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Study Design and Methods
Published in Lisa Chasan-Taber, Writing Grant Proposals in Epidemiology, Preventive Medicine, and Biostatistics, 2022
The first step is to describe how you plan to collect data on your exposure of interest. Remember that “exposure” is broadly defined as the independent variable—the variable whose effect you are interested in. Examples of exposure assessment tools include questionnaires, medical records, biomarkers, or other methods. If you will be using a preexisting dataset, describe how the exposure data were originally collected regardless of the fact that you will not be collecting it yourself.
Modeling Exposure
Published in Samuel C. Morris, Cancer Risk Assessment, 2020
Environmental transport models get pollutants to where people can be exposed to them, but seldom take them right to the people. Exposure assessment involves more than just estimating environmental concentrations of pollutants in air and water; it involves determining the population exposed and the magnitude of the exposure. Integrated population exposure assessment also recognizes that people are exposed from multiple sources and through multiple routes. It takes the ambient concentrations in the various environmental media produced by transport models and combines them with population-related data to estimate total population exposure.
Exposure Assessment
Published in Ted W. Simon, Environmental Risk Assessment, 2019
In order for a risk to occur, there must be exposure to environmental media, i.e., soil, air, water, or sediment, and the medium must contain hazardous materials. The “Red Book” defines exposure assessment as the “process of measuring or estimating the intensity, frequency, and duration of human exposures to an agent currently present in the environment or of estimating hypothetical exposures that might arise from the release of new chemicals into the environment.”1
A harmonized protocol for an international multicenter prospective study of nanotechnology workers: the NanoExplore cohort
Published in Nanotoxicology, 2023
Irina Guseva Canu, Ekaterina Plys, Camille Velarde Crézé, Carlos Fito, Nancy B. Hopf, Athena Progiou, Chiara Riganti, Jean-Jacques Sauvain, Giulia Squillacioti, Guillaume Suarez, Pascal Wild, Enrico Bergamaschi
Importantly, the apparently small minimum sample size of this cohort with 120–160 workers actually corresponds to one of the largest studies of workers exposed to ENMs in the world. For instance, the unique cohort study of ENM workers (the EpiNano cohort) launched in 2012 in France, has included 130 workers so far (Guseva Canu et al. 2016c) while the future US National Institute for Occupational Safety and Health (US-NIOSH) cohort of carbon nanotube and nanofiber workers had 108 participants at baseline (Beard et al. 2018). The Taiwanese national panel study currently includes 206 exposed and 108 unexposed workers recruited at 14 different ENMs producing plants (Wu et al. 2019). It is noteworthy that in the US-NIOSH study, a personal exposure monitoring has been conducted while in the French cohort, the exposure is assessed only qualitatively since the (semi)quantitative exposure assessment has been discontinued (Renaudie et al. 2018). In the Taiwanese study, the exposure is assessed using control banding despite its high bias potential (Guseva Canu, Burstyn, and Richardson 2016b). The assessment of airborne exposure to ENMs based on aerosol sampling analysis should be considered as the minimal requirement pondering between the study feasibility in different occupational settings and the scientific value of its results. Whenever possible, it should be completed with a more thorough individual exposure assessment.
Radiological risk assessment of the Hunters Point Naval Shipyard (HPNS)
Published in Critical Reviews in Toxicology, 2022
Dennis J. Paustenbach, Robert D. Gibbons
This risk assessment followed the framework for risk assessments established by the National Academy of Science (NAS) and the USEPA, which requires that hazard identification, exposure assessment, dose-response assessment, and risk characterization be conducted (NAS 1983; United States Environmental Protection Agency [USEPA] 1989). The goal of hazard identification is to determine the capacity of a contaminant for causing an adverse effect by reviewing the relevant evidence. Exposure assessment is the process of “measuring or estimating the intensity, frequency, and duration of human or animal exposure to an agent currently present in the environment” (NAS 1983; Paustenbach 2002). The goal of dose-response assessment is to “quantitatively describe the relationship between the extent of exposure (the dose) and the likelihood of adverse health effects (responses)” (Lewandowski and Norman 2015). Finally, risk characterization integrates the results from the dose-response assessment and exposure assessment to estimate the risk of a particular contaminant to various receptors on- or off-site.
Overview on legislation and scientific approaches for risk assessment of combined exposure to multiple chemicals: the potential EuroMix contribution
Published in Critical Reviews in Toxicology, 2018
S. Rotter, A. Beronius, A. R. Boobis, A. Hanberg, J. van Klaveren, M. Luijten, K. Machera, D. Nikolopoulou, H. van der Voet, J. Zilliacus, R. Solecki
At the highest tiers, probabilistic exposure assessment may be conducted. In this approach, exposure to chemical mixtures in food is based on distributions of the concentrations of mixture components in different food items, as well as on distributions of the consumption of these foods in the population or in specific population groups. This allows conclusions to be drawn about, for example, the distribution of exposure levels in the population to different mixture components and the proportion of the population that may be at risk of exceeding specific exposure levels. Practical examples of integrated probabilistic cumulative risk assessments for exposures to organophosphorus and anti-androgenic pesticides as well as organophosphorus and carbamate insecticides in the Dutch population are shown in Boon et al. (2008), Bosgra et al. (2009), and Müller et al. (2009). Basic probabilistic methodology for modeling dietary exposure to pesticide residues has been described by the EFSA (2012). Van der Voet et al. (2015) proposed the implementation of the more advanced software system MCRA in the EFSA guidance and gave example calculations on the triazole group. The potential of this model is illustrated in case studies for different population groups in country-specific scenarios (Kennedy et al. 2015). Recently, probabilistic modeling is gaining recognition as an approach to exposure assessment, which is reflected in Europe by discussions between the European Commission and EFSA on the implementation of two probabilistic tiers for assessing risks from combined exposure to multiple chemicals. The degree of refinement of the estimates used at the start of the assessment (i.e. which tier) is determined by a number of factors, such as data availability, resources required, urgency of the assessment, and hence should be part of problem formulation.