Sequential Assessment of Carcinogenic Hazard and Risk

Author(s):  
John Ashby
Keyword(s):  
Author(s):  
A Rowan-Carroll ◽  
A Reardon ◽  
K Leingartner ◽  
R Gagné ◽  
A Williams ◽  
...  

Abstract Per- and poly-fluoroalkyl substances (PFAS) are widely found in the environment because of their extensive use and persistence. Although several PFAS are well studied, most lack toxicity data to inform human health hazard and risk assessment. This study focussed on four model PFAS: perfluorooctanoic acid (PFOA; 8 carbon), perfluorobutane sulfonate (PFBS; 4 carbon), perfluorooctane sulfonate (PFOS; 8 carbon), and perfluorodecane sulfonate (PFDS; 10 carbon). Human primary liver cell spheroids (pooled from 10 donors) were exposed to 10 concentrations of each PFAS and analyzed at four time-points. The approach aimed to: (1) identify gene expression changes mediated by the PFAS; (2) identify similarities in biological responses; (3) compare PFAS potency through benchmark concentration analysis; and (4) derive bioactivity exposure ratios (ratio of the concentration at which biological responses occur, relative to daily human exposure). All PFAS induced transcriptional changes in cholesterol biosynthesis and lipid metabolism pathways, and predicted PPARα activation. PFOS exhibited the most transcriptional activity and had a highly similar gene expression profile to PFDS. PFBS induced the least transcriptional changes and the highest benchmark concentration (i.e., was the least potent). The data indicate that these PFAS may have common molecular targets and toxicities, but that PFOS and PFDS are the most similar. The transcriptomic bioactivity exposure ratios derived here for PFOA and PFOS were comparable to those derived using rodent apical endpoints in risk assessments. These data provide a baseline level of toxicity for comparison with other known PFAS using this testing strategy.


Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 158
Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests using terms that appear to be the most logic and explicit as possible and describes methods to derive some of the main hazards and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized and diffuse hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed, and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the reach probability, and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (passage frequency) can be derived. This frequency is relevant for risk assessment when the element at risk can be damaged several times. If it is not replaced, the probability that it is impacted by at least one rockfall is more relevant.


Author(s):  
D. J. Bailey ◽  
M. C. Stennett ◽  
J. Heo ◽  
N. C. Hyatt

AbstractSEM–EDX and Raman spectroscopy analysis of radioactive compounds is often restricted to dedicated instrumentation, within radiological working areas, to manage the hazard and risk of contamination. Here, we demonstrate application of WetSEM® capsules for containment of technetium powder materials, enabling routine multimodal characterisation with general user instrumentation, outside of a controlled radiological working area. The electron transparent membrane of WetSEM® capsules enables SEM imaging of submicron non-conducting technetium powders and acquisition of Tc Lα X-ray emission, using a low cost desktop SEM–EDX system, as well as acquisition of good quality μ-Raman spectra using a 532 nm laser.


2021 ◽  
pp. 112334
Author(s):  
Serena Santonicola ◽  
Stefania Albrizio ◽  
Maria Carmela Ferrante ◽  
Mercogliano Raffaelina

2008 ◽  
Vol 23 (3) ◽  
pp. 286-288 ◽  
Author(s):  
Ali Ardalan ◽  
Faina Linkov ◽  
Eugene Shubnikov ◽  
Ronald E. LaPorte

AbstractImproving public awareness through education has been recognized widely as a basis for reducing the risk of disasters. Some of the first disaster just-in-time (JIT) education modules were built within 3–6 days after the south Asia tsunami, Hurricane Katrina, and the Bam, Pakistan, and Indonesia earthquakes through a Supercourse. Web monitoring showed that visitors represented a wide spectrum of disciplines and educational levels from 120 developed and developing countries. Building disaster networks using an educational strategy seizes the opportunity of increased public interest to teach and find national and global expertise in hazard and risk information. To be effective, an expert network and a template for the delivery of JIT education must be prepared before an event occurs, focusing on developing core materials that could be customized rapidly, and then be based on the information received from a recent disaster. The recyclable process of the materials would help to improve the quality of the teaching, and decrease the time required for preparation. The core materials can be prepared for disasters resulting from events such as earthquakes, hurricanes, tsunamis, floods, and bioterrorism.


2021 ◽  
Vol 97 (2) ◽  
pp. 199-209
Author(s):  
Biswajit Bera ◽  
Sumana Bhattacharjee ◽  
Meelan Chamling ◽  
Arijit Ghosh ◽  
Nairita Sengupta

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