By Arthur J. Horowitz, James J. Smith, and Kent A. Elrick
U.S. GEOLOGICAL SURVEY
Open-File Report 01-386
Atlanta, Georgia 2001
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A prototype 14-L Teflon® churn splitter was evaluated for whole-water sample-splitting capabilities over a range of sediment concentratons and grain sizes as well as for potential chemical contamination from both organic and inorganic constituents. These evaluations represent a "best-case" scenario because they were performed in the controlled environment of a laboratory, and used monomineralic silica sand slurries of known concentration made up in deionized water. Further, all splitting was performed by a single operator, and all the requisite concentration analyses were performed by a single laboratory.
The prototype Teflon® churn splitter did not appear to supply significant concentrations of either organic or inorganic contaminants at current U.S. Geological Survey (USGS) National Water Quality Laboratory detection and reporting limits when test samples were prepared using current USGS protocols. As with the polyethylene equivalent of the prototype Teflon® churn, the maximum usable whole-water suspended sediment concentration for the prototype churn appears to lie between 1,000 and 10,000 milligrams per liter (mg/L). Further, the maximum grain-size limit appears to lie between 125- and 250-microns (m). Tests to determine the efficacy of the valve baffle indicate that it must be retained to facilitate representative whole-water subsampling.
Materials and methods
Evaluating potential for sample contamination
Particle-size and concentration-range evaluations for the prototype 14-L Teflon® churn for a single withdrawal
Particle-size and concentration-range evaluations for the prototype 14-L Teflon® churn with multiple withdrawals
Evaluation of the efficacy of the valve baffle
Conclusions and recommendations
Appendix A: Organic parameters determined in the blank samples and source water
Appendix B: Inorganic parameters determined in the blank samples and source water