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Bells Corners, Canada

Ford J.D.,McGill University | Champalle C.,McGill University | Tudge P.,McGill University | Riedlsperger R.,Memorial University of Newfoundland | And 2 more authors.
Mitigation and Adaptation Strategies for Global Change

Vulnerability assessments (VAs) have been widely used to understand the risks posed by climate change and identify opportunities for adaptation. Few studies, however, have evaluated VAs from the perspective of intended knowledge users or with reference to established best practices. In this paper, we identify and evaluate VAs focusing on the built environment in northern Canada. We document 16 completed VAs, which range from engineering-based studies of the vulnerability of specific infrastructural assets (e.g. building foundations, roads) to community-based assessments characterizing the vulnerability of the built environment in general in specific communities. We then evaluate projects based on the extent to which they incorporate best practices for vulnerability assessment, informed by a review of the scholarship and interviews with practitioners and knowledge users in the north (n = 21). While completed VAs have increased our understanding of the risks posed by climate change, none perform well across all evaluation criteria, and interviewees identified the need for improvement to VAs to inform decision making. Specifically, there is a need for greater emphasis on stakeholder engagement and effective communication of research findings, and interdisciplinary collaboration to capture the multiple drivers of vulnerability, cost impacts, and examine the performance of infrastructural assets under different climate scenarios. © 2014 Springer Science+Business Media Dordrecht. Source

Krewski D.,University of Ottawa | Westphal M.,University of Ottawa | Andersen M.E.,Hamner Institutes for Health Sciences | Paoli G.M.,Risk science International | And 5 more authors.
Environmental Health Perspectives

Objectives: In 2011, the U.S. Environmental Protection Agency initiated the NexGen project to develop a new paradigm for the next generation of risk science. Methods: The NexGen framework was built on three cornerstones: the availability of new data on toxicity pathways made possible by fundamental advances in basic biology and toxicological science, the incorporation of a population health perspective that recognizes that most adverse health outcomes involve multiple determinants, and a renewed focus on new risk assessment methodologies designed to better inform risk management decision making. Results: The NexGen framework has three phases. Phase I (objectives) focuses on problem formulation and scoping, taking into account the risk context and the range of available risk management decision-making options. Phase II (risk assessment) seeks to identify critical toxicity pathway perturbations using new toxicity testing tools and technologies, and to better characterize risks and uncertainties using advanced risk assessment methodologies. Phase III (risk management) involves the development of evidence-based population health risk management strategies of a regulatory, economic, advisory, community-based, or technological nature, using sound principles of risk management decision making. Conclusions: Analysis of a series of case study prototypes indicated that many aspects of the NexGen framework are already beginning to be adopted in practice. Source

Willhite C.C.,Risk science International | Ball G.L.,National Science Foundation | Bhat V.S.,National Science Foundation
Human and Experimental Toxicology

The U.S. Congress [PL 107-188] amended the Safe Drinking Water Act and required each community water system serving more than 3,000 people to conduct vulnerability assessments. These assessments address potential circumstances that could compromise the safety and reliability of municipal water. The present evaluation concerns the concentrations of the blended phosphates (also known as polyphosphates, condensed complex phosphates, polyphosphate glassy balls, and pyrophosphates) intended to aid regulatory agencies in decisions to avoid contact with affected water. Polyphosphates are direct food additives and they are used to treat municipal drinking water, but depending upon the concentration and duration of exposure these substances can induce chemical burns. Ingested polyphosphates are degraded by phosphatase enzymes to monophosphates, substances that are over-the-counter bowel purgatives. High oral doses of the monophosphates can induce transient hyperphosphatemia in older and susceptible young people, which can lead to acute phosphate nephropathy. In some patients, the condition is fatal. Based on the acute diarrhea after the ingestion of a single oral dose of monobasic (NaH2PO4) and dibasic (Na2HPO4) monophosphates in adults, a do not consume concentration of 600 mg PO4/L can be derived. Based on mild local irritation after topical application of 1.0% sodium metaphosphate [(NaPO3)6 • H2O] to intact skin of sensitive volunteers, a do not use concentration of 8,000 mg PO4/L can be assigned. Given the lack of eye irritation in rabbits after direct instillation of 0.2% (NaPO3)6 • H2O, an acute ocular contact limit of 50 mg PO4/L serves as the overall do not use level. © The Author(s) 2013. Source

Cheng V.Y.S.,University of Toronto | Arhonditsis G.B.,University of Toronto | Sills D.M.L.,Cloud Physics and Severe Weather Research Section | Gough W.A.,University of Toronto | Auld H.,Risk science International
Nature Communications

Tornadoes represent one of natureâ (tm) s most hazardous phenomena that have been responsible for significant destruction and devastating fatalities. Here we present a Bayesian modelling approach for elucidating the spatiotemporal patterns of tornado activity in North America. Our analysis shows a significant increase in the Canadian Prairies and the Northern Great Plains during the summer, indicating a clear transition of tornado activity from the United States to Canada. The linkage between monthly-averaged atmospheric variables and likelihood of tornado events is characterized by distinct seasonality; the convective available potential energy is the predominant factor in the summer; vertical wind shear appears to have a strong signature primarily in the winter and secondarily in the summer; and storm relative environmental helicity is most influential in the spring. The present probabilistic mapping can be used to draw inference on the likelihood of tornado occurrence in any location in North America within a selected time period of the year. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Willhite C.C.,Risk science International | Willhite C.C.,ughlin Center for Population Health Risk Assessment | Karyakina N.A.,Risk science International | Yokel R.A.,University of Kentucky | And 8 more authors.
Critical Reviews in Toxicology

Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007). Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of "total Al"assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+3to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+2and Al(H2O)6+3] that after complexation with O2•-, generate Al superoxides [Al(O2•)](H2O5)]+2. Semireduced AlO2•radicals deplete mitochondrial Fe and promote generation of H2O2, O2•-and OH•. Thus, it is the Al+3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer's disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances. © 2014 Informa Healthcare USA, Inc. Source

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