New Jersey Zinc/Mobil Chemical
Fact Sheet #14
February 2011
Bureau County, DePue, Illinois
Because of the complexity of the site, the Illinois EPA organized the site
into five Operable Units (OU’s):
- OU1 – The South Ditch Sediment
- OU2 – The Phosphogypsum Stack
- OU3 – The Former Plant Site Area (FPSA)
- OU4 – Off-Site Soils
- OU5 – DePue Lake Sediments and Floodplain
Introduction
The purpose of this fact sheet is to update the residents of DePue and other
interested parties about activities associated with the New Jersey Zinc/Mobil
Chemical Superfund site (Site) to answer questions and clarify statements that
have recently been circulating about the Site. Charged as the responsible
regulatory agency, the Illinois EPA works to maintain an open and transparent
dialogue with all stakeholders while ensuring the site is remediated and managed
under applicable state and federal laws and regulations.
Frequently Asked Questions
I’ve heard there is a new citizens’ group in DePue pertaining
to the Site?
Yes, The Illinois EPA held an informational Community Advisory Group (CAG)
meeting on November 17, 2010. A CAG serves as a public forum that allows
citizens of a community to discuss their needs and concerns relating to the
Superfund decision making process. This provides the community a voice
in the Superfund process. A CAG committee has been established and they
have elected their officers. The CAG Leadership indicated that they would
meet again sometime in early 2011, however, no meeting date has been set at
this time.
This is the second CAG formed for this site. The first CAG operated
from 1997 to 2002 and was terminated at the request of the CAG members.
Has the remediation schedule for the DePue site been updated?
As new information becomes available, schedules are updated to reflect the
progress that has been made and challenges that have arisen. The master
site schedule was last published in the summer of 2009. Since that time,
significant additional data have been collected, including: results from
the railroad right-of-way to assess impacts from the former lithopone plant,
results from the groundwater investigation in the former plant site area; and
results from the DePue Lake human health and ecological risk assessments.
Activities anticipated for 2011 include:
- Completion of the DePue Lake human health and ecological risk assessments
and start the feasibility study for DePue Lake
- Complete and evaluate the hydrogeologic study for the phosphogypsum stack
- Evaluate future surface use options for the phosphogypsum stack
- Begin the remedial investigation for off-site soils
- Submit the draft Phase 2 Remedial Investigation (RI) groundwater report
for the former plant site
The master site schedule is being updated and will be available in the near
future.
Is this Site really the 14th worst Superfund site in the U.S.?
Illinois EPA agrees this Site is one of the most complex Superfund sites in
Illinois, but does not consider it the most contaminated. For example,
other Illinois Superfund sites have more toxic chemicals, and other Illinois
Superfund sites have caused contamination of community drinking water supplies.
The Site is not ranked as the 14th worst Superfund site in the U.S. It
appears that the “14th worst” claim is based on someone’s
inappropriate evaluation of the hazard ranking score USEPA uses to determine
if a site is eligible for the National Priorities List (NPL or Superfund). The
purpose of the hazard ranking assessment process is to determine if a site
qualifies for listing on the NPL. Sites with scores greater than 28.5
qualify for being listed on the NPL. USEPA does not use the scores to
rank sites relative to each other and does not designate sites as “the
worst, second worst, third worst, etc.” because that would be an improper
use of the score. The Hazard Ranking System (HRS) score is often prepared
before very much is known about the site. Scores are not necessarily based
on the same quantity and quality of data, and cannot be directly compared to
each other.
Why is the DePue Group allowed to manage the contamination rather than to
remove it?
Containment of wastes in place is a standard remediation strategy for low
toxicity, high volume wastes, such as the primary zinc slag pile. Unless
there is a very compelling health or environmental reason for removing the
waste from where it is located, it is less disruptive to contain the waste
at the site than to move it to another location. Illinois’ existing
landfill capacity would not easily accommodate the 750,000 tons of primary
zinc slag that are estimated to be present at the Site and the act of trucking
it to another location would create additional safety risks. In order
for wastes to be considered for on-site containment, proper investigations
and engineering design must first be conducted so the final remediation is
protective.
Are metals, from the Site, the reason people say we shouldn’t eat the
fish from DePue Lake?
