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Appendix E - Detailed Description of Alternative 1: DoFnt1.-2oo1-11
Full Removal and Disposal Rev. A raft B
r I Redline/Strikeout
1 be prohibited to ensure that the groundwater and Columbia River water quality are protected.
2 Specific institutional controls associated with this alternative would be developed as part of the
3 remediation activities specified in the 221-U Facility Record of Decision. Generally, these
4 activities would include physical and legal methods of controlling land use. Physical methods of
5 controlling access include signs, entry control, artificial or natural barriers, and active
6 surveillance. The DOE, or subsequent land managers, could enforce land-use restrictions as long
7 as risks were above unrestdcted land-usc levels. The DOE would continue to use fencing,
8 excavation permits, and the badging program to control access to the area for as long as it
9 maintains control over the land. Signs would be maintained prohibiting public access. In
10 addition, maintenance of vegetative or man-made covers for reduction of infiltration would be
11 required.
12
13 Legal restrictions would include both administrative and reat-property actions intended to reduce
14 or prevent future human exposure to contaminants remaining on site by restricting the use of the
15 land, including groundwater use for drinking water or irrigation. Land-use restrictions and
16 controls on real-property development are effective in providing a degree of human health
17 protection by minimizing the potential for contact with contaminated media. Land-use
18 restrictions will be put in place, as necessary, until such time as the federal government ceases
19 ownership of the property. The DOE, or subsequent land managers, would enforce land-use
20 restrictions as long as risks were above acceptable levels.
+O'N.21
22 Restrictions on the removal of remaining soil or debris above unrestricted-use cleanup levels
23 would also be required. Removal of soil or debris would be controlled at both the surface and at
24 depth ( i.e., below 4.6 m(15 ft]). Any soil removed from the 221-U Facility area would be sent
25 to a disposal facility approved in advance by the U.S. Environmental Protection Agency.
26
27 Groundwater-use restrictions would be required to ensure that groundwater is not used as a
28 drinking water source as long as contaminant concentrations aro above federal and state drinking
29 ^ water standards and WAC 173-340 #4TCA-B groundwater protection standards. Irrigation
30 would also need to be restricted if it is demonstrated that remaining contaminants could impact
31 groundwater or river water quality under an irdgation scenario. Well drilling, except for the
32 purposes of monitoring, research, or other uses authorized by the Tri-Parties, would be
33 prohibited until groundwater cleanup levels comply with these drinking water standards. As
34 further protection of groundwater, infiltration controls (e.g., revegetation, asphalt, concrete) may
35 need to be maintained depending on the contaminant concentrations left at the site and their
36 potential for mobilization to groundwater.
37
38 E3.4.2 Groundwater Monitoring Component of Alternative 1. A groundwater monitoring
39 system for ERDF would be implemented. The purpose would be to monitor groundwater at
40 ERDF for contaminants from the 221-U Facility waste that Is disposed there. A monitoring
41 system for ERDF that adequately covers the underlying groundwater area and includes all
42 contaminants of concern associated with the facility would be developed. The specific
('43 monitoring system design and its requirements would be established as part of the operations and
44 maintenance plan for ERDF.
45
Final Feasibility Siadyfor the Canyon Disposition /nlriative (221-U FacHiry)
^ in e 1^^ E-16