P.L. Fernández

Natural gamma radiation map (MARNA) and indoor radon levels in Spain

During the last decade, the Department of Applied and Medical Physics has been involved in the development of a radiation protection programme. In the framework of this programme, measurements of indoor radon, principally, have been carried out nationwide. Geometric mean radon concentrations of 45 Bq m(-3) in the whole country and 130 Bq m(-3) in the high natural radiation area have been estimated. On the other hand, the so-called MARNA Project is developed into the framework of an agreement subscribed between the Spanish Nuclear Safety Council (CSN) and the National Uranium (ENUSA), the first phase of which has been the elaboration of the Natural Gamma Radiation Map of Spain on the scale of 1:1,000,000 using radiometric data generated in the 30 years of the lifetime of the ancient National Uranium Exploration and Investigation Plan mainly through airborne, carborne, and by foot surveys, within the MARNA Project itself. The lowest averaged dose rate from external gamma radiation (19.3 nGyh(-1)) was found in carbonate bedrock and the highest (87.7 nGyh(-1)) was found in granite and clay bedrock. This paper summarizes the main results obtained from the measurements performed in both projects, with special interest in those concerning the correlation between the data reported in order to conclude about the potential benefit of the MARNA maps in the definition of affected areas in the country.

Conversion factors for external gamma dose derived from natural radionuclides in soils

Field in situ gamma radiation exposure rates and laboratory measured radioactivity contents of 1500 Spanish soils were compared. The main objective was to determine if published theoretically derived conversion factors would yield accurate quantitative activity concentration (Bq kg(-1)) for the data carried out in different surveys developed by our laboratory during the last ten years. The in situ external gamma dose rate results were compared to laboratory gamma analysis of soils samples gathered from each site, considering the concentrations of seven radionuclides: 40K, 214Pb, 214Bi, 212Bi, 212Pb, 208Tl and 228Ac. The coefficient of correlation found between these variables indicate a good relationship. A discussion of the factors contributing to the uncertainties as well as measurement procedure are also given in this paper.

National survey on indoor radon in Spain

A national survey on indoor radon levels in Spain has been carried out by measuring the radon concentration in 1555 randomly chosen houses. Measurements were performed during the winter season of 1988 with complementary measurements in the winter of 1989. Radon in air was determined using modified alpha-scintillation cells under specified conditions in the sampling collection and nuclear track detectors in selected houses. The distribution of indoor radon levels has been found to be approximately log-normal with a geometric mean of 41.1 Bq·m−3 and a standard deviation of 3.0. The highest value of the radon concentration found was 15 400 Bq·m−3 In about 4% of the houses, the radon concentration was found to be in excess of the recently recommended value of 400 Bq·m−3, suggested by the Commission of the European Communities (CEC). Elevated indoor levels were found to be more prevalent in the west and northwest than in the rest of the country. Also shown in this paper is an evaluation of the median effective dose equivalent to the individual in Spanish houses for different regions.

Indoor radon in a Spanish region with different gamma exposure levels.

In the beginning of 1990s within the framework of a national radon survey of more than 1500 points, radon measurements were performed in more than 100 houses located in Galicia region, in the Northwest area of Spain. The houses were randomly selected only bearing in mind general geological aspects of the region. Subsequently, a nationwide project called MARNA dealt with external gamma radiation measurements in order to draw a Spanish natural radiation map. The comparison in Galicia between these estimations and the indoor radon levels previously obtained showed good agreement. With the purpose of getting a confirmation of this relationship and also of creating a radon map of the zone, a new set of measurements were carried out in 2005. A total of 300 external gamma radiation measurements were carried out as well as 300 measurements of 226Ra, 232Th and 40K content in soil. Concerning radon, 300 1-m-depth radon measurements in soil were performed, and indoor radon concentration was determined in a total of 600 dwellings. Radon content in soil gave more accurate indoor radon predictions than external gamma radiation or 226Ra concentration in soil.

7Be concentrations in air, rain water and soil in Cantabria (Spain)

Abstract 7Be concentrations present in air, rain water and soil have been measured in the region of Cantabria (Spain) during the last 4 yr. There was a relationship between rainfall and the deposited areal activity of the nuclide at the study site which was consistent with observed annual global rainfall and fallout.

