Potential carcinogenic effects of world trade center dust after intratracheal instillation to Sprague-Dawley rats: first observation

Our plain-English summary of Potential carcinogenic effects of world trade center dust after intratracheal instillation to Sprague-Dawley rats: first observation, by M. Soffritti, L. Falcioni, L. Bua, et al (American Journal of Industrial Medicine, 2013).

The study

• Authors: M. Soffritti, L. Falcioni, L. Bua, E. Tibaldi, M. Manservigi, F. Belpoggi
• Journal: American Journal of Industrial Medicine
• Published: 2013;56(2):155-62
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: More than 10 years have passed since the terrorist attack on the New York City World Trade Center on September 11, 2001. It is well known that long-term carcinogenic bioassays on rodents can predict the potential carcinogenic effects of chemical and physical agents for humans.

Objective: A life-span carcinogenicity bioassay was conducted on Sprague-Dawley rats at the CMCRC of the Ramazzini Institute to test the potential carcinogenic effects of settled dust collected at the WTC immediately after the terrorist attack.

Methods: The WTC material tested is a complex mixture of coarse particles (95%) contain pulverized cement, glass fibres, asbestos, lead, polycyclic aromatic hydrocarbons (PAH(S) ), polychlorinated biphenyls (PCB(S) ) and polychlorinated furans, and dioxin. The test matter was suspended in sterile saline and administered by intratracheal instillation (IT) to 8-week-old Sprague-Dawley rats (100 animals/sex), 3-4 days/week for 4 weeks. A group of 200 male and female rats served as controls. The animals were kept under observation until natural death.

Results: Histopathological evaluation of the lungs (target organ) of instilled control and treated male and female rats, did not show any significant increased incidence of lung tumors. Two hemangiomas (one with endothelial atypia) and one hemangiosarcoma were found in the lungs of treated males. Moreover a modest increased incidence of terminal bronchiolar hyperplasia (TBH) and squamous metaplasia occurred in the lung of treated males and females compared to the controls.

Conclusion: Hemangioma and hemangiosarcoma are extremely rare tumors in the lung of our colony and we believe they are caused by WTC dust.

Copyright © 2012 Wiley Periodicals, Inc.

In plain English

This was an animal experiment at the Cesare Maltoni Cancer Research Center of the Ramazzini Institute in Bologna, Italy. Settled dust collected near Ground Zero after the World Trade Center collapse was suspended in saline and instilled directly into the windpipe of 100 male and 100 female Sprague–Dawley rats over 4 weeks, starting at 8 weeks of age. The dust was a mixture that included cement, glass fibers and chrysotile asbestos. Another 100 males and 100 females received saline only. All rats were followed until natural death. This first report covered only the lungs. The authors found no significant increase in lung tumors. Treated males had two hemangiomas (benign blood-vessel tumors), one hemangiosarcoma (a malignant blood-vessel tumor) and one alveolar/bronchiolar adenocarcinoma. Squamous metaplasia went from 2 to 5 cases in males and from 4 to 11 in females. The authors stated that these vessel tumors are extremely rare in their colony and that they believe they were caused by the dust. They noted that the rats were not also exposed to fire gases. Other organs, and a separate group injected in the abdomen, were still to be reported.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment: life-span (lifetime) carcinogenicity bioassay in rats, with dust given by intratracheal instillation. This article is the first observation and covers lung findings only.
• Who was studied: Sprague–Dawley rats aged 8 weeks at the start, at the Cesare Maltoni Cancer Research Center/Ramazzini Institute, Bologna, Italy. There were 100 males and 100 females given WTC dust by intratracheal instillation, and 100 males and 100 females instilled with sterile saline as controls. A separate group of 40 males and 40 females got intraperitoneal injection, which this article does not report. The experiment started in December 2005 and the last animal died in May 2008.
• Exposure: Total settled World Trade Center dust collected near Ground Zero and used without modification. According to Table I (data adapted from Lioy et al. 2002), it was 50.0% cement/carbon, 40.0% glass fiber, 9.2% cellulose and 0.8% chrysotile. It also contained metals including lead, PAHs, PCBs and dioxins. The dust was suspended in sterile saline and instilled into the trachea at 0.2 mg/0.2 ml in week 1, 0.3 mg/0.2 ml in week 2 and 0.5 mg/0.2 ml in week 3, on 3 days each week. In week 4 the dose was 0.5 mg/0.2 ml on 4 consecutive days.
• Main results:
  • In treated and control males and females, examination of the lungs did not show any significant increase in lung tumors.
  • Two treated males had lung hemangiomas and died at 70 and 102 weeks of age. Both tumors were locally non-invasive, and one showed endothelial cell atypia.
  • One treated male that died at 110 weeks of age had an invasive lung hemangiosarcoma.
  • Among the laboratory's 2,180 male historical control rats, lung hemangioma occurred in 0.2% (4 cases) and hemangiosarcoma in 0.1% (3 cases).
  • One treated male had a highly malignant alveolar/bronchiolar adenocarcinoma. The incidence in the 2,180 male historical controls was 0.1% (range 0 to 1%). One fibrosarcoma occurred in a treated male and one in a control male.
  • Squamous metaplasia showed a modest increase in treated animals, mainly females: from 2 to 5 cases in males and from 4 to 11 in females (control compared with treated). Terminal bronchiolar hyperplasia showed only minor differences between treated and control rats.
  • Mean body weight did not differ between treated and control groups. Survival at 72 weeks of age was almost 90% in males and females of all groups.
• The authors' conclusion: The authors concluded that hemangioma and hemangiosarcoma are extremely rare lung tumors in their rat colony and that they believe these tumors were caused by WTC dust. They also wrote that the three rarely occurring lung tumors should be cause for concern.
• Limitations the authors state:
  • The study could not simulate workers' simultaneous exposure to the dust and to the gases released by the fires in the first days after the collapse.
  • Only the lungs of the intratracheally instilled and control rats had been examined. Evaluation of other tissues and organs was ongoing, and results of the intraperitoneal (abdominal injection) group were to be reported later.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Carcinogenic, Settled Dust.

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• Summary of the development of a signature for detection of residual dust from collapse of the World Trade Center buildings — H.A. Lowers, G.P. Meeker, et al. (2009)
• Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002 — A.S. Geyh, S. Chillrud, et al. (2005)
• Health consequences of the September 11 World Trade Center attacks: a review — J. Moline, R. Herbert, et al. (2006)
• Development of an exposure assessment method for epidemiological studies of New York State personnel who responded to the World Trade Center disaster — M.L. Herdt-Losavio, M.P. Mauer, et al. (2008)

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