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PUBLIC HEALTH ASSESSMENT

DEPUE/NEW JERSEY ZINC/MOBIL CHEMICAL CORPORATION
DEPUE, BUREAU COUNTY, ILLINOIS


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

This section summarizes the data reviewed and evaluated for this report and includes discussionsof the contaminants of interest and the public health significance of this site. The tabulated datais included at the end of the public health assessment. IDPH selects and discusses contaminantsof interest based upon the following factors:

  1. Concentrations of contaminants on and off the site;
  2. Field data quality, laboratory data quality, and sampling design;
  3. Comparison of on-site and off-site concentrations with health assessment comparison values for noncarcinogenic and carcinogenic endpoints; and
  4. Community health concerns.

The discussion of a substance as a contaminant of interest does not mean that it will causeadverse health effects from exposures. Instead, the list shows the contaminants that will beevaluated further in the public health assessment. When selected as a contaminant of interest inone medium, that contaminant will be evaluated in all media.

Comparison values used to select contaminants of interest are contaminant concentrations inspecific environmental media. These values include Environmental Media Evaluation Guides(EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. EMEGs arecomparison values derived to protect against noncancerous health effects, and CREGs are basedon a probability of one excess cancer in a million persons exposed to a chemical over a lifetime,calculated from USEPA cancer slope factors. Maximum Contaminant Levels (MCLs) representregulatory contaminant concentrations for public drinking water that USEPA deems protective ofpublic health (considering the availability and economics of water treatment technology) over alifetime (70 years) at an exposure rate of drinking two liters of water each day. USEPA developsRfDs (Reference Doses) and ATSDR develops MRLs, which are estimates of daily exposures tocontaminants below which are not expected to cause adverse health effects.

IDPH conducted a search of the USEPA Toxic Chemical Release Inventory (TRI) database forlocal zip codes (Table 10). The only reports filed from five local zip codes were those fromindustry in Spring Valley, approximately 6 miles upstream from DePue.

Much of the environmental sampling data reviewed was collected in the early 1990s, beforeactivities that occurred after the consent order was finalized. We expect that more data will beavailable for review in the future as the RI and clean up efforts continue.

A. On-site Contamination

On-site Solid Waste Materials

Substances used or generated at the site included "gypsum" sludge (inorganic waste fromfertilizer production), a vanadium pentoxide catalyst, smelting wastes, cinders, sulfur dioxide gas(a feedstock for sulfuric acid production), phosphoric acid, phosphate rock, zinc ores, ammonia,diammonium phosphate, lithopone (a zinc pigment consisting of zinc sulfide, barium sulfate, andzinc oxide), solvents (xylene and toluene), coal, gasoline, and diesel fuels. The chemicals andprocess feed stocks were stored in railroad tank cars, aboveground tanks, underground tanks, anddrums. At one time, the quantity of waste at the smelting facility was estimated to exceed onemillion cubic yards (Illinois EPA, 1982).

Smelting wastes were placed on the ground at the site for many years. Illinois EPA sampled thegob pile north of Marquette Street in March 1992 (Table 1, samples X112 and X113). USEPAand their contractors sampled the same area in March 1993 (Table 1, sample ZN10). Wastes fromthe lithopone operations placed in ridges north of the gob pile were also sampled by bothagencies (Table 1, samples X114, X115, and LP20). A 30 by 50 foot area contained about 25drums of spent vanadium catalyst, which consisted primarily of quartz rock and a small amountof vanadium pentoxide. A composite sample of the drummed catalyst waste was collected inMarch 1993 by USEPA (Table 1, DC10). This area and the drummed waste were cleaned up in March 1994.

Waste from the smelting operations was also found south of Marquette Street near the SouthDitch. This fill (Table 1, sample X116) appears to be similar to the types and levels ofcontamination as the on-site gob pile and lithopone ridges. A composite of six samples from thisarea was collected in 1993 by USEPA (Table 1, sample SM40). This area was also used as amunicipal dump many years ago. Residents reported that children easily accessed that area in thepast and frequently played there. A cyclone fence has been installed around the South Ditch area.

Samples were collected from the gypstack area north of DePue by Illinois EPA in March 1992(Table 1, X107) and by USEPA in March 1993 (Table 1, GY30). Calcium, a component ofgypsum, was found at elevated levels in the solid waste. Calcium has no health comparisonvalues and is not usually a toxic substance, so we will not evaluate it as a contaminant of interest.Sulfate, another component of gypsum, was elevated in the water sample collected from the area(Table 7, S305). Ammonia was also elevated in sample S305. The character of the gypsum wastepile is very different from the waste on the main smelting operations area where metalconcentrations are elevated. The solid gypstack sample (X107) was also analyzed for organiccompounds; however, the only detected compound was bis(2-ethylhexyl)phthalate, estimated at120 parts per billion (ppb).

The gob pile and lithopone pigment waste contain some of the highest concentrations of themetals tested. The metals found in the on-site solid wastes at concentrations higher than theTiskilwa background samples included arsenic, barium, beryllium, cadmium, cobalt, copper,chromium, iron, lead, manganese, selenium, silver, sodium, and zinc. Cyanide was also found inthe gob pile. Many activities have occurred on the site properties since the 1992 and 1993sampling events. Remediation efforts should prevent further erosion, migration, and workerexposure. Data generated from these older sampling events is useful when considering past exposure.

