Assessment of dietary background exposure of the Irish adult population to dioxins and PCBs particularly taking into account additional exposure due to the 2008 Irish dioxin food contamination incident

Irish monitoring data on PCDD/Fs, DL-PCBs and Marker PCBs were collated and combined with Irish Adult Food Consumption Data, to estimate dietary background exposure of Irish adults to dioxins and PCBs. Furthermore, all available information on the 2008 Irish pork dioxin food contamination incident was collated and analysed with a view to evaluate any potential impact the incident may have had on general dioxin and PCB background exposure levels estimated for the adult population in Ireland. The average upperbound daily intake of Irish adults to dioxins Total WHO TEQ (2005) (PCDD/Fs & DLPCBs) from environmental background contamination, was estimated at 0.3 pg/kg bw/d and at the 95th percentile at 1 pg/kg bw/d. The average upperbound daily intake of Irish adults to the sum of 6 Marker PCBs from environmental background contamination ubiquitous in the environment was estimated at 1.6 ng/kg bw/d and at the 95th percentile at 6.8 ng/kg bw/d. Dietary background exposure estimates for both dioxins and PCBs indicate that the Irish adult population has exposures below the European average, a finding which is also supported by the levels detected in breast milk of Irish mothers. Exposure levels are below health based guidance values and/or Body Burdens associated with the TWI (for dioxins) or associated with a NOAEL (for PCBs). Given the current toxicological knowledge, based on biomarker data and estimated dietary exposure, general background exposure of the Irish adult population to dioxins and PCBs is of no human health concern. In 2008, a porcine fat sample taken as part of the national residues monitoring programme led to the detection of a major feed contamination incidence in the Republic of Ireland. The source of the contamination was traced back to the use of contaminated oil in a direct-drying feed operation system. Congener profiles in animal fat and feed samples showed a high level of consistency and pinpointed the likely source of fuel contamination to be a highly chlorinated commercial PCB mixture. To estimate additional exposure to dioxins and PCBs due to the contamination of pig and cattle herds, collection and a systematic review of all data associated with the contamination incident was conducted. A model was devised that took into account the proportion of contaminated product reaching the final consumer during the 90 day contamination incident window. For a 90 day period, the total additional exposure to Total TEQ (PCDD/F &DL-PCB) WHO (2005) amounted to 407 pg/kg bw/90d at the 95th percentile and 1911 pg/kg bw/90d at the 99th percentile. Exposure estimates derived for both dioxins and PCBs showed that the Body Burden of the general population remained largely unaffected by the contamination incident and approximately 10 % of the adult population in Ireland was exposed to elevated levels of dioxins and PCBs. Whilst people in this 10 % cohort experienced quite a significant additional load to the existing body burden, the estimated exposure values do not indicate approximation of body burdens associated with adverse health effects, based on current knowledge. The exposure period was also limited in time to approximately 3 months, following the FSAI recall of contaminated meat immediately on detection of the contamination. A follow up breast milk study on Irish first time mothers conducted in 2009/2010 did not show any increase in concentrations compared to the study conducted in 2002. The latter supports the conclusion that the majority of the Irish adult population was not affected by the contamination incident.

Training in and assessment of the procedural skills required to perform peripheral nerve blockade

The training and ongoing education of medical practitioners has undergone major changes in an incremental fashion over the past 15 years. These changes have been driven by patient safety, educational, economic and legislative/regulatory factors. In the near future, training in procedural skills will undergo a paradigm shift to proficiency based progression with associated requirements for competence-based programmes, valid, reliable assessment tools and simulation technology. Before training begins, the learning outcomes require clear definition; any form of assessment applied should include measurement of these outcomes. Currently training in a procedural skill often takes place on an ad hoc basis. The number of attempts necessary to attain a defined degree of proficiency varies from procedure to procedure. Convincing evidence exists that simulation training helps trainees to acquire skills more efficiently rather than relying on opportunities in their clinical practice. Simulation provides a safe, stress free environment for trainees for skill acquisition, generalization and transfer via deliberate practice. The work described in this thesis contributes to a greater understanding of how medical procedures can be performed more safely and effectively through education. The effect of feedback, provided to novices in a standardized setting on a bench model, based on knowledge of performance was associated with an increase in the speed of skill acquisition and a decrease in error rate during initial learning. The timing of feedback was also associated with effective learning of skill. A marked attrition of skills (independent of the type of feedback provided) was demonstrable 24 hrs after they have first been learned. Using the principles of feedback as described above, when studying the effect of an intense training program on novices of varied years of experience in anaesthesia (i.e. the present training programmes / courses of an intense training day for one or more procedures). There was a marked attrition of skill at 24 hours with a significant correlation with increasing years of experience; there also appeared to be an inverse relationship between years of experience in anaesthesia and performance. The greater the number of years of practice experience, the longer it required a learner to acquire a new skill. The findings of the studies described in this thesis may have important implications for the trainers, trainees and training bodies in the design and implementation of training courses and the formats of delivery of changing curricula. Both curricula and training modalities will need to take account of characteristics of individual learners and the dynamic nature of procedural healthcare.

