UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 
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REGION II
DATE: 
0 8 NOT 19M
Tutu Wells Site, St. Thomas, VI
!ECT: Draft Remedial Investigation Report
FROM: Dore LaPosH^av Chief
Ground Water Management Section
TO: Carole Petersen, Chief
New York/Caribbean Superfund Section II
In accordance with the Memorandum of Interdivisional Coordination
between the Emergency and Remedial Response Division and the
Water Management Division (WMD) and as requested in your memo of
October 13, 1994, WMD has reviewed the Tutu Wells Site Draft
Remedial Investigation from the perspective of the water programs
and have the following comments:
1. The water level measurements were claimed to have been
synoptic (taken at the same time) but in fact were obtained
between May 23rd and May 24th. It should be demonstrated that
levels do not change significantly in the period over which they
were taken.
2. Please explain the 12-ft decrease in water level in SW-1,
between May 10th and May 23-4, given that the water levels in the
six other wells of the SW series did not change by more than
about 1 ft. Similarly, explain why the water level increased by
>12 ft in MW-22D and decreased by 4 ft in MW-21D while the levels
in the other twelve deep wells remained essentially the same.
3. It should be noted that the lack of significant VOC detects
in the fifteen supply wells that were sampled (Table 5.7) may be
misleading. Because the wells draw water from the entire
thickness of the aquifer rather than from just a 10-20-ft
interval, contaminants entering the borehole at a particular
depth would very likely be significantly diluted.
4. The very high level of vinyl chloride (1300 ppb) observed in
monitoring well MW-16 is not approached anywhere else on site.
Because vinyl chloride is a particularly dangerous compound,
additional efforts should be made to pinpoint and identify its
source by means of additional sampling in the vicinity of MW-16.
5. Please justify the absence of significant ground water
monitoring to the east of the 100-ppb VOC contour (Figure 5-18).
It would be helpful to establish the full width of the
contaminant plume.
Thank you for the opportunity to comment on this document. If
you have any questions, please contact either me or Steve Gould
of my staff at extension 5665.
cc: C. Kwan, RPM
REGION II FORM 132O-1 (9/86) 
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