On-site Soil

During a research project conducted by the Illinois State Geologic Survey (ISGS) and WaterSurvey in 1976, four borings up to 18 feet in depth were removed from the former plant area andanalyzed for cadmium, copper, lead, and zinc. The most concentrated, on-site soil sampleintervals are shown on Table 2, listed as ISGS1, ISGS4, ISGS6, and ISGS7. Monitoring wellswere then installed in those four areas.

Three on-site soil samples were collected at different depths from the main operations area inMarch 1992 and analyzed for metals and cyanide (X109, X110, and X111). The results of thesesamples are compared in Table 2 with two background soils (from Tiskilwa) collected during thesame sampling event. Compared with the background soil samples, most of the metals on the sitehave higher concentrations than the metals found in Tiskilwa. However, no cyanide wasdetected, and aluminum, antimony, potassium, and sodium levels are lower than the background sample.

Lead was highly concentrated in on-site soil samples X110 (17,800 ppm) and X111 (33,400ppm). Lead paint may have been used on buildings, equipment, or other structures, adding to thelead burden on these properties. Cadmium levels in the samples collected from the site rangedfrom 20.6 to 278 ppm. Arsenic in the on-site soils was also greater than background, rangingfrom 14.3 to 268 ppm.

The DePue Group collected composite surface soil samples in August 1994 at three proposedvegetative test plot areas on the site (Terra, 1995). The sample results are included on Table 2 asTPA1, TPA2, and TPA3. This effort was part of the owners' investigation about which species would be selected to plant on the site.

Dust and erosion control measures have been implemented, so contaminated surface soils on thesite properties appear to be controlled and less likely to be affected by wind and water erosionthan at the time of the sampling.

On-site Surface Water

Illinois EPA collected a sample of leachate from the gob pile in June 1975 (Table 7). In 1992,two water samples were collected in the discharge area on the bank of Lake DePue (S304 andS303). Lagoons near the South Ditch were used for settling impoundments and were sampled in1992 and 1993 (Table 7). Dewatering or evaporative ponds were intentionally engineered at thegypstack. Illinois EPA sampled a large settling pond next to the gypstack's southeast perimeterin March 1992 (S305). Lake Turner was selected as a background water sampling site for thesampling event of 1992.

The collection and treatment of surface water that finds its way onto site properties have been afocus of remediation activities this decade, and potential exposures to contaminants in surfacewater should not be as problematic today as in past years. Additional data regarding the metalconcentrations found in the on-site surface water will be evaluated as they become available.

On-site Sediments

In March 1992, four sediment samples were collected on the site, and one background sedimentsample was collected from Lake Turner (Table 5). The sediments had more detections of organicchemicals than any other environmental media (Table 15), but all were at levels less thancomparison values. Three ditch sediment samples were collected from the northern end of theSouth Ditch in May 1994 and analyzed for metals (Table 5) (Terra, 1995).

Additional sediment samples were collected from the uppermost layer (0-6") of the South Ditchin March 1996 (Table 6) (Golder, 1997). Four background surface sediment samples were alsocollected from Lake Turner during this sampling event. More data will likely be generated as thecleanup of the South Ditch continues.

On-site Groundwater

The ISGS and the Illinois State Water Survey initiated a study of site groundwater in 1976 and14 monitoring wells were installed in 7 locations around the former plant site. In 1990, fourmonitoring wells were installed on the site at the west end of the former plant. Ten additionalwells were installed in 1992 in the former underground storage tank area.

Four piezometers were installed in the gypstack area in late 1992, and three more were added inthe fall of 1993 to monitor groundwater elevations. In 1994, 17 more piezometers were installedat the former plant site. Groundwater was collected from the former plant site area monitoringwells and piezometers from December 12, 1992, through May 6, 1994, (Terra, 1995) and wasanalyzed for metals (Table 8).

The DePue Group installed 10 monitoring wells around the South Ditch in 1995 (Golder, 1997)to determine groundwater quality for the RI. Three wells south of Marquette Street were sampledon January 29, 1996 (Table 8) (Illinois EPA, 1997).

B. Off-site Contamination

Off-site Wastes

Limited information is available regarding site-related wastes that may have been transported offthe site and used on private and public properties. Long-time residents have reported that raillines built in this community used site waste materials in the rail bed. In the past, as a goodneighbor policy, the site operators may have allowed residents to use site wastes for fill,driveways, or other uses.

Off-site Soil

Off-site contamination does not appear to occur in any regular patterns in the residentialproperties of DePue. In other words, residential soil several blocks away from the site may haveless, more, or equal amounts of contamination than residential soil next to the site. All of the off-site soil samples reviewed for the public health assessment were collected from an area less than0.25 miles from the site. Many residents do not know how their yards have been managed sincethe early part of the century.

Some public and private properties in DePue have elevated metal concentrations. Illinois EPAcollected 20 surface soil samples in March 1992 that were analyzed for several metals (Table 3).Generally, Illinois EPA scraped away the uppermost layer of soil with a stainless steel scoopbefore collecting the sample. If sod was present, it was removed before the sample collection.

