Laserfiche WebLink
Review of the <br /> Draft DDJC-Sharpe Operable Unit 2 Human Health Risk Assessment <br /> Sampling and Analysis Plan <br /> March 2006 <br /> GENERAL COMMENTS <br /> 1. Under the discussion of Site History,presented in Section 1.1, the Draft DDJC-Sharpe <br /> Operable Unit 2 Human Health Risk Assessment Sampling and Analysis Plan (the report) <br /> indicates that previous site investigations and remedial actions including soil removal <br /> have been conducted at the site. Appendix A provides a brief overview of these previous <br /> activities. However, it is not clear from the text of the report nor the investigation <br /> summaries provided in Appendix A,where previous investigations were conducted, what <br /> data have been collected, and where remedial activities including soil removal have been <br /> conducted. Please revise the report to provide a figure that clearly shows areas of <br /> remediation and analytical results from previous characterization and/or confirmation <br /> studies. <br /> 2. Due to the remedial activities that have been conducted at the site over the past I 1 years, <br /> the facility deemed that additional data were required to assess human health risks due to <br /> exposure to existing levels of contamination and under current conditions. However, the <br /> report does not provide a clear indication whether the proposed risk assessment is to be <br /> based solely on the data collected through the implementation of this sampling and <br /> analysis plan or whether the proposed data will be used to augment an existing database. <br /> The report alludes in several places that previously collected data may be used in <br /> conjunction with the proposed data in evaluating health risks. For example,paragraph <br /> 1.2.3 on page 1-2 indicates that, "...an updated assessment of risk posed by chemical <br /> concentration in site soil to human receptor populations, supported by additional data, is <br /> warranted." However, neither a listing of these historical data nor a map showing the <br /> sample locations for where these data were collected was provided. Thus, it is difficult to <br /> assess whether the proposed sampling plan will provide sufficient data for conducting the <br /> risk assessment. It would be helpful to overlay the proposed sample locations over a map <br /> with the locations and results,of data from previous sampling events that will also be <br /> used. This would allow for a better picture of sample coverage and identification of data <br /> gaps. Please clarify if additional data are to be used in conjunction with data collected <br /> from the implementation of this sampling plan, and if so, please provide a figure showing <br /> the sample locations of these data as well as a summary of the analytical results. <br /> In the event that the proposed data will be the only data used in the risk assessment,it <br /> appears that there may be some data gaps and there will be insufficient data to conduct <br /> the risk assessment. The sampling and analysis plan does not provide a clear discussion <br /> of site activities, especially with respect to the Central Area. In reviewing the figure <br /> provided in Appendix C, it does not appear that there are any Solid Waste Management <br /> Units (SWMUs) or areas of soil contamination in the bottom center(east of the main <br /> Central Area building) of Operable Unit 2 (OU-2) or in the far northeast comer of OU-2. <br /> 1 <br />