What is a representative sample? Where can I find guidance on representative sampling?
Representative sample means a sample of a universe or whole which can be expected to exhibit the average properties of the universe or whole. To be representative, a sample must be collected and handled by means that will preserve its original form and composition, as well as prevent contamination or changes in concentration of parameters to be analyzed.
Sites where the wastes are of large size or varied composition, including landfills and drum dumps, present severe difficulties to investigators attempting to collect representative samples to facilitate site cleanup.
"Characterizing Heterogeneous Wastes", http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=30002LXF.txt, summarizes the planning tools and sampling design strategies now in use, identifying the advantages and disadvantages of each. The discussion of the study planning process emphasizes the establishment of reasonable goals and the participation of the decision maker and the technical specialists.
"Samplers and Sampling Procedures for Hazardous Waste Streams", http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=30000APW.txt, describes a variety of sampling devices designed to meet the needs of those who regulate and mange hazardous waste.
"RCRA Waste Sampling and Draft Technical Guidance", http://www.epa.gov/sites/production/files/2015-10/documents/rwsdtg_0.pdf, updates the information provided in Chapter Nine of SW-846. It provides many improvements and new features.