Risk assessment of chemicals in foundries: the International Chemical Toolkit pilot-project

In Brazil, problems regarding protection from hazardous substances in small-sized enterprises are similar to those observed in many other countries. Looking for a simple tool to assess and control such exposures, FUNDACENTRO has started in 2005 a pilot-project to implement the International Chemical Control Toolkit. During the series of visits to foundries, it was observed that although many changes have occurred in foundry technology, occupational exposures to silica dust and metal fumes continue to occur, due to a lack of perception of occupational exposure in the work environment. After introducing the Chemical Toolkit concept to the foundry work group, it was possible to show that the activities undertaken to improve the management of chemicals, according to its concept, will support companies in fulfilling government legislations related to chemical management, occupational health and safety, and environmental impact. In the following meetings, the foundry work group and FUNDACENTRO research team will identify "inadequate work situations". Based on the Chemical Toolkit, improvement measures will be proposed. Afterwards, a survey will verify the efficiency of those measures in the control of hazards and consequently on the management of chemicals. This step is now in course.     

The use of maintenance indicators to evaluate the effects of maintenance programs on NPP performance and safety

Nuclear Power Plants (NPPs) under commercial operation are under continuous demand to meet higher levels of performance and safety by NPP owners, regulatory authorities and the public in general. Maintenance plays an important role in achieving such a goal, therefore, many programs are being conducted in order to improve their effectiveness. A common link between these programs is the necessity to evaluate how maintenance affects NPP performance and safety. This paper presents the foundation of a methodology for a maintenance evaluation program based on maintenance indicators and how it is applied to monitoring the effectiveness of the maintenance at the Cofrentes NPP. The methodology is general and might be applied in other fields of industrial engineering, particularly in those activities which devote many resources to maintain plant equipment, and also in those with less but very critical maintenance.     

Catastrophe model for the exposure to blood-borne pathogens and other accidents in health care settings

Catastrophe models, which describe and predict discontinuous changes in system state variables, were used to model the exposure to blood and bodily fluids and more conventional occupational accidents among 1708 health care workers. Workers at three hospitals completed a survey measuring HIV-relevant exposures (needlesticks, cuts, splashes, contact with open wounds), the accident rate for broadly-defined injuries, and several occupationally relevant themes: safety climate, shift work, depression symptoms, work pace, verbal abuse, and professional group membership. A cusp (cubic polynomial) model predicting HIV-relevant exposures specifically was more accurate (R²=0.56) than a comparable linear model containing the same variables (R²=0.07). Some of the foregoing variables predisposed workers to greater differences in HIV-relevant and general accident exposures: shiftwork, climate, depressive symptoms, and work pace. Other variables governed how close an individual was to a critical threshold where a harmful incident would take place: verbal abuse, professional group membership. Similarly, a cusp model for accident incidents predicted from HIV-relevant exposures and occupational variables was also more accurate (R²=0.75) than comparison models. Two variables predisposed the worker to a greater accident risk: depression symptoms and shift work. Four other variables predisposed the worker to lesser accident risk: job satisfaction, safety climate, environmental stressors, and work pace. Compliance with the universal precautions and HIV-related training were not relevant to either of the models.     

Resonance of human brain under head acceleration

Although safety standards have reduced fatal head trauma due to single severe head impacts, mild trauma from repeated head exposures may carry risks of long-term chronic changes in the brain''s function and structure. To study the physical sensitivities of the brain to mild head impacts, we developed the first dynamic model of the skull–brain based on in vivo MRI data. We showed that the motion of the brain can be described by a rigid-body with constrained kinematics. We further demonstrated that skull–brain dynamics can be approximated by an under-damped system with a low-frequency resonance at around 15 Hz. Furthermore, from our previous field measurements, we found that head motions in a variety of activities, including contact sports, show a primary frequency of less than 20 Hz. This implies that typical head exposures may drive the brain dangerously close to its mechanical resonance and lead to amplified brain–skull relative motions. Our results suggest a possible cause for mild brain trauma, which could occur due to repetitive low-acceleration head oscillations in a variety of recreational and occupational activities.     

Factors Affecting the Permanence of Occupational Health and Safety Topics in Engineering Courses

This paper presents an evaluation of the permanence of changes introduced within the curriculum of the College of Engineering at Tufts University. These changes involved the integration of occupational health and safety engineering resource materials into existing course work. Employing this model, Tufts faculty members developed their own lectures, case studies and laboratory materials for integration into existing courses. The evaluation, that was based on structured interviews of participating faculty and the Dean of the College, suggests that the permanence of changes to curriculum is influenced by a set of intramural parameters within the academic milieu (student interest, available class time, interest on the part of the faculty and administration) as well as by extramural factors such as the increasing prominence of legal liability of practitioners, growing interest on the part of employers and lack of readily usable materials in standard texts concerning occupational health and safety. Recommendations for future activities in these areas are offered and discussed.     

