ARCHIVED REPORTS_HUMAN HEALTH SCREENING SUPPORTING DOCUMENTS

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Mr.M. Scott Mansholt—CEMC Presentation of Additional Metals Evaluation May 25,2007 Historic Pipeline Portfolio Page 3 of 5 As all metals levels in oil are within or below the background ranges, it is not likely that oil is a contributor of any metal at HPP sites. Further,the average metals concentrations in the oil are all below the lowest SSL(with the exception of arsenic discussed above), demonstrating that the metals in the oil do not pose a health risk. Figures 3 and 4(Figure 4 presents the same data at a different scale) show the average metals concentrations in oil compared to soil containing less than 100mg/kg TPH and greater than 100 mg/kg TPH. These figures illustrate that the metals concentrations in oil are typically lower than the concentrations of metals in soil containing TPH. Further,there is no pattern of metals concentrations being higher in soil containing greater than 100 mg/kg relative to soil containing less than 100 mg/kg TPH. These findings further demonstrate that metals in crude oil are not increasing metals concentrations in soil. METALS IN SOIL SAMPLES A review of Table 1 shows that the maximum detected concentration for each metal is commonly higher than one or both background concentrations,but the average metals concentrations are all within or below the range of background concentrations,with the exception of lead. The average lead concentration was raised due to lead concentrations at the former TAOC Trent Pump Station,where the lead concentrations were noted within two"ash areas,"suggestive of a source other than crude oil. As noted above,the lead concentrations in oil are less than background, and therefore lead at HPP sites is not considered to be associated with crude oil. Table 1 also indicates that the concentrations of metals detected in the 66 soil samples from HPP sites are typically below the SSLs. The maximum detected concentration in soil for arsenic, cobalt, copper, lead, nickel,thallium,vanadium, and zinc exceed the lowest SSL(note that the maximum antimony, cadmium, and thallium concentrations exclude the results from two non-detectable samples with elevated detection limits from samples GP-1 and BP-14 in Table 1). However,the average concentrations of the metals in soil are below the SSLs, except arsenic and cobalt. As shown on Figure 1, arsenic and cobalt concentrations in the oil are all lower than background concentrations, indicating that the TPHc in soil is not the cause of the SSL exceedances for these metals. CORRELATION ANALYSES To further evaluate whether the crude oil carried in the OVP and the TAOC pipelines increased metals concentrations in the soil of HPP sites, correlation analyses between the metals and TPHc concentrations were performed. To evaluate the correlation,metals concentrations were plotted against TPHc concentrations. Note that samples without both a metals and TPHc analysis were omitted from the correlation, and non-detectable results were assigned a value of the detection limit. As noted above,two data points were omitted due to elevated metals detection limit for the antimony, cadmium, and thallium correlations. The correlation coefficient(R)was calculated to measure the degree to which TPHc and metals concentrations were linearly related(Table 1). The correlation is expressed as a correlation coefficient (R), and is expressed as a number between A and 1. A correlation coefficient of 1 shows a straight line could be fitted to the plot of TPHc and the metal of interest(perfect correlation; i.e.,metals concentrations increase as TPH increases). A correlation coefficient of 0 shows no linear association between TPHc and the metal(no correlation). A negative correlation coefficient indicates that the two variables are inversely related(i.e.,metals concentration increases as TPHc decreases). The correlation plots are presented as Attachment A. Based on the correlations of the metals data in soil to TPH concentration,the R values ranged from-0.2 for thallium to 0.45 for cadmium, indicating a weak apparent or no association between all of the metals and TPHc. The calculated R values for arsenic and cobalt—metals which were present in oil above the