Mercury Experiments In Class Can Be Poison
Mercury and schools. The combination can make for engaging science classes, or potentially lethal consequences.
Are the risks worth the wow? The answer, increasingly, is no.
As stories about mercury spills at schools tumble across newspaper headlines, more states and districts are deciding that the educational benefits that mercury might have in lessons do not outweigh the hazards associated with handling the toxic, and enticing, element. Eleven states, at a minimum, have taken steps to rid schools of the substance through legislation or other means.
"It's too dangerous," declared Kenneth R. Roy, the head of the safety advisory board for the National Science Teachers Association.
When mercury—specifically, metallic mercury—is released, it breaks apart into tiny beads and releases a vapor that can cause shortness of breath, nausea, vomiting, diarrhea, and possibly death.
At least seven U.S. schools, in separate incidents, have been evacuated because of major spills so far this school year.
The latest, and possibly the most dramatic, incident happened at Ballou Senior High School in Washington this month.
After taking about half a cup of mercury from an unlocked science lab at the 1,300-student school on Oct. 2, a student shared it with some classmates, who played with the dangerous material.
The student's actions resulted in a massive cleanup involving school district officials, the District of Columbia fire department's hazardous-materials team, the federal Environmental Protection Agency, and the local health department.
Nearly 300 people came into direct contact with the mercury, and more than 1,200 students, teachers, and staff members at Ballou High were screened for mercury poisoning.
No one was identified as having symptoms of such poisoning, but 165 people required additional checkups as of last week, according to Briant K. Coleman, a health department spokesman.
In addition, 86 houses were tested for mercury exposure, 11 of which have shown elevated levels and will need to be decontaminated, Mr. Coleman said.
Mercury was also found on one of five public buses that city emergency workers examined and took out of service, he said.
When the cleanup will be finished and what it will cost were still up in the air last week.
Meanwhile, Ballou students are attending classes at the former Washington Convention Center and taking field trips to the capital's landmarks and museums.
Some of the same properties that make mercury so attractive are also what make it difficult to clean up. Unlike water, which will adhere to almost anything, mercury adheres to itself. To demonstrate that principle, science teachers commonly have students compare one graduated cylinder containing water and one containing mercury, said Mr. Roy of the science teachers' association.
The top of the water appears concave, while the mercury appears convex because the glass sides of the cylinder are attracting the water, and mercury is trying to attract itself.
"Mercury tends to be anti-social," said Mr. Roy, who is also the safety-compliance officer for the 8,000-student Glastonbury, Conn., school district.
That self-possessed property is why, when released, mercury forms little balls that tend to roll into cracks and crevices. Trying to sweep up the beads with a broom and dustpan—a common mistake, according to Mr. Roy— only spreads the mercury around more and releases its toxic vapor.
In the case of a mercury spill, schools must immediately isolate the area around the spill and shut down the ventilation system, which can carry the vapors throughout the building. They should also call the local fire marshal, Mr. Roy advised.
Depending on the size of the spill, teachers may be able to use specially designed cleanup kits that are available from chemical-supply companies, he said.
Careful attention needs to be paid to students' and teachers' clothing and shoes, because mercury can attach itself to certain fibers and, as was the case in the Washington spill, travel to students' homes.
"It is the gift that keeps on giving," Mr. Roy said jokingly.
Even when mercury is not used in experiments or demonstrations, it can show up in school science labs in the form of such commonly used equipment as thermometers, barometers, and manometers.
Now, many supply companies are sponsoring exchange programs so that teachers can trade in their old devices for newer models that are safer and more accurate, Mr. Roy said.
Mercury is becoming so unpopular that at least 11 states—including Connecticut, Indiana, Kansas, Maine, Maryland, Michigan, Minnesota, Oregon, Vermont, Virginia, and Wisconsin— have introduced programs or passed legislation to remove the metal from schools, according to the Environmental Protection Agency.
The EPA will hold an online workshop Nov. 14 for teachers and administrators to discuss different mercury-reduction programs. More information on the Webcast can be found at www.epa.gov/mercury/classroom.htm.
"The initiatives are there," Mr. Roy said. "Unfortunately, some behaviors are very difficult to change."
Ingrained behavior is exactly what complicated cleanup efforts in Onaway, Mich. Even though the 750-student district had rid its single school of mercury three years ago, this fall three students took about half a cup of mercury from an abandoned house last month, brought it to school, and spilled it in a busy hallway.
Then a well- intentioned custodian vacuumed it up, said Superintendent Robert Szymoniak. "You don't do that," Mr. Szymoniak emphasized. "That puts mercury vapors in the air, where it is most dangerous."
The custodian followed what was for years the standard cleanup procedure at the school, Mr. Szymoniak said. As soon as the superintendent heard about the spill, he evacuated the school and hired a professional company to test the air and decontaminate the building.
In the end, Onaway Area School was closed for four days. The cleanup bill will amount to more than $40,000, Mr. Szymoniak said. Because the students didn't know what they had, they were not disciplined, he said.
In response to that kind of price tag, some school administrators have decided to close down science labs altogether, Mr. Roy said.
"Let's not throw the baby out with the bath water," he said. Instead, Mr. Roy suggests that science teachers receive annual professional-development instruction on the topic, and that schools make their laboratories safer. ("Science-Lab Safety Upgraded After Mishaps," April 30, 2003.)
The federal Occupational Safety and Health Administration, or OSHA, requires schools with science labs to have a chemical-hygiene plan, outlining the safety procedures and equipment employees should use when dealing with potentially dangerous chemicals. In essence, those plans promote "professional responsibility," Mr. Roy said.
Still, he added, "most schools are handling this responsibly."
Vol. 23, Issue 8, Pages 1,18-19