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Biomedical subjects

S Risica

Publications and source records attributed to S Risica.

14 recordsLinked to original sources
PubMed2001

Radioactivity in building materials: room model analysis and experimental methods.

First, models (room models) published in the international literature allowing the exposure to gamma radiation indoors due to building materials to be assessed are reviewed and discussed. For one of them, a sensitivity analysis concerning the effect of changing the parameters (e.g. dimensions of the room, thickness and density of the walls, etc.) used in calculations is performed. Second, a method is proposed for calculating the activity concentration in the walls of a room using: (a) the measured absorbed dose rate in air in the room; (b) the contributions of natural radionuclides (238U, 232Th and 40K) to the absorbed dose rate in air assessed by means of gamma spectrometry indoors; and (c) the specific dose rate (nGy h(-1) per Bq kg(-1)) of natural radionuclides, for the chosen room geometry, calculated with the room model.

Air Pollution, Indoor↗
PubMed2001

Experimental and measurement issues in natural radioactivity.

The paper deals with some open experimental problems in the field of natural radioactivity. Its aim is to stimulate discussion on the type of research efforts needed in the field and to be planned for the future. The review, which makes no claims to completeness. analyses some issues in gamma spectrometry of natural radionuclides, and the measurement of natural radioactivity in non-nuclear industries and of 222Rn and 220Rn concentration in air.

Background Radiation↗
PubMed1999

Prenatal exposure to ionizing radiation: sources, effects and regulatory aspects.

Knowledge and awareness of physicians and the general public concerning the risks of prenatal exposure to ionizing radiation are important when developing a correct attitude to ionizing radiation. This is particularly important in the justification of medical diagnostic exposure of pregnant women and in case of possible accidents. The present paper reviews the most recent data on the effects of prenatal exposure to ionizing radiation reported in the scientific literature and in documents of international organizations dealing with this subject. Potentially significant exposure for women of childbearing age in medical diagnostics, working conditions and environmental contamination following the Chernobyl accident are reported. Some examples of doses associated with medical exposure in the course of diagnostic examinations with X-rays and radiopharmaceuticals, and occupational exposure in workplaces are given. Lastly, the regulatory aspects of the European Union directives and the Italian legislation on medical and occupational exposure of women during pregnancy or in reproductive age are reviewed.

Dose-Response Relationship, Radiation↗
PubMed1997

[The Chernobyl incident: emergency management in Italy and other European countries].

Several measures were adopted by European countries in the aftermath of the Chernobyl accident. In this paper these measures are reviewed and the European Communities initiatives for food marketing and exports are analyzed, together with the reference levels for radioactive concentration in the main food matrices chosen in different European countries in the very few days after the accident. A particular attention has been devoted to the emergency management in Italy, outlining exhaustively the laws enforced at the time of the accident and explaining how the reference levels for food contamination were chosen. Finally, a tentative balance about emergency management in Italy is struck and some questions are raised about the commitments undertaken or to be undertaken by international institutions.

Animals↗
PubMed1996

Results of the representative Italian national survey on radon indoors.

A representative national survey on population exposure to radon in Italian dwellings was carried out from 1989 to 1994, with the co-operation of the National Health Service. The measurements were performed by 19 Regional Laboratories, all using the same techniques and protocols. A stratified, two-stage sampling procedure was used to sample families. The sampled families were approached door-to-door to maximize response. To optimize the quality of the measurements, two dosimeters, each containing two alpha track detectors, were placed together in one room (typically the bedroom) for two consecutive 6-mo periods. The distribution of annual radon concentration was derived from measurements in 4,866 dwellings. The average value is 75 Bq m(-3) and the fractions of dwellings above the reference levels of 150, 200, 400, and 600 Bq m-3 are 8.7%, 4.7%, 1.0%, and 0.2%, respectively. The geometric mean is 57 Bq m-3 while the geometric standard deviation is 2.0. The average values in the Italian Regions fall within the 20-120 Bq m-3 range. When the average radon concentration is examined vs. story, building materials seem to play a significant role. The average lifetime risk of lung cancer for chronic radon exposure of Italian population at home would be about 5 x 10(-3), using the risk factor proposed by the ICRP in 1993.

Air Pollutants, Radioactive↗
PubMed1992

Caesium contamination in human milk and transfer factor from diet.

A study on caesium contamination in human milk, as a consequence of the Chernobyl fallout, was conducted in 1989 on a group of women from one of the areas of northern Italy most heavily affected by the radioactive fallout. Their diet was studied, and the caesium intake was calculated by using the mean food activity concentration in that area. The caesium transfer factor was evaluated both as the ratio of caesium concentration in mother's milk to the daily intake, and by using a simplified milk compartment model.

Accidents↗
PubMed1990

Radioactivity in human milk.

A brief introduction outlines the sources of radionuclides in the environment, their diffusion and transfer to different environmental compartments and their pathways to individuals; definitions of the main quantities and measurement units used in the study are included. A review is given on published data concerning the radioactive contamination of human milk after the Chernobyl accident. The authors' investigation on breast milk contamination in Italy in the same period is discussed together with an examination of the natural radioactive content. Finally, possible future developments and prospects of the research on this issue are explored.

Accidents↗
PubMed1985

Radioactivity connected with coal burning.

The enhanced environmental radioactivity resulting from the operation of a 72 MWe brown coal-fired power plant in central Italy is considered. A source-related control procedure is suggested. The calculated values for the atmospheric dispersion of radioactive effluents and the results of some measurements on brown coals, ash, environmental samples and gamma-exposure levels performed at representative points are reported.

Coal↗
PubMed1985

Radon and radon daughter evaluation in a natural radioactivity survey indoors.

An indoor survey in order to estimate the population exposure in five towns of an Italian Region is presented. A particular methodology for the campaign was planned and is being applied. Gamma spectrometry of building materials, exposure rate measurements indoors and outdoors and radon concentration measurements indoors were taken with different techniques. A correlation was found between mean gamma exposure rate and mean radon concentration in the houses investigated. An evaluation of mean effective dose equivalents for the inhabitants of the five towns is reported.

Construction Materials↗
PubMedDate not supplied

A preliminary intercomparison of gamma-ray spectrometry on building materials.

A preliminary intercomparison on gamma-ray spectrometry determination of natural radionuclides in building materials was carried out in 1999-2002. Samples measured were fly ash, sand and tuff. Laboratories used different experimental equipment and procedures. Corrections for blank, spectral interference, self-absorption and coincidence summing effects were applied in most cases. The agreement between results was within 15-20%, most often within the reported uncertainties. Several general conclusions can be drawn regarding procedures correctness, uncertainty budget, secular equilibrium condition, and radionuclide representativeness in each natural series. Further studies are needed to draw more specific conclusions.

Construction Materials↗