Cleaning Up New England        SITE  UPDATE
                                                                                                 JULY 2011
                        Centredale  Manor
                        Restoration  Project Superfund Site
                        North Providence/Johnston, RI
                       U.S. EPA  |  HAZARDOUS  WASTE  PROGRAM AT EPA  NEW  ENGLAND
                                                        THE  SUPERFUND  PROGRAM  protects human  health
                                                         and  the environment by investigating and cleaning up often-abandoned
                                                         hazardous waste sites and engaging communities throughout the process.
                                                         Many of these sites are complex and  need  long-term cleanup actions.
                                                         Those responsible for  contamination are held  liable  for cleanup costs.
                                                         EPA strives to return  previously  contaminated land and groundwoter
                                                         to productive use.
The Woonasquaiucket River, which forms the border between Johnston and North Providence, Rhode Island, has wide-
spread dioxin contamination resulting from the former operations of a chemical company and a drum recycler from the
early 1940s to the early 1970s. The main part of the Centredale Manor Site, called the Source Area, is approximately
9 acres and is currently occupied by the Centredale Manor and Brook Village apartment complexes on Smith Street,
North Providence. The site also includes free-flowing reaches and ponds of the Woonasquatucket River next to and
downstream from the Source Area. Contamination was first found in fish in 1996. EPA has since documented elevated
levels of contaminants including dioxin, PCBs, Volatile Organic Compounds (VOCs), semi-VOCs, and metals In soil,
sediment, wetlands and surface water at the site. The Rhode Island Department of Health recommends that the public
not eat fish caught from the Woonasquatucket below the Johnston/Smithfield town line.

The Superfund process, conducted in  several steps over multiple years, leads to the ultimate goal  of protecting
the environment and health of those people living and working around the Centredale Manor site and using the
Woonasquatucket River. Since becoming a federal Superfund site in 2000, EPA and the Potentially Responsible Parties
have taken several short-term actions to control current exposure of residents and visitors to contaminants. These
actions included capping of contaminated soil in the Source Area, installation of a fence to control access, removal of
contaminated soil from residential properties along the river, reconstruction of the breached Allendale Dam, and the
removal of contaminated soil to limit the movement of contamination through groundwater into the river.
The site is organized into five cleanup areas:

1. Source Area Soil
The nearly 9 acre Source Area is the main part of the
site where the contamination originally occurred and
now includes two apartment buildings, paved and land-
scaped surfaces, and three temporary capped areas.
These three  temporary soil covers were constructed
from the 1990s through mid-2000s in the area not occu-
pied by buildings, parking lots, or roadways; soil was also
removed under one of the parking lots in the late 2000s
as part of the groundwater short-term cleanup. Most of
the Source Area is located within the floodplain. and also
includes riverbank wetlands.
                                            2. Groundwater
                                            Groundwater is the water that is found  beneath the
                                            surface of the ground, The groundwater area contami-
                                            nated in excess of cleanup levels is located underneath
                                            the Source Area that is bound by the river  and streams.
                                            The 2009 short-term cleanup action addressed about
                                            0,13 acres on the west side of the Brook Village parking
                                            lot where contaminated groundwater was flowing into
                                            the river.

                                            3. Allendale Pond and Lyman Mill Pond Sediment
                                            This area includes all contaminated sediment in AHendale
                                            Pond and Lyman Mill Pond and monitoring further down-

                                                                            continued >

EPA New England
Project Manager
(617) 918-1232

EPA New England, Community
Involvement Coordinator
(617) 918-1403


5 Post Office Square
Suite 100
Boston, MA 02109-3912
(617)918-1111 region 1 /


             United States
             Environmental Protection
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                                                                SITE  UPDATE
                      SITE CONTAMINANTS  WHICH
                              WARRANT  ACTION

    Dioxins are a class of chemical contaminants that are formed during some industrial pro-
    cesses such as disinfectant (anti-bacterial) or herbicide manufacturing as well as combustion
    such as waste incineration.

