Research Q7 - Uncertainty factors in Risk assessment
Institution
Radboud Universiteit Nijmegen (RU)
Book
Casarett & Doull\'s Essentials of Toxicology
(Extended) Summary Research Q7 - Uncertainty factors in Risk assessment including all lectures, self study assignments and a COO Hazard Identification (E-learning).
Research Q7 - Uncertainty factors in Risk assessment
All documents for this subject (1)
2
reviews
By: michellec2000 • 4 year ago
By: NicoleCedella • 5 year ago
Seller
Follow
rdeveer
Reviews received
Content preview
Renske de Veer (rdeveer)
Q7 Research – Uncertainty factors in Risk assessment
HC 1. Introduction uncertainty factors in risk assessment
Fields/factors that determine individual health:
- Human biology (genetics)
- Health care organization
- Lifestyle
- Environment
Toxicology: study of the adverse effects of xenobiotics (compounds foreign to the body) in living
systems
- Toxicology applies safety evaluation and risk assessment.
- Important questions:
o Is the compound toxic?
o What are the harmful effects? What is the exposure?
o How large is the risk for man, animals and environment?
o Why is the compound toxic? What is the mechanism of action?
Pesticides, water, and mercury are toxic → paradigm of toxicity: Paracelsus. “It is the dose that
makes the poison”.
Most deadly poison in the world: Botox. → intrinsic toxicity is huge.
Why is benzene more toxic than toluene?: Formation of toxic metabolites
Risk assessment/Risk management
Exposition phase: Behaviour of a substance in the environment, changes in the application form,
available for uptake.
Toxicokinetic phase: Absorption, distribution, biotransformation (toxification, detoxification),
excretion.
Toxicodynamic phase: Interactions with receptors or other (macro)molecules at the site of operation.
➔ Phases together determine effect.
Risk = Hazards x Exposures
,Renske de Veer (rdeveer)
- NOAEL: No observed adverse effect level
- TDI is the same as ADI (Acceptable daily intake).
Dose response relationships
Important routes of exposure
Toxicokinetics – Dose frequency (how much of the compound gets in) and elimination rate
,Renske de Veer (rdeveer)
- Compound A gets really slowly eliminated: shaded area → toxic.
- Repeated exposure: compounds can build up in the body.
ConsExpo
- ConsExpo is a computer program that enables the estimation and assessment of exposure to
substances from consumer products such as paint, cleaning agents and personal care
products
- Exposure routes for all consumer product:
o Inhalation:
▪ Gas/vapour
▪ Aerosols (sprays)
o Dermal absorption
o Ingestion
- Deterministic model: algorithm-based
o Calculation-generated output
- Some predefined exposure scenarios:
o Inhalation exposure: evaporation, paint and spray scenarios
o Oral exposure: hand-mouth contact, residue-on-plate scenario
o Dermal exposure: fixed volume scenario
- Exposure situation:
o Use amount (g)/source strength (g/s)
o Use frequency (per year)
o Use duration (hours)
o Exposure duration (hours)
- Environmental factors
o Temperature (C)
o Ventilation rate (1/h)
- Physicochemical substance properties
o Molecular weight
o Vapour pressue (mbar)
- Input
o Biometric data of exposed individuals
▪ Body weight (kg)
▪ Inhalation frequency (m3/24h)
• Rest
, Renske de Veer (rdeveer)
• Light exercise
• Heavy exercise
- Output
o Point value
o Distribution
▪ Median
▪ Mean
▪ 90-percentile
▪ 99-percentile
Advantages of modelling
Modelling
- Distributional or probabilistic calculations account for:
o Uncertainty: variation due to imperfect/incomplete knowledge
o Variability: natural variation in a parameter
- Modelling can be effective and efficient especially in the preparation phase
- Modelling can increase insight in the contribution of personal and environmental factors that
determine exposure exposure (sensitivity analysis)
- The uncertainty and variability in these factors can be calculated and visualized using Monte
Carlo simulation (distributional or probabilistic calculations
Sensitivity analysis
- Model sensitivity depends on:
o Model structure
o Range of parameter values
- Study the effect of changing one parameter at a time on the output
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller rdeveer. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R81,36. You're not tied to anything after your purchase.
