US EPA

86197 

Journal Article 

Co-carcinogenic effects in rats of combined exposure to radon and ozone 

Monchaux, G; Morlier, JP; Morin, M; Rochefort, P; Maximilien, R; Tredaniel, J 

1996 

Yes 

Environment International
ISSN: 0160-4120
EISSN: 1873-6750 

221 

S909-S915 

English 

#The aim of this study was to estimate in rats the potential carcinogenic or co-carcinogenic risk of ozone, acting either alone as acomplete carcinogen, or as a promoter after pulmonary irradiation by inhalation of radon and its decay products. Three experimental groups were used: Group 1 was exposed to radon and daughters at a cumulative exposure of 3.6 J h m-3 (1000 WLM); Group 2 was exposed first to radon in the same conditions as Group 1, and one month after the end of radon exposure, to ozone by inhalation at a concentration of 0.2 mu-L L-1 , 6 hd-1, 5 d/week for 6 months; Group 3 was exposed to ozone alone in the same conditions as Group 2. The incidence of lung cancer was 16% in Group1, 24% in Group 2, and 4% in Group 3, compared with 0.8% in controls. Lung carcinomas induced by ozone alone showed a trend toward a preferential differentiation pattern to the squamous cell type. These results show a direct carcinogenic effect of ozone in rats for levels of exposure in the same range as those observed during peak levels of urban airborne pollution and suggest a potential co-carcinogenic effect of combined exposure to radon and ozone. 

ADULT-RATS; LUNG; INHALATION; JUVENILE 

6th International Symposium on The Natural Radiation Environment (NRE-VI) 

JUN 05-09, 1995