New Jersey Zinc/Mobil Chemical
Site Summary
October 2011
Related Documents
Legislative Updates
DePue, Illinois
Bureau County
Illinois EPA 0110300003
Rockford Region
Site Description
Total Acreage: 950
Lead Agency: Illinois EPA
NPL Listing: June 9, 1999
Congressional District 11
House 76 / Senate 38
The DePue/New Jersey Zinc/Mobil Chemical Corporation site is located along
the north side of the Village of DePue and constitutes roughly one half of
the village land mass. Initial plans for investigation and cleanup of the site
were organized by unit, e.g., plant site soils, Interim Water Treatment Plant,
Phosphogypsum Stack, Zinc Slag Pile, Lithipone Ridges and South Ditch. As the
cleanup plans for the South Ditch progressed, this organization was found to
be inappropriate for the complex site and the site was divided into five operable
units (OUs) for investigation and remediation:
- OU 1: South Ditch Contaminated Sediments
- OU 2: Phosphogypsum Stack
- OU 3: Former Plant Site Area (FPSA)
- OU 4: Off-site Soils
- OU 5: DePue Lake Sediments and the Flood Plain
The South Ditch, OU 1, is a drainage canal that feeds into Lake DePue and
received discharges of contaminated groundwater and surface water from the
site. The northern 120 to 150 feet of the ditch is incised into fill consisting
of placed soil and slag material. The remainder of the ditch traverses marshy
lowlands adjacent to Lake DePue. These discharges resulted in unnatural sediment
containing total metals in concentrations up to 200,000 mg/kg each of copper
and zinc. Pursuant to a 2003 Record of Decision, removal of contaminated sediment
from the South Ditch was accomplished in 2005. The ditch and its immediate
vicinity is included in the Lake DePue investigation.
The Phosphogypsum Stack, OU 2, is a large waste pile of phosphogypsum (resulting
from conversion of phosphate rock into diammonium phosphate fertilizer), and
its associated water control structures including drainage swales, clearwater
dam, and constructed treatment wetland. The stack has been mostly covered with
native prairie vegetation. A groundwater investigation is ongoing.
The FPSA, OU 3, includes the plant site property and adjacent bluffs. The
Interim Water Treatment Plant, which treats and discharges treated surface
and groundwater, is located in one of the former plant buildings. Soil and
groundwater investigations are ongoing.
Off-site soils within the surrounding community, OU 4, have yet to
be investigated systematically, though some select properties have been sampled.
This investigation is to begin in 2012.
Lake, DePue a 524-acre backwater lake and the floodplain, OU 5, have been
the focus of intense study in recent years. Recreational use of the lake has
been degraded by accumulation of sediment from the Illinois River. (see http://www.isws.illinois.edu/pubdoc/CR/ISWSCR-176.pdf)
The remedial investigation has been recently completed and risk assessments
(human health and ecological) are currently under review. The next step will
be a Feasibility Study.
Site History
Mineral Point Zinc Company originally developed the site in 1905 as a primary
zinc smelter producing slab zinc for use in the automobile and appliance industries.
In addition, the site has at various times been the location of sulfuric acid
manufacturing, paint pigment production, ammonium phosphate fertilizer manufacturing,
refining and recovery of secondary metals from zinc ore (e.g., cadmium), secondary
zinc smelting and zinc dust production. Between 1905 and 1989, portions of
the site were owned and operated by New Jersey Zinc Company, Mobil Oil Corporation,
Gulf & Western Industries, Horsehead Industries, and the Zinc Corporation
of America. In 1990, the facility ceased operation and shortly after that,
New Jersey Zinc demolished most of the remaining structures. Through various
corporate mergers, acquisitions and the bankruptcy of Horsehead, responsibility
for the site has fallen to Viacom International Incorporated/CBS and the ExxonMobil
Corporation. These two companies have formed an entity known as “The
DePue Group,” which collectively represents the potentially responsible
parties (PRPs) for the site. In 1995, the DePue Group entered into an interim
consent order with Illinois EPA and the Illinois Attorney General’s Office
(IAGO) for investigation of the site and evaluation of possible remedial actions.
