Assessment of COVID-19 barrier effectiveness using process safety techniques.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a respiratory illness called the novel coronavirus 2019 (COVID-19). COVID-19 was declared a pandemic on March 11, 2020. Bow tie analysis (BTA) was applied to analyze the hazard of SARS-CoV-2 for three receptor groups: patient or family member at the IWK Health Centre in acute care, staff member at a British Columbia Forest Safety Council (BCFSC) wood pellet facility, and staff member at the Suncor refinery in Sarnia, Ontario. An inherently safer design (ISD) protocol for BTA was used as a guide for evaluating COVID-19 barriers, and additional COVID-19 controls were recommended. Two communication tools were developed from the IWK bow tie diagram to disseminate the research findings. This research provides lessons learned about the barriers implemented to protect people from contracting COVID-19, and about the use of bow tie diagrams as communication tools. This research has also developed additional example-based guidance that can be used for the COVID-19 pandemic or future respiratory illness pandemics. Recommended future work is the application of BTA to additional industries, the consideration of ISD principles in other control types in the hierarchy of controls (HOC), and further consideration of human and organizational factors (HOF) in BTA.

Application of Process Hazard Analysis and Inherently Safer Design in Wood Pellet Production.

Wood pellets are a fuel used for heat and power generation. Wood pellets are manufactured from forest residues and byproducts of other sectors in the wood processing industry, such as sawmilling. Wood pellet production generates combustible wood dust, which presents the risk of fire and explosion. The objective of this research was to incorporate the principles of inherently safer design (ISD) for the management of combustible dust hazards associated with wood pellet production. Using bow tie analysis to explicitly consider ISD within process hazard analysis (PHA), ISD barriers were successfully identified, including the use of paved surfaces to store feedstock to minimize rocks entering the process and presenting a risk of ignition sources, the use of reduced-size silos to minimize the inventory and increase the turnover frequency, the removal of unnecessary or hazardous equipment, such as fans, following a redesign, and the relocation of hazardous equipment, such as cyclones, outside and away from personnel. A summary of example-based guidance for combustible dust hazards was collected to support additional ISD implementation within PHA as part of the process safety management (PSM). The research also highlights learnings for conducting virtual PHA workshops, as well as identifying opportunities for incorporating ISD within operating wood processing facilities through the incident investigation and risk assessment elements of PSM.

Application of bow tie analysis and inherently safer design to the novel coronavirus hazard.

This work involves the application of process safety concepts to other fields, specifically bow tie analysis and inherently safer design (ISD) to COVID-19. An analysis framework was designed for stakeholders to develop COVID-19 risk management plans for specific scenarios and receptor groups. This tool is based on the incorporation of the hierarchy of controls (HOC) within bow tie analysis to identify priority barriers. The analysis framework incorporates inherently safer design (ISD) principles allowing stakeholders to assess the adequacy of controls along with the consideration of degradation factors and controls. A checklist has also been developed to help stakeholders identify opportunities to apply the ISD principles of minimization, substitution, moderation, and simplification. This work also considers barrier effectiveness with respect to human and organization factors (HOF) in degradation factors and controls. This paper includes a collection of bow tie elements to develop bow tie diagrams for specific receptor groups and scenarios in Nova Scotia, Canada. The pandemic stage (At-Peak or Post-Peak) and its influence on different scenarios or settings is also considered in this work. Bow tie diagrams were developed for numerous receptor groups; bow tie diagrams modelling a generally healthy individual, a paramedic and a hair salon patron contracting COVID-19 are presented in this work.

Diurnal variation in blood pressure and arterial stiffness in chronic kidney disease: the role of endothelin-1.

