Lexikon

a sample taken from a larger quantity (lot) for analysis or recording purposes.

composite sample is a combination of multiple individual samples taken at pre-selected times to represent the integrated composition of the wastewater being sampled. Usually all samples added to the composites are equal in size, but flow-proportional composite samples collect amounts proportional to flow.

control sample is a sample with pre-determined characteristics which undergoes sample processing identical to that carried out for test samples and that is used as a basis for comparison with test samples. Examples of control samples include reference materials, spiked test samples, method blanks, dilution water (as used in toxicological testing), and control cultures (i.e., samples of known biological composition).

control site sample, also known as “background sample”. These are samples of the media similar to the test sample matrix and are taken near to the time and place where the analytes of interest may exist at background levels. Usually the frequency of their analysis should be equivalent to that of the reagent blank. They are used to demonstrate whether the site is contaminated or truly different from the norm. Some sort of background sample is always necessary for a valid scientific comparison of samples suspected of containing environmental contaminants. Control site samples may further be differentiated as “local control site” and “area control sites” samples.

environmental sample is a sample of any material that is collected from an environmental source.

provides a selection of techniques to take solid, liquid or gasous samples for measurements. (Source: EUGRIS)

to select and adapt the proper sampling and analytical/testing protocols for the environment and its specific contaminants as well as for specific applications is essential for environmental risk management. Environmental sampling concept and design, sampling techniques, and quality assurance/quality control (QA/QC) are essential to acquire quality environmental data. The deviation of sampling may multiply exceed the error of chemical analyses or biological tests.

Main problem of site assessment and monitoring is the heterogeneity of the environment. Sample is able to represent the real environment, only when sampling design takes into consideration the heterogeneity and the statistics, the necessary number and volume (or mass) of the sample, the space and time dimensions of the samples. The aim of sampling is also an important factor: which analyses (physical, chemical?) or testing (biological, ecological, ecotoxicological?) will be carried out with the sample. Identification, trasportation, storage, conservation of the sample should be decided also in advance and make the necessary preparatory tasks.

It is reasonable to carry out sampling in more steps: first the screening, than a detailed sampling and assessment. To use in situ mesurements and testings, on site or laboratory testing or the combination of these two, is also an important decision.

Sampling may differ according to the phisical phase of the sample: air sampling (athmosphere, soil air, dissolved air, indoor air, outdoor air, technological gases, etc.); water sampling (surface waters, subsurface waters, pore water, leacheate, drainage, moisture, industrial waters, waste waters, etc.); soil and solid matter (soil, sediment, solid waste) or sludges (waste-water sludge, sediments, waste sludges, etc.).

a portion or piece of a whole. A selected subset of a population or subset of whatever is being studied. For example, in a study of people the sample is a number of people chosen from a larger population. An environmental sample (for example, a small amount of soil or water) might be collected to measure contamination in the environment at a specific location.

The sample should truly represent the population or environment is being studied. It is ensured by statistically suitable sample size and sample and sample type.

To collect a representative sample-set from the environment we have to design sampling carefully. In case of contaminated sites our sampling should be based on the risk of the contaminant and on the integrated risk model or conceptual model of the site.