Investigative History / Contaminants
Environmental concerns were created by waste disposal activities and discharges
from the former smelter, sulfuric acid plant, paint pigment plant and the diammonium
phosphate fertilizer plant. These activities produced a primary zinc smelter
slag pile in excess of 750,000 tons; several ridges of paint pigment plant
waste, sometimes referred to as the lithipone ridges, containing in excess
of 250,000 tons; a veneer of industrial waste varying from 6 inches to several
feet over the entire 195-acre former plant site; a more than 140-acre Phosphogypsum
Stack; discharges of wastewater and sediment to DePue Lake; and many other
impoundments and waste piles. Significant discharges of metals to groundwater
and surface water have occurred. All sources were found to contain elevated
levels of metals including zinc, lead, arsenic, cadmium, chromium, and copper.
In addition to metals contamination, there are elevated concentrations of sulfate,
ammonia, and other compounds in the groundwater and surface water. The following
investigations and actions have taken place.
- December 1980 – A preliminary assessment was completed.
- July 1983 – A second preliminary assessment was conducted.
- March 1992 – The Illinois EPA conducted an expanded site inspection.
- November 1995 – Negotiations with the DePue Group resulted in an
interim consent order
- 1994 to 1996 – air study to verify that airborne metals were not
being released off-site
- 1995 to 1997 – The Remedial Investigation/Feasibility Study (RI/FS) for
the South Ditch was conducted.
- May 10, 1999 – The site was placed on the National Priorities List.
- 1999 – A site-wide remedial investigation work plan was developed
and approved. Site efforts were soon re-organized into separate efforts
for each operable unit; however, this work plan has provided the basis for
much of the work in OU3.
- 2006 – 2007 – Soil sampling from the surrounding region was
conducted to establish background conditions and support the forthcoming
off-site soils investigation.
- 2006 - 2009 – The remedial investigation for DePue Lake was conducted.
- 2000 – 2011: The hydrogeologic investigation of the phosphogypsum
stack was initiated and is in its last stages of data collection, including
sampling in off-site areas.
- 2007 - 2011 – Consistent with the 1999 work plan, a
remedial investigation for groundwater is currently underway and is in its
last stages of data collection, including data collection in off-site areas.
Human Health Risks
Human health risks from the site have been formally evaluated at OUs 1 and
5 to date. For both OUs, metals are responsible for human health risks. Metals
will likely be significant contributors to any potential risks from OUs 3 and
4.
The sediments in the South Ditch were determined to exceed the U.S. EPA’s
acceptable risk range for soil ingestion and dust inhalation for both child
trespassers and on-site constructions workers under current and potential future
exposures. These sediments were removed from the South Ditch in 2005. The
risk assessment for OU5 is currently under review and its conclusions are not
yet finalized.
Ecological Risks
Ecological risks from the site have been formally evaluated at OUs 1 and 5
to date. For both OUs, metals are primarily responsible for ecological risks.
Lake DePue has a fish advisory for carp, white bass, and channel catfish due
to detections of PCBs in fish tissue samples. In addition, there is a state-wide
fish advisory for methyl mercury in predator fish. The site is not thought
to be a significant contributor to the lake of PCBs and methyl mercury.
Results of the benthic organism testing indicated acute toxicity of South
Ditch sediments to the test organisms. Numerous fish species, great blue herons,
egrets and certain other waterfowl rely on these benthic organisms as food
sources. In addition, some waterfowl, (e.g., mallard ducks) are dabblers and
could ingest the contaminated sediments. These sediments were removed from
the South Ditch in 2005.
The Lake DePue ecological risk assessment is currently under review and its
conclusions are not yet finalized.
Remediation Acitvities
The major sources of contamination from the New Jersey Zinc site have been
intercepted and prevented from entering DePue Lake. The following remedial
activities have been completed:
- In the 1980s, constructed a permeable reactive barrier south of the Zinc
Slag Pile, known as the Iron-Rich Material trenches, to remove zinc and
copper from the groundwater
- Construction and operation of an Interim Water Treatment Plant to
collect and treat contaminated runoff that previously flowed uncontrolled to
the South Ditch
- Construction of Surface Water Redirection and Protection System to
segregate water in a 40-acre off-site drainage basin from contact with waste
on the Plant Site
- Reestablishment of vegetation on most of the plant site to mitigate dust
generation and migration
- Capping the Phosphogypsum Stack
- Excavation of grossly contaminated unnatural sediments in the South
Ditch. Contaminated sediments were placed in an on-site
corrective action management unit (CAMU) on the plant site.