    Furans are by-products usually created when herbicides or other products are made or burned.

    PCBs,  or Pol/chlorinated Biphenyls, are man-made chemicals that were used in electrical
    manufacturing and were banned in 1979,

    Pesticides are substances used to destroy or repel insects, weeds, or other animal life that
    are considered to be pests.

    VOCs, or Volatile Organic Compounds, include a variety of chemicals that are used in glue,
    paint, solvents, and other products and easily evaporate. Common VOCs include TCE, or
    Trichloroethylene,  and PCE, or Tetrachloroethylene.

    SVOCs, or Semivolatile Organic Compounds, are chemicals that may vaporize when ex-
    posed to temperatures above room temperature. SVOCs include phenols found in coal and
    wood tar, and polynuclear aromatic hydrocarbons (PAHs),  a widespread pollutant from
    petroleum production and fuel emissions.

    Metals, including lead, cadmium, copper, arsenic, zinc and others, occur  naturally in the
    environment but high concentrations result from man-made activities such as smelting, fuel
    manufacturing, and electroplating.
4. Allendale Fioodplain Soil
A floodplain  is the flat or nearly flat land next to a
river that floods easily. This cleanup area includes
riverbank and floodplain areas  next to the Woon-
asquatucket River along the Source Area and Allen-
dale Pond.

5. Lyman Mill Stream Sediment and Flood-
plain Soil (including the Oxbow Area)
This cleanup  area includes the  stream channel and
old  mill raceway connecting Allendale Pond and
Lyman  Mill Pond, the Oxbow Area, and  riverbank
and floodplain  areas along Lyman  Mill Pond. The
Oxbow Area is a large forested wetland area below
the Allendale Dam.
EPA conducted a detailed study, the Remedial Inves-
tigation, to better understand the site's contamina-
tion and collect the kind and amount of information
needed to identify any potential human health and
ecological risks. It is used to make decisions regard-
ing the long-term cleanup of the site. The Remedial
Investigation  concluded that past industrial opera-
tions resulted in the contamination of the site's sedi-
ment, soil, surface water, groundwater, and animal
life. EPA's investigations have found:

   • Source Area Soil contaminants include
     dioxin/furans, polychlorinated biphenyls
     (PCBs), selected pesticides, semi-volatile
     organic compounds (SVOCs), metals, and
     volatile organic compounds (VOCs);

   • Fish and Birds, Sediment and Floodplain
     Soil contaminants include dioxin/furans,
     PCBs, selected pesticides, SVOCs, and

   • Surface Water contaminants include dioxin.
     PCBs, pesticides, VOCs, SVOCs and metals; and

   • Groundwater contaminants at the Source
     Area include dioxm, PCBs. pesticides,
     SVOCs. VOCs [such as tetrachloroethylene
     (PCE) and trichloroethylene (TCE)], and

Source Area  Soil sampling data  indicates wide-
spread contamination  above  the state's  residen-
tial direct exposure criteria for PCBs/pesticides,
VOCs. SVOCs. and metals; the state's leachability
(movement of contaminants from soil into water)
criteria for PCBs, pesticides, VOCs, and SVOCs;
and  EPA's recommended  residential  levels for
dioxin and PCBs.

Groundwater sampling data at the Source  Area
indicates contamination is above federal deanup levels
at 25 out of 37 monitoring wells tested. The  most
common  contaminant detected  is tetrachloroethyl-
ene,  followed  by trichloroethylene. Dioxin has also
been detected in groundwater.

The Allendale Pond and Lyman Mill Pond  Sedi-
ment area data showed  widespread  sediment
contamination.  Dioxin levels were above cleanup
levels in more than  90%  of the surface sediment
(top 1 foot)  at  Allendale Pond and Lyman Mill
Pond. Contamination in sediment at depths of 2 to
2.5 feet was typically above cleanup levels. Other
contaminants like PCBs,  pesticides,  SVOCs, and
metals, were  also present at levels above cleanup
levels in surface and subsurface sediment.

