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Risk Assessment Process (risk + assessment_process)
Selected AbstractsAssessing environmental risks of transgenic plantsECOLOGY LETTERS, Issue 2 2006D. A. Andow Abstract By the end of the 1980s, a broad consensus had developed that there were potential environmental risks of transgenic plants requiring assessment and that this assessment must be done on a case-by-case basis, taking into account the transgene, recipient organism, intended environment of release, and the frequency and scale of the intended introduction. Since 1990, there have been gradual but substantial changes in the environmental risk assessment process. In this review, we focus on changes in the assessment of risks associated with non-target species and biodiversity, gene flow, and the evolution of resistance. Non-target risk assessment now focuses on risks of transgenic plants to the intended local environment of release. Measurements of gene flow indicate that it occurs at higher rates than believed in the early 1990s, mathematical theory is beginning to clarify expectations of risks associated with gene flow, and management methods are being developed to reduce gene flow and possibly mitigate its effects. Insect pest resistance risks are now managed using a high-dose/refuge or a refuge-only strategy, and the present research focuses on monitoring for resistance and encouraging compliance to requirements. We synthesize previous models for tiering risk assessment and propose a general model for tiering. Future transgenic crops are likely to pose greater challenges for risk assessment, and meeting these challenges will be crucial in developing a scientifically coherent risk assessment framework. Scientific understanding of the factors affecting environmental risk is still nascent, and environmental scientists need to help improve environmental risk assessment. [source] Influence of sediment ingestion and exposure concentration on the bioavailable fraction of sediment-associated tetrachlorobiphenyl in oligochaetes,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2008Arto J. Sormunen Abstract The desorption and bioavailability of 3,3,,4,4,-tetrachlorobiphenyl (PCB 77) were studied in spiked natural sediments at six concentrations. The desorption kinetics were measured in a sediment,water suspension using Tenax® resin extraction, and the bioavailability was measured by exposing Lumbriculus variegatus (Oligochaeta) to PCB 77,spiked sediment in a 14-d kinetic study. In addition, freely dissolved pore-water concentrations were measured using the polyoxymethylene solid-phase extraction method. The present study examined whether bioavailability can be defined more accurately by measuring the size of desorbing fractions and the pore-water concentrations than by using the standard equilibrium partitioning approach. The importance of ingested sediment in bioaccumulation also was investigated. Our data showed a clear, decreasing trend in the rapid-desorbing fractions and in the standard biota,sediment accumulation factors (BSAF) with increasing concentration in sediment. Desorbing fractions,refined BSAFs were more uniform across the concentration treatments, and the pore-water PCB 77 concentration predicted tissue concentrations close to observed values. In the risk assessment process, pore-water concentration or desorbing fractions would lead to more precise bioavailability estimates compared with those from the traditional equilibrium partitioning approach. The result also showed, however, that sediment-ingesting worms had access to an additional bioavailable chemical fraction that was especially evident when PCB 77 pore-water concentrations most likely approached the solubility limit. Thus, feeding may modify the bioavailable fraction that cannot be explained by simple equilibrium partitioning models. [source] Using a Geographic Information System to identify areas with potential for off-target pesticide exposureENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006Thomas G. Pfleeger Abstract In many countries, numerous tests are required as part of the risk assessment process before chemical registration to protect human health and the environment from unintended effects of chemical releases. Most of these tests are not based on ecological or environmental relevance but, rather, on consistent performance in the laboratory. A conceptual approach based on Geographic Information System (GIS) technology has been developed to identify areas that are vulnerable to nontarget chemical exposure. This GIS-based approach uses wind speed, frequency of those winds, pesticide application rates, and spatial location of agricultural crops to identify areas with the highest potential for pesticide exposure. A test scenario based on an incident in Idaho (USA) was used to identify the relative magnitude of risk from off-target movement of herbicides to plants in the conterminous United States. This analysis indicated that the western portion of the Corn Belt, the central California valley, southeastern Washington, the Willamette Valley of Oregon, and agricultural areas bordering the Great Lakes are among those areas in the United States that appear to have the greatest potential for off-target movement of herbicides via drift. Agricultural areas, such as the Mississippi River Valley and the southeastern United States, appears to have less potential, possibly due to lower average wind speeds. Ecological risk assessments developed for pesticide registration would be improved by using response data from species common to high-risk areas instead of extrapolating test data from species unrelated to those areas with the highest potential for exposure. [source] The EPPO pest risk analysis scheme: comments on using risk scalesEPPO BULLETIN, Issue 1 2010A. MacLeod The pest risk assessment component of the EPPO pest risk analysis (PRA) scheme requires many factors to be considered before the overall risk from a pest or pest-pathway combination is estimated. Each risk factor to consider appears as a question in the risk assessment stage of the PRA scheme. The way in which risk factors are rated within the EPPO scheme are described and compared with two pest risk assessment systems from North America that use