Completed in 1994:
- Installed six more shallow piezometers
- Initiated daily dust inspections and dust suppression with water truck
- Fenced the plant site area
- Implemented perimeter air monitoring plan
- Implemented draft dust suppression plan
- Regrading of Phosphogypsum Stack continued
- Seeded northwest quadrant of Phosphogypsum Stack
- Initiated sampling for PM-10 (10 micron) dust
Completed in 1995:
- Regrading of Phosphogypsum Stack continued
- Began conceptual design of Interim Water Treatment Plant
- Submitted work plan for South Ditch Focused RI/FS
- Submitted South Ditch Corridor Hydrogeologic Study technical memo
- Submitted Plan for Collection and Treatment of Water
- Authorized work for design of sump and piping for Interim Water Treatment Plant
Completed in 1996:
- Continued placement of compost and final grading on Phosphogypsum Stack
- Completed second treatability study for Interim Water Treatment Plant
- Conducted field work for South Ditch Focused RI/FS
- Completed construction of South Interceptor Trench
Completed in 1997:
- Construction of the Interim Water Treatment Plant
Completed in 1998:
- Modified Lift Station so it would operate during a 25-year flood
- Began work on phased Site-Wide RI Work Plan
- Conducted biweekly sampling of Outfall 002 at Phosphogypsum Stack
- Submitted Site-Wide Remedial Investigation Work Plan for Soil and Groundwater
to IEPA on 4/30/99
- Updated RI schedule and submitted it in the 4/30/99 Site-Wide RI Work Plan.
Table 1 shows status of deliverables.
Completed in 1999:
- Interim Water Treatment Plant filter upgrade
Completed in 2000:
- Regrading of the southwest evaporation basin in the Phosphogypsum Stack Area
- Groundwater sampling for the Phase 1 Remedial Investigation
- Discharge from Interim Water Treatment Plant diverted to Illinois River
- Completed stormwater management improvements north and south of Route 29
- Conducted four rounds of groundwater sampling for the Site-Wide Remedial Investigation
Completed in 2001:
- Scoping documents for the Presumptive Remedy at the South Ditch
- Closure work for the Phosphogypsum Stack Area
Completed in 2002:
- IEPA preparation of the Proposed Plan for the South Ditch
- Review of Surface Water Flow Patterns Work Plan; first submittal was rejected by IEPA
- Submittal of Draft Phase 1 RI Report for Soil and Groundwater
Completed in 2003:
- Ongoing field work in accordance with the Closure Plan for the Phosphogypsum Stack Area
- Issued Record of Decision for the South Ditch
- Revised Contaminants of Potential Concern Screening Process
Completed in 2004:
- Lower Swale Investigation Plan reviewed and work implemented
- Removed beaver dams from South Ditch
- Remedial Design/Remedial Action Design for the South Ditch
- Final Surface Water Flow Patterns Work Plan
- Ongoing revisions to RI Report Phase 1 Soil and Groundwater
- Corrective Action Management Unit (CAMU) Investigation Work Plan
- Proposed Approach for Screening Ecological Contaminants of potential Concern
Completed in 2005:
- Closure and final grading of the 4th and final pond at the 140-acre
Phosphogypsum Stack
- Completion of the earthwork components of a 2+ acre treatment wetlands to
supplement water treatment at the Phosphogypsum Stack
- Construction of a 2.5-acre Corrective Action Management Unit (CAMU) at the
plant site for storage of 8,000 cubic yards of contaminated sediments from
the South Ditch Remedial Action
- First-round assessment of the 17 properties of specific interest from past
Illinois Department of Public Health sampling
- Preliminary drafting of the Off-Site Soils and DePue Lake RI work plans
Completed in 2006:
- Re-vegetation of the Phosphogypsum Stack, including pilot testing of native
prairie grass establishment on approximately 75 acres
- The completion of the Phosphogypsum Stack treatment wetland