To further characterize the extent of the residential soil contamination, IDPH collected 65 surfacesoil samples in December 1992 and analyzed them for cadmium, lead, and zinc (Table 4). IDPHcollected the top inch of soil from five bores within a square foot area to make up one compositesample. A common confounding factor is that yard fertilizers, especially phosphates, containtrace metals. Amending soils in the area may have been a common practice, since fertilizer wasproduced locally and was readily available.

Metals generally do not leach into subsurface soils, so levels of metals tend to decrease withdepth. Metals can be taken up by garden vegetables dependant upon soil conditions and the typeof plants cultivated. No data are available at this time regarding the concentration of metals in theedible portions of garden vegetables grown in DePue. Educational efforts have been made to giveresidents information on methods that should reduce exposures to metals if present in garden products.

Off-site Surface Water

Water runoff from the site frequently resulted in standing surface water along the sidewalk northof Marquette Street. Sometimes those temporary pools would cover the walkway. A sample ofstanding water collected by IDPH in December 1992 contained high levels of cadmium, lead,and zinc. After discussing the results with Illinois EPA, the project manager arranged foradditional samples to be collected from pools next to Marquette Street in April 1993 (Table 7 samples S102 and 103).

IDNR continues assessment of the wetlands and conservation areas around Lake DePue.

Off-site Sediments

The condition of Lake DePue and Illinois River sediments has been followed since theconstruction of navigational dams on the Illinois River in 1933. As the river currents slowed,many backwater lakes were created. Cahill and Steele conducted a survey of backwater lakesediments along the entire length of the river (Illinois State Geologic Survey, 1986). Lake DePuewas determined to contain more metals and had the greatest sedimentation rate of the lakesmeasured. Sediment samples were collected in 1975, 1978, and 1982. The highest concentrationsof metals found were 5,000 ppm of zinc, 116 ppm of cadmium, 211 ppm of lead, and 130 ppm ofcopper on the east end of the lake (ISGS, 1986).

As with surface water, the sediments that are part of the wetlands and conservation areasmanaged by IDNR are currently under investigation.

Off-site Ambient Air

Because of concerns about fugitive dust, a sampling plan was developed to measure metals inambient air. The DePue Group installed six air monitoring stations in the fall of 1994 around theperimeter of the site properties to determine if metals were being transported off the site infugitive dust. Twice a week, from September 1994 through December 1995 and during someintervals in 1996, 24-hour samples were collected. Samples collected until June 1995 were testedfor 24 metals and total suspended particulates. After 1995, air samples were analyzed for ninemetals. In more than 800 samples, only a few metals were occasionally detected (Table 16).USEPA concluded that no hazard exists due to exposure to metals and airborne particles. Withthe approval of Illinois EPA, the air monitoring program was stopped. Dust control programs,grading, and planting vegetative cover will aid in reducing wind erosion and fugitive dust formation.

Off-site House Dust

IDPH collected indoor dust samples from 15 DePue homes in 1993 and 1994. Dust fromcarpeting and from smooth surfaces were analyzed for cadmium, lead, and zinc (Table 11). Metal residues deposited on rigid surfaces, such as roads, sidewalks, porches, and parking areas,can be brought indoors by tracking. Some homes in DePue contained metal levels in house dustthat exceed typical Illinois soil concentrations (Table 4). At the same time, other homes sampledhad very low levels of metals in dust. The median house dust concentrations were 18 ppm ofcadmium, 139 ppm of lead, and 150 ppm of zinc, all lower than the median concentrations foundin DePue residential surface soils (Table 4).

The ranges of metal dust concentrations were from below the detection level to 128 ppm forcadmium; 27 to 2,760 ppm for lead; and 35 to 4,100 ppm for zinc. This may be attributed todifferences in house cleaning. For example, the residents of the home with the carpet sample thatcontained the highest lead dust loading value (26,188 micrograms per square foot) did not have a vacuum cleaner.

The house dust standard for lead in Illinois homes where children with elevated lead levels resideis 200 micrograms per square foot on smooth surfaces. There are no standards for cadmium orzinc in house dust. Cigarette smoke contributes to the metal concentrations found in indoor dust,especially cadmium. Metals are added to some formulations of latex and rubber products, such asthose found in non-skid backings on rugs. Leaded paint is a well-known source of lead found in interior dust.

Biota

Some metals have been shown to accumulate in plants and animals. As discussed under the off-site soil section, area residents may be consuming garden vegetables grown in soils containingheavy metals. Uptake of metals into plants may be accelerated if acidic conditions and loworganic materials are found in residential vegetable gardens. In 1992, a garden was growing neara highly contaminated area (near sample site X108) close to the South Ditch. Some farminginterests may have used gypsum as fertilizers. No data are known to exist regarding theconcentration of metals in garden vegetables produced in DePue.

A fish kill in Lake DePue in 1974 was attributed to plant activities, and the company paid a fineto Illinois EPA. Illinois EPA and IDPH established a sport fish consumption advisory for thissection of the Illinois River in 1986 because of PCB contamination from other areas upstream (Illinois EPA, 1996).