No. The 2011 fish advisory for DePue Lake cautions people to limit their
consumption of carp, white bass and channel catfish due to the presence of
polychlorinated biphenyls (PCBs) in the fish and mercury in predatory fish. The
Illinois River also has a fish advisory for these same species for the same
reasons. Fish advisories are based on fish sampled for 14 chemicals, including
pesticides, mercury (in predator fish only) and PCBs. DePue Lake’s
first fish advisory was in 2006, and an advisory has been issued every year
since then. In 2010, white bass were added to the advisory. The
Site is not believed to be a significant contributor of these contaminants
that have resulted in the fish advisories in DePue Lake.
While metals are not on the list of the 14 chemicals that the Illinois Department
of Public Health analyzes as part of its Fish Advisory Program, fish from DePue
Lake were analyzed for metals as part of the Lake Remedial Investigation in
2008. The type of fish analyzed were those that people are most likely
to eat: freshwater drum, bluegill, bullhead, carp, and catfish. While
several metals were detected in fish tissues, none were at levels that posed
a risk to adults or children.
For more information on the fish advisories, go to http://www.idph.state.il.us/envhealth/factsheets/fishadv.htm,
or contact IDPH at (217) 782-5830.
Why is DePue Lake filling with silt?
DePue Lake is an oxbow lake created by a channel change in the Illinois River. Over
time, oxbow lakes become shallower due to deposition of sediment from the surrounding
area and from the river.
Historical survey data indicate an overall rate of siltation of DePue Lake
of roughly 2-3 centimeters (cm) or one inch per year (ISWS/ISGS 2002) with
deeper portions of the lake silting in more rapidly, up to 8 cm/year (about
3 inches/year). A more recent study conducted on behalf of the DePue
Group indicates an overall sedimentation rate of 0.89 inch/year (Arcadis 2009). In
some areas of the lake, sediments have accumulated to a thickness of 10 feet.
As a former oxbow, DePue Lake has a finite life expectancy and will continue
to silt in and eventually become part of the floodplain, as do all oxbow lakes.
For more information on oxbow lakes, refer to the following websites:
- http://www.britannica.com/EBchecked/topic/436435/oxbow-lake
-
http://www.cleo.net.uk/resources/displayframe.php?src=309/consultants_resources/_files/meander4.swf
-
http://www.ideals.illinois.edu/bitstream/handle/2142/1969/RR-98.pdf
-
http://www.isws.illinois.edu/pubdoc/CR/ISWSCR-176.pdf
Will the DePue Group dredge DePue Lake?
The DePue Group is legally responsible only for contamination emanating from
the Site. When a remedy is selected for contaminated lake sediment, the
remedial action will address only the levels of contamination deemed unacceptable
for exposure to soil, sediment and surface water by people, plants or animals. Dredging
this contaminated sediment is one possible way to address the contamination. However,
other technological options may be available.
Why does the Interim Water Treatment Plant flood and dump contaminated water
into DePue Lake?
Treated effluent from the Interim Water Treatment Plant discharges to the
Illinois River, not to DePue Lake. On occasion in the past, extremely
heavy precipitation events have caused flooding of the lift station and the
bypass of water around the Interim Water Treatment Plant and discharge to DePue
Lake. This happened a few times a year until the surface water controls
along the bluff line were installed in 1998. Since then, there have been
only a few bypass events which were caused by the record and near-record river
stages during September and December 2008, and March 2009. These events
are related to extreme conditions and rarely occur.
According to a petition that is circulating in the DePue community and surrounding
areas, the 1995 Interim Consent Order requires removal of the slag pile. Is
that accurate?
No. The Interim Consent Order requires the DePue Group to conduct a focused
Remedial Investigation for the Primary Zinc Slag Pile. Following that,
the DePue Group will have the option of proceeding with a Feasibility Study
or submitting a Conceptual Presumptive Remedy Document and a later Design Study,
which would define parameters for in-place closure of the Primary Zinc Slag
Pile.
Who is the State’s new project manager for the Site?
The Illinois EPA has designated Charlene Falco as the new project manager
for Site. Ms. Falco will be managing the project from Illinois EPA’s
Springfield office, where she has worked for almost 20 years.
For more information, you may contact:
Jay A. Timm
Community Relations Coord.
Office of Community Relations
Illinois EPA
(217) 557-4972
|
Charlene Falco
Project Manager
Illinois EPA
(217) 785-2891 |
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