Review of the US Navy's Human Health Risk Assessment of the Naval Air Facility at Atsugi, Japan (2001)

TCDD TEQs in soil samples on the base typically increase as the distance from the SIC decreases. The soil-trend analysis also indicates that the concentrations of total 2,3,7,8-TCDD TEQs exceeded RBSCs (risk-based screening concentrations) throughout the base for soil samples at up to 3 in. (7.6 cm) and about half the base for soil samples at 3-12 in. (7.6-30.5 cm).

• In the second paragraph on p. 29 of the NEHC draft summary report, the last sentence should be replaced with the following, based on the Radian report (1998b; p. 4-46):

On the basis of the lack of spatial trends, and the generally isolated occurrence of the SVOCs, their presence in soils does not appear to be associated with the Jinkanpo Incineration Complex.

The subcommittee also recommends the following:

• Reporting averages and ranges of concentrations detected and the RBC in Table 2.6 (NEHC 2000) rather than the RME and average concentration. The geometric mean and geometric standard deviation (or the 5-95% range of observed or calculated values) should also be included.

• Showing the reference areas (background soil areas) on Figure 1-2 in the NEHC draft summary report (the figure of the layout at NAF Atsugi).

• Showing the wind rose on any plots of the trend-analysis results that NEHC presents.

The subcommittee has reviewed the air-monitoring data and quality-assurance audits and has confidence in them. In general, the techniques used for air sampling and meteorologic monitoring appear to be adequate and to represent the state of the art. The subcommittee's main concerns are with the planning, the analysis of the data collected, and the connection between the analysis and the sample-collection strategies. Although the techniques used for air sampling are appropriate, there should be more discussion of the limitations and of possible alternative methods. Some minor comments on the air monitoring are presented below.

The second column in Table 2-2, titled “U.S. Data” (NEHC 2000; p.18), is confusing because it is not stated whether the values are means and, if so, of which cities. If they are means, it is not appropriate to use them as a basis for comparison with the highest or second-highest concentration in the National Ambient Air Quality Standards (NAAQS). It would also be helpful to include the NAAQS in this table.

The documentation (such as, Radian 1998d) mentions that open-path FTIR was used at some time but does not clarify when it was used or report on the results of using it. For example, it is unclear what type of FTIR monitoring is being referred to in the statement that “the FTIR monitoring found high (ppm) levels of hydrogen chloride in the SIC plume exiting the stack” (Radian 1998d; p. 5-5).