In 1992, USFDA analyzed the levels of arsenic, lead, cadmium, chromium, nickel, and zinc infive Lake DePue fish species (Table 9). The USFDA lab filleted each species and analyzed thefillets as a composite. Zinc was the most concentrated metal detected. No detectable levels ofarsenic, cadmium, or lead in edible fish samples were found. Some low levels of chromium,nickel, and zinc were found; however, they were within typical ranges of concentrationspublished in ATSDR Toxicological Profiles.

In 1996, the DePue Group's contractor (Golder, 1995) collected composites of three 0 to 6 inchsurface sediment samples from eight transects of the South Ditch for an ecotoxicologicalinvestigation using two benthic invertebrates common in Illinois. The test was conducted for 4days instead of the usual 10-day period. All of the organisms died in 15 of the samples, and only15% were alive in one sample after four days.

Waterfowl visit the wetlands in the area, and hunting is permitted periodically. IDNR is currently investigating the status of metal concentrations in the nearby conservation areas.

C. Quality Assurance and Quality Control

In preparing this public health assessment, IDPH relied on the information provided in thereferenced documents and assumed that adequate quality assurance and quality control measureswere followed regarding chain-of-custody of samples, laboratory procedures, and data reporting.The analyses and conclusions in this public health assessment are valid only if the referencedinformation is complete and reliable.

D. Physical and Other Hazards

Fire and explosive conditions may have existed when large volumes of fuel, acids, and productswere being stored at the site. Presently, no fire or explosive hazards exist. The site has been graded, and a fence with several locked gates restricts access from Marquette Street.

At one time the fencing consisted of different materials, including a wooden privacy fence at thesouth border. Gaps in the fence existed through the years along the eastern overpass, andtrespassers could access the site along railroad spurs. In the 1990s, the owners upgraded thesecurity of the site by making improvements in the fencing and by increasing monitoring,especially with the development of the interim water treatment plant.


PATHWAYS ANALYSES

A chemical can affect people only if they contact it through an exposure pathway at a sufficientconcentration to cause a toxic effect. This requires a source of exposure, an environmentaltransport medium, a point at which a person contacts the contaminant, a route of exposure, andan exposed population. A pathway is complete if all of its components are present and peoplewere exposed in the past, are currently exposed, or will be exposed in the future. If parts of apathway are absent, data are insufficient to determine if it is complete, or exposure may occur atsome time (past, present, future), then a potential exposure pathway exists. If part of a pathway isnot present and will never exist, the pathway is incomplete and is not evaluated further.

During years of industrial operations, air emissions, and accumulation of tons of solid wastes, thesite became the source of contamination of several environmental media. The contaminants ofinterest in DePue are metals. The levels of volatile and semi-volatile organic chemicals werebelow health-based comparison values.

During rain storms, surface residues and soil contaminants can migrate in surface water runoff tosidewalks, streets, the village sanitary sewer, ditches, creeks, Lake DePue, and rivers. Once inwaterways, contaminants can be transported downstream until they are deposited as sediment. Inaddition, rain water may percolate through contaminated surface soil and leach contaminants intogroundwater beneath; however, metals do not readily leach into subsurface soils or groundwaterunless acidic conditions exist. The leaching of contaminants into subsurface areas is more of aconcern with chemicals found in the gypstack. A few private wells may be in this area. Once ingroundwater, contaminants may migrate in the direction of groundwater flow.

Another pathway involves contaminants adsorbed to surface soils and particles that drift throughthe wind to nearby areas. The potential for off-site migration of wind-borne contaminated surfacesoil has been diminished because site owners have provided vegetative cover to prevent erosion,and apply water to the gypstack, which maintains a moistened surface and vegetative cover. Inthe past, industrial air emissions carried contaminants off the site, so the accumulation of metals in off-site soil was likely. Residents may track surface contamination into homes.

Once humans are exposed to a chemical in an environmental medium, absorption may occur byinhalation, ingestion, or skin contact. Heavy metals are not readily absorbed through the skin, sothis exposure route will not be discussed.

A. Completed Exposure Pathways

Table 16 shows the completed exposure pathways at this site. Many of these pathways are likelyto have occurred in the past, but because of cleanup activities, they may no longer be complete.

Former workers inhaled and ingested contaminants in on-site air emissions, products, and solidwastes. Presently, only a few workers are employed at the site, and their exposures are limitedbecause of cleanup activities. All of the workers at the site have received the Occupational Safetyand Health Administration (OSHA) 40-hour safety training and have access to personalprotective equipment, if needed. Trained workers who follow approved cleanup proceduresshould not be part of a completed exposure pathway.

Trespassers may have been exposed to on-site contaminants in the past. Former residentsreported that children would regularly play in waste piles. Because of improved securitymeasures, trespassers, including children, are no longer exposed to waste pile contaminants.

On-site waste and contaminated soils containing inorganic chemicals and metals may have beentransported or migrated into residential yards, gardens, low areas, and farm fields. The IllinoisDepartment of Agriculture has approved gypsum as a soil amendment. Before the plant closed,air emissions and wind-borne particles settled onto residential surfaces including yards, streets,sidewalks, patios, and driveways. Drip-lines around homes might contain elevated levels ofcontaminants because rain washed residues from roofs. Past air emissions are reported to havebeen visible and nearly always present. Off-site migration of contaminants by wind or surfacerunoff may have been problematic for any of the larger piles before they were vegetated. Thesepathways are not problematic today because vegetative covers have been established and becausea dust control program has been implemented.

