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Bromma, Sweden

Sohlenius G.,Geological Survey of Sweden | Saetre P.,Swedish Nuclear Fuel and Waste Management Company | Norden S.,Swedish Nuclear Fuel and Waste Management Company | Grolander S.,Facilia AB | Sheppard S.,ECOMatters Inc
Ambio | Year: 2013

To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (regolith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (K d values) for most elements varied significantly among regolith types. For most elements, the observed variations in K d values could be explained by variations in soil properties. For many elements, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionuclide retention in soils, taking account of soil properties and processes. © 2013 The Author(s). Source

Ciffroy P.,Electricite de France | Tanaka T.,Catholic University of the Sacred Heart | Johansson E.,Facilia AB | Brochot C.,INERIS
Environmental Geochemistry and Health | Year: 2011

In the present study, we demonstrate an integrated modeling approach for predicting internal tissue concentrations of chemicals by coupling a multimedia environmental model and a generic physiologically based pharmacokinetic (PBPK) model. A case study was designed for a region situated on the Seine river watershed, downstream of the Paris megacity, and for benzo(a)pyrene emitted from industrial zones in the region. In this case study, these two models are linked only by water intake from riverine system for the multimedia model into human body for the PBPK model. The limited monitoring data sets of B(a)P concentrations in bottom sediment and in raw river water, obtained at the downstream of Paris, were used to re-construct long-term daily concentrations of B(a)P in river water. The re-construction of long-term series of B(a)P level played a key role for the intermediate model calibration (conducted in multimedia model) and thus for improving model input to PBPK model. In order to take into account the parametric uncertainty in the model inputs, some input parameters relevant for the multimedia model were given by probability density functions (PDFs); some generic PDFs were updated with site-specific measurements by a Bayesian approach. The results of this study showed that the multimedia model fits well with actual annual measurements in sediments over one decade. No accumulation of B(a)P in the organs was observed. In conclusion, this case study demonstrated the feasibility of a full-chain assessment combining multimedia environmental predictions and PBPK modeling, including uncertainty and sensitivity analyses. © 2011 Springer Science+Business Media B.V. Source

Saetre P.,Swedish Nuclear Fuel and Waste Management Company | Valentin J.,Oregrundsgatan 15 | Lageras P.,Swedish National Heritage Board RAA | Avila R.,Facilia AB | Kautsky U.,Swedish Nuclear Fuel and Waste Management Company
Ambio | Year: 2013

The radiation doses to humans resulting from a potential release of radionuclides from a geological repository for long-lived waste are assessed over tens or even hundreds of thousands of years. Ingestion is expected to be the major exposure pathway, and the group with the highest exposures will be those that consume the most contaminated food. In this paper, we characterize the group of individuals with the highest exposures by considering the physical and biological characteristics of the contaminated area and human requirements for energy and nutrients. We then calculate intake rates based on land-use scenarios drawn from self-sustained communities spanning prehistoric times to an industrial-age agrarian culture. The approach is illustrated by simulating groundwater release of four radionuclides to an expected discharge area. We argue that the derived intake rates may serve as credible bounding cases when projected doses are evaluated for compliance with regulatory criteria. © 2013 The Author(s). Source

Van Holderbeke M.,Flemish Institute for Technological Research | Fierens T.,Flemish Institute for Technological Research | Standaert A.,Flemish Institute for Technological Research | Cornelis C.,Flemish Institute for Technological Research | And 4 more authors.
Science of the Total Environment | Year: 2016

In this study, we report on model simulations performed using the newly developed exposure tool, MERLIN-Expo, in order to assess inorganic arsenic (iAs) exposure to adults resulting from past emissions by non-ferrous smelters in Belgium (Northern Campine area). Exposure scenarios were constructed to estimate external iAs exposure as well as the toxicologically relevant As (tAs, i.e., iAs, MMA and DMA) body burden in adults living in the vicinity of the former industrial sites as compared to adults living in adjacent areas and a reference area.Two scenarios are discussed: a first scenario studying exposure to iAs at the aggregated population level and a second scenario studying exposure at the individual level for a random sub-sample of subjects in each of the three different study areas. These two scenarios only differ in the type of human related input data (i.e., time-activity data, ingestion rates and consumption patterns) that were used, namely averages (incl. probability density functions, PDFs) in the simulation at population level and subject-specific values in the simulation at individual level.The model predictions are shown to be lower than the corresponding biomonitoring data from the monitoring campaign. Urinary tAs levels in adults, irrespective of the area they lived in, were under-predicted by MERLIN-Expo by 40% on average. The model predictions for individual adults, by contrast, under-predict the biomonitoring data by 7% on average, but with more important under-predictions for subjects at the upper end of exposure. Still, average predicted urinary tAs levels from the simulations at population level and at individual level overlap, and, at least for the current case, lead to similar conclusions. These results constitute a first and partial verification of the model performance of MERLIN-Expo when dealing with iAs in a complex site-specific exposure scenario, and demonstrate the robustness of the modelling tool for these situations. © 2016 Elsevier B.V. Source

Tanaka T.,Catholic University of the Sacred Heart | Ciffroy P.,Electricite de France | Stenberg K.,Facilia AB | Capri E.,Catholic University of the Sacred Heart
Environmental Toxicology and Chemistry | Year: 2010

In the framework of environmental multimedia modeling studies dedicated to environmental and health risk assessments of chemicals, the bioconcentration factor (BCF) is a parameter commonly used, especially for fish. As for neutral lipophilic substances, it is assumed that BCF is independent of exposure levels of the substances. However, for metals some studies found the inverse relationship between BCF values and aquatic exposure concentrations for various aquatic species and metals, and also high variability in BCF data. To deal with the factors determining BCF for metals, we conducted regression analyses to evaluate the inverse relationships and introduce the concept of probability density function (PDF) for Cd, Cu, Zn, Pb, and As. In the present study, for building the regression model and derive the PDF of fish BCF, two statistical approaches are applied: ordinary regression analysis to estimate a regression model that does not consider the variation in data across different fish family groups; and hierarchical Bayesian regression analysis to estimate fish group-specific regression models. The results show that the BCF ranges and PDFs estimated for metals by both statistical approaches have less uncertainty than the variation of collected BCF data (the uncertainty is reduced by 9%-61%), and thus such PDFs proved to be useful to obtain accurate model predictions for environmental and health risk assessment concerning metals. Environ. Toxicol. Chem. 2010;29:2417-2425. © 2010 SETAC Copyright © 2010 SETAC. Source

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