Total Error and Its Sources

As we already know, an environmental sample is a fragile living matter that can be severely damaged at every step of its existence. Due to the inherent nature of environmental media and a host of potential errors associated with sampling, analysis, and data management, the collection of environmental chemical data is not an exact science. In fact, all environmental chemical data are only the estimates of the true condition that these data represent. In order to make these estimates more accurate, we must examine the sources of errors and take measures to control them. 

for example, errors originating in the planning phase. They cannot be quantified, but their effects on data relevancy and validity could be devastating. As a 

The sources of sampling error, which is a combination of quantifiable components and qualitative factors, can be divided into four groups  

The quantifiable components of sampling error are the natural variability within a sample itself and the variability between sample populations that may be randomly selected from the same sampled area. Both of these errors can be evaluated quantitatively in the form of statistical variance and controlled to some extent through the application of appropriate sampling designs. 

The qualitative components of sampling error are the following errors in the planning process and in the implementation of field procedures  

---