In calculating a Reference dose (RfD) for a chemical, uncertainty factors are considered. Which of the following statements are true?

Question

BlackTom AI · Accepted Answer

When evaluating how uncertainty factors (UFs) contribute to calculating a Reference Dose (RfD), it's helpful to map each statement to common concepts in toxicology risk assessment.
Option 1: 'An example of an uncertainty factor would be that we only have animal data and lack human data.' This is accurate. Interspecies extrapolation, from animals to humans, is a primary reason for applying an uncertainty factor to account for potential differences in sensitivity and biology between species.
Option 2: 'To account for individual susceptibility/sensitivity, divide the NOAEL by 10.' This aligns with the standard intraspecies (human variability) UF, which is commonly set at 10 to protect sensitive individuals within the human population.
Option 3: 'The target tissue of the chemical is not fully understood would also be considered an uncertainty factor.' Ambiguity about which tissue or organ is most affected contributes to uncertainty in toxic effects and thus can be encompassed within database or target-organ uncertainty factors; recognizing gaps in knowledge about targets supports applying an UF to be precautionary.
Option 4: 'Another uncertainty factor would be if we do not know the solubility of the chemical.' Lack of knowledge about solubility affects exposure characterization and chemical bioavailability, but the standard framework of uncertainty factors in RfD calculations primarily encompasses toxicokinetic/toxicodynamic extrapolations and data gaps rather than a specific UF labeled for solubility. Therefore this statement is not typically considered a separate UF in the RfD paradigm.
Option 5: 'To account for individual susceptibility/sensitivity, divide the NOAEL by 10.' This is a repetition of Option 2 and still reflects the same intraspecies UF concept; as a duplicate, it remains a true depiction of that same factor.
In summary, the true statements correspond to the established rationale for UFs: animal-to-human extrapolation (Option 1), intraspecies variability (Option 2 and its duplicate Option 5), and uncertainty about the target tissue/organ (Option 3) as part of data gaps. The solubility knowledge gap (Option 4) is not a standalone standard UF in the classic RfD framework, making it not a universally recognized UF. The combination of true statements includes Options 1, 2, 3, and 5, while Option 4 would typically not be counted as a separate UF in this context.

PUBHP6040_001_2025_3 - DETERMINANTS OF HEALTH 2025 Week 9 - Learning Check

In calculating a Reference dose (RfD) for a chemical, uncertainty factors are considered. Which of the following statements are true?

View Explanation

Log in for full answers

Similar Questions

In basic pharmacology, what does the LD50 refer to?

Which one of the following statements about toxic molecules and their possible antidotes is correct?

What are extrinsic factors that can modify your vulnerability to a dose of a chemical? You can choose more than one.

What is Toxicology?

How true does this statement feel to you, “I know how to critically interpret current events of toxicologic importance.”

Which of the following observations is undertaken in repeat-dose but not single-dose toxicity studies?

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler