The Contract Laboratory Program

Certain laboratories can, after a contract has been awarded, register under the Contract Laboratory Program (CLP) of the EPA. To earn a contract, one or more specifically prepared samples must be analyzed under very similar conditions to those used in standard protocols. Only if the data are deemed satisfactory will a contract be awarded. Further evaluation samples must be analyzed at three-month intervals afterward to ensure that performance is being maintained. 

Staples et al. (1985) reported that acrylonitrile was not present at detectable concentrations in 352 sediment samples collected from lake and river bottoms across the United States. Preliminary data from the contract Laboratory Program (CLP) Statistical Database (CLPSD 1988) indicated that acrylonitrile was detected in soils at 3 of 862 hazardous waste sites (including NPL and other sites) being investigated under Superfund. The median concentration of five samples was 120 pg/kg. 

Dibromoethane has been detected in an estimated 0.23% of the groundwater samples analyzed for the 2,783 hazardous waste sites participating in the Contract Laboratory Program (CLP) a positive geometric mean concentration value was not reported. 1,2-Dibromoethane has not been detected in surface water samples taken at hazardous waste sites (CLPSD 1988). Note that the CLP Statistical Database (CLPSD) includes data from both NPL and non-NPL sites. 

Hall et al. (1985) reported that no 1,2-diphenylhydrazine (less than pg/L) was detected in the Nanticoke River near the Chesapeake Bay. The analytical method involved liquid-liquid extraction, concentration, and. analysis by GC/MS. The Contract Laboratory Program statistical database (queried April 13, 1987) reported that 1 2-diphenylhydrazine has been detected n water at i of 357 hazardous waste sites at a concentration of (96 ppb (CLPSDB 1987), and has been reported at 7 of 117, sites. n the national Priority List database (ATSDR 1990) The U.S. EPA Contract laboratory Program uses GC methods to analyze the contaminants of interest. Since 1,2-diphenylhydrazine oxidize, to azobenzene in the GC injector port and both 1,2-diphenylhydrazine and azobenzene, have the same GC retention time and mass spectra, reports of 1,2-diphenylhydrazine from the Contract Laboratory Program may actually represent detections of 1,2-diphenylhydrazine, azobenzene, or both (see Chapter 6 for more details). 

Diphenylhydrazine has been identified in soil only at hazardous waste sites. The Contract Laboratory Program statistical database (queried April 13, 1987) reported that 1,2-diphenylhydrazine has been detected in the soil at 2 of 357 hazardous waste sites in both cases at 18,200 ppm (CLPSDB 1987). The Contract Laboratory Program uses GC methods to analyze the contaminants of interest. As discussed in Section 5.4.2, this may actually represent detections of either... 

Hexanone has been detected in both surface water and groundwater at hazardous waste sites. Data from the Contract Laboratory Program (CLP) Statistical Database indicate that 2-hexanone was found at 2% of the sites at a geometric mean concentration of 7.5 pg/L (ppb) in positive surface water samples and 12 pg/L (ppb) in positive groundwater samples (CLPSD 1989). This database provides data from both NPL and non-NPL waste sites. 

The only direct measurements of isophorone in soil were found for samples taken from hazardous waste sites. Ghassemi et al. (1984) found isophorone in leachates from hazardous waste landfills, and Hauser and Bromberg (1982) detected the presence of isophorone in the "sediment/soil/water" of Love Canal. These studies suggest that isophorone also was present in the soil. The Contract Laboratory Program Statistical Data Base (queried April 13, 1987) reported that isophorone has been detected at 4 of 357 hazardous waste sites at a concentration range of 1.68-6500 ppm. 

Isophorone has been identified in soil only at hazardous waste sites. The contract laboratory program statistical data base reports that isophorone has been detected at 1.68-6500 ppm in 4 of 357 hazardous waste sites. 

Dichloromethane has been detected in both surface water and groundwater samples taken at hazardous waste sites. Data from the Contract Laboratory Program Statistical Database of the United States Environmental Protection Agency indicate that dichloromethane was present at geometric mean concentrations of 68 and 98 pg/L in surface water and groundwater samples, respectively, at about 30% of the sites sampled (Agency for Toxic Substances and Disease Registry, 1993). 

The Contract Laboratory Program (CLP) statistical database indicates that silver has been detected with a geometric mean concentration of 4.5 ppm in soil samples from 1,807 of 2,783 (65%) hazardous waste sites that have had samples analyzed by the CLP (CLP 1988). 

Dichloroethane has been detected in groundwater samples taken at an estimated 9% of the NPL hazardous water sites participating in the Contract Laboratories Program (CLP) at a geometric mean concentration of 23.1 ppb for the positive samples (CLP 1989). The compound was also detected in surface water samples taken at an estimated 2% of the NPL hazardous waste sites participating in the CLP at a geometric mean concentration of 24 ppb for the positive samples. Note that these data from the CLP Statistical Database represent frequency of occurrence and concentration information of NPL sites only. 

Windholz 1983). The Contract Laboratory Program statistical data base reports that NDMA has been detected in groundwater samples at one out of 1177 hazardous waste site on the National Priorities List (NPL). This site is Martin Marietta (Denver Aerospace) in Waterton, CO (VIEW Database 1989) ... 

Quantitation and Detection Limits Reviews. Because the quality of laboratory analyses of chemical contamination is critical to the validity of any conclusions about risk, EPA initiated the Contract Laboratory Program (CLP) to ensure consistent, high quality analyses. By comparing reported quantitation limits for samples at a site to quantitation limits specified by CLP, Risk Assistant will provide a report on a key feature of analytical quality sensitivity. 

User s Guide to the Contract Laboratory Program, U. S. Environmental Protection Agency, U.S. Government Printing Office Washington, DC, 1987. 

The Contract Laboratory Program procedure required delivery of specified documents included data summary forms, calibration data, chromatograms, and mass spectra and were generally shipped by air freight. Upon receipt by EPA, the documents were reviewed for data usability which was based on consideration of completeness of documentation and adherence to quality control requirements... 

Stoddard solvent is not listed in the Contract Laboratory Program Statistical Database (CLPSD) of chemicals detected in groundwater and surface water samples taken only at NPL sites. Stoddard solvent itself, as a hydrocarbon mixture, is not included as a target chemical at NPL sites, but some components of the Stoddard solvent mixture such as alkanes, substituted benzenes, and naphthalenes have been detected in groundwater and surface water samples (CLPSD 1989). However, the presence of these compounds does not necessarily imply contamination by Stoddard solvent. 

Target Compound List (TCL) A list of organic compounds that are determined during Superfund site remediations. Created by the EPA for use in the Contract Laboratory Program, this list was formerly referred to as the... 

Method 6020-CLP-M under the Contract Laboratory Program is available as a Special Analytical Services (SAS) method. 

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