Air deposition and surface runoff carried metals to waterways and served to contaminate areasediments. Dredging workers who may not have followed good work practices in the past mayhave incidentally ingested contaminants as they dredged Lake DePue. Residents visiting the areawaterways for recreational purposes may contact contaminated sediments while fishing, hunting,swimming, or wading. A sport fish consumption advisory is in effect for this section of theIllinois River because of upstream contamination sources. This may serve as an administrativecontrol and limit the amount of fishing in the area.

Since industrial operations ceased, exposures to air emissions are no longer a concern. Airsampling for several metals and particulates conducted by the DePue Group in recent years hasshown that the dust control program has been successful.

Residues on hard surfaces or from contaminated soils can be tracked into homes. House dust cancontain contaminants that can be ingested, especially by younger children. Dust from the sitecould have been picked up by older children playing on the site and brought home to a youngersibling. A family pet that wanders onto the site may track contaminated residues into a home.This exposure pathway may have been more problematic in the past than today, especially sinceeducational efforts have been made to give residents information regarding at-home dust control methods.

Another historical, completed exposure pathway is the accident spill of acid on the site in 1980that leaked into the municipal storm sewer producing hydrogen sulfide gas in residentialbasements. One death was attributed to this accident.

B. Potential Exposure Pathways

Table 17 lists the potential exposure pathways that may result in some exposure for the currentand future DePue residents and site workers. Because metals do not degrade, they will remain inall contaminated media until physically displaced. Contaminants that can move through the soil,like those found at the gypstack, can percolate to subsurface soils and may reach the shallowgroundwater. Therefore, this pathway may be a potential problem for residents using privatewells in the area north of DePue where the gypsum waste was stored. Clay was reportedlyinstalled under at least part of the gypstack, and the clay might inhibit or hinder release of thewaste to groundwater. Limited information is available regarding the extent or thickness of this clay layer.

The groundwater in the area generally moves in a southerly direction toward the lake.Groundwater is the source of DePue's municipal drinking water, which is drawn from a deep,bedrock aquifer. Heavy metals do not move readily through subsurface soils. The community hasa water treatment plant regulated by Illinois EPA.

Rainwater can percolate through source areas and pick up contaminants that might eventuallyleach to groundwater or discharge to surface water. In addition, residual surface contaminantstransported by surface water run-off might be transported to neighboring residences. Thesepathways could add to the sediments that exist from previous contaminant deposition. A ditch onthe northern bank of Lake DePue contains unnatural sediment and water that is carried towaterways as run off. Sediment transport may be accelerated during periods of excessive rainfall.

In the past, individuals might have been exposed to soil contamination and waste residues on thesite primarily from activities involving disturbing, moving, or grading solid waste andcontaminated soils. Exposure to trespassers may have also occurred in the past but is unlikelytoday because site security has greatly improved and community educational efforts have warnedagainst trespass onto contaminated areas.

Lake DePue and the nearby Illinois River are used for recreation. No community water suppliesin the area draw from Lake DePue. IDNR is conducting independent assessments of theseproperties and some of its associated biota. Discussions regarding the remediation of sedimentsand contaminated soils in the conservation areas and in private properties are ongoing. Otheragencies are gathering data and information regarding the impacts on wildlife. Once thisinformation is available, more will be known regarding the potential present and future exposure pathways.


PUBLIC HEALTH IMPLICATIONS

This section includes discussions on potential health effects in persons exposed to specific site-related contaminants and addresses specific community health concerns.

A. Toxicology Evaluation

ATSDR developed Minimal Risk Levels (MRLs) to help evaluate whether an exposure to acontaminant warrants further examination for potential health effects. An MRL is an estimate ofthe daily human exposure to a contaminant below which adverse, noncancerous health effects arenot likely to occur. MRLs are screening values developed for different routes of exposure,including ingestion and inhalation, and for three different exposure periods: acute (less than 14days); intermediate (15-365 days); and chronic (more than 365 days). When an MRL was not available for a contaminant of concern, a USEPA Reference Dose (RfD) was used.

To help evaluate health effects, ATSDR presents information and study data summaries onspecific chemicals in Toxicological Profiles. IDPH used ATSDR Toxicological Profiles to helpevaluate exposures to contaminants of interest at this site. The number of contaminants ofinterest may change when more information becomes available.

Much of the toxicological information presented in this section focuses on potential site-relatedexposures. Frequently, adverse human health effects are known only from occupational exposuresituations where individuals have been exposed to very high levels of chemicals. Often, humancomparison values are developed using information obtained from laboratory animal studies, sosafety factors are included in these calculations. The probability that an adverse health effect willoccur is dependant upon the exposure concentration, how the exposure occurs (ingestion,inhalation, dermal contact), and the amount of time an individual is exposed. For this site, thefocus will be the residential DePue population.

The organic chemicals measured in the 1992 samples were found at levels below comparisonvalues and are not discussed in this section because any exposure to them would not be expectedto cause adverse health effects (Table 15).

