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

Remedial Action Completion Report
June 2008
Remediation of Soils and Dry Sediments at RVAAP 08-11 (LLs 1-4)
Page 3-20
Laboratory results for the confirmatory multi-increment samples indicate that COCs have been
reduced to below the cleanup goals at all excavation areas at LL 1 with the exception of
Aroclor-1254 at sample location LL1ss-029-cs. The Aroclor-1254 concentration at this location
is 54.3 mg/kg and is less than an order of magnitude above the cleanup goal of 35 mg/kg. This
sample location is situated adjacent to the northeast of the melt pour building CB-4A and is
surrounded by the concrete building foundation and bedrock outcrops. The base of the
excavation consists of ledge and cannot be advanced any further using the conventional methods
specified for this scope of work. The Ohio EPA concurred that no additional soils could be
removed from this excavation and that the COC in soils at this location had been removed to the
best extent possible with only isolated residual soils or a limited quantity remaining on top of
bedrock (Ohio EPA 2008b).
One sample location, LL1ss-038-cs, required re-excavation due to concentrations of TNT at
2,010 mg/kg and 1,790 mg/kg in the multi-increment sample and its duplicate, respectively.
These concentrations were above the cleanup goal of 1,648 mg/kg for TNT. After additional
soils were removed, a follow-up multi-increment sample was submitted for laboratory analysis
and the TNT result was below the laboratory detection limit indicating that any remaining
impacted soils had been adequately removed.
3.6.4.2 Load Line 2
There were 24 discrete areas (LL2ss-047-cs through -070-cs) at LL 2 that required excavation
(Figure A-2). As with LL 1, several of the discrete areas were combined to form one
multi-increment sample resulting in a total of 22 multi-increment samples that were collected.
The COCs at LL 2 consisted of Aroclor-1254; TNT; RDX; and the metals aluminum, antimony,
arsenic, hexavalent chromium, lead, and manganese. One excavation location, LL2ss-049-cs,
did require re-excavation due to an arsenic concentration of 76.3 mg/kg that was above the
cleanup goal of 31 mg/kg. After the removal of the additional soils, a follow-up multi-increment
sample was submitted for analysis for arsenic and the result was well below the applicable
cleanup goal at a concentration of 14.1 mg/kg. Laboratory results for all other confirmatory
multi-increment samples collected at LL 2 indicate that COCs have been removed to below
cleanup goals at all excavation areas.
3.6.4.3 Load Line 3
There were a total of 35 discrete areas (LL3ss-071-cs through -105-cs) at LL 3 that required
excavation (Figure A-3). Several of the discrete excavation areas were expanded based on field
screen results, and due to the relative close proximity to other discrete areas, the excavations
were combined into a single multi-increment sample. As a result, a total of 27 multi-increment
samples were collected at LL 3. The COCs at LL 3 consisted of Aroclor-1254; benzo(a)pyrene;
TNT; and the metals aluminum, antimony, arsenic, hexavalent chromium, lead, and manganese.
Laboratory results for the confirmatory multi-increment samples collected at LL 3 indicate that
COCs have been removed to below cleanup goals at all excavation areas. One excavation
location, LL1ss-072-cs, did require re-excavation due to manganese concentrations of
3,830 mg/kg and 2,000 mg/kg in the multi-increment sample and its duplicate, respectively.
These concentrations exceeded the cleanup goal of 1,800 mg/kg for manganese in surface soils
(0 to 1 foot). Once the additional soils were removed, the excavation was resampled and
manganese was found to be below the cleanup goal.
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