Environmental Exam 2

Hazard

probability of adverse effects in a particular situation

leading to potential harm or damage.

Risk

measure of the probability. The likelihood of injury, disease, or disaster. (Falling down stairs, food poisoning)

Environmental Risk

the risk resulting from exposure to a potential environmental hazard (chemical exposure, pathogens, climate change)

Risk Perception

Judgement people make when asked to characterize hazardous activities.

Voluntary Risk

What people accept with consent

Involuntary risk

Risk without consent or choice

Dose

Magnitude of exposure

LD_50

Lethal Dose 50 (measurement of dose to kill 50% of population)

Pathway

Water, air, food

Evaporation

Transfers of earths water into the atmosphere

Transpiration

Where water is absorbed by plants and released to atmosphere

Evaprotranspiration

Combined process between evaporation and transpiration

Precipitation

Where water falls to the earth as a liquid

Infiltration

Where water enters the soil and moves into the soil profile

Interflow

Horizontal water movement in soil before the water table

Surface runoff

Where the water doesn’t infiltrate the soil

Base flow

Steady flow of water in streams and rivers supplied by groundwater

Overland flow

Oversaturated soil becomes

Embodied water

Amount of water in a water supply system

Point source

Introduction of impurity of a surface through a direct route

Non point source

Rainfall, snow, or other sources that are spread out

Dissolved oxygen

Oxygen that is dissolved

Oxygen Demand

Refers to the amount of oxygen required by microorganisms to decompose organic matter in water.

Pathogens

Disease producing organisms

Aerobic

In the presence of oxygen

Anaerobic

In the absence of free oxygen

Biodegradation

The process by which organic substances are broken down by living organisms, often by microorganisms, into simpler, non-toxic compounds.

Nanoparticles

Incredibly small particles that increase aerobic and anaerobic conductivity in water.

Potable

Water free of chemicals and is safe to drink

Palatable

Water that is pleasant to drink

Radionuclides

Harmful radioactive wastes

MCL

maximum containment levels

SMCL

secondary maximum containment levels for aesthetically pleasing water

Coagulation

The addition of chemicals to water to destabilize particles in water

Flocculation

Follows coagulation, stir the water to help the flocs stabilize and grow

Softening

Where water hardening ions are removed

Hardness

More concentration of calcium and magnesium ions

Lime

Used for water treatment due to its alkaline properties

Soda

Sodium carbonate

Sedimentation

Water treatment using gravity to separate particles from water.

Backwashing

Moving water through a filter to remove debris.

Ion exchange

Reversible exchange of an ion on a solid phase

Disinfection

Used to kill pathogens

UV

Penetrates the cell wall of organisms to prevent reproduction

Aeration

Injecting air into water to increase oxygen which helps biological processes

Weir

V - notch weir that separates clean water

Residuals

Waste from the water treatment process

Sludge

One type of residual that can be caused by pre sedimentation

Distribution system

Has pumps, holding tanks, pipe networks, and hydrants

Pretreatment

To remove large suspended solids that could damage wastewater

Headworks

The device that conducts “pretreatment”

Primary treatment

To remove 60% of suspended solids.

Secondary treatment

Remove soluble organic waste and additional suspended solids

Heterotrophic bacteria

Required to break down waste

Autotrophic bacteria

Bacteria that can produce their own food using carbon dioxide and other inorganic substances.

Tertiary treatment

Advanced treatment process used to remove remaining contaminants from water after primary and secondary treatment.

Activated Sludge

A process used in sewage treatment where microorganisms break down organic matter in the presence of oxygen, forming a mixture that is aerated and subsequently settled to separate treated water from sludge.

Oxidation ponds

To treat water in reservoirs using sunlight and settling

Thickening

Removing sludge by increasing concentration of solids and removing water

Stabilization

Removing organic contents or pathogens by chemical or biological concerns

NPDES

National Pollutant Discharge Elimination System

ADEM

Alabama Department of Environmental Management

TMDL

Total maximum daily load of pollutants in a body of water.

What are some factors that affect risk perception and how/why do they affect it?