Metals are the contaminants present in completed exposure pathways. Metals are not appreciablyabsorbed through the skin, and ambient air is not a current completed pathway; therefore, thediscussion in this section focuses on the residential population's ingestion of contaminantsthrough hand-mouth behavior. We compared all the metals detected in the residential soilsamples to health-based levels determined for adults, children, and pica children. The residentialsoil levels were used because those levels were higher than the carpet and indoor dust levels. Anumber of metals were eliminated from further evaluation because exposure to them at theconcentrations found in the 1992 analyses of off-site surface soils (Table 3) is not expected to cause adverse health effects.

IDPH developed an exposure scenario for incidental soil ingestion for children playing outdoorsin contaminated residential areas. For these potential residential exposures, we assumed that a16-kilogram child would play outdoors at least 4 days a week for 39 weeks per year for about 5years. A typical child would incidentally ingest 200 milligrams of soil daily, whereas a child witha propensity to mouth non food items (pica behavior) would ingest 5,000 milligrams of soildaily. Children would not likely be exposed to contaminated soil during the winter. Noadjustment were made for the increases in children's body weight for the five-year scenario.

The estimated exposures were calculated and listed for the range of residential soilconcentrations and were included in Table 18. Exposure to contaminants in soil is much morelikely in yards with poor vegetative cover. Adult residential exposure levels would be lower thanthose calculated for a normal child, and exposure is more likely for individuals who work in theiryards. Several metals do not appear to exceed health guidelines for exposures to contaminatedresidential soil. The metals of interest that may exceed health guidelines include arsenic, barium,cadmium, chromium, lead, manganese, vanadium, and zinc. A discussion of exposure to thosemetals is presented in alphabetical order.

Arsenic

Arsenic was present in residential surface soil at an estimated range of 4.7 to 32.4 ppm, which iswithin background levels found in some areas of the United States. Typical children would notreceive an estimated dose that exceeds the MRL; however, a child who exhibits pica behavior(eating non food items) may ingest a dose that exceeds the MRL (Table 18). The exposure toadults would not exceed health guidelines.

At 0.072 mg/kg/day, ingestion of arsenic may irritate the stomach and intestines, and vomitingand diarrhea may result. That dose is about an order of magnitude higher than the estimated dosefor a pica child. Long-term exposures at 0.05 mg/kg/day could decrease the production of bloodcells. That is also about an order of magnitude greater than the estimated dose for a pica child.Skin changes have been seen at 0.29 mg/kg/day (ATSDR, a1998). Ingestion of arsenic over timehas also been associated with skin cancer. Historically, arsenic has been associated withintentional poisoning. However, some researchers believe that small amounts of arsenic (10 - 50parts per billion) may be beneficial to health. It is naturally found in soil, water, and food (ATSDR, a1998).

Barium

Barium was estimated in residential soils at a range of 88.2 to 8,710 ppm. Pica children playingin the areas with the highest concentration of barium would exceed the USEPA RfD. Little isknown about the health effects of barium exposure in humans. Some researchers have attributeddifficulties in breathing, blood pressure, and cardiovascular problems with barium exposure. Inrats, breathing and cardiovascular problems developed with a dose of 198 mg/kg/day, which isconsiderably higher than the 1.2 mg/kg/day estimated dose for a pica child (ATSDR, a1990). Nohuman data are available. Barium has also been measured in concentrations above background levels in solid waste and sediments on site properties and in off-site sediments.

Cadmium

Children playing in contaminated residential soil regularly could ingest enough cadmium toexceed the MRL. This would be more likely to occur in play areas without any ground cover.

No historical biological or exposure data were found for former workers. Zinc ores processed inyears gone by at this site apparently contained relatively large concentrations of cadmium.Workers on site today receive training on personal protection and good work practices. Dustcontrol programs appear to have been effective in controlling the levels of metals in ambient airand limiting wind erosion via fugitive dust.

The human body does not readily take up cadmium from the gastrointestinal tract. An estimated90% of the cadmium ingested is not absorbed. Cadmium has no known beneficial health effectand, with long-term ingestion, too much can accumulate in the kidneys and in the bones anddamage them. No information on what doses cause less serious health effects was found forhumans. Hypertension was seen in rats who ingested 0.0089 mg/kg/day for five months(ATSDR , a1997). That is the same order of magnitude of the estimated dose for a pica child, butit is an order of magnitude more than the estimated exposure dose for a typical child.

The IDPH biological screening in 1993 (see Health Outcome Data Evaluation section and Tables12, 13, and 14) did not find any children with elevated cadmium blood or urine levels among theDePue volunteers. Only one adult worker, who currently works at a facility known to usecadmium, had an elevated blood cadmium concentration. One retired senior citizen with asmoking history had an elevated urine cadmium level. Cadmium exposure has been associatedwith cigarette smoking. Cadmium was found in house dust in some DePue homes. There are nostandards for cadmium in dust similar to those developed for lead dust.

Cadmium is also known to be taken up into garden vegetables under some soil conditions.Different plants can absorb different amounts of cadmium, depending upon the soil type, soilacidity, the amount of organic matter present, other metals present, and other inorganiccompounds available (ATSDR, a1997). We do not have data on garden soil conditions fromDePue or what levels of metals may be present in locally-grown vegetables.

Because of the multiple potential sources for cadmium, the length of time metals havecontaminated the environmental media, the concentrations of cadmium found in some off-siteproperties, and the inherent toxicity and cumulative nature of this metal, cadmium is acontaminant of interest at this site.

