ENST 221 Risk Assessment and Biomarkers Review

Flashcards covering key vocabulary and concepts from ENST 221 focused on risk assessment, biomarkers, and remediation.

Condition Markers

Measure the chances of an illness based on biological factors.

Exposure Markers

Measure how much of a chemical one has to be exposed to in order to see effects.

Why are sentinel organisms and sentinel organs useful?

Provide information on the level of contamination in a designated area.

Biomarkers

Signal or indicator of the status of a biological system.

Homeostasis Response

The state in which an organism maintains a stable internal environment despite external changes.

Susceptibility Biomarker

Predicts individual variability of disease risk related to environmental exposure.

Hazard Identification

Identifies the source of contamination, the contaminated media, potential chemicals released, and potential exposure groups.

Exposure Assessment

Determines all potential exposure pathways.

Dose-Response Assessment

Evaluates toxicity data for all contaminants in relation to daily intake rates.

Risk Characterization

Calculates risk for all contaminants.

Hazard Index Equation

HI = CDI/RfD, used for non-carcinogenic chemicals.

Acceptable Hazard Index Value

HI < 1.0 is considered an acceptable risk.

Risk Calculation

Risk = SF x CDI, used for carcinogenic chemicals.

Acceptable Risk Threshold

Risk < 1 in 1 million is considered acceptable by the EPA.

Ex Situ Treatment

Involves transporting polluted soil or water to another place for treatment.

In Situ Treatment

Treats contamination on the spot.

Pump and Treat Process

An ex situ technique for groundwater remediation.

Granular Activated Carbon (GAC)

Uses a carbon source to process chemicals at a high temperature.

Air Stripping

Removes contaminants from water by converting them into air.

Biological Treatment

Transforms hazardous chemicals into a non-hazardous form.

Why would we use different biomarkers with different response times?

To allow identification of “organism state”: homeostasis response illness – this allows for risk level assessment

Are all hazardous waste sites cleaned up to a pristine level? Why or why not?

No, as results in numerical values are helpful to determine if a site requires remediation, and what level is acceptable to reduce contamination to.

Advantages of GAC

Common in homes - Can be sole or final process in a series - Offers many adsorption sites

Advantages of Air Stripping

Low cost - Easy operation - Proven and readly available

Advantages of Bioremediation

Complete destruction of hazardous chemical - Cost is often cheaper than GAC and air stripping

Disadvantages of GAC

Chemicals only released from GAC by regenerating the GAC

Disadvantages of Air Stripping

Too much air flow causes flooding - Only mass transfer - May require pre or post treatment

Disadvantages of Bioremediation

Living systems take more time and effort to set up - More intense operator training and daily monitoring

What is “flooding” in an air stripper system?

It prevents water from moving downward

What are the 3 main requirements for microbes involved in bioremediation, and where might these come from?

1. An energy source 2. A carbon source 3. An oxygen source

Aerobic use …

O2

Anoxic use …

nitrate, NO3

Anaerobic use …

CO2 or sulfate, SO4