1. MASARYK UNIVERSITY Brno – Czech Republic RECETOX
HUMAN HEALTH RISK ASSESSMENT 1

2. Risk Assessment Process (U.S. EPA)
Hazard Identification
Exposure Assessment
Toxicity Assessment
Source: U.S. EPA
It is important to note that both the exposure assessment (i.e., to how much a typical individual may be exposed) and the toxicity assessment (i.e., what are the health effects of that chemical at that dose) are used to determine the likelihood of harm from the situation being evaluated.
Risk Characterization
4 Main parts of this methodology

3. RISK ASSESSMENT METHODOLOGY Advantage of this approach
Probability
Of Cancer
and Noncancer
RISK ASSESSMENT
Prediction
of Exposure
scenarios

4. Step 1:Hazard Identification
Collect data on presence of chemical
Sampling
Modeling
Chemical fate and transport
Determine if chemical may be toxic
Develop model of how chemical may move through environment
Conceptual Site Model is used to organize information regarding chemicals and potential transport to people
AFCEE, 2002
© Vermont DPS, 2000

5. Step #2: Exposure Assessment
Who is Exposed?
Adult, Child, Special Populations
How Are They Exposed?
Ingestion, Inhalation, Skin Contact
What is the Concentration of Chemical to Which They are Exposed?
ppm in Water or Soil
How Often Are They Exposed?
Days per year, Number of years
Prediction
of Exposure
scenarios

6. Putting it all together. . .
Intake Equation for Drinking Water Example
C= Chemical Concentration (Obtain from sampling)
CR= Contact Rate (2 liters water/day)
EF= Exposure Frequency (350 days/year)
ED= Exposure Duration (30 years)
BW=Body Weight (70 kg.)
AT= Averaging Time (10,950 days)

7. Step 3: Toxicity assessment / Dose-Response Curve relationship
Noncancer risks
(noncancer chemicals)
Reference Dose – Chemical concentration per unit body weight without significant effects
Graphic Source:
Dose – Chemical concentration per unit body weight
Response – Level of measured adverse effect

8. Relevant to Cancer risks
(cancer chemicals)
!!! Databases of these RISK INDEXES - WEB

9. Step #4: Risk Characterization
The risk characterization combines the information obtained on toxicity with the calculated exposure to provide an estimate of risk.
Purdue, Pesticides and Ecological Risk Assessment: History, Science, and Process. PPP-41.
Purdue, 1997

10. RISK ASSESSMENT METHODOLOGY
[C] concentrations
RISK = 1 - exp (-CDI * SF)
Cancer
Noncancer
Exposure scenario models
Internal dose
Chronic Daily Intake
RISK = CDI / Rfd
7 PCBs
DDT
DDE
DDD
Total RISK
(aditive sum of individual Chemical-risks)
= expressed as a probability of health effects
Gama-HCH
Beta-HCH
Alpha-HCH
Cancer and Noncancer
RISK ASSESSMENT
U.S. EPA probabilistic approach
physiologically based pharmacokinetic (PBPK) model

11. only ONE of all stresors
Water pollutant
levels
Air pollutant
levels
Soil/dust
levels
!!Emphasize!!
Chemical stress is
only ONE of all stresors
and relevant PREDICTORS for final Human Health RISKs!!
Food pesticide
levels
Nutritional
health
Overall
health
Lifestyle
Predicted level of
toxicant in people
Personal
habits
Genetic
predisposition
Metabolism
Accumulation
Excretion
Lung, intestine, and
skin absorption rates

12. RISK ASSESSMENT METHODOLOGY
Detail description

13. http://cfpub.epa.gov/ncea/iris/index.cfm IRIS (CAS, chemicals..
example:
309–00–2 13

14. 14

15. 15

16. 16 http://www.inchem.org/ http://www.epa.gov/iris/ 16

17. Thank you for your attention17 17