Final Remedial Action Completion Report for the ... - Rvaap.org

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Comment
Shaw Environmental, Inc. 26 of 39
Recommendation
Response
LL4mw198 (0.115 mg/L).
All the concentrations listed above
for dissolved manganese exceed the
drinking water Secondary Standards.
All the concentrations listed above
for dissolved antimony, barium,
beryllium, cobalt, lead, nickel,
selenium, thallium and zinc exceed
the applicable background criteria.
Arsenic concentrations exceeded the
Region 9 PRG at all the well
locations identified above. A
dissolved arsenic concentration of
0.0104 milligrams per liter (mg/L)
just exceeded the drinking water
MCL of 0.01 mg/L at LL2mw263.
None of the arsenic concentrations
exceeded the background criteria of
0.0117 mg/L.
3.2.8.5 Pesticides and PCBs
Concentrations of the pesticide 4,4’-
DDT were detected in groundwater
samples above the method detection
limits at the following two well
locations on LL 2:
• 4,4’-DDT – LL2mw262
(0.0311 µg/L J, 0.0433 µg/L
J, 0.0631 µg/L J and 0.075
µg/L J), LL2mw266 (0.022
µg/L J and 0.030 µg/L J)
These pesticide concentrations
exceed the Region 9 PRG of 0.2
µg/L. No PCBs were identified
above the method detection limits in
any of the groundwater samples
collected.