In the Allendale Floodplain  Soil  area, dioxin
contamination was above  cleanup levels in approxi-
mately 40% of the floodplain areas sampled. This
suggests that low-lying areas next  to the  Woon-
asquatucket River and Allendale Pond  have  been
impacted by contamination from the Source Area,
especially during flooding  and times  of high water.
SVOCs and lead at concentrations above the  state
residential direct exposure criteria were also found
in this cleanup area.

Lyman Mill Stream & Floodplain Soil (including
the Oxbow Area) data showed dioxin contamination
above deanup levels in more than 90% of the surface
sediment and approximately 30% of the floodplain soil
locations sampled. Other contaminants, including PCBs,
pesticides,  SVOCs, and metals, were also frequent-
ly measured  at levels above cleanup levels. EPA
investigations  indicate that the  low-lying   areas
in the  Oxbow  forested  wetland area have  been
impacted  by high water flow and by contamination
from the  Source  Area. Based on sampling which
occurred in 2010 and is still being analyzed, the above
numbers and condusions may change.
Just because contamination exists does not mean
the environment or people are at risk. One has to
have exposure to the contaminant to have a poten-
tial risk.  Exposure occurs when people or other
living organisms eat, drink, breathe or have direct

Cleanup Action Areas
Centredale Manor Restoration Project Superfund Site
                                                                          Source Area
                                                                              Ground v/dter
                                                                          Action Area
                                                                            Centredale- •'
                                                                    Cap Area 2
                                                     ' S^ourc^^J

                                                                           Allendale and Lyman
                                                                           Mill Reach Sedlmenl
                                                                           Action Area
                                                                           AJIendale Reach
                                                                           Roodplaln Soil
                                                                           Action Area
                                                                           Lyman Mill Reach
                                                                           Stream Sediment and
                                                                           Roodplaln Soil
                                                                           Action Area
                                                                           Source Area Soil and
                                                                           Groundwater Action Area
                                                                           (see inset map!

                                    :•-'•••:'    V

                                                                  SITE   UPDATE
skin contact with a substance or waste material.
Based on existing or reasonably  anticipated future
land use at a site, EPA develops different possible
exposure  scenarios to determine potential  risk,
appropriate  cleanup levels for contaminants, and
potential cleanup approaches.

Site human health and ecological risk assessments
use a number of contamination exposure scenarios
to determine if and where there are  current or
potential future unacceptable risks.
 People have the potential for exposure to the site's
contaminants through eating fish from the river and
having contact with site sediment and  floodplain
soil. Overall, the risk assessment  determined that
the following exposure pathways pose an unaccept-
able risk:

Allendale Pond:
  •  Eating contaminated fish  may pose a 5  in
     1,000 chance of causing cancer and may
     pose non-cancer health effects  30 times
     greater than the acceptable level of 1 for
     residents along the river  and visiting
     recreational anglers;

  •  Having direct  skin contact with  or accidently
     ingesting contaminated sediment may
     pose a 2 in 10,000 chance of causing
     cancer for residents along the river.

Lyman  Mill Pond:
   •  Eating contaminated fish  may pose a 6  in
     1,000 chance of causing cancer and may
     pose non-cancer health effects  30 times
     greater than the acceptable level of 1 for
     residents along the river  and visiting
     recreational anglers;

  •  Having direct skin contact with or
     accidently ingesting contaminated  sediment
     may pose a 3 in 10,000 chance of causing
     cancer for residents along the river.

