The Army Corps of Engineers removed the last elevated levels of arsenic on the 5100 block of Tilden Street last week.
The Army eliminated soil containing arsenic levels of 22.8 parts per million at five feet deep during a dig of a 4-by-4-foot area.
“Twenty is the number that’s been developed for the child-acceptable risk range,” said Steve Hirsh, a representative from the Environmental Protection Agency for the Restoration Advisory Board of Spring Valley.
This risk range assumes a child will consume about a teaspoon of dirt a day through breathing, eating and playing, according to Hirsh.
“It’s possible that the five feet of dirt is new from outside property. We had five feet of clean dirt before we got above 20 parts per million,” he said. “That dirt was from 100 years ago.”
In 2001, the Army sampled every property in the Spring Valley Formerly Used Defense Site, which includes parts of the AU campus.
“The reason for that lag between 2001 and now is that we wanted to get the worst done first,” Chris Augsburger, spokesman for the Army Corps, said.
Tilden Street marks the last arsenic removal for the Corps.
AU students cannot serve on the board, according to the board’s regulations. Any board member must be a community member who lives and/or works in the area and who might be affected by restoration activities in the Spring Valley area.
The board’s Membership Chair Malcolm Pritzker said the board’s regulations define residents as people who live on a long-term basis in Spring Valley.
Contamination at AU
The Army will test parts of the AU campus for antimony this month. The Army has sampled 17 properties in the area, including campus.
“Antimony is not a special metal of any sort but it is a metal that has a toxicity level,” Hirsh said. Currently, the Army is looking for additional information on the metal.
The Army will also continue sampling for perchlorate near Kreeger Hall. Perchlorate is a man-made chemical used in some fertilizers and explosives, according to the EPA’s website. This chemical can potentially harm the thyroid if consumed.
The Army found the highest levels of perchlorate in the wells at Kreeger Hall in July, according to Army Corps of Engineers Project Manager Dan Noble.
The arsenic and other potentially harmful chemicals are left over from a munitions camp set up at AU during World War I.
Neighbor Asks for Relocation, Denied Twice
Christine Dietrich, who lives directly across the street from the site at 4825 Glenbrook Road with two children, said she is worried about adverse effects from chemicals will harm her family during the construction. The Army Corps denied her two requests for the Corps to pay for her temporary relocation because the construction would be monitored and precautions were in place.
“Systems fail, things go wrong and engineers are human, not God,” Dietrich said during the Spring Valley meeting on Sept. 11.
Dietrich appealed to the board, but members said they could not make a decision until they had more evidence of the site’s risks. However, only Corps Headquarters would be able to overturn the current decision.
Dr. Peter deFur, an environmental scientist who served on the National Research Council Board on Environmental Studies and Toxicology, will release a study on the construction site’s chemical risks.
“The point is to see whether those mitigating steps are effective,” deFur said.