Characterizing human health damage from ionizing radiation in life cycle assessment

Purpose: Although a wide number of industrial processes routinely release radionuclides into the environment, the resulting potential impacts on human health have been largely overlooked in life cycle assessment (LCA). As part of the Life Cycle Initiative project on Global Guidance for Life Cycle Impact Assessment Indicators and Methods (GLAM), we aim to develop a consensus-based source-to-damage framework and factors for characterizing human health damage from ionizing radiation in LCA. Methods: Our framework comprises four modules. The fate and exposure modules are based on UCrad, an earlier developed compartment-based environmental model for radionuclides. The focus of the present work is on the dose response and severity modules, which are based on most recent data from the International Committee on Radiological Protection and the Global Burden of Disease project series. The characterization factors are expressed in terms of DALY per kBq released. Results and discussions: We obtain characterization factors for 115 radionuclides and 8 environmental compartments. To evaluate our approach, we compare both effect factors (combining dose response and severity) and characterization factors with those proposed in earlier studies. Our analysis demonstrates that differences are explicable by the different approaches used in the fate and exposure modelling. We also test the sensitivity of our factors to different approaches for filling data gaps, suggesting that our factors are robust. Finally, we apply our factors in an illustrative case study on rice production and consumption under various scenarios to identify dominant radionuclides and how these differ when other approaches are used. Conclusions: Our framework is aligned with widely adopted methodologies for human health impact assessment, thus enabling robust comparisons, and covers nearly all radionuclides released by anthropogenic activities, including those that may arise from disposal of nuclear waste. Our factors are readily applicable for assessing radionuclide emissions in LCA. As next step we recommend (i) incorporating decay products into the fate model and (ii) integrating a model for indoor emissions of radon and indoor exposure to naturally occurring radionuclides (NORM)

Insecticide Exposures on Commercial Aircraft: A Literature Review and Screening Level Assessment

The objective of this project was to provide initial estimates of the relationship between insecticide use on passenger aircraft and exposure levels present in the cabin environment. The work was initially divided into three tasks including 1) a review of insecticide application practices in commercial aircraft, 2) exploratory measurements of insecticide concentrations in treated aircraft and 3) screening level exposure modeling. Task 1 gathered information that is needed to assess the time-concentration history of insecticides in the airline cabin. The literature review focused on application practices, information about the cabin environment and existing measurements of exposure concentrations following treatment. Information from the airlines was not available for estimating insecticide application rates in the U.S. domestic fleet or for understanding how frequently equipment rotate into domestic routes following insecticide treatment. However, the World Health Organization (WHO) recommends several methods for treating aircraft with insecticide. Although there is evidence that these WHO guidelines may not always be followed, and that practices vary by airline, destination, and/or applicator company, the guidelines in combination with information related to other indoor environments provides a plausible basis for estimating insecticide loading rates on aircraft. The review also found that while measurements of exposure concentrations following simulated aerosol applications are available, measurements following residual treatment of aircraft or applications in domestic aircraft are lacking. Task 2 focused on developing an approach to monitor exposure concentrations in aircraft using a combination of active and passive sampling methods. An existing active sampling approach was intended to provide data immediately following treatment while a passive sampler was developed to provide wider coverage of the fleet over longer sampling periods. The passive sampler, based on a thin-film polymer-coated glass design, was developed specifically for deployment in the airliner ventilation system for long-term unattended monitoring of insecticide loading in the aircraft. Because access was not available for either treated aircraft or treatment records during the course of this study, the development and calibration of the passive samplers was halted prior to completion. Continued development of a field ready passive sampler for insecticides in aircraft would require collaboration with the airline industry to finalize the method for deployment and calibration conditions for the sampler. The Task 3 screening level modeling assessment used a dynamic two-box mass balance model that includes treated surfaces and air to explore the time-concentration history of insecticides in the cabin. The model was parameterized using information gathered during the literature review and run for several different insecticide use scenarios. Chemical degradation or sequestration in the surface compartment and mass transfer from the surface to the air limit the rate at which insecticides are removed from the system. This rate limiting process can result in an accumulation of insecticide in the airliner cabin following repeated applications. The extent of accumulation is a function of the overall persistence of the chemical in the system and the amount of chemical applied during each treatment

