Skip directly to search Skip directly to A to Z list Skip directly to site content




The concentration of each contaminant detected during sampling was compared with appropriate health screening comparison values used to select contaminants for further evaluation for carcinogenic and noncarcinogenic health endpoints [3,4]. Contaminants with concentrations that exceeded comparison values or with concentrations greater than National or Illinois soil background levels for which no comparison value was available were selected for further evaluation [5,6]. A discussion of each of the health screening comparison values used is found in Attachment 1.

Table 1 lists the contaminants in groundwater that exceed comparison values. No volatile organic compounds, semi-volatile organic compounds, or pesticides were found at levels above comparison values in the groundwater, sediment, or soil. The soil and sediment contained a few polycyclic aromatic hydrocarbons (PAHs) but not at levels above comparison values. Some inorganic compounds were the only contaminants found above comparison values (Table 2). The groundwater contained benzene and some inorganic compounds, and the soil and sediment samples contained PAHs, arsenic, and beryllium. Tables 3 and 4 list the contaminants found above comparison values during the STEP inspection.

Antimony was found at levels above the comparison value in all of the groundwater samples, including the private well samples, collected during the 1993 SSI. In the 1996 STEP samples, antimony was present at levels above comparison values in the groundwater samples collected on the site; however, the two drinking water well samples collected in 1996 did not contain antimony at levels above comparison values.

Small amounts of antimony are found in the earth's crust. Refuse incinerators and coal-burning power plants can release antimony into the environment. Most antimony will settle onto soil or sediment, where it attaches strongly to particles that contain iron, manganese, or aluminum. As a natural constituent of soil, antimony is transported into streams and waterways from natural weathering of soil and from human sources. If the levels of antimony that were found in monitoring wells should migrate to the private drinking water wells, people who consume the water could experience adverse health effects. People who drank much larger amounts of antimony than found on the site usually vomited. Other adverse health effects of antimony in humans following oral exposure include increased blood pressure, abdominal distress, ulcers, and heart problems. Studies on human oral exposure to antimony are limited [7].

Arsenic is a naturally occurring element. In areas where crops were historically grown, arsenic levels may be higher than usual area background levels because of pesticides that were used on crops. Arsenic was found above comparison values in one off-site groundwater sample collected during the 1993 SSI, and in the soil/sediment samples collected in 1993 and 1996. Of the soil/sediment samples, only samples ST03 and X204 contained arsenic at a level above the comparison value for children. The SSI samples were collected at a depth of 2 to 6 inches. The depth that STEP samples were collected is unknown. The maximum level of arsenic detected in the soil and sediment would not be expected to cause adverse health effects to children or adults if ingested or inhaled.

On the other hand, levels of arsenic found in private well water may result in an exposure dose that exceeds the chronic oral minimal risk level (MRL) for arsenic, which is 0.0003 milligrams per kilograms per day. The noncarcinogenic effects that may be associated with ingestion of inorganic arsenic include irritation of the stomach and intestines with symptoms including nausea, vomiting, and diarrhea, a decrease in the production of red and white blood cells, abnormal heart function, blood vessel damage, and impaired nerve function. Arsenic is most hazardous to children less than 6 years old [8]. Only one sample was collected from the private well; the level found at that time is likely not representative of the exposure because levels tend to fluctuate with seasonal variation and other factors.

The arsenic level detected in the private well also could pose a low increased risk of carcinogenic health effects to those who consume the water. When ingested, it is associated with skin cancers in humans, and may cause other internal cancers as well [8].

Manganese was detected at levels above the comparison value in all of the Sanitary District's monitoring wells and in one sample collected from an on-site groundwater well during the STEP inspection. Manganese is a naturally occurring substance found in many types of rock. Some manganese compounds can dissolve in water. Small amounts of manganese are beneficial to health, but too much can cause serious illness. Neurological effects have been shown in persons who consumed water with elevated levels of manganese [9]. Since the elevated levels were detected only in the monitoring wells and not in private wells, exposure to manganese at these levels is unlikely at this time.

During the STEP inspection, selenium was detected in one on-site monitoring well at a level slightly above the comparison value. Selenium is a naturally occurring, solid substance. It is widely but unevenly distributed in the earth's crust. Ingestion of large amounts of selenium can be life-threatening. Smaller amounts consumed over long periods of time can cause brittle hair, deformed nails, and loss of feeling in arms and legs [11]. Exposure to selenium at the level detected would not be expected to cause adverse health effects.

Thallium was detected at a level above the comparison value in one groundwater sample and in the duplicate sample collected during the STEP inspection. Thallium is used mostly in the manufacture of electronic devices, switches, closures, and before its ban, in a pesticide primarily used for rat control. When thallium is swallowed, most of it is absorbed and rapidly goes to the kidneys and liver. Thallium can accumulate in the body. Ingesting large amounts of thallium can affect the nervous system, lung, heart, liver, and kidney. It can cause temporary hair loss, vomiting, diarrhea, and even death [12]. Thallium has only been found in monitoring wells to date; therefore, people have not been exposed to thallium in drinking water.

Benzene was detected at a level slightly above the comparison value in one monitoring well sample and a duplicate sample during the STEP inspection. Drinking water with high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, rapid heart rate, coma, and death. Benzene is a known human carcinogen [13]. No apparent increased risk of cancer would be expected from exposure to the levels detected in the monitoring well. No other adverse health effects would be expected.

PAHs were present in the STEP soil and sediment samples at levels above comparison values, but levels were well below the national background level. PAHs are present naturally in the environment, and everyday activities, such as cooking, produce some exposure on a daily basis [6]. Periodic exposure to the PAHs found in soil and sediment is not likely to result in adverse health effects.

Beryllium was detected above the conservative comparison value in all soil/sediment samples collected during the STEP inspection. When large amounts of beryllium are inhaled over a short period of time, lung damage resembling pneumonia can occur [14]. Since the detected levels were well below the Illinois background level, no adverse health effects would be expected from any type of exposure to beryllium at the levels found.

Exposure to contaminants present in soil/sediment samples collected to date should not result in adverse health effects. Exposure to contaminated groundwater is of most concern. Only 3 on-site groundwater samples and 3 off-site private well samples were collected during both inspections. Because of the limited data, private wells contamination is difficult to evaluate. Off-site private wells appear to be upgradient of the site, but groundwater flow direction from the site has not been fully characterized.

Next Section          Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #