Tritium in the World Trade Center September 11, 2001 Terrorist Attack: It's Possible Sources and Fate

Conference · Fri May 03 04:00:00 EDT 2002

OSTI ID:15013327

Parekh, P; Semkow, T; Husain, L; Haines, D; Woznial, G; Williams, P; Hafner, R; Rabun, R

Traces of tritiated water (HTO) were determined at World Trade Center (WTC) ground zero after the 9/11/01 terrorist attack. A method of ultralow-background liquid scintillation counting was used after distilling HTO from the samples. A water sample from the WTC sewer, collected on 9/13/01, contained 0.174{plus_minus}0.074 (2{sigma}) nCi/L of HTO. A split water sample, collected on 9/21/01 from the basement of WTC Building 6, contained 3.53{plus_minus}0.17 and 2.83{plus_minus}0.15 nCi/L, respectively. Several water and vegetation samples were analyzed from areas outside the ground zero, located in Manhattan, Brooklyn, Queens, and Kensico Reservoir. No HTO above the background was found in those samples. All these results are well below the levels of concern to human exposure. Several tritium radioluminescent (RL) devices were investigated as possible sources of the traces of tritium at ground zero. Tritium is used in self-luminescent emergency EXIT signs. No such signs were present inside the WTC buildings. However, it was determined that Boeing 767-222 aircraft operated by the United Airlines that hit WTC Tower 2 as well as Boeing 767-223ER operated by the American Airlines, that hit WTC Tower 1, had a combined 34.3 Ci of tritium at the time of impact. Other possible sources of tritium include dials and lights of fire and emergency equipment, sights and scopes in weaponry, as well as time devices equipped with tritium dials. It was determined that emergency equipment was not a likely source. However, WTC hosted several law-enforcement agencies such as ATF, CIA, US Secret Service and US Customs. The ATF office had two weapon vaults in WTC Building 6. Also 63 Police Officers, possibly carrying handguns with tritium sights, died in the attack. The weaponry containing tritium was therefore a likely and significant source of tritium. It is possible that some of the 2830 victims carried tritium watches, however this source appears to be less significant that the other two. The fate of tritium in the attack depended on its chemistry. Any tritium present in the vicinity of jet-fuel explosion or fire would convert to HTO. The molecular tritium is also known to quickly exchange with water adsorbed on surfaces at ambient temperatures. Therefore, the end product of reacted tritium was HTO. A part of it would disperse into the atmosphere and a part would remain on site. The dynamic aspect of HTO removal was investigated taking into a consideration water flow at ground zero. Most of ground zero is encircled by the Slurry Wall, 70 ft deep underground, called a Bathtub. Approximately three million gallons of water were hosed on site in the fire-fighting efforts, and 1 million gallons fell as rainwater, between 9/11 and 9/21 (the day of the reported measurement). The combined water percolated through the debris down to the bottom of the Bathtub dissolving and removing HTO with it. That water would meet and combine with the estimated 26 million gallons of water that leaked from the Hudson River as well as broken mains, during the same period of 10 days after the attack. The combined water was collecting in the PATH train tunnel and continuously being pumped out to prevent flooding. A %Box model of water flow was developed to describe the above scenario. Considering the uncertainty in the amount of tritium present from sources other than the aircraft, as well as the dynamic character of tritium removal from the site, it is feasible to provide only a qualitative picture of the fate and behavior of tritium at WTC with the limited experimental data available. If the time history of tritium concentration at WTC had been measured, this study could have been a tracer study of water flow at WTC possibly useful to civil engineering.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15013327
• Report Number(s): UCRL-JC-148360
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
AMBIENT TEMPERATURE
CIVIL ENGINEERING
FIRE FIGHTING
HUDSON RIVER
SCINTILLATION COUNTING
TRITIUM
TRITIUM OXIDES
WATER