Radiological protection is a matter of concern for members of the public and thus national authorities are more likely to trust the quality of radioactivity data provided by accredited laboratories using common standards. Normative approach based on international standards aims to ensure the accuracy or validity of the test result through calibrations and measurements traceable to the International System of Units. This approach guarantees that radioactivity test results on the same types of samples are comparable over time and space as well as between different testing laboratories. Today, testing laboratories involved in radioactivity measurement have a set of more than 150 international standards to help them perform their work. Most of them are published by the International Standardization Organization (ISO) and the International Electrotechnical Commission (IEC). This paper reviews the most essential ISO standards that give guidance to testing laboratories at different stages from sampling planning to the transmission of the test report to their customers, summarizes recent activities and achievements and present the perspectives on new standards under development by the ISO Working Groups dealing with radioactivity measurement in connection with radiological protection.

A new shellfish Standard Reference Material 4358 was developed by the National Institute of Standards and Technology through an international interlaboratory comparison that involved twelve laboratories-participants from nine countries. The results from the participants were statistically evaluated, and the most robust certified values were based on the median of laboratories’ reported means and the uncertainties derived using the bootstrap method. Massic activity certified values were established for fourteen radionuclides, five activity ratios, and informational massic activity values for eight more radionuclides and two activity ratios.

Water is vital to humans and each of us needs at least 1.5 L of safe water a day to drink. Beginning as long ago as 1958 the World Health Organization (WHO) has published guidelines to help ensure water is safe to drink. Focused from the start on monitoring radionuclides in water, and continually cooperating with WHO, the International Standardization Organization (ISO) has been publishing standards on radioactivity test methods since 1978. As reliable, comparable and 'fit for purpose' results are an essential requirement for any public health decision based on radioactivity measurements, international standards of tested and validated radionuclide test methods are an important tool for production of such measurements. This paper presents the ISO standards already published that could be used as normative references by testing laboratories in charge of radioactivity monitoring of drinking water as well as those currently under drafting and the prospect of standardized fast test methods in response to a nuclear accident.

Radon is considered to be the main source of human exposure to natural radiation. As stated by the World Health Organization, the exposure due to the inhalation of indoor radon is much greater than the one via the ingestion of water as radon degasses from water during handling. In response to these concerns about the universal presence of radon, environmental assessment studies are regularly commissioned to assess the radon exposure of public and workers. The credibility of such studies relies on the quality and reliability of radon analysis as well as on the sample representativeness of the radiological situation. The standard-setting approach, based on consensus, seemed to lend itself to a settlement of technical aspects of potential comparison. At present, two Working Groups of the International Standardization Organization are focussing on drafting standards on radon and its decay products measurement in air and water. These standards, which aim for a set of rigorous metrology practices, will be useful for persons in charge of the initial characterisation of a site with respect to natural radioactivity as well as to those performing the routine surveillance of specific sites.

Monitoring of French Polynesia coral reefs and their recent development.-French Polynesia, consisting of 118 islands in the centre of the Pacific Ocean, has more than 15 000 km(2) of reefs and lagoons managed by the local government. Tourism and pearl culture are the two main economic resources of the country. Polynesian coral reefs are extremely diverse and are among those for which we have thorough knowledge. The exploitation of local resources has been recorded for multiple decades and includes : coral materials, fishing, harvest and export of mother-of-pearl molluscs, pearl production, and ornamental fish. All over the country, many monitoring programmes have been launched to measure the health of reefs and the natural and anthropogenic perturbations that they suffer : hurricanes and seismic events, water quality, health of benthic and fish communities, pearl oyster pathology and radiobiology. These data, collected over the last few decades, allowed to define the relative importance of natural and anthropogenic degradation on reefs and lagoons, and to explain the present status of reefs at different spatial scales. Devastating hurricanes are rare (1903-1906, 1982-1983 and occasionally at other times), but they may annihilate outer slope coral communities on some islands. Bleaching events with considerable coral mortality at different geographical scales occurred mainly in 1991, 1994 and 2003. Outbreaks of Acanthaster destroyed numerous reefs (lagoons and outer slopes) from 1978-1982 and a new demographic wave began in 2006 at many Society islands. Eutrophication events only occurred occasionally and only in some lagoons. Whereas natural catastrophic events degrade the coral reef ecosystem across many islands, at the archipelago or even regional scale, anthropogenic degradation is limited to a few Society Islands, occurring rarely on atolls and not at all on those (one third) which are uninhabited. The main causes of reef degradation in some areas of Tahiti and Moorea include the embankment of fringing zones, coral mining, overfishing, absence of urban sewage treatment and the development of leisure and tourism activities. Because of its large geographical extent, one may conclude that major reef degradation in French Polynesia is caused by catastrophic natural events. On the other hand, anthropogenic degradation is more localized. Unfortunately, the synergistic effects of these causes of degradation prevent reefs from recovering. Optimum coral cover on French Polynesian outer reef slopes is between 50-60%. After a major destructive impact (hurricane, bleaching, Acanthaster) a reef is reduced to less than 10% coral cover, however if no more major disturbance events occur a reef will recover in about 12 years. Most of the 15 000 km(2) of reefs and lagoons in French Polynesia are in good health, and along with their neighbouring reefs in East and Central Pacific they are considered as the least degraded reefs worldwide and at a low risk of becoming degraded in the few next decades. However, we are more and more anxious about the future of reefs in the world particularly because present simulations predict that major impacts of climate change would include : elevation of sea surface temperatures, increase in the strength of hurricanes and acidification of seawater which will affect the formation of coral structures.