- Second-round Removal Action Assessment of 6 or 8 private off-site properties
that continue to present potential but lower levels of specific interest
- Phase I Plant Site RI Report
- Completed DePue Lake (OU5) Floodplain Soil Sampling Technical Memorandum
Completed in 2007:
- RI sampling of Operable Unit 5 (DePue Lake)(some data gaps were identified)
- Reseeding of several areas in the Phosphogypsum area to address lack of viable
prairie grass cover
- Repaired erosion problems caused by excessive precipitation in OU 2
- Constructed test plots at OU2
- Submitted Phase II RI WP Quality Assurance Project Plan (QAPP) Addendum
- Inspected and redeveloped OU 3 wells, and issued Technical Memorandum
- Completed surface water sampling at OU 3
- Initiated groundwater sampling pursuant to the Phase II RI WP at OU 3
- Excavated Iron-Rich Material (IRM) Trench test pits at OU 3
- Completed Phase II RIWP drilling at OU 3
- Completed background soil sampling at OU 4
- Completed RI Sediment Sampling Technical Memorandum for OU 5
- Completed DePue Lake (OU5) Biological Sampling Technical Memorandum
Completed in 2008:
- Completed Phase III Work Plan for OU 2
- Conducted well pumping tests in OU 3 monitoring wells
- Completed Background Soil Sampling Report for OU 4
- Completed Phase II RI WP test pits along the southern property boundary of OU 3
Completed in 2009:
- DePue Lake RI
- Installation of 11 additional groundwater monitoring wells
- Planting of a native shrub hedge around the Phosphogypsum Stack wetland as
an alternative to traditional chain-link fencing
- Processed 24 million gallons of groundwater through the interim water
treatment plant and removed 229,000 pounds of zinc, copper and manganese
Completed in 2010:
- Finalized the Removal Action Level Assessment Report for off-site soils (OU 4)
- Conducted a controlled burn of the prairie established on the Phosphogypsum Stack
- Conducted a 5-Year Review of the South Ditch (OU 1) remedy
- Sampled the railroad right-of-way to investigate impacts of previous discharges
from the former Lithopone Plant
- Completed the Phase III Groundwater Investigation Work Plan for OU 3 and installed
14 wells in eight locations between the former plant site and DePue Lake, to determine
extent of potential groundwater contamination
- Completed two quarters of sampling (of four scheduled quarterly sampling events) of
the Phase III Groundwater Investigation wells for OU 3
- Initiated work on the DePue Lake Human Health Risk Assessment
- Initiated work on the DePue Lake Ecological Risk Assessment
- Implemented IRM Trench evaluation in accordance with Phase II RI WP
- Initiated Geotube Pilot Study at the interim water treatment plant
- Collected samples to fill data gaps in the DePue Lake RI.
- Completed field sampling for the Phase III Phosphogypsum Stack extent of
groundwater contamination study
- Conducted a public meeting for re-establishment of the Citizens’
Advisory Group (CAG)
Completed in 2011:
- Completed DePue Lake (OU5) Floodplain Supplemental Soil Sampling Technical Memorandum
- Issued Fact Sheet #14
- Finalized Removal Action Limit Assessment Report for OU4, off-site soils
- Installed additional wells associated with phosphogypsum stack to determine extent of contamination
- Conducted test pits at the six-acre municipal dump area near the South Ditch
Future Remedial Acitvities
- Complete the DePue Lake Human Health and Ecological Risk Assessments and initiate the Feasibility Study
- Complete the Phase III Phosphogypsum Stack Hydrogeologic Study
- Complete sampling and remediation of Operable Unit 4, off-site soils
- Complete the remedial investigation for OU3, former plant area, and initiate Feasibility Study
Reuse Efforts
The Village of DePue was awarded a grant of services in July 2002 by the U.