Study of areas of spain with high indoor radon

Abstract Data for natural radiation from a national survey were used to identify areas in Spain with a high level of natural background radiation. Specific measurements were made in these areas to evaluate indoor radon levels as well as the main sources of this natural gas in houses. Values of indoor radon as high as 800 Bq m −3 were measured and 39% of the houses showed levels over 150 Bq m −3 . For this area, exhalation rates from soil range from 40 Bq m −2 h −1 to 900 Bq m −2 h −2 . Normal values, lower than 10 Bq 1 −1 , for radon dissolved in water were also measured. The results are examined and compared with the values obtained in houses located in other areas of Spain.

Evaluation of uncertainty and detection limits in 210Pb and 210Po measurement in water by alpha spectrometry using 210Po spontaneous deposition onto a silver disk

An easy and accurate method for the determination of (210)Pb and (210)Po in water using (210)Po spontaneous deposition onto a silver disk is proposed and assessed for its detection capabilities according to the ISO Guide for the expression of uncertainty in measurement (GUM) and ISO Standard 11929-7 concerning the evaluation of the characteristic limits for ionizing radiation measurements. The method makes no assumption on the initial values of the activity concentrations of (210)Pb, (210)Bi and (210)Po in the sample to be analyzed, and is based on the alpha spectrometric measurement of (210)Po in two different aliquots: the first one measured five weeks after the sampling date to ensure radioactive equilibrium between (210)Pb and (210)Bi and the second after a sufficient time for the ingrowth of (210)Po from (210)Pb to be significant. As shown, for a recommended time interval of seven months between (210)Po measurements, the applicability of the proposed method is limited to water samples with a (226)Ra to (210)Pb activity ratio C(Ra)/C(Pb) ≤ 4, as usual in natural waters. Using sample and background counting times of 24h and 240 h, respectively, the detection limit of the activity concentration of each radionuclide at the sampling time for a 1L sample typically varies between 0.7 and 16 mBq L(-1) for (210)Pb in water samples with an initial activity of (210)Po in the range 0-200 mBq L(-1), and between 0.6 and 8.5 mBq L(-1) for (210)Po in water samples with an initial activity of (210)Pb in the same range.

Comments on the 2016 ESC Guidelines for the Diagnosis and Treatment of Acute and Chronic Heart Failure

In accordance with the policy on clinical practice guidelines established by the Executive Committee of the Spanish Society of Cardiology, the current article discusses the most notable and novel aspects of the European Society of Cardiology (ESC) guidelines for the diagnosis and treatment of acute and chronic heart failure (HF). The aim of the guidelines is to update our knowledge of the diagnosis and treatment of HF based on the best clinical evidence available.

A Study of the Impact of Industrial Fluoride Emissions on a Rural Environment

In this note we study current fluoride levels in the area of Onton, Cantabria (Spain), in the vicinity of a factory whose main industrial activity is the production of fluoride compounds. When the factory opened in the early 1970s, it was the source of a serious pollution problem; an increasing number of cases of fluorosis in cattle on farms near the factor were detected in addition to extensive damage to vegetation. Although the company implemented an antipollution plan to minimize fluoride emission levels in 1975, this problem has not yet been solved. The factory is situated by the sea on the north coast of Spain in a mountainous area. Two valleys stretch south and southeast of the factory in the direction of the prevailing winds. The climate is mild and wet. Since stock-raising is the dominant activity in the region, the area is mostly devoted to pasture. The study, which was done in 1986, measured fluoride concentrations in air, surface water, and pastures, and in milk and urine samples from cattle.

Natural radioactivity of some Spanish building materials

The penetrating radiation from 226Ra, 232Th and 40K in conventional building materials has been measured by gamma spectrometry. A simple model is applied to the results to calculate the external radiation dose for people living in a typical Spanish house constructed with these materials. The radioactivity concentrations in the building materials were found to be similar to those reported for other countries. The average specific concentrations of 226Ra, 232Th and 40K for the total of 125 samples analyzed ranged from 5 to 421, 3 to 266 and 11 to 599 Bq kg-1, respectively. The results are examined in the light of standards for indoor exposure adopted by the Federal Republic of Germany and the criteria set up in the OECD/NEA Report, 1979.