Multi-parametric metabolic assessment of cells under stress conditions

Glycolysis, glutaminolysis, the Krebs cycle and oxidative phosphorylation are the main metabolic pathways. Exposing cells to key metabolic substrates (glucose, glutamine and pyruvate); investigation of the contribution of substrates in stress conditions such as uncoupling and hypoxia was conducted. Glycolysis, O2 consumption, O2 and ATP levels and hypoxia inducible factor (HIF) signalling in PC12 cells were investigated. Upon uncoupling with FCCP mitochondria were depolarised similarly in all cases, but a strong increase in respiration was only seen in the cells fed on glutamine with either glucose or pyruvate. Inhibition of glutaminolysis reversed the glutamine dependant effect. Differential regulation of the respiratory response to FCCP by metabolic environment suggests mitochondrial uncoupling has a potential for substrate-specific inhibition of cell function. At reduced O2 availability (4 % and 0 % O2), cell bioenergetics and local oxygenation varied depending on the substrate composition. Results indicate that both supply and utilisation of key metabolic substrates can affect the pattern of HIF-1/2α accumulation by differentially regulating iO2¬, ATP levels and Akt/Erk/AMPK pathways. Inhibition of key metabolic pathways can modulate HIF regulatory pathways, metabolic responses and survival of cancer cells in hypoxia. Hypoxia leads to transcriptional activation, by HIF, of pyruvate dehydrogenase (PDH) kinase which phosphorylates and inhibits PDH, a mitochondrial enzyme that converts pyruvate into acetyl-CoA. The levels of PDH (total and phosphorylated), PDH kinase and HIF-1α were analysed in HCT116 and HCT116 SCO2-/- (deficient in complex IV of the respiratory chain) grown under 20.9 % and 3 % O2. Data indicate that regulation of PDH can occur in a manner independent of the HIF-1/PDH kinase 1 axis, mitochondrial respiration and the demand for acetyl-CoA. Collectively these results can be applied to many diseases; reduced nutrient supply and O2 during ischemia/stroke, hypoglycaemia in diabetes mellitus and cancer associated changes in uncoupling protein expression levels.

Improved image analysis based corrosion assessment using preprocessing techniques

The importance of non-destructive techniques (NDT) in structural health monitoring programmes is being critically felt in the recent times. The quality of the measured data, often affected by various environmental conditions can be a guiding factor in terms usefulness and prediction efficiencies of the various detection and monitoring methods used in this regard. Often, a preprocessing of the acquired data in relation to the affecting environmental parameters can improve the information quality and lead towards a significantly more efficient and correct prediction process. The improvement can be directly related to the final decision making policy about a structure or a network of structures and is compatible with general probabilistic frameworks of such assessment and decision making programmes. This paper considers a preprocessing technique employed for an image analysis based structural health monitoring methodology to identify sub-marine pitting corrosion in the presence of variable luminosity, contrast and noise affecting the quality of images. A preprocessing of the gray-level threshold of the various images is observed to bring about a significant improvement in terms of damage detection as compared to an automatically computed gray-level threshold. The case dependent adjustments of the threshold enable to obtain the best possible information from an existing image. The corresponding improvements are observed in a qualitative manner in the present study.

Management of safety climate and the psychosocial work environment – new challenges for occupational health and safety professionals?