Site Exposure Assumptions
EPA  used the  following  exposure assumptions to
figure out its risk results for the site:

   •  For eating fish, it is assumed that residents
     along the river and visiting recreational
     anglers would eat 14 grams per day
     (adult), 9.3 grams per day (older child), or
     4.7 grams per day (young child) for 350
     days a year for a total of 30 years;

     For having direct skin contact with or
     accidently ingesting contaminated
     sediment, it is assumed that a resident
     along the river would wade and swim 4
     days a week between June and August for
     a total of 30 years.
Fish and wildlife are exposed to site contaminants in
sediment on the bottom of the Woonasquatucket
River and its ponds, or floodplain  soil associated
with  wetlands  immediately  downstream of the
site.  Site contaminants  are also in  the tissue and
organs of animals living in the contaminated river
and its wetlands.  Predatory fish and wildlife feed on
contaminated animals or organisms  such as forage
fish,  crayfish or larval  stages  of aquatic  insects
that  live in the mud bottom  (benthic macroinver-
tebrates) or small mammals,  birds,  amphibians or
benthic  macroinvertebrates in  wetlands, and are
at risk from their foraging activities  (direct contact
with contaminated sediment or floodplain soil) and
feeding upon contaminated prey.

A high-level  of  exposure to  site  contaminants
and a significant  negative reproductive effect was
measured in tree  swallow populations (reduced
egg hatchability)  in ponds downstream of the site
as this bird species preys upon  emergent, flying
aquatic insects that develop from benthic macroin-

Threats to the environment from greater to lesser
amounts exist for:

   •  Birds and mammals that use Allendale
     Pond aquatic and  wetland habitats to
     forage for food (1,000 times greater than
     the acceptable level of 1):

   •  Birds and mammals that use Oxbow Area
     aquatic habitat in  between Allendale Pond
     and Lyman Mill Pond to forage for food
     (100 times greater than the acceptable
     level of 1);
     Birds and mammals that use Lyman Mill
     Pond wetland habitats to forage for food
     (100 times greater than the acceptable
     level of 1).
Once possible exposure  pathways and  potential
risk have been identified at a site, cleanup alterna-
tives are developed to address the identified risks
and achieve the site's cleanup objectives. A detailed
description and analysis of each alternative  devel-
oped to reduce risks from contaminated  soil, sedi-
ment, and groundwater is presented  in the 2010
Centredale Manor Restoration Project Superfund
Site Feasibility Study (which EPA is in the process
of amending).

The  cleanup  approaches for  each  action  area
detailed in the Feasibility Study can be generalized
as follows.

For Source Area Soil the general options are:
  I.  Take no action (an alternative that we are
     legally required to evaluate);
  II.  Maintain existing caps or upgrade or
     reconstruct them.

For Groundwater, a cleanup action was performed
in 2009/2010 while the Feasibility Study was near-
ing completion. At that time, EPA determined that
a short-term cleanup  was necessary to  prevent
contamination from  this  soil  and  groundwater
moving  into  the Woonasquatucket River. This
action included removal of nearly 2.300 tons of
contaminated soil to limit the movement of contam-
ination through groundwater into the river. Future
long-term monitoring will be done to check that this
action has been  successful by confirming contami-
nated groundwater is not  leaving the Source  Area,

For sediment and floodplain soil (cleanup areas
J-5) the general options are:
  I.  Take no action (an alternative that we are
     legally required to evaluate);
  II.  Cap or cover contaminated soil and
     sediment in place;
  III.  Excavate and dispose of  contaminated

