Midterm 1

Question 1

• Xenobiotics
• Toxicant vs toxin
• Founder of Modern Toxicology
• DOB & DOD?
• Concept coined by him?
• Is a toxicon a chemical entity or a mixture?
• 2 reasons to study toxicology

Answer 1

• Substance foreign to biological system
• Toxicant: man-made
  Toxin: produced naturally
• Paracelsus
• 1493-1541
• The dose makes the poison
• Chemical entity
• Always relevant and many jobs

Question 2

• Hazard vs risk?
• Risk function
• Exposure function
• 5 parts of exposure pathway
• 4 issues in measuring exposure
• 4 questions to ask to define question to develop sampling scheme
• 5 sources of sampling
• 2 things we test for in air?
• Particle size that stay stuck in lungs?
• Which size is most sampled?
• 2 ways to sample air?

Answer 2

• Hazard: potential to harm
  Risk: likelihood of harm
• Risk = f(hazard, exposure)
• Exposure = intensity x frequency x duration
• Source, Transport (air, ground water), Point of exposure, Route of exposure (eating, breathing), Population
• Factors influencing biodistribution, time activity patterns, homogenous vs heterogenous, and mixtures
• Why do we sample?
  Who samples?
  How many samples?
  How to sample?
• Air, water, soil, food, tissue
• Pollutants and particulates
• < 10 µm
• 2.5 (particulate matter 2.5)
• Directing air through a filter (particles) or through an absorbents (gases)

Question 3

• You collect soil samples according to what at least 5 categories?
• 3 types of soil sampling
• EPA
• 3 considerations when sampling water
• 3 strategies to sample water
• 3 ways to assess food exposure
• TDI. What is it?
• What’s the amount of toxicants allowed in food dependent on?
• 3 situations where we sample tissue?

Answer 3

• Soil type, slope, crop, history, fertilizer
• Simple random
  Stratified random
  Systematic
  -Environmental Protection Agency
• Pollutants, up/downstream effects, speed of flow of water
• Surface water, continuous monitoring, entrapment by filters
• Dietary surveys + consumption rates/capita, direct sample analysis
• Tolerable daily intake. Qt of contaminants that we can be exposed over a lifetime w/o posing significant health risk
• TDI, it has to be below that after consuming the food
• Forensics/medicine, experiments, environmental studies

Question 4

• 4 differences between medical and forensic sampling
• 3 areas of sampling tissues discussed in class
• Which drug is undetectable in urine?
• How long does weed stay?
  Opiates?
  Cocaine metabolites?
• 3 steps before measuring
• Goal of extraction?
• 2 phases of chromatography
• 3 columns of stationary phase in HPLC and their composition
• What other compound is present in stationary phase?
• Cheap columns for chromatography?

Answer 4

• Patient consent, specimen identity, screening results for decisions, and medical vs legal action
• Workplace, human performance, urine tests
• LSD
• 3-30 days
  2 days
  2-4 days
• Extraction, separation, identification
• Make sample homogeneous
• Stationary and mobile (solid/liquid) phase (liquid/gas)
• Reverse phase: hydrocarbon chains
  Anion exchange: ammonium groups that bind (-) compounds
  Cation exchange: carboxyl groups that bind (+) compounds
• Silica
• Solid-phase extraction columns

Question 5

• 4 considerations for identification/quantification method
• Best method for identification
• Other methods for ID?
• 3 important assessments for evaluating data
• Which measurement is the best indicator of exposure?

Answer 5

• a) Sensitivity
  b) Throughput
  c) Specificity
  d) Identification vs quantification
• Mass spectrometry
• IR/Vis/UV spectra, colorimetric/optical
• a) Compare samples to controls
  b) Statistical significance
  c) Relevance and risk assessment
• None. Depends on the population you are asking about