Fort Devens Sudbury Training Annex Middlesex County Massachusetts Remedial (Data Gap) Investigations of Area of Contamination A4 and Areas of Combination A7/A9 (Management-of-Migration Operable Unit) and Supplemental Site Investigation Unit and Supplemental Site Investigations of Selected Study Areas.

摘要

The purpose of this Work Plan is to provide a basis and plan for collecting additional required data at the identified sites. The RIs will focus on providing additional information on the presence, extent, and concentrations of certain contaminants in specific areas near the subject AOCs. These data will be compared to previously calculated human health and ecological quantitative risk assessments in technical memoranda for the A4 and A7/A9 AOCs. For the Management-of-Migration OU at AOCs A7/A9, the data will also be incorporated as appropriate in an addendum to the current Feasibility Study (FS) (OHM, May 1995). Additional 551 field investigations will be conducted at SAs P20, P22, and P59. The collection of additional data is not required for SAS P1, P4, P17, P35, and P60. All available data for each SA will be evaluated along with the previously acquired data for each SA in recommending: 1) no further action (NFA); 2) a removal action; 3) inclusion in a facility-wide arsenic investigation; or 4) a remedial investigation (RI). Human health and ecological preliminary risk evaluations (PREs) will be performed as part of the SSIs for all eight SAs. The planned RI data-gap investigations and SSIs will consist of field observations and measurements, the collection of environmental samples, and chemical analysis of the samples.