Radon I

Rikhvanov Leonid P., professor,DSc in Geology and Mineralogy

Nadeina Luiza V., associate professor,PhD in Philology

TOMSK -2015

Radon is a class a known human carcinogen

• Alpha particles from radon decay products can damage lung tissue

• Lung cancer is the main health effect

HISTORY

• An “unknown” lung disease in miners in the 1400s

• Identified in 1879 in autopsies of European miners as lung cancer (Limphosarcoma).

• Excess lung cancer deaths observed in uranium miners in US, France, Czechoslovakia, Canada.

• Excess lung cancer deaths in other underground miners in Sweden, Britain, France, Australia, China and US

Mechanism of Lung Cancer Induction

• Radon and RDPs breathed in.

• Radon exhaled.

• RDPs remain stuck to lung issue.

• Po-218 and Po-214 emit alpha particles.

• Alpha particles strike lung cells causing physical and chemical damage to DNA.

Physical and chemical damage to DNA from radiation

• Physical damage occurs when DNA stuck directly.

• Chemical attack can occur from ions and free radicals created when radiation impacts fluid surrounding DNA

Scientific basis for radon risk estimates

• Studies on miners.

• Committee on the biological effects of ionizing radiation.

• Studies on residential occupants.

• Laboratory animal studies.

EPA Risk Assessment

Radon-related lung cancer risk:

- life time risk at 4 pCi/L Action Level:

1:100 for smokers

1:1000 for non-smokers

- Central risk estimate:

14000 lung cancer deaths/year

uncertainty range: 7000 to 30000

deaths/year

IDNS state policy recommends that people not have long-term exposures above 4.0 pCi/L

It is in the interest of people to establish a comprehensive program for determining the extent to which radon and radon progeny are present in dwellings and in other buildings at levels that pose a potential risk to the occupants and foe determining measures that can be take to reduce and prevent such a risk.

Working level month

• The actual potential for contracting lung cancer increases with the dose received and the duration of expose to a given dose.

• A time and a dose measure is used to quantify lung cancer potential. This is the Working Level Month (WLM).

• Equivalent to 170 hours of exposure at I Working Level (WL).

Conclusions:Estimates for U.S.

-15000 lung cancer deaths/year

10000 in smokers

5000 in never smokers

Uncertainty Range = 6000-36000/yr

Liner dose-response

Little credible evidence for a threshold effect

Increased risk for nonsmokers confirmed

Higher risk associated with exposure received at low rates