549 research outputs found

    Safe Drinking Water Policy for Canada - Turning Hindsight into Foresight

    Get PDF
    Much of Canada lags international leaders in adopting management systems for assuring safe drinking water. Despite some clear progress in individual provinces, Canada, and small communities in particular, need a system that better promotes and rewards competence among drinking water providers. In much of the developed, industrialized world, including most of urbanized Canada, public drinking water poses a negligible health risk. But in the wake of a series of management failures with severe negative health consequences, Canada’s drinking water regulation is still managed in a fragmented way that leaves us vulnerable to water-quality failures, most likely in small systems. The problem is not that numerical water safety criteria are inadequately stringent; the documented failures have been caused by an inability to operate water systems effectively, pointing to poor operator competence and inadequate support systems. Canada needs the universal adoption of a “know your own system” water safety plan approach, based on a tangible demonstration of operator competence in understanding and delivering safe drinking water.Water Series, Canada, safe drinking water

    Oil Sands Contaminants

    Get PDF

    Sources and Characteristics of Liquid Process Wastes From Arctic Offshore Hydrocarbon Exploration

    Get PDF
    Increased interest in offshore hydrocarbon exploration in Arctic waters raises concern regarding liquid waste management from drilling operations. The typical sources of process liquid waste from exploratory drilling operations is described and data on the quantity and quality of liquid waste discharges is provided from monitoring at two offshore sites. The chemical and toxicological characteristics of the waste fluids indicate that a potential exists for water pollution in specific circumstances. However, close process control to reduce the quantities of waste fluid generated and judicious selection of drilling mud additives should prevent the occurrence of significant water pollution problems from waste fluid disposal at exploratory Arctic offshore drilling operations

    Potential carcinogenic hazards of non-regulated disinfection by-products: Haloquinones, halo-cyclopentene and cyclohexene derivatives, N-halamines, halonitriles, and heterocyclic amines

    Get PDF
    Drinking water disinfectants react with natural organic material (NOM) present in source waters usedfor drinking water to produce a wide variety of by-products. Several hundred disinfections by-products(DBPs) have been identified, but none have been identified with sufficient carcinogenic potency to account for the cancer risks projected from epidemiological studies. In a search for DBPs that might fill this risk gap, the present study projected reactions of chlorine and chloramine that could occur with substructures present in NOM to produce novel by-products. A review of toxicological data on related compounds, supplemented by use of a quantitative structure toxicity relationship (QSTR) program TOPKAT identified chemicals with a high probability of being chronically toxic and/or carcinogenic among 489 established and novel DBPs. Classes of DBPs that were specifically examined were haloquinones (HQs), related halocyclopentene and cyclohexene (HCP&H) derivatives, halonitriles (HNs), organic N-chloramines (NCls), haloacetamides (HAMs), and nitrosamines (NAs). A review of toxicological data available for quinones suggested that HQs and HCP&H derivatives appeared likely to be of health concern and were predicted to have chronic lowest observed adverse effect levels (LOAELs) in the low g/kg day range. Several HQs were predicted to be carcinogenic. Some have now been identified in drinking water. The broader class of HNs was explored by considering current toxicological data on haloacetonitriles and extending this to halopropionitriles. 2,2-dichloropropionitrile has been identified in drinking water at low concentrations, as well as the more widely recognized haloacetonitriles. The occurrence of HAMs has been previously documented. The very limited toxicological data on HAMs suggests that this class would have toxicological potencies similar to the dihaloacetic acids. Organic N-halamines are also known to be produced in drinking water treatment and have biological properties of concern, but no member has ever been characterized toxicologically beyond bacterial or in vitro studies of genotoxicity. The documented formation of several nitrosamines from secondary amines from both natural and industrial sources prompted exploration of the formation of additional nitrosamines. N-diphenylnitrosamine was identified in drinking waters. Of more interest, however, was the formation of phenazine (and subsequently N-chorophenazine) in a competing reaction. These are the first heterocyclic amines that have been identified as chlorination by-products. Consideration of the amounts detected of members of these by-product classes and their probable toxicological potency suggest a prioritization for obtaining more detailed toxicological data of HQs > HCP&H derivatives > NCls > HNs. Based upon a ubiquitous occurrence and virtual lack of in vivo toxicological data, NCls are the most difficult group to assign a priority as potential carcinogenic risks. This analysis indicates that research on the general problem of DBPs requires a more systematic approach than has been pursued in the past. Utilization of predictive chemical tools to guide further research can help bring resolution to the DBP issue by identifying likely DBPs with high toxicological potency

    COVID-19 crisis management of German ICU clinicians in leadership – a metaphor analysis

    Get PDF
    The COVID-19 pandemic coincided with an already long-standing crisis in health systems around the world characterized by economic pressure and increasing staff shortage. “Crisis” became a global metaphor to convey collective experiences of the COVID-19 threat. Little is known on how crisis metaphors influence thought and speech on crisis management and the challenging staff situation of intensive care unit (ICU) clinicians in leadership positions and how they act. Therefore, we were interested in (1) which metaphorical concepts ICU clinicians in leadership use to express experiences and strategies in dealing with coinciding crises, (2) how these change over time, and (3) how metaphors in speech reveal self-images of crisis management. We conducted a systematic metaphor analysis focusing on data from three participants of a qualitative interview study with twenty-four healthcare professionals in ICUs in Germany. The participants were interviewed at two time points between April 2020 and March 2021. We identified and reconstructed metaphorical concepts of three interviewees (ICU clinicians in leadership) with regard to the pandemic management, and developed a typology based on the dimensions of mood, modus operandi, location, and scope. The typology consists of eight self-images (protagonists) for the crisis management of ICU clinicians in leadership, such as the figure of the soldier (“to unite everyone behind this flag”), the distributor (“sometimes it is a crazy patchwork [wahnsinniges Gestückel]”) or the critic (“we are the fool for everything”). They embody different qualities of a leader and refer to intra- and inter-role conflicts within multiple crisis conditions. Metaphor analysis reveals different self-images of ICU leadership clinicians in relation to crisis management. This illustrates that thinking and perceptions of crisis management may strongly differ between and within leaders and may change over the course of crises. Our findings highlight the need both to improve knowledge on challenges associated with leadership in crises and preparedness, and to support clinicians in their leadership by recognizing and addressing differences and changes in leaders’ self-image

    Lysis of Microcystis aeruginosa with Extracts from Chinese Medicinal Herbs

    Get PDF
    Boiling water extracts of 66 selected Chinese medicinal herbs were screened for their anticyanobaterial activity against Microcystis aeruginosa by the soft-agar overlayer (SAO) method. Results indicated that extracts from 16 materials could inhibit the growth of this bacterial species. Among these anticyanobacterial samples, eight extracts showed low minimum inhibitory concentrations (MIC), including four extracts with MICs between 1 and 6 mg/mL, and four extracts with MICs < 1 mg/mL which could be considered useful to prevent the outbreak of cyanobacteria before the appearance of cyanobacterial blooms. Further study showed that three extracts with MIC values < 1 mg/mL induced intensive chlorophyll-a lysis within 7 days at the MIC. The results suggested that highly efficient anticyanobacterial compounds must be involved in the inhibitory activities. The final results indicated these three extracts (from Malaphis chinensis, Cynips gallae-tinctoriae and Fructus mume) had the potential to be developed as algicides due to their remarkably anticyanobacterial activities
    • …
    corecore