rank-order measures to represent composite risk factors during the risk assessment process. It is concluded that a description or metric for each division of a scale that describes the risk factor, for example area occupied, frequency of occurrence and likelihood of an event, would help risk assessors to use the EPPO PRA scheme and should make the risk assessment stage of the scheme more consistent, leading to improved PRAs. [source] Sequential analysis of lines of evidence,an advanced weight-of-evidence approach for ecological risk assessmentINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006Ruth N Hull Abstract Weight-of-evidence (WOE) approaches have been used in ecological risk assessment (ERA) for many years. The approaches integrate various types of data (e.g., from chemistry, bioassay, and field studies) to make an overall conclusion of risk. However, the current practice of WOE has several important difficulties, including a lack of transparency related to how each line of evidence is weighted or integrated into the overall weight-of-evidence conclusion. Therefore, a sequential analysis of lines of evidence (SALE) approach has been developed that advances the practice of WOE. It was developed for an ERA of chemical stressors but also can be used for nonchemical stressors and is equally applicable to the aquatic and terrestrial environments. The sequential aspect of the SALE process is a significant advancement and is based on 2 primary ideas. First, risks can be ruled out with the use of certain lines of evidence, including modeled hazard quotients (HQs) and comparisons of soil, water, or sediment quality with conservative soil, water or sediment quality guidelines. Thus, the SALE process recognizes that HQs are most useful in ruling out risk rather than predicting risk to ecological populations or communities. Second, the SALE process provides several opportunities to exit the risk assessment process, not only when risks are ruled out, but also when magnitude of effect is acceptable or when little or no evidence exists that associations between stressors and effects may be causal. Thus, the SALE approach explicitly includes interaction between assessors and managers. It illustrates to risk managers how risk management can go beyond the simple derivation of risk-based concentrations of chemicals of concern to risk management goals based on ecological metrics (e.g., species diversity). It also can be used to stimulate discussion of the limitations of the ERA science, and how scientists deal with uncertainty. It should assist risk managers by allowing their decisions to be based on a sequential, flexible, and transparent process that includes direct toxicity risks, indirect risks (via changes in habitat suitability), and the spatial and temporal factors that can influence the risk assessment. [source] A critical assessment of the ecological risk assessment process: A review of misapplied conceptsINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2005Lawrence V. Tannenbaum Abstract A frank assessment of present-day ecological risk assessments (ERA) for managed contaminated sites reveals that fundamental concepts regarding the receptors that are considered and the chemical exposures they experience are commonly misapplied. As a consequence, environmental managers are not being supplied with the information needed for proper decision making. The stepwise review of ecological risk issues provided here suggests that the ERA process needs to be severely revamped. Further, what is likely hindering the development of a refined ecological assessment process that is better suited to environmental problem solving and land management is the unwillingness of stakeholders to agree that much of the current ERA practice and convention is flawed. [source] Analytical epidemiology of periodontitisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2005Luisa N. Borrell Abstract Aims: To review the literature related to the analytical epidemiology of periodontitis generated over the past decade. This review does not deal with descriptive epidemiologic studies of the prevalence, extent and severity of periodontitis with respect to global geography, but focuses exclusively on analytical epidemiology issues, including the challenges posed by the use of different case definitions across studies, current theories and models of disease progression, and risk factors associated with the onset and progression of periodontitis. Methods: Relevant publications in the English language were identified after Medline and PubMed database searches. Findings and conclusions: There is a conspicuous lack of uniformity in the definition of periodontitis used in epidemiologic studies, and findings from different research groups are not readily interpretable. There is a lack of studies that specifically address the distinction between factors responsible for the onset of periodontitis versus those affecting its progression. Colonization by specific bacteria at high levels, smoking, and poorly controlled diabetes have been established as risk factors for periodontitis, while a number of putative factors, including specific gene polymorphisms, have been identified in association studies. There is a clear need for longitudinal prospective studies that address hypotheses emerging from the cross-sectional data and include established risk factors as covariates along with new exposures of interest. Intervention studies, fulfilling the "targeting" step of the risk assessment process, are particularly warranted. Obvious candidates in this context are studies of the efficacy of elimination of specific bacterial species and of smoking cessation interventions as an alternative to the traditional broad anti-plaque approach in the prevention and control of periodontitis. Ideally, such studies should have a randomized-controlled trial design. [source] Organizational Risk as it Derives from What Managers Value: A Practice-Based Approach to Risk AssessmentJOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT, Issue 3 2010Hervé Corvellec Two observations serve as starting points for this paper. First, conventional risk assessment techniques provide sophisticated ways to identify and estimate hazards, but eschew the fact that there is no risk unless