hazards and risks. risk assessment hazard identification dose-response assessment exposure...

Hazards and Risks

Risk Assessment

Hazard Identification Dose-Response Assessment Exposure Assessment Risk Characterization

Modeling Probability

Major Types of Hazards

Cultural Hazards Chemical Hazards Physical Hazards Biological Hazards

Chemical Hazards

Hazardous Chemicals Mutagens Teratogens Carcinogens Endocrine disruptors

Hazardous Chemicals

Flammable or explosive Irritant Asphixiant allergen

Common Chemical Agents with Adverse Health Affects

Arsenic Asbestos Benzene Chlorine Formaldehyde Lead Mercury Dioxins

Biological Agents Pathogenicity Route of transmission Agent stability Infectious dose Concentration Origin Data from animal studies Prophylaxis

Common Human Diseases TB Dengue Fever Malaria Yellow Fever Cholera Trypanosomiasis Cryptosporidosis Anthrax Encephalitis

Lassa Fever Leprosy Giardiasis Salmonella Plague Encephalitis Ebola Influenza Hepatitis

Toxicity: Determining if a chemical is harmful

Size of dose over time How often exposure occurs

Acute vs. chronic Age of person exposed

Adult, very old, child, infant State of health

Immune compromised Body fat

How well body detoxifies Lungs, liver, kidnies

Exposure

Inc

ide

nc

e in

life

tim

e

health studies

Linear Risk Model

Response threshold

Since we rarely have good data about threshold effects, we assume they are not present

When does a contaminant become just a harmless environmental tracer

1E-08

1E-06

1E-04

1E-02

0.001 0.1 10 1000

Exposure (ppb PCE in water)

Inc

ide

nc

e o

f c

an

ce

r (l

ife

tim

e)

public health goal

detection limit

maximum contaminant level

health studies

10-8

10-6

10-4

10-2

Tetrachloroethylene (PCE, dry cleaning fluid) is a common contaminant

Radioactive tritium (3H) is of concern at very low concentration and is present in the environment at

exceedingly low concentration

1E-10

1E-08

1E-06

1E-04

1E-02

1E+00

1.00E-15 1.00E-12 1.00E-09 1.00E-06

Exposure (ppb tritium in water)

Inci

denc

e of

can

cer

(life

time)

possible public health goal

detection limit

maximum contaminant level

health studies

10-1510-12 10-9 10-6

10-10

10-8

10-6

10-4

10-2

1

1E-08

1E-06

1E-04

1E-02

1E+00

0.001 0.01 0.1 1 10 100 1000

Exposure (ppb Arsenic in water)

Inci

denc

e of

out

com

e (li

fetim

e)

possible public

health goal

detection limit

maximum contaminant

level

health studies

1

10-2

10-4

10-6

10-8

Arsenic is an example of a different pattern where the detection limit is large compared

to possible health goals

Endocrine-Disrupting Compounds (EDC) in wastewater are a concern

An environmental endocrine disruptor is defined as an exogenous agentexogenous agent that interferes with the synthesis, secretion, transport, binding, action, or elimination of natural hormonesnatural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development, and/or behaviorhomeostasis, reproduction, development, and/or behavior." (EPA 1997)

NP is a metabolite of alkylphenol ethoxylate (APEO) surfactants and is commonly detected in treated wastewater (g/L).

• APEOs are among the most widely used groups of surfactants. Worldwide, about 500,000 tons are produced annually.

Nonylphenol (NP) is an important EDC

Nonylphenol

OH

(C9H19)

17-Estradiol

OH

HO