High risk consists of “untrustworthy sources, few benefits, involuntary, uncontrollable”

Low risk consists of the opposite of everything for high risk

They affect it due to the grade like system for all the risks that we take

Define Risk Assessment

To characterize the nature and magnitude of health risks to humans, workers, and ecological receptors from chemical contaminants and other stressors that may be in the environment.

Focuses more on hazardous wastes and and toxic chemicals

4 Step Risk Assessment Process

1. Hazard Identification - what health problems are caused by the pollutant?

2. Dose response assessment - what are the health problems at different exposures?

3. Exposure assessment - how much of the pollutant do people inhale during a specific time period? How many people are exposed?

4. Risk Characterization - integrates the three above. What is an acceptable level of risk? Loved ones?

Difference between acceptable and unacceptable level of risk

Acceptable: lifetime risk of 1/million chance of adverse effect

unacceptable: lifetime risk of 1/1000 chance of adverse effect.

What is Risk Management and how does it interplay with Risk Assessment?

Risk management is the action taken based on consideration of that and other information.

Risk assessment provides information on potential health or ecological risks.

Risk assessment is the scientific factors, while risk management is the legal, economic, social, technological, and political factors.

Explain Engineering ethics and give an example

Engineers must understand environmental risk in order to protect all segments of society and all inhabitants of ecosystems.

Example: engineer is designing bridge and uses lower quality materials to reduce costs. The bridge becomes unsafe. Safety comes first

What is environmental justice? Injustice?

It is the fair treatment and meaningful involvement of all people regardless of who they are.

The goal is spreading environmental disadvantages equally among everyone.

Define Hydrology

The science that encompasses the occurrence, distribution, movement, and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle. (USGS)

Explain what a water budget is. Be able to identify the different regions on a graph.

It reflects the relationship between input and output of water through a region.

What is a watershed?

Also called “drainage basin”.

It is the area of land where all of the water that falls in it and drains off of it and goes to a common outlet.

Biggest one is Mississippi River

How are watersheds determined?

They are based on topography. Boundary lines are drawn using information from contour lines. (Contours joining the highest elevations surrounding a basin)

What is a hydrograph and how is it used?

A graph of the water level or rate of flow of a body of water as a function of time.

They are used to find out discharge patterns of a particular drainage basin.

They are also used to help predict flooding events and influence implementation of flood prevention measures.

How do watersheds influence hydrographs? what are some factors?

They help predict flooding events and they influence implementation of flood prevention measures.

Factors: Area, Slope, Land use, Soil, Rock type, Precipitation, Temperature

Identify the components of a hydrograph.

Overland flow + Through flow = Storm flow

Basin lag time, peak flow, rising limb, recession limb

What is meant by a 100 year storm event?

It is a statistical way of expressing the probability of something happening in a given year.

(1% chance per year, and expected 24 hr rainfall is 14 inches)

What are the ways water is used?

1. Public Supply - refers to water withdrawn by public and private water suppliers that provide water to atleast 25 people or have a minimum of 15 connections.

2. Irrigation - to sustain plant growth

3. Thermoelectric power

4. Industrial water use

5. Mining

6. Livestock - watering animals

7. Aquaculture- raising organisms that live in water

What are the kinds of pathogens transmitted through water?

1. Bacteria - cholera, typhoid fever

2. Viruses - polio, hepatitis

3. Protozoa - amoebic dysentery

4. Helminths (Parasitic Worms)

What are the exposure routes? Explain each one.

1. Ingestion - water borne diseases

2. Water contact - skin, ear infections. Helminths

3. Water may be indirectly involved with transmission - (insect vectors and scarcity)

What is the United States regulatory response for pathogens?

1. Clean Water Act - limits concentration of coliforms

2. Safe Drinking Water Act

What are the sources for oxygen demanding waste?

1. Municipal wastewater treatment plans

2. Industrial discharges

3. Agriculture runoff

4. Naturally occurring sources

What is the effect of oxygen demanding wastes in water?

Oxygen demanding wastes can deplete dissolved oxygen levels in water, leading to hypoxia, which harms aquatic life and disrupts ecosystems.

What are three ways and differences of measuring oxygen demanding wastes?

