July 23, 2003

Dear Mr. Alcamo:

Tetra Tech EM Inc. (Tetra Tech) is submitting the of ficial hard copy of the analytical results for five fish samples that were collected by Viacom, Inc.'s (Viacom), contractor, Normandeau Associates, at various points downstream from the above-referenced site on May 27 and 28, 2003, and that were split with Tetra Tech. The analytical results were initially sent to you by electronic mail on July l l, 2003. Axys Analytical Services, Ltd. (Axys), of Sidney, British Columbia, Canada, analyzed Tetra Tech's split samples for polychlorinated biphenyl (PCB) congeners using U.S. Environmental Protection Agency (EPA) Method 1668A.

Tetra Tech reviewed Axys's analytical data to evaluate whether the data met 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 procedures were adjusted as necessary to meet the explicit requirements of EPA Method 1668A.

Enclosure 1 summarizes the split fish sample identification numbers, fish species and sample types collected, sample mass values, and sampling locations. Enclosure 2 summarizes Axys's analytical results for the five split samples. Axys's complete sample analytical results were reported in its data package deliverable, which was previously submitted to EPA.

No significant quality control problems arose during the analyses. Some low-concentration results exhibited ion abundance ratios outside quality control limits, indicating interference from nontarget compounds. These results are flagged "J" in Enclosure 2 to indicate that they are estimated, biased high. For three samples, some of the congener peaks in the chromatograms exceeded the calibration range. Axys reanalyzed the extracts of these samples at 10- or 1 00-fold dilutions, bringing the congener peaks within the calibration range; therefore, no further qualifications are warranted. Of the 209 PCB congeners analyzed for using EPA Method 1668A, 159 distinct peaks can be resolved in each sample chromatogram; Axys reports a combined concentration for various groups of congeners that co-elute at about the same retention time and that cannot be identified and quantitated separately using EPA Method 1668A.

The relative amounts of the homolog groups in the five split fish samples (10 to 16 percent trichlorobiphenyls [TriCB], 56 to 62 percent tetrachlorobiphenyls [TetraCB], 19 to 27 percent pentachlorobiphenyls [PeCB], and 4 to 6 percent other congeners) are consistent with past sample analytical results. Fish samples associated with Neal's Landfill are usually identified as containing Aroclor 1248, and a typical homolog analysis of that PCB mixture shows about 20 percent TriCB, 60 percent TetraCB, and 20 percent PeCB. For comparison, a typical homolog analysis of Aroclor 1242 shows about 20 percent dichlorobiphenyls, 40 percent TriCB, 35 percent TetraCB, and 5 percent PeCB, and a typical homolog analysis of Aroclor 1254 shows about 16 percent TetraCB, 60 percent PeCB, and 24 percent hexachlorobiphenyls.

Tetra Tech has not received Viacom's analytical results for the five fish samples as of the date of this submittal. Upon receipt of Viacom's data, Tetra Tech will prepare a detailed summary report that will include a comparison of the two sets of analytical results for the samples.

The Axys analytical results are usable for all purposes as qualified. If you have any questions regarding the split fish sample analytical results, please call me at (312) 946-6491.

Sincerely,
Jeffrey Lifka
Site Manager