Harmonisation (legal, dosimetric, quality aspects) of individual monitoring, and integration of monitoring for external and internal exposures (EURADOS Working Group)

The EURADOS Working Group II on 'Harmonisation of individual monitoring' consists of experts from almost all EU Member States and Newly Associated States (NAS), involved in tasks related to the assessment of doses for internal and external radiation. The final objective is to achieve harmonisation in individual monitoring for occupational exposures. Sub-group 2 activities are focused on investigating how the results from personal dosemeters for external radiation and workplace monitoring and from monitoring for internal exposure can be combined into a complete and consistent system of individual monitoring. Three questionnaires were prepared, covering 'Individual monitoring of external radiation' (Questionnaire 1), 'Internal exposure' (Questionnaire 2) and 'Natural sources of radiation at the workplace' (Questionnaire 3). With the agreement of a 'contact-person', selected in each country, the distribution of the three EURADOS 2002 questionnaires was carried out by e-mail among the dosimetry facilities of 28 European countries. The preliminary results of these actions are presented here.     

Assessment of uranium exposure from total activity and 234U:238U activity ratios in urine

Radiation workers at Atomic Weapons Establishment (AWE) are monitored for uranium exposure by routine bioassay sampling (primarily urine sampling). However, the interpretation of uranium in urine and faecal results in terms of occupational intakes is difficult because of the presence of uranium due to intakes from environmental (dietary) sources. For uranium in urine data obtained using current analytical techniques at AWE, the mean, median and standard deviation of excreted uranium concentrations were 0.006, 0.002 and 0.012 μg per g creatinine, respectively. These values are consistent with what might be expected from local dietary intakes and the knowledge that occupational exposures at AWE are likely to be very low. However, some samples do exceed derived investigation levels (DILs), which have been set up taking account of the likely contribution from environmental sources. We investigate how the activity and isotopic composition of uranium in the diet affects the sensitivity of uranium in urine monitoring for occupational exposures. We conclude that DILs based on both total uranium in urine activity and also (234)U:(238)U ratios are useful given the likely variation in dietary contribution for AWE workers. Assuming a background excretion rate and that the enrichment of the likely exposure is known, it is possible to assess exposures using (234)U:(238)U ratios and/or total uranium activity. The health implications of internalised uranium, enriched to <5-8 % by mass (235)U, centre on its nephrotoxicity; the DILs for bioassay samples at AWE are an order of magnitude below the conservative recommendations made by the literature.     

Optimal Scheduling of Track Maintenance on a Railway Network

To ensure the safety and continued operation of the railway network system, many maintenance and renewal activities are performed on the track every month. Unplanned maintenance activities are expensive and would cause low service quality. Therefore, the track condition should be monitored, and when it has degraded beyond some acceptable limit, it should be scheduled for maintenance before failure. An optimal timetable of the maintenance activities is needed to be scheduled, planning the monthly workload, to reduce the effect on the transportation service and to reduce the potential costs. Considering the uncertainties of the deterioration process, the safety of transportation service, the lifetime loss of the replaced track, the maintenance cost and the travel cost, this article advances an optimisation model for the maintenance scheduling of a regional railway network. An enhanced genetic algorithm approach is proposed to search for a solution producing maintenance schedule such that the overall cost is minimised in a finite planning horizon. A case study is given to demonstrate the application of the method. The case study results were derived by using an enhanced genetic algorithm method, which is specifically developed to deal with the characteristics of the railway maintenance problem. Copyright © 2012 John Wiley & Sons, Ltd.     

Individual monitoring for internal exposures in Europe: conclusions of an EURADOS action

Once the EC Directive 96/29 has been implemented into national regulation across Europe, the coordination of dosimetry laboratories for the monitoring of occupational exposures becomes the principal aim to achieve. Within this framework the European Radiation Dosimetry Group, EURADOS, carried out an Action on 'Harmonisation of Individual Monitoring' (2000-2004) to promote coordination in the field of individual monitoring of occupational exposures throughout Europe. With reference to internal exposures, the main aims were the completion of a catalogue of internal dosimetry services and an inventory of methods and techniques used for individual monitoring at European internal dosimetry facilities. At the end of this EURADOS Action, a report was published in Radiation Protection Dosimetry in 2004. The information collected related to various topics: the equipments used for the measurement of internal exposures, calibration and sensitivity data, the methods applied for the assessment of internal doses, Quality Control procedures, Quality Assurance Programmes in the facilities and legal requirements. The information to be presented here will give a general overview of the actual status of individual monitoring for internal exposures in Europe.     

