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Site Number: |
01LU |
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Contract Number: |
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D.O. Number: |
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Action Memo Date: |
8/5/2015 |
Response Authority: |
CERCLA |
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Response Type: |
Time-Critical |
Response Lead: |
EPA |
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Incident Category: |
Removal Action |
NPL Status: |
Non NPL |
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Operable Unit: |
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Mobilization Date: |
10/1/2015 |
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Start Date: |
10/1/2015 |
Demob Date: |
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Completion Date: |
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CERCLIS ID: |
MAN000100745 |
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RCRIS ID: |
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ERNS No.: |
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State Notification: |
Yes |
FPN#: |
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Reimbursable Account #: |
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1.1.1 Incident Category
Time
Critical Removal Action
1.1.2 Site Description
The
Site consists of a 10.36 acre parcel containing 30 buildings, 28 of which are
multi-apartment unit dwellings, a maintenance building, and a community center.
The property includes a ballfield, several play areas containing swing sets,
slides, etc., and a small raised bed community gardening area. All of the utilities associated with the MHA
(water, sewer, electric, cable, etc.) are below ground.
The Willis Avenue Apartment
complex is currently owned and operated by the MHA. The complex’s operation and maintenance is
funded by income generated from its rent controlled (income dependent)
apartments and by annual funding provided by the U.S. Housing and Urban
Development Agency (HUD). It is home to
approximately 470 individuals, the majority being of Haitian-Creole
descent. About 79.4 percent of the
population, or 371 residents, is classified as minority (Black, Asian, or
American Indian). There are roughly 69
children living there between the ages of 0-6 and 75 children between the ages
of 7-12.
According
to the EPA flex viewer software program, there are 1,400 and 4,861 people
living (nighttime population) within ¼ mile and ½ mile respectively of the
center of the Site. There are also 2
public schools and 3 tier 2 facilities within ½ mile.
1.1.2.1 Location
The
property that comprises the Site is located on Bonner, Willis, Congress and
Exchange Avenues in Medford, Middlesex County, Massachusetts. The geographic coordinates of the
intersection of Congress and Exchange Avenues are 42°24’13.1” north and 71°6’11.8”
west. The Site is bordered to the north
by Bonner Avenue and residential properties, to the south by primarily
commercial structures which run along Hicks Avenue, to the east by commercial
properties and Mystic Avenue, and to the west by Willis Avenue and residential
properties.
1.1.2.2 Description of Threat
Lead has been detected in surface
soils at the MHA Willis Avenue Apartments.
Although lead is a naturally occurring element and found in higher
concentrations in urban settings due to anthropogenic sources, the
concentrations detected in this neighborhood are close to, and in many cases exceed,
typical urban background concentrations as well as EPA Regional Removal
Management Levels (RMLs). These RMLs are not meant to be action or cleanup levels but rather a
starting point to determine if further action is warranted, should the numbers
be met or exceeded. The RML for lead in a residential setting is 400 parts per
million (ppm). As a screening technology
was used to identify lead levels (X-Ray fluorescence) in the field, the OSC
selected a concentration of 350 ppm in his analysis of site conditions. This concentration represents a site-specific
action level that accounts for the uncertainty of the screening technology. A minimum of 10% of the samples analyzed by
XRF were also sent to a laboratory for confirmatory analysis.
During the PA/SI,
five of the seven playground locations exceeded the 350 ppm limit within the
top foot of soil. In addition, soil within some of the community raised bed
gardens and one private garden exceeded the concentration of concern. Lead in surface soil is the primary
contaminant at this Site. Lead is a
listed CERCLA hazardous substance in 40 CFR 302.4.
Lead in surface soils in the playgrounds and some
of the gardens presents a potential health threat through direct exposure to
local residents, including children.
1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results
During
the summer of 2014, EPA conducted a preliminary assessment / site investigation
(PA/SI). Soil samples were collected
throughout the approximately 10 acre development from 38 accessible, discrete grassy
areas (grids) in between the multi-unit apartment buildings. One additional
grid that had been previously sampled by a contractor for the MHA and was not
resampled. These grids include 7 designated
play areas containing playground equipment such as swing sets and sliding
boards. In most instances, multiple
samples were collected from each grid and composite samples from the 0 – 1’, 1
– 2’, and 2 – 3’ below grade were collected and analyzed. Individual grab samples were also collected
from the community raised bed garden location as well as from private gardens.
The
following table indicates the number of exceedances
of the site specific action level of 350 ppm for a particular grid and depth,
as well as the ranges, averages, and/or concentrations of lead within the
specific depths of soil.
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0 – 1’ below grade
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1 - 2’ below grade
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2 -3’ below grade
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Grids: 32
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Exceed 350 ppm
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12 grids
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23 grids
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25 grids
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Range
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398-770 ppm
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437-2874 ppm
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437-2134 ppm
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Average
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492 ppm
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1088 ppm
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1146 ppm
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Play Areas: 7
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Exceed 350 ppm
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5 play areas
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7 play areas
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7 play areas
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Range
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393-920 ppm
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523-2074 ppm
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437-1556 ppm
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Average
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635 ppm
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1075 ppm
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963 ppm
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Public Raised Bed Gardens: 5
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Exceed 350 ppm
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2 gardens
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NA
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NA
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Concentrations
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435, 448 ppm
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Private Gardens: 5
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Exceed 350 ppm
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1 garden
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NA
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NA
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Concentrations
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387 ppm
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2.1.1 Narrative
Surface
soil (0-1’ bg) contains lead above 350 ppm, the level of concern, in five of the seven designated playground
areas within the housing complex, the public raised garden bed area, and one
private garden. The average
concentration of lead in the five play areas is 635 ppm. This concentration is slightly higher than
the 600 ppm background level of lead in soil containing coal or wood ash
associated with fill material as stated in a MassDEP guidance[1]
document. In most cases, this removal
action will be limited to removing the top foot of contaminated soil and
replacing it with clean fill in the playgrounds as well as the identified
gardens. In 2 of the playground grids, the
play areas will be raised in a manner similar to the raised garden beds.
Twelve of the 32 non-play area grids are also
above 350 ppm in surface soil. Although
the average lead concentration in the top foot of soil in these locations is
492 ppm, these areas will not be subject to the removal action. Please refer to the Action Memorandum for the
reasoning involved.
On
September 30, 2015, a community meeting was held at the MHA to inform residents
of the impending removal action. To
augment this meeting, a fact sheet in both English and Haitian was distributed
to all of the apartments.
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2.2.1 Anticipated Activities
The removal action is underway.
Following site prep, a tree service has been contracted to remove a number of
trees from within grids being excavated or brought up in grade. An independent arborist was subcontracted to
provide input with regard to tree health and steps that need to be taken to
protect the trees not being removed in the vicinity of the work zones. All tree removal activities have been
coordinated with the directors of the MHA.
A company that will be supplying
the fill material (sandy base soil and topsoil) has been subcontracted and
samples will be collected prior to it being brought to the site to ensure its
cleanliness.
Once the trees have been removed,
excavation and/or fill operations will begin. The ground will be wetted prior
to any intrusive activities, but air monitoring will be conducted to make sure
that potentially contaminated dust is not being released from the work
zone.
It is unsure if any of the playground equipment
can be salvaged due to its age and condition, so it is likely that a minimum of
3 sets of play equipment will have to be replaced.
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