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

When does a contaminant become just a harmless environmental tracer Since we rarely have good data about threshold effects, we assume they are not present

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

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 agent that interferes with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development, and/or behavior." (EPA 1997)

Nonylphenol (NP) is an important EDC NP is a metabolite of alkylphenol ethoxylate (APEO) surfactants and is commonly detected in treated wastewater (mg/L). APEOs are among the most widely used groups of surfactants. Worldwide, about 500,000 tons are produced annually. Nonylphenol OH (C9H19) 17b-Estradiol OH HO