Monitoring of French Polynesia coral reefs and their recent development. — French Polynesia, consisting of 118 islands in the centre of the Pacific Ocean, has more than 15 000 km2 of reefs and lagoons managed by the local government. Tourism and pearl culture are the two main economic resources of the country. Polynesian coral reefs are extremely diverse and are among those for which we have thorough knowledge. The exploitation of local resources has been recorded for multiple decades and includes : coral materials, fishing, harvest and export of mother-of-pearl molluscs, pearl production, and ornamental fish. All over the country, many monitoring programmes have been launched to measure the health of reefs and the natural and anthropogenic perturbations that they suffer : hurricanes and seismic events, water quality, health of benthic and fish communities, pearl oyster pathology and radiobiology. These data, collected over the last few decades, allowed to define the relative importance of natural and anthropogenic degradation on reefs and lagoons, and to explain the present status of reefs at different spatial scales. Devastating hurricanes are rare (1903-1906, 1982-1983 and occasionally at other times), but they may annihilate outer slope coral communities on some islands. Bleaching events with considerable coral mortality at different geographical scales occurred mainly in 1991, 1994 and 2003. Outbreaks of Acanthaster destroyed numerous reefs (lagoons and outer slopes) from 1978-1982 and a new demographic wave began in 2006 at many Society islands. Eutrophication events only occurred occasionally and only in some lagoons. Whereas natural catastrophic events degrade the coral reef ecosystem across many islands, at the archipelago or even regional scale, anthropogenic degradation is limited to a few Society Islands, occurring rarely on atolls and not at all on those (one third) which are uninhabited. The main causes of reef degradation in some areas of Tahiti and Moorea include the embankment of fringing zones, coral mining, overfi shing, absence of urban sewage treatment and the development of leisure and tourism activities. Because of its large geographical extent, one may conclude that major reef degradation in French Polynesia is caused by catastrophic natural events. On the other hand, anthropogenic degradation is more localized. Unfortunately, the synergistic effects of these causes of degradation prevent reefs from recovering. Optimum coral cover on French Polynesian outer reef slopes is between 50-60 %. After a major destructive impact (hurricane, bleaching, Acanthaster) a reef is reduced to less than 10 % coral cover, however if no more major disturbance events occur a reef will recover in about 12 years. Most of the 15 000 km2 of reefs and lagoons in French Polynesia are in good health, and along with their neighbouring reefs in East and Central Pacifi c they are considered as the least degraded reefs worldwide and at a low risk of becoming degraded in the few next decades. However, we are more and more anxious about the future of reefs in the world particularly because present simulations predict that major impacts of climate change would include : elevation of sea surface temperatures, increase in the strength of hurricanes and acidification of seawater which will affect the formation of coral structures.

Different approaches are found in the literature to compute the characteristics limits used to decide whether an activity measurement result for a radionuclide is significantly above the background level for the analyte in the sample. Comparing the different working expressions of the characteristic limits (critical level and detection limit) that can be used by any measurement laboratory; this paper shows that they are similar under the routine conditions of a majority of radioactivity measurement laboratories.

