GEOLOGY (Water Pollution)

Water Pollution

• Any natural water contains dissolved chemicals and minerals (both natural and man-made)

• Pollution occurs when materials reach concentrations that become dangerous to humans or aquatic ecosystem

Global Statistics Impact

UNICEF & WHO (2019), 2.2 billion people around the world do not have access to clean, safe drinkable water

Residence Time formula

• The rate at which a substance will cycle through a reservoir
  
  

$$\text{Residence Time} = \frac{\text{Capacity}}{\text{Rate of Influx}}$$

• It varies significantly based on human activities

Point Source

Pollutants from an easily identifiable, single course

Example of Point Source Pollutants

• Septic tanks

• Industrial Plant Pipes

• Wastewater treatment discharge

Nonpoint Source

• Pollutants coming from widespread, diffused sources

• Harder to trace to one single spot

Examples of Nonpoint Source

• Road Salts

• Agricultural runoff

• Tailing piles from mining

3 main types of Organic Pollutants

1. Oxygen-Demanding Waste

2. Pathogens

3. Persistent Organic Pollutants (POPs)

Oxygen-Demanding Waste

Organic matter whose decay consumes oxygen

Oxygen-Demanding Waste (The Source)

• Feedlot runoff

• Algae

• Organic material from highways

Oxygen-Demanding Waste (The Process)

Organic material are broken down aerobically by bacteria

Pathogens

Disease causing agents like bacteria, viruses, and parasitic worms

Pathogens (The Impact)

Causes severe health issues and intestinal disease

Persistent Organic Pollutants (POPs)

Toxic synthetic chemicals such as DDT and PCBs

Persistent Organic Pollutants (The Impact)

They do not break down easily and biomagnify (increase in concentration) up the food chain

Type of Inorganic & Industrial Pollutants

• Industrial Pollution

Industrial Pollution

Pollution produced through manufacturing, mining, energy production and etc.

Industrial Pollutants (Added Information)

• Hundreds of new chemicals are created every year

• By 1990, 10 million new chemicals had been identified since 1957

• Out of 66,000 common drugs, pesticides, and industrial compounds, most have no toxicity data

• Only about 2% have undergone complete health evaluations

Types of Industrial Pollutants

1. Burning of Fossil Fuels

2. Oil Spills

3. Volatile Organic Compounds (VOCs)

Burning of Fossil Fuels

Releases gases into the air like CO2, NO (nitrogen oxides), and SO2 (sulfur dioxide), along with particulates

Oil Spills

• Contaminates water, shorelines, and air

• Lethal to many species

Volatile Organic Compounds

Synthetic chemicals created through manufacturing that vaporize into the atmosphere at room temperature

Volatile Organic Compounds Examples

• Scents

• Perfumes (Whales vomit)

• Paints

• Refrigerants

• Thinners

Type of Inorganic Pollutant

Heavy Metals & Acids
- Inorganic substance like arsenic, cadmium, zinc, and sulfuric acid

Biochemical Oxygen Demand (BOD)

• A measure of the organic matter load in water

• It quantifies the amount of oxygen needed by bacteria to aerobically decay organic material

Biochemical Oxygen Demand (Added Information)

• High organic waste → High bacterial activity → HIGH BOD

• BOD can exceed the total amount of dissolved oxygen (O2) in the system!

Oxygen Sag Curve

When organic waste is dumped into a stream, bacteria consumes oxygen rapidly, causing a sharp drop (“sag”) in dissolved oxygen downstream before it slowly recovers

The important information of Oxygen

Oxygen dissolves most easily in cold water

Eutrophication

The breakdown of excess organic matter when a water body becomes overly enriched with plant nutrients
- specifically, nitrates, phosphates, and sulfates

Eutrophication: How can this create “Dead Zones”?

1. Nutrient runoff enters the water
   - from fertilizers, sewage, or feedlots

2. Certain photosynthesis plants (especially algae) thrives on these excess nutrients

3. Triggers massive algal blooms

4. When massive algal bloom dies, aerobic bacteria decompose the dead algae

5. The bacteria consume large dissolve oxygen (o2), depleting it completely

6. The lack of oxygen creates an anoxic/hypoxic “dead zone” where fish and other aquatic organisms suffocate and die