Abstract of Meeting Paper

Society for Risk Analysis - Europe 1998 Annual Meeting

Evaluation of the Risks Incurred by the Public Residing in the Proximity of an Area Contaminated With Radium 226 - Saint Nicolas D’aliermont. P. Verger, Institut de Protection et de Sûreté Nucléaire, Département de Protection de la santé de l'Homme et de Dosimétrie, Service d'Evaluation et de Gestion des Risques, B.P.6, F-92265 Fontenay-aux-Roses Cedex, France, telephone 0146.54.96.19, fax 01.46.57.03.86, e-mail: pierre.verger@ipsn.fr; A. Deloraine, Centre Rhône-Alpes d’Epidemiologie et de Prévention Sanitaire, Grenoble; and F. Mansotte, Direction Départementale des Affaires Sanitaires et Sociales, Seine Maritime

Radium 226 is an alpha emitter which concentrates in bone after incorporation. Its main decay products are radon 222, a radioactive gaz, and polonium 210 and lead 210. Paint containing radium 226 was used in the dial industry during the first half century. Excess risks of bone sarcomas and head carcinomas occurring many years later were demonstrated in female radium dial workers. During the sixties or seventies, radium was replaced by tritium, less dangerous.

In 1992, the Social and Sanitary Services of the "département" Seine Maritime requested and supported an evaluation of the risks incurred by the public residing in the vicinity of an ancient dial factory, at Saint-Nicolas d’Aliermont. This request followed the detection of elevated levels of radioactivity measured on the factory site and on a building-site close to it.

The dial factory had ceased its activities in 1989 and used paint containing radium 226 from 1945 to 1970. It was located on two different sites, some fields of which were sold in 1981 and 1988 to build dwellings. In 1992, approximately 160 persons including 70 children lived in these dwellings. Interviewing several inhabitants and former workers revealed that children used to play on one of the site where radioactive wastes (contaminated paint, dials...) had been buried. Various environmental measures carried out in 1993 and 1994 showed several hot spots splitted on both sites of the factory and also in several dwellings’ gardens close to the factory. Dose rates reaching 50 to 100 times the natural background and significant concentrations of radium 226 in several samples of earth or green vegetables were measured.

Due to the limited number of measurements and to the lack of individual retrospective information on exposure of the residents, two exposure scenarios were distinguished: a pessimistic one taking into account the highest measures of radioactivity and a mild one. The evaluation was carried out for an adult and a 5 years old child, taking into account the various possible exposure pathways (external irradiation, ingestion of contaminated food and earth, dust inhalation). Information on the way of life was sought from the scientific literature when possible (e.g. food consumption, earth ingestion...) but hypotheses had also to be done for example to quantify the time spent outdoors or the degree of self-sufficiency.

Results of the quantification are presented for all cancers and specific organs (lung, bone and bone marrow), compared to spontaneous rates and discussed in the light of the various hypotheses done for the quantification. The pertinence of an epidemiological follow-up of the residents is discussed. This evaluation also highlights the need for updated information on the ways of life of the French population to allow proper risk assessment for various environmental radiological or chemical pollutants.