1. Biochemical Oxygen (BOD) - amount of

   oxygen required for microorganisms to degrade the

   wastes (can be also known as Biological Oxygen

   Demand)

2. Chemical Oxygen Demand (COD) - oxygen needed to

   chemically oxidize wastes

3. Theoretical Oxygen Demand - oxygen required to

   oxidize completely based on stoichiometry (from

   known chemical formula)

What is nutrient pollution? What are the sources of nutrient pollution?

Considered pollutants when concentrations are

sufficient to allow excessive growth - aquatic plants (algae)

Major Sources:

1. Municipal WW discharges,

animal feedlot runoff, chemical fertilizers,

some industrial wastes.

2. Certain bacteria and blue-green algae can obtain N

directly from atmosphere. Acid Rain: Nitric Acid

3. Washout following lightning storms. Lightning causes

nitrogen fixation.

What is Liebig’s Law of the Minimum and how does it relate to water quality?

• Theory states: "Plant growth is limited by the nutrient that

is least available relative to its needs”.

• Each plant requires certain kinds and quantities of

nutrients. If one is absent, the plant dies. If one is present

in minimal quantities only, growth will be minimal.

• It states that growth is controlled not by the total

of resources available, but by the scarcest resource

(limiting factor)

What are sources of heavy metal pollution?

• Industrial wastewaters,

 Mining wastes,

 Atmospheric deposition from combustion of coal,

solid wastes, etc.,

 Past usage (mercury as fungicide, lead as gasoline

additive, barite mud with high mercury content used

in the drilling of new oil and gas wells, etc.),

 Corrosion of piping and plumbing fixtures.

 Trace amounts from the chemical weathering of

rocks and soil leaching.

Explain the effects lead has on human health.

• Nervous system – headaches, disturbed sleep,

depression, difficulty concentrating.

 Immune system – decreasing the body’s ability to fight

infection.

 Cardio-vascular system – high blood pressure.

 Children are at higher risk – exposure can result in brain

damage, learning and behavioral problems, and can

affect growth

Explain the problems that solids cause in water systems.

 Aquatic habitat destruction

 Directly impacts aquatic animals

 Increases channel bank erosion

 Damages pumps, etc.

 Harbors other pollutants (pathogens, heavy metals)

 Fills up harbors, shipping channels.

How can temperature (heat), be recognized as a pollutant?

Elevated temperatures can harm aquatic life by reducing dissolved oxygen levels, disrupting ecosystems, and impacting species distribution.

How can groundwater (aquifers), be contaminated?

Groundwater becomes contaminated when harmful substances from surface activities like agriculture, industry, and waste disposal, or from leaks and spills, seep down through the soil or enter via direct pathways to pollute the aquifer.

What happened at Minamata, Japan?

Minamata, Japan, experienced a severe environmental disaster due to methylmercury poisoning from industrial waste released into Minamata Bay. This led to neurological damage, health issues in the local population, and widespread contamination of the marine ecosystem.

Discuss the 4 categories used to describe drinking water.

1. Physical - usually associated with the appearance of water

2. Chemical - indicates the identification of its components and their concentrations

3. Microbiological - pathogenic organisms

4. Radiological - radioactive elements

What are the 2 types of water quality standards and what are the differences?

1. Primary - designed to protect human health, the reason why MCL’s exist and are required and enforced.

2. Secondary: purpose is to provide esthetically pleasing water. SMCL’s are recommended.

What are the sources for potable water and their characteristics?

• Groundwater – water pumped from wells (high mineral content, low turbidity, low color, low bacteria)

• Surface water – water from rivers, lakes, and

  reservoirs

Name and describe the three types of water treatment systems.

• Coagulation plants – most common

• Softening plants – used to treat groundwater with

high mineral content

• Limited treatment plants – have a high-quality

source with little to no risk of pathogen

contamination

Sketch a coagulant treatment plant, label all the parts and explain their function.

What are the three key properties of coagulants?

1. Trivalent Cation: colloids are negatively charged;

a cation is needed to neutralize the negative charge.

A trivalent cation is the most efficient cation.

2. Nontoxic: makes sense!

3. Insoluble in the neutral pH range: coagulant must

precipitate out of solution

What are the most commonly used coagulants and why?

Aluminum and Ferric iron:

Both meet the three key properties

 Aluminum in the form of aluminum sulfate (Alum)

 Ferric iron in the form of either ferric sulfate or ferric

chloride