CE Introduction to Environmental Engineering and Science Readings for This Class: Chapter 4 O hio N orthern U niversity Introduction Chemistry, Microbiology & Material Balance Water & Air Pollution Env Risk Management Risk and Risk Assessment We always make decisions based upon the amount of risk involved in a given activity. However, we often overstate the risk for events that are unlikely to happened and down play the risk for events that happen all the time. Here we discuss risk and how risk assessment factors in to environmental decision making.

Indoor Air Quality  Common indoor air pollutants  Challenges with regulating indoor air quality

Lecture 30 Risk Assessment (Risk I)

Risk & Risk Assessment  Topics Covered Include:  Class definition of risk  Risk in reality  Annual vs lifetime risk  Risk Assessment Paradigm

What is risk?

Risk in Reality  What is the riskiest activity you do?  How does risk factor into your decision making?  Does this risk apply equally to everyone? Should it?  Do you take steps to minimize risk?

Risk in Reality - Top Annual Risk of Death (2004) Total Death = 2,397,615 # of DeathAnnual Risk Heart disease 652, E-03 Cancer 553, E-03 Stroke (cerebrovascular diseases) 150, E-04 Chronic lower respiratory diseases 121, E-04 Accidents (unintentional injuries) 112, E-04 Diabetes 73, E-04 Alzheimer's disease 65, E-04 Influenza/Pneumonia 59, E-04 Nephritis, nephrotic syndrome, and nephrosis 42, E-04 Septicemia 33, E-04 Lightning strike 511.0E-06 Shark attack 71.1E-09

Life-time and annual risk Life-time risk of death from all causes: In 2001, 3.9 million deaths, 541,532 were cancer-related. The risk of dying from cancer in a lifetime: If average life expectancy is 70 years, then annual risk of dying from cancer is

Risk in Reality If cancer, heart disease, and respiratory disease are responsible for the over whelming majority of deaths each year, how do we reduce these outcomes? What causes cancer? Heart Disease? Respiratory Disease? How do we make decisions to reduce mortality and morbidity across a population? Why are we interested in doing so?

Risk Assessment Paradigm

In developing standards for environmental protection, EPA selects a lifetime incremental risk in the range of – as acceptable

Risk Assessment – 4 Steps

Step 1: Hazard Identification Does situation/agent pose an adverse risk? Adverse risk: “...any biochemical, physiological, anatomical, pathological, and/or behavioral change that results in functional impairment that may affect the performance of the whole organism or reduce the ability of the organism to respond to an additional challenge."

– Dose is the mass of chemical received by the exposed individual Step 2: Dose-response assessment If an adverse risk is present what is the relationship between the dose of an agent received by a receptor (organism or ecosystem) and the incidence of an adverse effect on that receptor - Receptor is the organism receiving the dose

Virtually all data used to derive the dose-response curve are from animal studies Difficulties using the animal study data: Step 2: Dose-response assessment

Dose-Response Curve Response (e.g. mortality) 20% 0% 60% 80% 40% 100% Dose ( mg/kg-body mass) LD 50 Compound ACompound B LD = Lethal Dose, LD 50 =Dose causing 50% mortality NOAEL NOAEL = No Observed Adverse Effect Level Step 2: Dose-response assessment

Step 3: Exposure Assessment Through what exposure pathways (source) and routes (media) are people exposed? How often and how long is the exposure?

Step 4: Risk Characterization What is the likelyhood of an adverse effect due to a given exposure? Effect Level –LOAEL –NOAEL

Threshold vs. Non-threshold effects – Cancer – Non-cancer Step 4: Risk Characterization

Quantitative Risk Assessment To Quantitatively assess the risk we need to: 1. Magnitude, frequency, and duration of every pathway of exposure 2. biological characteristics of receptors (body weight, absorption,etc.) 3. Potency (dose-response) character of agent