Environmental assessment studies are regularly commissioned to study the impact of radioactive substances on the environment and the public, in response to concern about the presence of such substances. The credibility of such studies relies on the quality and reliability of radionuclide analysis as well as the sample representativity of the radiological situation. The recent expansion from national stakeholders to those involving other states requires that activity measured in effluents or environmental samples in a country are reliable and reproducible so as to be accepted by all states potentially concerned by regional contamination. The standard-setting approach, based on consensus, seemed to lend itself to a settlement of technical aspects of potential dispute. This document describes standardization organizations, French and international, the standards published, as well as standardization work under way on the measurement of radionuclides found in environmental matrices.

129I, the only natural radioactive isotope of iodine (T1/2=15.7×106a), has been artificially produced since the end of the forties by the different nuclear, civil as well as military, activities leading to an increase of the background levels especially in the Northern hemisphere. In the marine environment, seaweed is known to accumulate iodine isotopes at high concentration levels. 16 seaweed species were collected at Goury (France), under the direct influence of discharges of authorised low-level radioactive liquid effluents of La Hague nuclear fuel reprocessing plant, in October 1998 and March 1999. 129I/127I ratios, computed with stable iodine concentration and 129I activities measured on each sample, are significantly higher than the background levels. The heterogeneity of 129I levels with seaweed species is studied as well as temporal variations that are related to the data of the 129I liquid effluents released by the La Hague NRP. Concentration factors, estimated for all seaweed, agree with the recommended values and the 129I activity in seawater was evaluated and shows a variation factor of 1.7 between the two sampling periods.

In recent years, particular attention was paid to the long-lived radionuclides discharged with authorized low-level radioactive liquid and gaseous effluents by the nuclear spent fuel reprocessing plants of La Hague and Sellafield. The knowledge of (129)I (half-life=15.7 x 10(6) a) distribution in the environment is required to assess the radiological impact to the environment and population living in the area under the direct influence of La Hague NRP discharges. Measurement difficulties of (129)I in environmental matrices, where it is usually present at trace level, limited data published on (129)I activity levels in the European and more particularly in the French territory. Studies conducted to qualify a new alternative measurement method, direct gamma-X spectrometry with experimental self-absorption correction, led to test samples collected in the La Hague marine and terrestrial environment : seaweeds, lichens, grass, bovine thyroids, etc. All these results, often already published separately for analytical purposes and treated for intercomparison exercises, are presented here together in a radioecological manner. The levels of (129)I activity and (129)I/(127)I ratios in these samples show the spatial and temporal influence of the La Hague NRP in its local near-field environment as well as at the regional scale along the French Channel coast.

i2, I, is a natural long-lived isotope, with a half-life of 15.7 million years, also artificially produced in nuclear power plan! and released in liquid and gaseous effluents of nuclear fuel reprocessing plants. Due to the lack of environmental international reference material for 129 I, interlaboratory comparison exercises are very rare and validation of new measurement techniques is very difficult to achieve. This study presents three intercomparison exercises on the 129 I and 129ynil measurements using three different techniques : Radiochemical Neutron Activation Analysis, Accelerator Mass Spectrometry and direct y-X spectrometry associated with Ionic Chromatography. The first intercomparison was performed on a Fucus mmtiis sample, leading to propose it as a reference material. The others intercomparison exercises were performed on samples of different biological matrices, marine and terrestrial, presenting various 129 I activity levels. The different intercomparison exercises results showed a good agreement between the three, techniques on the considered environmental matrices, for samples with 129 I activity comprised between 0.2 and 200 Bq.kg"1 dry weight.