                 SITE  UPDATE
                        ENVIRONMENTAL  ACTIONS
    1943 - 1970s     Source Area used for chemical manufacturing activities. Metro
                      Atlantic Chemical Company manufactured  hexachlorophene around
                      1965 in a building on the eastern bank (current!/ Brook Village parking
                      lot).  Dioxin  associated with process. Other manufacturing activities
                      resulted in additional contamination.
    1952-1970s     New England Container Company, Inc.  operated incinerator-based
                      drum reconditioning facility at Source Area. Chemical residues dumped
                      or burned prior to and during drum reconditioning and are source of
                      site dioxins, furans and other chemicals.
    1972              Fire destroyed most structures.
    1977              Brook Village apartment complex constructed.
    1982              Centerdaie Manor apartment complex constructed and approximately
                      400 drums and 6,000 cubic yards of contaminated soil removed and
                      disposed of off-site under RIDEM supervision.
    1991              Floodwaters  breached  Allendale Dam  reducing pond surface water
                      level and exposing bottom sediment. Dam breached again in 2001.
    1996              EPA found dioxin and other contaminants in  fish.
    1998              RIDOH issued fish advisories for dioxin, mercury and PCBs.
    1996 to 2004     EPA conducted numerous investigations to characterize nature and
                      extent of site contamination.
    1999 to 2000     First Source  Area short-term  cleanup to  reduce  immediate health
                      threat to residents included: construction of two interim soil caps and
                      installation of fencing to restrict access to potentially contaminated
                      areas in Source Area and Allendale Pond. Repairs to fence were
                      performed in 2005.
    2000 to 2003     Second short-term cleanup included reconstruction of breached
                      Allendale Darn, restoration of Allendale Pond to pre-1991 levels, and
                      excavation and off-site disposal of contaminated floodplain soil from  11
                      residential properties  ana recreational  access points along Allendale
                      Pond and Lyman Mill Pond.
    2000              Added to Superfund Program's National Priorities List.
    2003 to 2004     Third short-term cleanup covered contaminated soil and sediment in
                      Source Area's former tailrace (a narrow channel that moved away
                      industrially used water).
    2005              Remedial Investigation identifies extensive contamination  in site soil,
                      sediment, surface water, plants and animals and localized groundwater
                      contamination at Source Area.
    2004 to 2005     Baseline Human Health and Ecological Risk Assessments concluded
                      current and future exposures pose elevated  risks.
    2009 to 2010     Fourth short-term cleanup addressed Source Area groundwater
                      contamination by excavating and disposing off-site contaminated soil
                      and installing a cap made to cover hazardous waste over the excavated
                      area next to river.
    2010              Feasibility Study identified long-term cleanup  options for contaminated
                      soil, groundwater, surface water and sediment.
    2010              Additional investigations conducted  in the Oxbow Area.
    2011              Addendum to Feasibility Study to be issued.
     soil and sediment using the following
     disposal approaches (with dams in place or
     replacing dams with smaller weirs):
        a. Consolidate and cap contamination
           within river or floodplain along
        b. Consolidate and cap contamination
           in upland area next to river;
        c. Ship contamination off site to
           permitted facility;
        d. Incinerate contaminated soil and
           sediment using temporary facility at
           the site.
Based upon the Feasibility Study and Addendum.
EPA will issue  a  Proposed Plan  that will include
the agency's preferred cleanup approach as well
as other alternatives. The public will be invited to
comment on the Proposed Plan and the preferred
alternative during a 60-day comment period. Once
the comment period closes, EPA will consider public
comments received in making its cleanup decision.
The cleanup plan ultimately selected is formalized
in a Record of Decision and includes a Responsive-
ness Summary  that reflects the public's input and
the agency's response. EPA  expects to issue the
Proposed Plan in fall 2011.
Over the years, EPA and the Rhode Island Depart-
ment of Environmental  Management  have held
Dialogue Group  meetings with interested stake-
holders, including the Towns of North Providence
and Johnston, the Woonasquatucket River Water-
shed Council, the Audubon Society, the Natural
Resources Trustees, and the Potentially Responsi-
ble Parties. These meetings have provided a forum
to exchange ideas and give stakeholders input into
EPA's investigation and cleanup selection process.

Since January 2005, EPA has awarded $125,000
to the Woonasquatucket River Watershed Council
through a Superfund Technical Assistance Grant.
This grant has been used to hire an independent
expert to help the impacted communities  better
understand technical data and site hazards.


Louis Maccarone
Senior Engineer
Rl Dept. of Environmental Management
(401) 222-2797 ext,7142