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TABLE 5 <br />SULFATES IN SOIL <br />EPA METHOD 300.0 <br />mg/Kg (ppm) <br />BORING . SAMPLE. D) 'SULFATE - mg/14 (13Prn) DEPTH <br />MW-1 0.5 MW-1B/0.5 9,400 <br />MW-1 10.0 MW-1A/10.0 680 <br />MW-1 10.0 MW-1B/10.0 910 <br />Note: MW-1A/10.0 is a duplicate sample of MW-1B/10.0 <br />The concentration of Sulfates appears to decrease with depth. No regulatory standard presently <br />exists for sulfates in soil. <br />4.2 DISCUSSION OF SULFATE VERSUS TOTAL SULPHUR RESULTS <br />Based on comparison to total sulphur results, the above detections of sulfate in Parcel III soil <br />appear to be anomalous. Sulfate and total sulphur results should be comparable by reducing the sulfate <br />results to determine the minimum total sulphur concentration. The concentrations of sulfate reported, <br />when reduced, yield the following minimum total sulphur concentrations: <br />Sample No. Projected minimum total sulphur concentration Reported sulphur concentration <br /> <br />MW-1B/0.5 <br />MW-1A/10.0 <br />MW-1B/10.0 <br />3,133.02 mg/Kg <br />226.44 mg/Kg <br />303 mg/Kg <br />737 mg/Kg <br />162 mg/Kg <br />187 mg/Kg <br />In an attempt to resolve the discrepancy, several consultations with the analytical laboratory were <br />made. The laboratory reportedly performed a detailed evaluation of the data and found no errors in the <br />testing methods or quantifications. The EPA presently does not have a prescribed method for analyzing <br />total sulphur. Although our prime laboratory contractor validated the total sulphur results, Dames & <br />Moore speculated that an error may have been made in the analysis. <br />To further investigate the discrepancy, Dames & Moore retrieved the soil samples from the prime <br />laboratory (D&M Laboratories) and resubmitted them to an alternate laboratory (Enseco, California <br />SAC28.013 <br />15 <br /> December 20, 1991 <br />;\.,11.4 S -A- Y;