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Biomedical subjects

J Tickner

Publications and source records attributed to J Tickner.

9 recordsLinked to original sources
PubMed2005

Evaluation and further development of EASE model 2.0.

EASE (Estimation and Assessment of Substance Exposure) is a general model that may be used to predict workplace exposure to a wide range of substances hazardous to health. First developed in the early 1990s, it is now in its second Windows version. This paper provides a critical assessment of the utility and performance of the EASE model, and on the basis of this review, recommendations for the structure of a revised model are outlined. Twenty-seven stakeholders were interviewed about their previous use of EASE, perceived advantages and limitations of the model and suggestions for improvement. A subset of stakeholders was contacted on a second occasion to determine their views on the preferred outputs for an ideal exposure assessment model. Overall, stakeholders felt that the model should be updated to provide more accurate and precise exposure assessments. However, users also expressed the view that the simplicity and usability of the software model should not be compromised. Six studies investigating the validity of the inhalation exposure assessment section of EASE were identified. These showed that the model generally either predicted close to the measured exposures or overestimated exposure; though performance was highly variable. Two studies investigated the validity of the dermal exposure assessment and found that EASE produced considerable overestimates of actual dermal exposure (the amount of a substance that actually lands on the skin). A conceptual model of exposure was developed to investigate whether the structure of the EASE model is appropriate. Although EASE has a number of characteristics that describe exposure, it is a greatly simplified model and does not include all the important exposure determinants. More importantly, EASE can produce estimates of exposure that are ambiguous or incomplete. Our conceptual model may provide a rational basis for developing an improved version of EASE but further consultation is needed to decide the purpose and intended use of any successor to EASE.

Air Pollutants, Occupational↗
PubMed2001

Workshop on harmonization of serving future needs with occupational exposure databases--inhalation modeling, session IIIA.

This workshop was one of several that took place at the International Symposium on Occupational Exposure Databases and Their Application for the Next Millennium held in London from November 1-3, 1999. About 30 delegates participated in the workshop. The agenda for the discussions was provided by a white paper prepared by the organizers. The workshop produced a conceptual outline for a general-purpose prediction model for inhalation exposure, and constructed a list of important input variables for successful model development. Evaluation of prototype models was discussed in some detail, and the workshop concluded with suggestions for taking forward the ideas discussed and maintaining the momentum and interest generated during the symposium.

Databases, Factual↗
PubMed2001

Retrospective collection of exposure data from industry: results from a feasibility study in the United Kingdom.

In the United Kingdom the Health and Safety Executive for some years has stored chemical exposure data in their National Exposure Database. However, it has been difficult to persuade industry and other organizations to contribute to this resource. The aim of this project was to devise a cost-effective method of obtaining occupational exposure data on chemicals from U.K. industry and other sources. Five strategies were used to identify data for three different substances: toluene, acrylonitrile, and ethylene oxide. In total, 810 organizations were contacted and over 45 percent responded. However, only 40 had relevant exposure data. Almost equal numbers of acceptable measurements were identified for toluene and acrylonitrile (2,770 and 2,000 respectively) with lesser ethylene oxide data (800). These measurements were drawn from a wide range of industries and are probably representative of measurements made by U.K. industry, although most of the data were from companies employing more than 100 people. During the second phase of the project, more than 3,000 measurements and associated contextual information were collected (499 for toluene, 1,516 for acrylonitrile, and 17 for ethylene oxide, with a further 1,004 measurements for 1 of 27 substances collected simultaneously with one of the above). The costs of identifying and collecting exposure data ranged from ł7 to ł380 per valid measurement, depending on the source of the data. We suggest that, rather than trying to retrospectively collect data, it is likely to be more cost-effective to enlist a number of occupational hygiene consults and industrial organizations to prospectively provide anonymized exposure measurements for inclusion in the Health and Safety Executives National Exposure Database.

Data Collection↗
PubMed2001

The precautionary principle in environmental science.

Environmental scientists play a key role in society's responses to environmental problems, and many of the studies they perform are intended ultimately to affect policy. The precautionary principle, proposed as a new guideline in environmental decision making, has four central components: taking preventive action in the face of uncertainty; shifting the burden of proof to the proponents of an activity; exploring a wide range of alternatives to possibly harmful actions; and increasing public participation in decision making. In this paper we examine the implications of the precautionary principle for environmental scientists, whose work often involves studying highly complex, poorly understood systems, while at the same time facing conflicting pressures from those who seek to balance economic growth and environmental protection. In this complicated and contested terrain, it is useful to examine the methodologies of science and to consider ways that, without compromising integrity and objectivity, research can be more or less helpful to those who would act with precaution. We argue that a shift to more precautionary policies creates opportunities and challenges for scientists to think differently about the ways they conduct studies and communicate results. There is a complicated feedback relation between the discoveries of science and the setting of policy. While maintaining their objectivity and focus on understanding the world, environmental scientists should be aware of the policy uses of their work and of their social responsibility to do science that protects human health and the environment. The precautionary principle highlights this tight, challenging linkage between science and policy.

Decision Making↗
PubMed2001

Reenergizing public health through precaution.

The precautionary principle has provoked a spirited debate among environmentalists worldwide, but it is equally relevant to public health and shares much with primary prevention. Its central components are (1) taking preventive action in the face of uncertainty; (2) shifting the burden of proof to the proponents of an activity; (3) exploring a wide range of alternatives to possibly harmful actions; and (4) increasing public participation in decision making. Precaution is relevant to public health, because it can help to prevent unintended consequences of well-intentioned public health interventions by ensuring a more thorough assessment of the problems and proposed solutions. It can also be a positive force for change. Three aspects are stressed: promoting the search for safer technologies, encouraging greater democracy and openness in public health policy, and stimulating reevaluation of the methods of public health science.

Decision Making, Organizational↗
PubMed2000

Determination of the spatial response of neutron based analysers using a Monte Carlo based method

One of the principal advantages of using thermal neutron capture (TNC, also called prompt gamma neutron activation analysis or PGNAA) or neutron inelastic scattering (NIS) techniques for measuring elemental composition is the high penetrating power of both the incident neutrons and the resultant gamma-rays, which means that large sample volumes can be interrogated. Gauges based on these techniques are widely used in the mineral industry for on-line determination of the composition of bulk samples. However, attenuation of both neutrons and gamma-rays in the sample and geometric (source/detector distance) effects typically result in certain parts of the sample contributing more to the measured composition than others. In turn, this introduces errors in the determination of the composition of inhomogeneous samples. This paper discusses a combined Monte Carlo/analytical method for estimating the spatial response of a neutron gauge. Neutron propagation is handled using a Monte Carlo technique which allows an arbitrarily complex neutron source and gauge geometry to be specified. Gamma-ray production and detection is calculated analytically which leads to a dramatic increase in the efficiency of the method. As an example, the method is used to study ways of reducing the spatial sensitivity of on-belt composition measurements of cement raw meal.

Journal Article↗