conditions.
A series of water samples taken over a given period of time and weighted by flow rate.
A combined water sample consisting of a series of discrete water samples taken over a given period of time and mixed according to a specified weighting factor such as river flow. A composite sample is often collected with the use of an automated sampler over the duration of a runoff event.
A sample comprised of two or more subsamples.
A mixture of single or "grab"samples. A composite is intended to produce a typical or average sample when wide variations in quality or characteristics occur in the various grab samples. A composite may be made up of equal volumes of individual samples or of single samples which are proportioned to variations in flow or usage