S. EPA. The purpose of the grant was to assist the community in developing
a set of future land use recommendations for the DePue/New Jersey Zinc/Mobil
Chemical Superfund site. The consultant team guiding this process was E2 Inc.
who, after meeting twice with Village officials and residents, released a project
report in August 2004 with the following recommendations:
- Adapt the former New Jersey Zinc plant facility as a
museum of history and industry that showcases DePue’s natural and industrial
heritage
- Promote DePue as a tourist destination and emphasize ecotourism
- Create recreational opportunities at the site and link the site to regional
recreational amenities
- Provide opportunities for ecological restoration, wildlife habitat enhancements
and general environmental education
- Create new economic opportunities in DePue
The report outlines challenges to site reuse and resources that can help DePue
reach its redevelopment goals.
Illinois EPA provided a $50,000 Brownfields Grant to
the Village of DePue to hire a contractor.
Current Issues
During 1984 and 1985, Illinois DNR removed approximately 400,000 cubic yards
of contaminated sediment from the lake. The dredged area is used by the National
Power Boat Racing Association for its National Championship races, an event
that draws participants and spectators from across the nation. The Village
of DePue reports attendance for the three days of races ranges from 35,000
to 50,000 persons. Dredging was undertaken to prevent the loss of these races
due to shallow water. The contaminated sediment was placed on state-owned property
in dredge spoil lagoons. These lagoons are currently used as waterfowl habitat
and public hunting areas.
The dredging was funded by an appropriation from the state legislature. The
primary sponsor of this bill was former Representative Richard Mautino. Current
State Representative Frank Mautino has explored the possibility of a second
dredging bill. The dredged race oval is filling with sediment at a rate of
3 inches per year. Dredging plans may be renewed in conjunction with the Lake
DePue (OU5) remedy selection.
In August 2006, the Village posted Notices to Abate Nuisance at the site.
The notices ordered Exxon to remove the materials and clean the site of all
contaminants to the satisfaction of the Village within ten days. If Exxon failed
to comply within ten days, the notices required Exxon to pay a nuisance fine
of $ 750 per day until the site cleanup was complete and the site was removed
from the NPL. The notices did not define the terms “materials” or
“contaminant”. In 2007, the Village of DePue filed a complaint against
Exxon in Illinois state court, asserting that Exxon had violated and continued
to be in violation of the Village's nuisance ordinance. It sought three forms
of relief: a judgment declaring that Exxon had violated the ordinance, daily
fines of up to $750 for that alleged violation and injunctive relief requiring
Exxon immediately to clean the site and have it removed from the NPL. Exxon
moved the case to U.S. District Court and filed a motion to dismiss the
complaint because the causes of action stated in the complaint were preempted
by federal and state law. The district court agreed. In 2008, the Village of
DePue appealed the District Court’s decision to the U.S. Court of Appeals,
7th Circuit and the District Court’s verdict was affirmed because the
Village’s claims are preempted by Illinois law.
On September 8, 2008, the Village of DePue enacted a new ordinance against
hazardous waste, and on November 4, 2008, the Village became a home-rule municipality
under the Illinois constitution. The Village filed a new suit in Illinois circuit
court, making claims against the PRPs based on the new ordinance. The PRPs
moved the case to U.S. District Court, which dismissed the Village’s
claims because the new ordinance was an invalid exercise of home-rule authority
under the Illinois constitution. The Court also dismissed the Village’s
common law trespass and nuisance claims. The Village filed an amended complaint
on July 27, 2009, re-alleging its trespass and nuisance claims under Illinois
law. The District Court dismissed this complaint on May 12, 2010. The Village
is currently pursuing an appeal.
The Village of DePue has re-established a Citizens Advisory Group (CAG and
held an introductory public meeting on November 17, 2010. The CAG continues
to meet regularly, on an approximately monthly basis.
Illinois EPA has restored the information repository at the Selby Township
Library by providing the documents on compact disc.. Much of the Illinois EPA’s
site file has been digitized in order to facilitate future responses to Freedom
of Information Act requests. Future draft documents will be provided to the
Village of DePue and the CAG for their review and comment.
On June 23, 2011, a site tour was conducted for elected officials. Illinois EPA
provided written responses to questions asked during the tour and committed to
providing quarterly updates to these elected officials.
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