Optimization of lifetime maintenance strategies for deteriorating structures considering probabilities of violating safety, condition, and cost thresholds

Modern maintenance strategies for deteriorating structures are typically based on minimizing total cost. Extensions of this concept into the nondeterministic range allow to take into account the uncertainty in total cost. In this paper, the probability of exceeding a total cost threshold is included in the structure maintenance optimization problem. In addition, the probabilities of violating acceptable levels of safety and condition are computed. Based on this, an optimization task can be formulated and solved in which these probabilities can be included into the formulation of the objective function and the constraint conditions. Smoothing of the Monte-Carlo-based results is carried out utilizing a smoothing procedure by regression methods which are well-known for the response surface approach.Both time-based maintenance and performance-based maintenance are taken into account. The total maintenance cost is minimized with respect to parameters of both types of maintenance. Taking into account the cost of failure, optimal values for the threshold safety level and the time interval between subsequent maintenance applications are obtained.It is shown that different design parameters can lead to the same total cost thus allowing for a trade-off between time-based maintenance and performance-based maintenance at the discretion of the structure maintenance manager.     

Resources assignment model in maintenance activities scheduling

This paper proposes an analytical model for resources assignment in the context of maintenance activities scheduling. It takes into account the human as well as material resources availability constraints. It allows the decision maker to consider not only the preventive maintenance activities but also the potential failures which may occur during the scheduling horizon. Opportunistic maintenance may be considered as an option to improve the occupational rate mainly for maintenance operators. Additional constraints such as the completion time of some specific maintenance activities and the earliest starting works on a given machine may easily be considered in the model. Recall that the main purpose of this paper is to suggest an improved model for resources assignment to be implemented into a planning and scheduling module in CMMS software. The proposed model generates a feasible plan and makes sensitivity analysis possible in order to take into account the material and human resources fluctuations. A numerical example has been treated in order to illustrate the modelling process and to validate the coherence of the model. An attempt is made to develop a generic model which must be flexible and user friendly. Authors are investigating many other extensions of this work to fulfil some specific needs for the company which develops CMMS software. For the illustrative example presented in this paper, the explicit form of the mathematical model is provided in the Appendix of the paper.     

An overview on extremity dosimetry in medical applications

Some activities of EURADOS Working Group 9 (WG9) are presently funded by the European Commission (CONRAD project). The objective of WG9 is to promote and co-ordinate research activities for the assessment of occupational exposures to staff at workplaces in interventional radiology (IR) and nuclear medicine. For some of these applications, the skin of the fingers is the limiting organ for individual monitoring of external radiation. Therefore, sub-group 1 of WG9 deals with the use of extremity dosemeters in medical radiation fields. The wide variety of radiation field characteristics present in a medical environment together with the difficulties in measuring a local dose that is representative for the maximum skin dose, usually with one single detector, makes it difficult to perform accurate extremity dosimetry. Sub-group 1 worked out a thorough literature review on extremity dosimetry issues in diagnostic and therapeutic nuclear medicine and positron emission tomography, interventional radiology and interventional cardiology and brachytherapy. Some studies showed that the annual dose limits could be exceeded if the required protection measures are not taken, especially in nuclear medicine. The continuous progress in new applications and techniques requires an important effort in radiation protection and training.     

Individual safety performance in the construction industry: development and validation of two short scales

In the current research a short measure of safety performance is developed for use in the construction industry and the relationships between different components of safety performance and safety outcomes (e.g., occupational injuries and work-related pain) are explored within the construction context. This research consists of two field studies. In the first, comprehensive measures of safety compliance and safety participation were shortened and modified to be appropriate for use in construction. Evidence of reliability and validity is provided. Both safety compliance and safety participation were negatively related to occupational injuries, yet these two correlations were not statistically different. In the second study, we investigated the relationships between these two components of safety performance and work-related pain frequency, in addition to replicating Study 1. Safety compliance had a stronger negative relationship with pain than safety participation. Implications for research are discussed.     

Educational and training activities in personal dosimetry in Greece

An individual monitoring programme is one of the main components of any radiation protection programme since it constitutes the mean for assessing and thus optimising the doses of occupationally exposed workers. The Greek Atomic Energy Commission (GAEC) is the competent authority for radiation protection and nuclear safety in Greece. GAEC's educational and training activities in the field of occupational radiation protection at the national and regional (Eastern Europe) level are presented, along with the relevant activities of the University of Ioannina in the region of North-West Greece, as an example of a local education and training programme. The curricula of two postgraduate courses addressed to qualified experts and medical physics experts and mainly the modules dedicated to individual monitoring are discussed as well.     

