Accession Number : ADA310390

Title :   Comparison Criteria for Environmental Chemical Analyses of Split Samples Sent to Different Laboratories: Corps of Engineers Archived Data.

Descriptive Note : Special rept.,

Corporate Author : COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH

Personal Author(s) : Grant, Clarence L. ; Jenkins, Thomas F. ; Mudambl, Anand R.

PDF Url : ADA310390

Report Date : MAY 1996

Pagination or Media Count : 38

Abstract : Data comparison criteria were developed for quality control (QC) and quality assurance (QA) chemical analyses obtained during environmental studies directed by the U.S. Army Corps of Engineers (USACE). Archived results for 124 sets of eight metals in soils, 69 sets of fourteen volatile organic compounds (VOCs) in soils, 163 sets of total petroleum hydrocarbons (TPH) in soils, 79 sets of six explosives in soils, and 153 sets of fourteen VOCs in groundwater were analyzed statistically. Concentration ratios (QC1/QC2 and QC/QA) were log normally distributed and this was the model used for comparisons. For both metals in soils and VOCs in groundwater, duplicate QC results should yield ratios between 0.50-2.00; less than 4% of the archived results were outside these limits. For QC/QA ratios, the limits suggested are 0.40-2.50; only 10.2% of metals ratios in soils and 5.6% of the VOCs in groundwater exceeded these limits. Considering that both methods are multi-analyte, we find only 4.0% of the metals samples and 2.0% of the VOC samples had more than one offending ratio per sample. Application of these limits to recent analyses produced very similar results. For V0Cs, TPH, and explosives in soils, temporary limits of 0.25-4.00 are suggested with the understanding that improvements leading to tightening should be energetically pursued. Even with these wide limits, approximately 42% of V0Cs, 14% of TPH, and 11% of explosives QC/QA ratios must be considered outliers. Here, too, recent analyses yielded very comparable percentages. The situation for VOCs in soils requires immediate attention to improve sampling and preparation procedures, but all methods can and should be capable of producing improved agreement between laboratories. Numerous recommendations are offered with this goal in mind.

Descriptors :   *COMPARISON, *SAMPLING, *ARMY CORPS OF ENGINEERS, *SPLITTING, *ENVIRONMENTAL MANAGEMENT, *CHEMICAL ANALYSIS, DATA PROCESSING, METALS, ENVIRONMENTS, PREPARATION, EXPLOSIVES, GROUND WATER, SOILS, WATER POLLUTION, HYDROCARBONS, QUALITY CONTROL, ORGANIC COMPOUNDS, VOLATILITY, QUALITY ASSURANCE, SOIL POLLUTION, PETROLEUM PRODUCTS.

Subject Categories : Physical Chemistry
      Inorganic Chemistry
      Organic Chemistry
      Logistics, Military Facilities and Supplies
      Solid Wastes Pollution and Control
      Water Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE