Monday, October 25, 1999
Federal expert reviews benzene level found in Sycamore Creek
By Carol Bogart
Staff Writer
SYCAMORE - The level of benzene detected by the Ohio EPA in Sycamore Creek could, if present in drinking water and consumed over a period of time, result in one additional leukemia per 10,000 people, according to Sharon Wilbur.
Wilbur is chemical manager for benzene in the division of toxicology at the Agency for Toxic Substances and Disease Registry at the Centers for Disease Control in Atlanta.
The yardstick for chemicals such as benzene is based on standards set for drinking water, even when considering amounts found in streams. This does not mean there are expectations that water would be consumed directly from streams without treatment.
The tests of Sycamore Creek that indicated the benzene levels followed what is being investigated as an arson fire, when millions of tires burned Aug. 22 at Kirby's Tire Recycling on SR 231 east of Sycamore. The effects of the fire and the resulting contaminants are still being investigated by state EPA and health officials.
Wilbur says U.S. EPA has determined that seven micrograms per liter in drinking water would mean one extra leukemia per 100,000 people. Seventy micrograms results in one in 10,000.
According to EPA test results, the level detected in a sampling of Sycamore Creek was 50.8 micrograms. Wilbur says, "and 50 is closer to 70 than it is to 7."
Wilbur says, "Personally, I wouldn't like to be exposed to any of it. Benzene is a very bad actor. I hold my breath when I pump gasoline."
Wilbur says the "latency period" - the time frame from exposure to death from cancer - is "seven to 20 years." She says there are some studies that give a range of 5 to 30 years but says she heard of one case of a young man exposed to low levels of benzene in air at his job who developed acute myelogenic leukemia. Wilbur says, "He worked there less than a year. But that was only one case."
Wilbur says, "Acute myelogenic leukemia is a very rare kind of cancer. If someone has it you can say, 'Wow. Were you exposed to benzene?' "
Wilbur cautions that not everyone exposed to even high levels of benzene will develop cancer. Exposure to high levels, she says, results in neurological effects such as dizziness or a "drunken" feeling. Wilbur adds, "You can recover from that." Without additional exposure, Wilbur says the body will clear the benzene.
Not good, she says, is ongoing exposure because the body will store benzene in the bone marrow and fat tissue. Urine, Wilbur says, can be screened for phenol, muconic acid, and S-phenyl-N-acetyl cisteine. Of the three, she says, "muconic acid is a more reliable indicator of benzene exposure," but adds that these tests, too, are for "recent exposures to high levels."
ATSDR says, "The health effects that may result from eating foods or drinking liquids containing lower levels of benzene are not known. People with benzene-contaminated tap water can be exposed from drinking the water or eating foods prepared with the water. In addition, exposure can result from breathing in benzene while showering, bathing, or cooking with contaminated water."
Symptoms of long-term exposure to low levels of benzene, according to the The National Institutes of Health, include: fatigue, nervousness, irritability, blurred vision, and labored breathing. Repeated skin contact, it says, can cause redness, blistering and dry, scaly dermatitis. NIH says chronic long-term exposure to benzene, "has produced anorexia and irreversible injury to the blood-forming organs. Effects include aplastic anemia and leukemia."
Contaminated runoff from the Kirby Tire fire was directed into a pit dug to contain it. U.S. EPA's Karla Aucker has indicated underlying soils at Kirby are clay. A clay layer would provide a shield between contaminated surface water and underground aquifers.
A well log for the Kirby site indicates a clay layer from 0 to 7 feet where the well was drilled. The Advertiser-Tribune has requested, in writing, that Ohio EPA provide soil borings to show if all soils surrounding, and under, the still-smoldering Kirby tires are clay. This written request also asked for a copy of a work order for a clay liner for the runoff containment pit. Ohio EPA has not responded to this and repeated verbal requests.
The EPA file indicates a field tile was "discovered" when liquid in the runoff pit "bubbled." That tile and others, according to the file, allowed contaminated runoff to enter Sycamore Creek. Microbiologist Paul Flathman says soil sampling in the pit is needed immediately.
The ATSDR says, "(US)EPA has set the maximum permissible level of benzene in drinking water at 5 ppb (micrograms). Because benzene can cause leukemia, EPA has set a goal of 0 ppb for benzene in drinking water and in water such as rivers and lakes."
The Ohio Department of Health says tests for people who have had a long-term exposure to low levels of benzene include blood tests which count types of blood cells and measure substances such as vitamin B12 in the blood. Wilbur says chronic exposure to low levels of benzene may be suspected if complete blood analysis reveals changes in the number of cells present.
She says, "People who are worried can have a hematological test to see if the number of blood cells has gotten smaller. A lowering of the red blood cells can cause anemia. Chronic long-term exposure to benzene can reduce all the blood cells. This can harm the immune system." Wilbur says reduction of blood cells "may be the leukemia mechanism."