Chromium

There are several forms of chromium found in the environment including chromium III andchromium VI. Chromium III is the naturally-occurring form and is an essential nutrient.Chromium VI is usually associated with industrial activities and is more toxic than chromium III.The analyses reviewed here measured total chromium and did not differentiate between the twotypes. The comparison values used are based on chromium VI. Only a pica child playing in themost contaminated residential area would exceed the USEPA RfD. Chromium has beenassociated with redness and swelling of skin in allergic individuals at 0.036 mg/kg/day, which isan order of magnitude greater than the estimated exposure dose for a pica child (ATSDR, b1998).Some people may be sensitized to chromium and might experience effects at a lower exposuredose than most people. However, for most of the population of DePue, no adverse health effectswould be expected.

Lead

ATSDR has no health guidelines for lead. Lead levels on the site are greater than levels thatUSEPA has used as a cleanup level for industrial areas. We do not know what levels in theenvironment can increase blood lead levels in people upon exposure. Changes in the blood havebeen seen at 0.02 mg/kg/day (ATSDR, b1997).

Lead in residential soils was greater than 400 ppm, which is sometimes used by USEPA as acleanup level for residential soil. Lead was also present in indoor dust, which provides anotherpotential exposure source. Additionally, people were historically exposed to lead from thefacility when it was in operation. The type of lead present in the soil, air, and dust is importantbecause some compounds of lead are more readily absorbed by the body than others; however,these analyses were not completed during the sampling events reviewed.

Only one child had an elevated blood lead level when IDPH tested area volunteers for lead.Further investigation of the child's environment suggested that lead dust from old paint mayhave contributed to the blood lead level. The exterior of the child's home had been scraped and painted, and visible paint chips were evident around the foundation of the home.

Children exposed to lead before they are born and young children exposed to lead can exhibit adecrease in their IQ (Intelligence Quotient) and may exhibit behavioral problems (ATSDR 1988). Lead is stored in the bone. Women who were exposed to lead in the past can pass lead totheir unborn child when lead stores are released from the bones to the blood stream and cross theplacenta (ATSDR, b1997). Because of the serious adverse health effects that could occur fromlead exposure to young children, lead is a contaminant of concern.

Manganese

Low levels of manganese are thought to be necessary for maintaining health. Since manganese isa naturally occurring element, the amount in the normal diet is between 2,500-5,000 mg/day(ATSDR, c1997). Based on the data reviewed, manganese is not expected to be a health concernfor adults or typical children in DePue. Pica children playing in the most contaminatedresidential soils may ingest excess manganese. The health effects associated with the ingestion ofmanganese may include weakness, trembling, and stiff muscles. Mild neurological signs havebeen seen in people who consumed 0.059 mg/kg/day for 50 years (ATSDR, c1997).

Vanadium

Pica children may exceed the MRL for vanadium if they play regularly in yards with elevatedlevels of this metal. Typical children and adults would not be expected to exceed this healthguideline. Little information exists about human health effects associated with long-term oralexposure to this metal. The main health effects are due to inhalation exposure. Animal studieshave associated some kidney effects associated with vanadium. Rats fed 0.57 mg/kg/day forthree months experienced some kidney effects (ATSDR, b1990). That is two orders ofmagnitude greater than the estimated exposure dose for a pica child.

Zinc

Adults or typical children exposed to the maximum levels of zinc found in residential yardswould not receive a dose associated with adverse health effects. Pica children may exceed thecurrent MRL for zinc. Zinc is found at very high concentrations in most areas tested around theformer smelting operations and on-site properties. Residents reported that in the past, childrenwould play on waste piles for recreation. No information regarding workers exposures during thepeak years of operations is known to exist.

Zinc remains a contaminant of interest because it is found at such high concentrations in all theenvironmental media tested. It was also measured in house dust in some DePue homes. Becauseof the multiple sources, exposure levels may be higher for some people. Zinc is an essentialnutrient, but ingestion of levels greater than in a normal diet or vitamin pill, ranging from 5mg/kg/day for infants to 15 mg/kg/day for an adult male, can cause some people to experiencenausea and anemia (ATSDR, 1994). Zinc is not believed to cause cancer.

B. Health Outcome Data Evaluation

In response to questions regarding cancer rates, the IDPH Division of Epidemiological Studiespublished a cancer incidence report in February 1994. Forty cases of cancer were observedwithin the DePue zip code area, 61322, with 45 cases expected. This difference was notstatistically significant.

To determine if an immediate public health hazard existed under current exposure conditions,IDPH conducted blood and urine screening in September 1993. One hundred ten participantsvolunteered to provide venous blood samples and random urine samples. These were sent eachday by courier to a commercial clinical laboratory.

Of the 106 whole blood samples analyzed for cadmium, one adult had a slightly elevated level(Table 12), a blood cadmium concentration greater than 5 micrograms per liter (g/L) (U.S.Department of Labor, 1990). This adult was working with cadmium in the work place at the timeof the investigation.

Of the 33 random urine samples analyzed for cadmium, 28 had no detectable levels of cadmium(Table 13). Of the five detectable results, four adults were more than 70 years of age. To comparethese results with the current cadmium standards developed for worker exposure, urine creatininewas also measured in these 33 samples and the results were normalized. One adult had anormalized urine sample greater than the national worker standard of 3.0 g cadmium per gram ofcreatinine (U.S. Department of Labor, 1992). This adult had smoked cigarettes for more than 30years and had worked at the site for more than 40 years. Older participants had more frequentdetections than younger participants, which is a typical finding in measurements of biologicalmetal concentrations and is often attributed to exposures from common sources.

Lead was measured in 109 whole blood samples from volunteers (Table 14). The mean and themedian for all blood lead samples were 3.4 g/dL and 2.7 g/dL, respectively. This is similar to theblood lead mean of 2.8 g/dL from 12,119 participants of all races aged 1-74 years during thethird National Health and Nutrition Examination Survey conducted from 1988 to 1991 (Pirkle,1994). Of the 109 volunteers, one child had a blood lead level greater than 10 g/dL, the Centersfor Disease Control and Prevention's level of concern for children. An investigation conducted atthis child's home determined that recent renovations had disturbed some lead painted surfaces.No child less than 6 years of age in the DePue investigation had a blood lead level greater than10 g/dL. In Illinois, 8.5% of children less than 6 years of age had at least one result of 15 g/dL,for a total of 18,537 children (IDPH, 1997). A lead exposure study conducted near a closed,secondary lead smelter by IDPH and ATSDR in 1991 included blood samples collected from 490children under the age of 6 with a mean of 6.9 g/dL (ATSDR, 1995). Not one participating adultin the DePue investigation had a blood lead level greater than 25 g/dL, the currently acceptablelevel for adults.

The biological screening for cadmium and lead exposures did not show an immediate publichealth hazard. IDPH provided those results to Illinois EPA staff who had originally askedwhether the site required an emergency cleanup. The elevated metal levels found in threeindividuals cannot be solely attributed to industrial or environmental exposures because ofadditional occupational and household metal sources. The lead and cadmium tests performedonly capture information on recent exposure. The tests do not indicate what may haveaccumulated in the body as a result of past exposure.

In the mid 1990s, community members informed IDPH that nine individuals had been diagnosedwith MS (MS). In response to this concern, IDPH contracted with the University of Rochester toconfirm these cases and compare this local incidence rate of MS with typical rates. Theyconcluded that a significant excess of MS cases existed during the period investigated (1971-1990). The reasons for the excess of MS cases are not known. The final report provided to IDPHdiscussing those findings is included as Attachment 1.


COMMUNITY HEALTH CONCERNS

People have raised several issues during public meetings, discussions during a door-to-doorsurvey, meetings with local agency and community leaders, and health professional workshops. Residents asked about exposures to the discolored water that used to pool along the sidewalk onMarquette Street. The DePue Group has remediated the problem of the accessible standing water.People living around the site had some questions about cancer, which were addressed by the 1994 IDPH cancer incidence report.

Former Bureau County Health Department staff and local health care providers have expressed a concern about individuals receiving dialysis treatment. Some residents have expressed concern about the number of MS cases in the area. Family members who lived near the gypsum waste stack north of town have asked about the potential health effects from living near the large pile of inorganic wastes. One individual reported to have an allergy to metals and questioned if growing up in this area contributed to this medical condition.

Question: What health effects are associated with cadmium exposure and how can a doctor test patients for cadmium?

Response:

The principal target organ from cadmium exposures is the kidney. The kidneys not only store cadmium for long periods, but if enough metal accumulates, kidney disorders can result. The bones do not store cadmium but can be adversely affected by long-term cadmium exposures. The skeletal effects are often called "itai-itai" or "the fragile bone disease." The estimated exposure dose that people living around the site might receive is much less than the doses associated with that disease. The liver also stores cadmium for long periods.

Clinical investigations usually consist of the measure of cadmium concentrations in body fluids and tissues including blood, urine, hair, nails, or biopsies of the kidney or liver. Kidney and liver function tests can be undertaken, but abnormal results do not prove that an excessive body burden of cadmium exists.

Information on cadmium exposure has been discussed at public meetings, community gatherings, and at two ATSDR-sponsored health professional educational workshops at area hospitals.

Question: Are the private wells north of Route 29 contaminated?

Response: Those wells are upgradient of the former operations area but might not be well isolated from the gypstack. The wells are not likely to contain site-related heavy metals. To verify that, IDPH recommends that the functional private wells be tested for the wastes found in the stack. Abandoned wells should be properly sealed.

Question: Are there more persons in the DePue area on kidney dialysis than would be expected? If so, could this be related to the site?

Response: IDPH does not know because we have not found any agencies or programs that collect records on dialysis use. Long-term cadmium exposure can have adverse effects on the kidney. Those people who were tested for cadmium exposure did not have an excess of cadmium that could be attributed to cadmium from the site.

Question: Nine individuals who grew up in DePue have been diagnosed with MS as adults. Why?

Response: No one knows the specific cause of this neurological disorder, although many medical researchers have developed several hypotheses. IDPH worked with a neurologist with experience treating MS patients to statistically evaluate the local incidence rate of the confirmed cases and to compare it to incidence rates found elsewhere. An elevated rate was found, and the report discussing those findings is included as Attachment 1.


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