Quelles sont les valeurs qui caractérisent sur le territoire français les rayonnements ionisants et les radionucléides d'origine naturelle ? Comment distinguer dans le résultat d'une mesure la part qui résulte éventuellement d'une activité humaine ? Afin d'essayer de répondre à ces questions, un questionnaire a été adressé aux différents organismes qui effectuent en France des mesures de radioactivité dans l'environnement. Les informations mentionnées dans cette étude se rapportent exclusivement à des observations faites dans l'environnement à l'extérieur des bâtiments et du périmètre des installations nucléaires de base (INB). En outre, elles ne concernent, sauf cas particuliers signalés, que des mesures de rayonnements ou de radioéléments d'origine naturelle dont les résultats n'ont pas été perturbés par l'action de l'homme. L'enquête montre la difficulté actuelle de dresser en France un bilan exhaustif des connaissances acquises concernant les caractéristiques du bruit de fond radioactif d'origine naturelle dans l'environnement. Aujourd'hui en France, dans le domaine de la radioactivité naturelle, les efforts consentis manquent de coordination et d'orientation vers certaines priorités. À ce titre, les mesures des 238U et 232Th précurseurs des 226Ra et 228Ra, des descendants solides émetteurs alpha du radon (par la mesure des EAP du 222Rn et 220Rn), des émetteurs gamma post émanation (214Pb, 214Bi, 212Pb), du 210Pb, 210Po et du 14C doivent être privilégiées.

129I, is a natural long-lived isotope, with a half-life of 15.7 million years, also artificially produced in nuclear power plant and released in liquid and gaseous effluents of nuclear fuel reprocessing plants. Due to the lack of environmental international reference material for 129I, interlaboratory comparison exercises are very rare and validation of new measurement techniques is very difficult to achieve. This study presents three intercomparison exercises on the 129I and 129I/127I measurements using three different techniques: Radiochemical Neutron Activation Analysis, Accelerator Mass Spectrometry and direct γ-X spectrometry associated with Ionic Chromatography. The first intercomparison was performed on a Fucus serratus sample, leading to propose it as a reference material. The others intercomparison exercises were performed on samples of different biological matrices, marine and terrestrial, presenting various 129I activity levels. The different intercomparison exercises results showed a good agreement between the three techniques on the considered environmental matrices, for samples with 129I activity comprised between 0.2 and 200 Bq.kg-1 dry weight.

Les préoccupations concernant la présence de substances radioactives dans l'environnement conduisent régulièrement à des expertises sur les niveaux d'activité des radionucléides dans l'environnement et à des évaluations de leurs impacts radiologiques sur les populations humaines. La crédibilité de ces expertises repose en partie sur la qualité et la fiabilité des mesurages. Ce document présente les systèmes d'organisations de la normalisation, nationale et internationale, ainsi que les documents normatifs publiés et les travaux de normalisation en cours relatifs à la métrologie des radionucléides présents dans les matrices environnementales.

Iodine-129 is routinely released in the gaseous and liquid low-level radioactive effluents of nuclear spent fuel reprocessing plants. Environmental impact assessment of these discharges are performed based on monitoring samples of different types of natural indicators. Thyroid is considered as a relevant organ to monitor radioactive iodine isotopes. In this study, bovine thyroids were collected in herds located in the Cotentin area under the influence of authorized low level gaseous effluents of the La Hague nuclear fuel-reprocessing plant. For low level 129I/127I ratios, characteristic of environmental samples (10(-12) to 10(-7)), RNAA or SMA that includes important radiochemical preparation steps are used. This paper demonstrates the interest of direct gamma-X spectrometry to measure 129I activities, associated to INAA to measure 127I to attain higher ratios levels (10(-6) to 10(-4)). This study shows the interest of monitoring bovine thyroids considered as sentinel organs to characterize the dispersion in space and time of 129I discharged in low level radioactive gaseous effluents by the La Hague reprocessing plant.

An evaluation of the dosimetric impact of discharge of low level radioactive effluents authorized to be released from the La Hague Cogema spent nuclear fuel reprocessing plant located in North Cotentin (France) led to an assessment of chlorine-36 (36Cl) dose contribution to local populations [1]. Though not usually systematically included in such assessments, Cl is produced in nuclear reactors by activation of Cl contained in nuclear fuel. It was measured in lichens sampled in the areas surrounding the Chernobyl NPP, at activity levels from 1 to 100 mBq.kg dry [2.]. It may therefore be liberated when processing nuclear fuel and released with the radioactive effluents. It was measured in radioactive effluent injected into the ground of a US reprocessing site in Idaho [3]. Cl found at natural levels in the environment is continuously produced by a series of natural nuclear reactions occurring in the atmosphere and the earth crust. It was likewise released and scattered at the global level during the explosion of nuclear devices in the atmosphere and particularly those done underwater in the ocean.