New Jersey Zinc/Mobil Chemical

Fact Sheet #16
August 2014

Bureau County, DePue, Illinois

Introduction

During ongoing interactions with the public, through meetings with the community and the Citizen’s Advisory Group (CAG), Illinois Environmental Protection Agency (Illinois EPA) has received questions about the Village of DePue’s drinking water supply and whether the New Jersey Zinc/Mobil Chemical Superfund site may be a threat to that supply. The purpose of this fact sheet is to address these questions.

The aquifer utilized by the DePue community wells is overlain by more than 900 feet of bedrock of which over 300 feet is low permeability shale bedrock. The top of the bedrock surface is overlain by permeable sand and gravel river deposits. The aquifer utilized by the Village of DePue is considered “confined” by the Illinois EPA. Due to its natural qualities (such as its depth and the geologic materials above it), the aquifer is isolated from contaminant sources and Illinois EPA does not consider the aquifer to be susceptible to inorganic, volatile, pesticide, or pathogenic contamination.

Is the Village’s water safe to drink?

The Village of DePue tests the Village’s water and reports its findings in a Consumer Confidence Report also known as a CCR. (See more information about the Village’s CCR below.) According to the information in the Village’s CCR, the water provided by the Village meets all relevant standards in Illinois regulation for a potable water supply.

Where does my drinking water come from?

The Village of DePue obtains its drinking water from a deep groundwater aquifer consisting of shale bedrock. The water is pumped from the aquifer by two wells. These wells are regulated as “community water supply” wells for the Village of DePue, and are designated Well #2 (also known as Village No. 4) and Well #3 (also known as Village No. 3). These two wells have depths of about 1,487 and 1,490 feet deep, respectively. The wells are located behind the Village Hall and old Public Works building. Water is pumped from the wells, monitored and treated by the Village as needed in a filter and ion exchange plant, (for example, chlorine is added as a disinfectant), pressurized, and distributed throughout the Village.

See Illinois EPA’s Source Water Assessment Program (SWAP) Fact Sheet for DePue for more information.

There may be some people within the Village or just outside its boundaries that use water wells installed on their property as a drinking water source or for other purposes such as watering a garden. If you have a shallow water well on your property, please contact Illinois EPA with information about the location of the well.

What kind of testing has been done of the Village’s water?

Due to the location of the Village’s water supply aquifer, the New Jersey Zinc/Mobil Chemical site is not considered a threat to the water supply. Illinois EPA has not required the Village’s water system to be tested in connection with the investigations of the New Jersey Zinc/Mobil Chemical site. The DePue Group has tested the Village’s water system at least once because they used the potable water for decontamination of drilling equipment. The sample was collected from a distribution location within the water system, and; therefore, would reflect the condition of the water after it had been treated by the Village.

The Village of DePue has obligations to periodically test the water supply, consistent with Illinois regulations. The Village tests the water supply for lead, copper, chlorine, haloacetic acids, total trihalomethanes, barium, fluoride, iron, nitrate, sodium, combined radium 226/228, gross alpha, and uranium. (Not all of these regulated contaminants are required to be monitored every year.) Radionuclide sampling is required because this aquifer contains naturally occurring radionuclides, unrelated to the presence of the New Jersey Zinc/Mobil Chemical site.

To report the findings of its testing, the Village of DePue is required to provide a Consumer Confidence Report (CCR) to the public, which includes detailed information about the Village’s water supply. The Village is responsible for the information in the CCR. The 2012 CCR, received at Illinois EPA on June 17, 2013, reported no violations. The CCR was published in the Bureau County Republican on May 25, 2013 in conformance with Illinois requirements. The 2013 CCR should be available no later than July 1, 2014. See IEPA's Drinking Water Watch for access to the Village’s CCR.

Illinois EPA’s Bureau of Water obtains water samples from Well #2 as part of a statewide monitoring network of community water supplies. Raw water (i.e., before treatment) from this well has been analyzed for inorganics and volatile organic contaminants every other year since 1996 (and periodically since 1987), and for pesticides every four years. Illinois EPA sampled raw water from Well #3 for inorganics, volatile organics and pesticides in 2004. Illinois EPA’s sampling of raw water from the wells indicates that volatile organics and pesticides have not been detected. Inorganics are naturally-occurring and are expected to be present. The inorganic analyses performed found the water from both wells to meet groundwater quality standards.

See IEPA's Drinking Water Watch for results of analyses conducted by the Village and Illinois EPA.

Has site contamination affected the Village of DePue’s water supply?

The Phase I Remedial Investigation Report for the former plant site states, “Due to the depth of the [bedrock] wells, the presence of low-permeability Pennsylvanian rocks at the bedrock surface, and the greater piezometric heads typical of the deep water-bearing zones, the bedrock aquifers are effectively isolated from near surface groundwater and are not part of the Study Area’s [the plant area’s] groundwater flow system.”

Illinois EPA agrees with this statement and does not consider site contaminants a threat to the bedrock aquifer which serves as a source of drinking water for the Village. In contrast to the depth of the drinking water supply wells, the wells used to monitor contaminants associated with the site are monitoring the more permeable sand and gravel water-bearing zone that occurs above the low-permeability bedrock. The base or bottom of the sand and gravel zone is approximately 30 feet below ground surface near the water supply wells.

The Illinois EPA has been working with the DePue Group (CBS and ExxonMobil) on the investigation and remediation of the New Jersey Zinc Superfund site in DePue, Illinois. 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.

Lake DePue Fish Advisory

The community has often asked questions about the ongoing fish advisory for Lake DePue and has requested that this information be provided in Illinois EPA fact sheets.

The 2013 State of Illinois fish advisory for Lake DePue (effective through 2015) 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. The specific advisories are:

  • Carp, all sizes: Limit consumption to 1 meal per month
  • Channel catfish, less than 24 inches: Limit consumption to 6 meals per year
  • Channel catfish, larger than 24 inches: Do not eat
  • White bass, all sizes: Limit consumption to 1 meal per month
  • Mercury advisory: All predator fish, including all species of black bass (largemouth bass, smallmouth bass, and spotted bass), striped bass, hybrid striped bass, white bass, walleye, sauger, saugeye, flathead catfish, muskellunge, and northern pike: limit consumption to 1 meal per week (The mercury advisory is state-wide and is not unique to Lake DePue.)

The fish advisories are meant to be protective of the most sensitive populations, such as women who may be pregnant and children younger than 15 years old. The advisories may be overprotective for women beyond childbearing age and males 15 years of age and older.

Fish advisories are based on fish sampled for 14 chemicals, including pesticides, mercury (in predator fish only) and PCBs. Lake DePue’s first fish advisory was in 2006, and an advisory has been issued every year since then. Based on the results of the remedial investigations, the New Jersey Zinc/Mobil Chemical site is not believed to be a significant contributor of these contaminants that have resulted in the fish advisories in Lake DePue.

Metals and fertilizer constituents are the principal contaminants of concern associated with the New Jersey Zinc/Mobil Chemical site. The fertilizer constituents are not expected to concentrate in fish tissue. The metals (except mercury) are not among the 14 chemicals that the Illinois Department of Public Health (IDPH) analyzes as part of its Fish Advisory Program. However, fish from Lake DePue 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:

See Fish Advisories in Illinois, an IDPH fact sheet, or contact the Illinois Department of Public Health at (217) 782-5830.

For more information, you may contact:

Charlene Falco
Project Manager
Illinois EPA
(217) 785-2891
Jay A. Timm
Community Relations Coordinator
Illinois EPA
(217) 557-4972