Introduction: The work environment and Occupational Health and Safety (OHS) practice have changed over the last number of years. A holistic OHS approach has been recommended by the authorities in this field (e.g. World Health Organisation (WHO), European Agency for Safety and Health at Work (EU-OSHA) and the International Labour Organisation (ILO)). This involves a unified action engaging elements of the physical and psychosocial workplace with greater focus on prevention and promotion of health and wellbeing. The health and safety practitioner (HSP) has been recognised as one of the main agents for implementation of OHS. Within an organisation they act as a leader of change and a professional who shapes health and safety while safeguarding the wellbeing of individuals at work. Additionally, safety climate (SC) has been developed as an essential concept for OHS of an organisation, its productivity and the wellbeing of its workforce. Scholars and practitioners have recognised the great need for further empirical evidence on the HSP’s role in a changing work environment that increasingly requires the use of preventative measures and the assessment and management of psychosocial work-related risks. This doctoral research brings together the different concepts used in OHS and Public Health including SC, Psychosocial workplace risks, Health Promotion and OHS performance. The associations between these concepts are analysed bearing in mind the WHO Healthy Workplace Framework and three of its main components (physical and psychosocial work environment and health resources). This thesis aims to establish a deeper understanding of the practice and management of OHS in Ireland and the UK, exploring the role of HSPs (employed in diverse sectors of activity) and of SC in the OHS of organisations. Methods: One systematic review and three cross-sectional research studies were performed. The systematic review focussed on the evidence compiled for the association of SC with accidents and injuries at work, clarifying this concept’s definition and its most relevant dimensions. The second article (chapter 3) explored the association of SC with accidents and injuries in a sample of workers (n=367) from a pharmaceutical industry and compared permanent with non-permanent workers. Associations of safety climate with employment status and with self-reported occupational accidents/injuries were studied through logistic regression modelling. The third and fourth papers in this thesis investigated the main tasks performed by HSPs, their perceptions of SC, health climate (HC), psychosocial risk factors and health outcomes as well as work efficacy. Validated questionnaires were applied to a sample of HSPs in Ireland and UK, members of the Institute of Occupational Safety and Health (n=1444). Chi-square analysis and logistic regression were used to assess the association between HSPs work characteristics and their involvement in the management of Psychosocial Risk Factors, Safety Culture and Health Promotion (paper 3). Multiple linear regression analysis was used to determine the association between SC, HC, psychosocial risk factors and health outcomes (general health and mental wellbeing) and self-efficacy. Results: As shown in the systematic review, scientific evidence is unable to establish the widely assumed causal link between SC and accidents and injuries. Nevertheless, the current results suggested that, particularly, the organisational dimensions of SC were associated with accidents and injuries and that SC is linked to health, wellbeing and safety performance in the organisation. According to the present research, contingent workers had lower SC perceptions but showed a lower accident/injury rate than their permanent colleagues. The associations of safety climate with accidents/injuries had opposite directions for the two types of workers as for permanent employees it showed an inverse relationship while for temporary workers, although not significant, a positive association was found. This thesis’ findings showed that HSPs are, to a very small degree, included in activities related to psychosocial risk management and assessment, to a moderate degree, involved in HP activities and, to a large degree, engaged in the management of safety culture in organisations. In the final research study, SC and HC were linked to job demands-control-support (JDCS), health, wellbeing and efficacy. JDCS were also associated with all three outcomes under study. Results also showed the contribution of psychosocial risk factors to the association of SC and HC with all the studied outcomes. These associations had rarely been recorded previously. Discussion & Conclusions: Health and safety climate showed a significant association with health, wellbeing and efficacy - a relationship which affects working conditions and the health and wellbeing of the workforce. This demonstrates the link of both SC and HC with the OHS and the general strength or viability of organisations. A division was noticed between the area of “health” and “safety” in the workplace and in the approach to the physical and psychosocial work environment. These findings highlighted the current challenge in ensuring a holistic and multidisciplinary approach for prevention of hazards and for an integrated OHS management. HSPs have shown to be a pivotal agent in the shaping and development of OHS in organisations. However, as observed in this thesis, the role of these professionals is still far from the recommended involvement in the management of psychosocial risk factors and could have a more complete engagement in other areas of OHS such as health promotion. Additionally, a strong culture of health and safety with supportive management and buy-in from all stakeholders is essential to achieve the ideal unified and prevention-focussed approach to OHS as recommended by the WHO, EU-OSHA and ILO.

Defending the 'public interest': an assessment of competing actor representations of 'solutions' to growing natural resource deficiencies.

This paper applies a SRT framework to the study of two case studies, namely the recent campaign of opposition to the legalization of hydraulic fracking in the State of New York and the more ongoing debate on land leasing in Africa. In relation to both campaigns, the analysis accounts for the arguments of a major financial institution and industry representatives who stress the safe and value-adding dimensions of these practices, as well as the views of opponents who refute the validity of industry's position and point to the unacceptable risks posed to the community, health and the environment. In spite of a number of obvious differences between these two case studies, not least differences arising from contrasting socio-economic and geo-political settings, there were also some notable similarities. First, was a tendency amongst protesters in both cases to formulate their role as contemporaries in a historically extended struggle for democratic justice. All perceived of themselves as guardians of their community's right to resist a corporate 'invasion' of their territories, like their forefathers and mothers before them. A theme of colonialism was explored in both settings through various identity and thematic anchoring devices that deliberately evoked shared understandings and historical memories of exploitation and human suffering. The evocation of powerful symbols of identity through visual narratives of protest further reinforced the cultural comprehensibility of opponents' message of protest in both contexts.