Safety analysis in design—Evaluation of a case study

Safety analysis was applied in the design of a section at a paper mill. The case study involved analysis of layout, transport system, machines, and a number of different activities. The purpose of the analysis was to find measures to decrease occupational accidents. Three years after the installation was finished the occurrence of accidents was investigated. There was a 56% decrease in the number of accidents; the number of working days lost due to accidents was diminished by 75% as compared to 4 years preceding. The results of the safety analysis were also evaluated with respect to the accidents which had occurred. The methods for safety analysis seem to have been efficient in identifying hazards. The general conclusion of the study is that safety analysis can be an effective tool to decrease occupational accident risks.     

Occupational exposure in angiography (Prague workplaces)

The results of measurements, which were performed at angiography departments, are presented. The aim of this work was not only to assess patient exposure but also to perform a survey of the occupational exposures of physicians during common angiography examinations of the skull, chest, abdomen and limbs. Patient data, type of examination, fluoroscopy time, the whole number of film frames, dose-area product (Diamentor E) and physician dose (Stephen 6000) were also recorded. There are many factors influencing the level of measured exposures. They include input parameters of X ray performance (kV, mA, projection, diaphragms, ZOOM, type of record etc) and individual approach of the physicians. This paper contributes to the discussion about the increasing exposures of the physicians specialising in diagnostic and interventional angiography.     

Personal dose monitoring in hospitals: global assessment, critical applications and future needs

It is known that medical applications using ionising radiation are wide spread and still increasing. Physicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radiation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures. in the university hospital, UZ Brussel, 600 out of 4000 staff members are daily monitored for external radiation exposures. The most obvious applications of ionising radiation are diagnostic radiology, diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical research and radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these applications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found. most of the studies are concentrated around nuclear medicine applications and IR. They contain assessments of both effective dose and doses at different parts of the body. The results contribute to better characterisation of the different workplaces in a way that critical applications can be identified. Moreover, conclusions point out future needs for practical routine dose monitoring and optimisation of radiation protection.     

Present and future activities of the IAEA on internal dosimetry: lessons learned from international intercomparisons

The International Atomic Energy Agency (IAEA) conducts safety activities to support the assessment of occupational exposure due to intakes of radionuclides; a comprehensive set of safety documents will soon be completed. In recent years, extensive improvements in measurement techniques, phantoms and computational tools have been made. Thus, it is important for laboratories involved in internal dosimetry to undergo performance testing procedures to demonstrate the correctness of the methods applied and also to determine the consistency of their results with those obtained by other laboratories. Several intercomparisons were organised, and they revealed significant differences among laboratories in their approaches, methods and assumptions, and consequently in their results. This paper presents the current and future IAEA activities in support of assessment of occupational exposure due to intakes of radionuclides in the IAEA Member States, as well as the lessons learned from several intercomparison exercises in the last 5 years.     

Integrating occupational health and safety in facility layout planning,part I: methodology

An influential factor affecting the efficiency of a manufacturing facility is its layout. In a production facility, measure for efficiency can be based on the total cost of transporting the items between different departments and throughout the facility. However, other factors may influence efficiency of the manufacturing facility too. As such are: supporting the organisation's vision through improved material handling, material flow and control; effectively assigning people, equipment, space and energy; minimising capital investment; adaptability and ease of maintenance; as well as providing for employee safety and job satisfaction. By incorporating health and safety measures in the initial design of a facility layout, the organisation may avoid money and manpower loss resulting from industrial accidents. This paper proposes a facility layout planning methodology which integrates the occupational health and safety (OHS) features in the early design of a facility layout. The model considers transportation cost in the facility as well as safety concerns. By this means, the OHS issues are reflected prior to the construction of a facility.     

Dose level of occupational exposure in China

This paper discusses the dose level of Chinese occupational exposures during 1986-2000. Data on occupational exposures from the main categories in nuclear fuel cycle (uranium enrichment and conversion, fuel fabrication, reactor operation, waste management and research activity, except for uranium mining and milling because of the lack of data), medical uses of radiation (diagnostic radiation, nuclear medicine and radiotherapy) and industrial uses of radiation (industrial radiography and radioisotope production) are presented and summarised in detail. These are the main components of occupational exposures in China. In general, the average annual effective doses show a steady decreasing trend over periods: from 2.16 to 1.16 mSv in medical uses of radiation during 1990-2000; from 1.92 to 1.18 mSv in industrial radiography during 1990-2000; from 8.79 to 2.05 mSv in radioisotope production during the period 1980-2000. Almost all the average annual effective doses in discussed occupations were lower than 5 mSv in recent years (except for well-logging: 6.86 mSv in 1999) and no monitored workers were found to have received the occupational exposure exceeding 50 mSv in a single year or 100 mSv in a five-year period. So the Chinese protection status of occupation exposure has been improved in recent years. However, the average annual effective doses in some occupations, such as diagnostic radiology and coal mining, were still much higher than that of the whole world. There are still needs for further improvement and careful monitoring of occupational exposure to protect every worker from excessive occupational exposure, especially for the workers who were neglected before.