something of value is considered to be at stake. Second, what managers consider as being of value follows from how they organize their managerial practice. Based on a case study of a Swedish public transportation administration, a claim is presented that organizational risk conceptions derive primarily, although not exclusively, from what managers consider being of value both in and for their organizational practice. In particular, it is suggested to begin the risk assessment process with a critical appraisal of what managers hold as being of value and why. [source] CLIMATE CHANGE IMPACTS ON WATER RESOURCES OF THE TSENGWEN CREEK WATERSHED IN TAIWAN,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2001Ching-pin Tung ABSTRACT: This study presents a methodology to evaluate the vulnerability of water resources in the Tsengwen creek watershed, Taiwan. Tsengwen reservoir, located in the Tsengwen creek watershed, is a multipurpose reservoir with a primary function to supply water for the ChiaNan Irrigation District. A simulation procedure was developed to evaluate the impacts of climate change on the water resources system. The simulation procedure includes a streamflow model, a weather generation model, a sequent peak algorithm, and a risk assessment process. Three climate change scenarios were constructed based on the predictions of three General Circulation Models (CCCM, GFDL, and GISS). The impacts of climate change on streamflows were simulated, and, for each climate change scenario, the agricultural water demand was adjusted based on the change of potential evapotranspiration. Simulation results indicated that the climate change may increase the annual and seasonal streamflows in the Tsengwen creek watershed. The increase in streamflows during wet periods may result in serious flooding. In addition, despite the increase in streamflows, the risk of water deficit may still increase from between 4 and 7 percent to between 7 and 13 percent due to higher agricultural water demand. The simulation results suggest that the reservoir capacity may need to be expanded. In response to the climate change, four strategies are suggested: (1) strengthen flood mitigation measures, (2) enhance drought protection strategies, (3) develop new water resources technology, and (4) educate the public. [source] Pesticide residues in food,acute dietary exposure,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2004Denis Hamilton Abstract Consumer risk assessment is a crucial step in the regulatory approval of pesticide use on food crops. Recently, an additional hurdle has been added to the formal consumer risk assessment process with the introduction of short-term intake or exposure assessment and a comparable short-term toxicity reference, the acute reference dose. Exposure to residues during one meal or over one day is important for short-term or acute intake. Exposure in the short term can be substantially higher than average because the consumption of a food on a single occasion can be very large compared with typical long-term or mean consumption and the food may have a much larger residue than average. Furthermore, the residue level in a single unit of a fruit or vegetable may be higher by a factor (defined as the variability factor, which we have shown to be typically ×3 for the 97.5th percentile unit) than the average residue in the lot. Available marketplace data and supervised residue trial data are examined in an investigation of the variability of residues in units of fruit and vegetables. A method is described for estimating the 97.5th percentile value from sets of unit residue data. Variability appears to be generally independent of the pesticide, the crop, crop unit size and the residue level. The deposition of pesticide on the individual unit during application is probably the most significant factor. The diets used in the calculations ideally come from individual and household surveys with enough consumers of each specific food to determine large portion sizes. The diets should distinguish the different forms of a food consumed, eg canned, frozen or fresh, because the residue levels associated with the different forms may be quite different. Dietary intakes may be calculated by a deterministic method or a probabilistic method. In the deterministic method the intake is estimated with the assumptions of large portion consumption of a ,high residue' food (high residue in the sense that the pesticide was used at the highest recommended label rate, the crop was harvested at the smallest interval after treatment and the residue in the edible portion was the highest found in any of the supervised trials in line with these use conditions). The deterministic calculation also includes a variability factor for those foods consumed as units (eg apples, carrots) to allow for the elevated residue in some single units which may not be seen in composited samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. Additional information such as percentage commodity treated and combination of residues from multiple commodities may be incorporated into probabilistic calculations. The IUPAC Advisory Committee on Crop Protection Chemistry has made 11 recommendations relating to acute dietary exposure. Copyright © 2004 Society of Chemical Industry [source] Major hazard risk assessment for existing and new facilitiesPROCESS SAFETY PROGRESS, Issue 4 2004Katherine (Kate) Filippin This paper outlines a risk assessment methodology that has been developed through work with major hazard facilities, including ammonia plants in Australia, satisfying regulations equivalent to the European Seveso II Directive. The methodology is an approach for ensuring an undertaking of effectively assessing the risks associated with major hazards that will not only satisfy regulations and corporate requirements, but also, more importantly, provide a framework for sustainable business processes, by enabling the methodology to be integrated into normal business management processes. The approach enables existing management systems to be effectively incorporated into the evaluation processes. Common pitfalls encountered during the risk assessment process are also discussed. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004 [source] | ||||||||||||||||