Results 1 - 10 of 1913
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[en] Mecoprop, dichlorprop and metolachlor concentrations and enantiomer signatures were determined in Ontario streams in 2006-2007 and compared to results from 2003 to 2004. Median concentrations of dichlorprop and metolachlor were not significantly different between the two campaigns, but mecoprop was higher in 2006-2007. Concentrations of mecoprop and dichlorprop in Lake Ontario surface water were 1-2 orders of magnitude lower than stream averages. Enantiomer fractions (EFs) > 0.5 of mecoprop in high-concentration stream water samples during 2006-2007 were related to replacement of racemic mecoprop by single (+) enantiomer mecoprop-P after 2004. EFs <0.5 in low-concentration samples suggested enantioselective degradation and/or interconversion. Metolachlor profiles were expressed as SF, the fraction of herbicidally active/(active + inactive) stereoisomers. Samples with higher concentrations of metolachlor had SFs similar to S-metolachlor which is enriched in the active stereoisomers. Low concentrations were associated with lower and more variable SFs, suggesting mixed input of racemic and S-metolachlor or stereoselective degradation. - Stereoisomer proportions of chiral herbicides in streams of Ontario, Canada reveal switches in pesticide product usage and in-watershed degradation.
[en] Several facets of government intervention in the Canadian nuclear industry are examined by reviewing the general historical evolution of intervention since the Second World War and by a more detailed analysis of three case studies. The case studies are the public sector - private sector content of the initial CANDU reactor program in the 1950's, the regulation of the health and safety of uranium miners in the late 1960's and early 1970's, and the Ontario Hydro decision in 1978 to enter into longer-term (40 year) contracts for uranium for its power reactors. (auth)
[en] Purpose: To investigate the prevalence of total quality culture (TQC) within radiation therapy (RT) departments across Ontario, Canada. Methods: A prospective quantitative survey was distributed within RT departments across Ontario, Canada using the Miller Consulting Group Quality Culture survey. Findings: Ninety percent of managers (9/10) and 50% of employees (261/519) participated. There was concordance between managers and staff that overall RT departments exhibit a work culture that somewhat resembles TQC. Both groups scored 55% of the categories as somewhat agree with TQC and 9% of categories as no TQC. There was discordance in views for 36% of the categories, where managers scored a higher prevalence of TQC compared to their therapists. Larger RT departments (>50 employees) had more prevalence of discrepancy between group scores. Conclusions: This is the first study to report on the prevalence of TQC within RT departments. Strategies designed for on-going continuous improvement will benefit staff, RT managers, continuity of patient care and patient safety within RT departments.
[en] In December 1986, partly as a response to public concerns raised by the accident at Chernobyl, the Ontario government commissioned a study of reactor safety, the Ontario Nuclear Safety Review (ONSR). The major conclusion of the ONSR report states that Ontario Hydro reactors are being operated safely, that no significant adverse impact has been detected in either the staff or the public, and the risk of serious accidents is very small. The author of this article argues that the reassuring words of this conclusion should not be taken as an adequate basis for judging that nuclear power is safe. The degree of certainty in the conclusion is not supported by the body of the report; and the type of uncertainties that arise in reactor safety cannot be adequately resolved by the technical and scientific examination considered in the ONSR. (20 refs.)
[en] Background and purpose: The scope and effect of radiation oncology (RO) outreach activities within centralized radiotherapy (RT) systems is poorly defined. The purpose of this study was to describe the outreach activities of Ontario’s regional cancer centres, and to explore the relationship between radiation oncology (RO) outreach clinics and rates of radiotherapy (RT) utilization at hospitals without RT on site (HWOS-RT).
[en] This report summarizes the preliminary results of geological and geophysical investigations of possible neotectonic features in Prince Edward County, southern Ontario, made by the Ontario Geological Survey during 1988. Low magnitude seismic events indicative of contemporary stress relief occurred during 1987-88 near Salmon Point and Consecon (M 2.2). These events were located proximal to a major regional fault system crossing Lake Ontario and consisting of the Clarendon-Linden Fault System in New York State and the Salmon River-Picton fault systems in Ontario. Detailed observations were made of regional jointing orientations (predominantly 60 degrees and 125 degrees), erosion of surficial deposits adjacent to open fractures, a local fault displacement (post-glacially), dome structures located at Point Petre, and dissolution/karst terrains in the eastern part of the study area. Excavations of four pop-up structures indicate that three are classical pop-ups and one is atypical in structure. Level transects were conducted across complex structures in the eastern part of the study area. Detailed refraction seismic and resistivity surveys were conducted on pop-up and fault features. Preliminary results indicate that the Picton Fault is a complex zone of fractures with differing bedrock on each side. The central zone of the East Duck Pond pop-up is fractured and may contain variable amounts of water. Overturned and upright folds in the Consecon Quarry located outside of the primary research area were documented and found to be trending in a west-northwest to northwest direction. This fold orientation is compatible both with a glacial shove origin and with the present stress field orientations. Although glacial shove can produce overturned folds, it cannot form upright folds. A regional, tectonic deformation oriented northeasterly is therefore suggested as the causative mechanism
[en] The processes that concentrated noble metals (gold, silver, platinum) in the earth's crustal rocks are studied. By neutron activation analysis, gold concentrations around 1 ppb can be analyzed with an accuracy of 15 to 20%. A study is being made of platinum mineralization in the Sudbury area. The theory that the Sudbury structure was formed by meteoric impact is supported by shatter cones in the rock. (N.D.H.)
[en] This white paper assesses Ontario's Regulated Price Plan (RPP), featuring time-of-use (TOU) pricing. By providing customers with more accurate price signals, TOU pricing can lead to lower electricity bills, more efficient utilization of the region's energy resources, and a more stable and reliable grid. The implementation of TOU pricing, however, poses a unique set of challenges. The Ontario Energy Board contracted with The Brattle Group to assess the current RPP TOU rate offering and to suggest solutions for making it better. The review involved four sequential steps. First, Ontario's TOU rate was benchmarked against industry best practices. The benchmarking identified some areas in which the TOU plan could be improved. A set of feasible alternatives was established to bring about these improvements.. Finally, based on this set of alternatives, several possible pathways to the future were developed, depending on the priorities of the OEB and the province.
[en] About 20,000 Chinook salmon (Oncorhynchus tshawytscha) from Lake Ontario enter the Credit River, Ontario, Canada every fall to spawn and die. In this study, samples of muscle and eggs collected from female Chinook salmon entering the Credit River contained total PCBs, DDT compounds and other organochlorine (OC) compounds at μg/kg concentrations. Semi-permeable membrane devices (SPMDs) were deployed at a reference site above the spawning grounds and at two downstream sites at intervals over a 14-month period that spanned two spawning runs. There was an increase in the concentrations of total PCBs, total DDT and other classes of OCs in the SPMDs deployed at the two downstream sites during and after both spawning runs; indicating that the decay of salmon releases contaminants into the river. Based upon the concentrations of contaminants in the salmon tissues, approximately 75 g of total PCBs and 35 g of total DDT compounds would be transported annually into the Credit River from this source. - Carcasses of adult Chinook salmon from Lake Ontario contribute persistent contaminants to a river ecosystem