Hypertension and arterial stiffness are important independent cardiovascular risk factors in chronic kidney disease (CKD) to which endothelin-1 (ET-1) contributes. Loss of nocturnal blood pressure (BP) dipping is associated with CKD progression, but there are no data on 24-hour arterial stiffness variation. We examined the 24-hour variation of BP, arterial stiffness, and the ET system in healthy volunteers and patients with CKD and the effects on these of ET receptor type A receptor antagonism (sitaxentan). There were nocturnal dips in systolic BP and diastolic BP and pulse wave velocity, our measure of arterial stiffness, in 15 controls (systolic BP, −3.2±4.8%, P<0.05; diastolic BP, −6.4±6.2%, P=0.001; pulse wave velocity, −5.8±5.2%, P<0.01) but not in 15 patients with CKD. In CKD, plasma ET-1 increased by 1.2±1.4 pg/mL from midday to midnight compared with healthy volunteers (P<0.05). Urinary ET-1 did not change. In a randomized, double-blind, 3-way crossover study in 27 patients with CKD, 6-week treatment with placebo and nifedipine did not affect nocturnal dips in systolic BP or diastolic BP between baseline and week 6, whereas dipping was increased after 6-week sitaxentan treatment (baseline versus week 6, systolic BP: −7.0±6.2 versus −11.0±7.8 mm Hg, P<0.05; diastolic BP: −6.0±3.6 versus −8.3±5.1 mm Hg, P<0.05). There was no nocturnal dip in pulse pressure at baseline in the 3 phases of the study, whereas sitaxentan was linked to the development of a nocturnal dip in pulse pressure. In CKD, activation of the ET system seems to contribute not only to raised BP but also the loss of BP dipping. The clinical significance of these findings should be explored in future clinical trials.

Lithium: the pharmacodynamic actions of the amazing ion.

Lithium has been used for the treatment of mood disorders for over 60 years, yet the exact mechanisms by which it exerts its therapeutic effects remain unclear. Two enzymatic chains or pathways emerge as targets for lithium: inositol monophosphatase within the phosphatidylinositol signalling pathway and the protein kinase glycogen synthase kinase 3. Lithium inhibits these enzymes through displacing the normal cofactor magnesium, a vital regulator of numerous signalling pathways. Here we provide an overview of evidence, supporting a role for the inhibition of glycogen synthase kinase 3 and inositol monophosphatase in the pharmacodynamic actions of lithium. We also explore how inhibition of these enzymes by lithium can lead to downstream effects of clinical relevance, both for mood disorders and neurodegenerative diseases. Establishing a better understanding of lithium's mechanisms of action may allow the development of more effective and more tolerable pharmacological agents for the treatment of a range of mental illnesses, and provide clearer insight into the pathophysiology of such disorders.

Membrane bioreactor technology: a novel approach to the treatment of compost leachate.

Compost leachate forms during the composting process of organic material. It is rich in oxidizable organics, ammonia and metals, which pose a risk to the environment if released without proper treatment. An innovative method based on the membrane bioreactor (MBR) technology was developed to treat compost leachate over 39days. Water quality parameters, such as pH, dissolved oxygen, ammonia, nitrate, nitrite and chemical oxygen demand (COD) were measured daily. Concentrations of caffeine and metals were measured over the course of the experiment using gas chromatography - mass spectrometry (GC/MS) and inductively coupled plasma - mass spectrometry (ICP-MS) respectively. A decrease of more than 99% was achieved for a COD of 116g/L in the initial leachate. Ammonia was decreased from 2720mg/L to 0.046mg/L, while the nitrate concentration in the effluent rose to 710mg/L. The bacteria in the MBR system adjusted to the presence of the leachate, and increased 4 orders of magnitude. Heavy metals were removed by at least 82.7% except copper. These successful results demonstrated the membrane bioreactor technology is feasible, efficient method for the treatment of compost leachate.

Membrane bioreactor treatment of commonly used organophosphate pesticides.

Five pesticide formulations registered for use in Canada containing organophosphate-insecticide active ingredients azinphos-methyl, chlorpyrifos, diazinon, malathion and phorate were subjected to treatment by membrane bioreactor (MBR) technology. The target active ingredients were introduced to the MBR at ppm level concentrations. The biodegradation of these compounds was analyzed daily using selected ion monitoring gas chromatography-mass spectrometry (GC/MS-SIM) following extraction of the analytes using solid-phase extraction (SPE). Amounts measuring 83 % to 98 % of the target analytes were removed with steady-state concentrations being reached within 5 days of their introduction. The dissolved oxygen, temperature, pH, and total heterotrophic bacterial population were monitored daily to ensure optimal conditions for biodegradation. The quality of the effluent from the MBR was assessed daily through spectrophotometric methods. Measurements were conducted for the concentration of ammonia, nitrate, nitrite, total and reactive phosphorus, as well as the chemical oxygen demand (COD) of the effluent. This study demonstrated that the MBR technology is feasible and efficient for treatment of organophosphate pesticides without introducing additional chemical additives.