January 16, 2003

Dear Mr. Alcamo:

Tetra Tech EM Inc. (Tetra Tech) is submitting analytical results for three surface water samples collected by Tetra Tech and its subcontractor, Earth Tech, Inc. (Earth Tech). Tetra Tech and Earth Tech collected the surface water samples directly from the South Spring orifice near the Neal's Landfill site during low-flow and high-flow conditions on December 13 and 19, 2002, respectively. In addition to these South Spring samples, Earth Tech collected an effluent sample from the spring treatment facility (STF), which Viacom, Inc. (Viacom), operates at the Neal's Landfill site. Tetra Tech's subcontractor laboratory, TriMatrix Laboratories, Inc. (TriMatrix), of Grand Rapids, Michigan, analyzed the three surface water samples and two associated trip blanks for volatile organic compounds (VOC) using U.S. Environmental Protection Agency (EPA) SW-846 Method 8260.

Tetra Tech evaluated whether TriMatrix's analytical data meet the data quality objectives specified in the quality assurance project plan for the above-referenced work assignment. Tetra Tech's review was conducted in general accordance with procedures discussed in EPA's "Contract Laboratory Program National Functional Guidelines for Organic Data Review" dated October 1999.

The enclosure to this letter includes TriMatrix's sample analytical results. The laboratory quality control (QC) results include the results for (1) initial and continuing calibrations, (2) the bromofluorobenzene (BFB) gas chromatograph/mass spectrometer (GC/MS) instrument tuning control, (3) a method blank, (4) matrix spike/matrix spike duplicate (MS/MSD) samples, and (5) laboratory surrogate recoveries and internal standard responses. The initial and continuing calibration results were acceptable for all analyses reported. The BFB GC/MS instrument tuning control was acceptable, samples were analyzed within 12 hours of the tuning, and the laboratory method blank was free of contaminants. MS/MSD sample analytical results were all within QC recovery limits. All surrogate recoveries and internal standard responses were also within QC limits.

The chromatograms for the three surface water samples were similar, indicating minimal differences between the low-flow (nonstorm), high-flow (storm), and effluent samples. TriMatrix reports that all three samples contained only one target analyte, trichloroethene (TCE). The quantitative TCE result for the December 13, 2002, South Spring nonstormsample is 7.9 micrograms per liter (ug/L). The quantitat TCE result for the December 19, 2002, South Spring storm sample is 2.0 ug/L. The storm sample probably contained a lower TCE concentration because the greater volume of water flowing from the South Spring orifice diluted the analyte's sample concentration. TriMatrix reports the STF effluents contained 8.0 ug/L TCE. The reported South Spring nonstorm and STF effluent sample TCE concentrations are above the maximum contaminant level (MCL) for TCE in Groundwater of 5.0 ug/L. In addition, TriMatrix reports that the two associated trip blanks had nondetect results for all analyses. No data qualifications are necessary. All nondetect results reported by TriMatrix represent the laboratory quantitation limit for each analyte.

All chain-of-custody procedures were adhered to, holding times were met, and the two sample shipments were both received at the laboratory with an acceptable sample cooler temperature of 2.0 °C.

One minor analytical matter must be noted. In its data package case narrative, TriMatrix states that or nontarget analyte was detected in two of the three samples. Specifically, TriMatrix reports that the South Spring nonstorm and STF effluent samples contained cis-1,2-dichloroethene (cis-1,2-DCE) at 2.5 and 1.3 ug/L, respectively. The presence of cis-1,2-DCE is probable because it is an environmental degradation product of TCE and also is commonly used as a commercial organic solvent similar to TCE. Despite its detection, the reported concentrations of cis-1,2-DCE are not considered significant because MCL for cis-1,2-DCE is 70.0 ug/L.