ExO: An Ontology for Exposure Science

An ontology is a formal representation of knowledge within a domain and typically consists of classes, the properties of those classes, and the relationships between them. Ontologies are critically important for specifying data of interest in a consistent manner, thereby enabling data aggregation, analysis and exchange. An exposure ontology, consistent with those being used in toxicology and other health sciences, is required to formally represent exposure concepts, the relationships between these concepts and most important, the relationships between exposure, susceptibility, and toxicology information. A successful exposure ontology must facilitate the semantic retrieval of exposure data in the context of environmental health science, medical surveillance, disease control, health tracking, risk assessment, and other public health and environmental science endeavors. To address this need, an Exposure Ontology, ExO, was designed and a prototype developed to provide the foundation for exposure data centralization and integration. The root classes forming the basis for the ontology are 'exposure event’ ‘exposure stressor', 'exposure receptor', and 'exposure outcome'. Although the initial development of ExO was focused on human exposure to chemicals, the ultimate intent is to provide domains that can be extended to address exposures to the full suite of environmental stressors

Estimating pesticide emission fractions for use in LCA: a global consensus-building effort

A practical challenge in LCA for comparing pesticide application in different agricultural practices is the agreement on how to quantify the amount emitted, while only the amount applied to the field is known. Main goal of this paper is to present an international effort carried out to reach agreement on recommended default agricultural pesticide emission fractions to environmental media. Consensual decisions on the assessment framework are (a) primary distributions are used as inputs for LCIA, while further investigating how to assess secondary emissions, (b) framework and LCA application guidelines and documentation will be compiled, (c) the emission framework will be based on modifying PestLCI 2.0, (d) drift values will be provided by German, Dutch and other drift modelers, (e) pesticide application methods will be complemented to develop scenarios for tropical regions, (f) climate, soil and application method scenarios will be based on sensitivity analysis, (g) default emission estimates for LCA will be derived from production-weighted averages, and (h) emission fractions will be reported spatially disaggregated. Recommendations for LCA practitioners and database developers are (a) LCA studies should state whether the agricultural field belongs to technosphere or ecosphere, (b) additional information needs to be reported in LCI (e.g. pesticide mass applied), (c) emissions after primary distribution and secondary fate processes should be reported, (d) LCIA methods should allow for treating the field as part of technosphere and ecosphere, (e) fate and exposure processes should be included in LCIA (e.g. crop uptake), (f) default emission estimates should be used in absence of detailed scenario data, (g) and all assumptions should be reported. The recommended pesticide emission fractions results and recommendations are presented and disseminated to strive for broad acceptance at a dedicated stakeholder workshop back-to-back with the current LCA Food 2016 conference in Dublin

Applications of Contaminant Fate and Bioaccumulation Models in Assessing Ecological Risks of Chemicals: A Case Study for Gasoline Hydrocarbons

Mass balance models of chemical fate and transport can be applied in ecological risk assessments for quantitative estimation of concentrations in air, water, soil and sediment. These concentrations can, in turn, be used to estimate organism exposures and ultimately internal tissue concentrations that can be compared to mode-of-action-based critical body residues that correspond to toxic effects. From this comparison, risks to the exposed organism can be evaluated. To illustrate the practical utility of fate models in ecological risk assessments of commercial products, the EQC model and a simple screening level biouptake model including three organisms, (a bird, a mammal and a fish) is applied to gasoline. In this analysis, gasoline is divided into 24 components or ''blocks'' with similar environmental fate properties that are assumed to elicit ecotoxicity via a narcotic mode of action. Results demonstrate that differences in chemical properties and mode of entry into the environment lead to profound differences in the efficiency of transport from emission to target biota. We discuss the implications of these results and insights gained into the regional fate and ecological risks associated with gasoline. This approach is particularly suitable for assessing mixtures of components that have similar modes of action. We conclude that the model-based methodologies presented are widely applicable for screening level ecological risk assessments that support effective chemicals management

The Composite Task Reveals Stronger Holistic Processing in Children than Adults for Child Faces

Background: While own-age faces have been reported to be better recognized than other-age faces, the underlying cause of this phenomenon remains unclear. One potential cause is holistic face processing, a special kind of perceptual and cognitive processing reserved for perceiving upright faces. Previous studies have indeed found that adults show stronger holistic processing when looking at adult faces compared to child faces, but whether a similar own-age bias exists in children remains to be shown. Methodology/Principal Findings: Here we used the composite face task – a standard test of holistic face processing – to investigate if, for child faces, holistic processing is stronger for children than adults. Results showed child participants (8–13 years) had a larger composite effect than adult participants (22–65 years). Conclusions/Significance: Our finding suggests that differences in strength of holistic processing may underlie the ownage bias on recognition memory. We discuss the origin of own-age biases in terms of relative experience, face-space tuning, and social categorization