Two sources of water pollution

Point sources - pollution that can be identified as coming from specific locations

Examples: sewer pipes, factory drainage

Non-point sources - pollution from many sources over a large area that converge and accumulate

Examples: farm run off, neighborhoods

Forms of water pollution

Toxic Chemicals

Come from pesticides, synthesized chemicals, and petroleum products

Can poison organisms (small animals and plants)

Can be detrimental to human health (cancer)

Pathogens

Pathogens, protests, bacteria contaminate the water

They come from human/animal waste

Examples: hepatitis A, typhoid

An estimated 20 million people become ill annually from drinking water contaminated by pathogens

Cause more health problems than any other type of water pollution

Types of water pollution cont.

Nutrient pollution

Come from fertilizers and other sources

Lead to eutrophication and hypoxia

Boosts algaes growth, algae covers waters surface and blocks sunlight from reaching photosynthetic organisms

Creates dead zones, areas with very low oxygen levels

Biodegradable Wastes

Human/Animal waste, paper pulp, grass clippings, leaves

Decreases dissolved oxygen levels as well

Wastewater- water polluted by human activities

Types of water pollution cont.

Sediment

Soil carried to waterways by runoff contain sediment

Aquatic habitats can be changed drastically from an introduction of a large amount of sediment

Organisms who can't adapt die

Can be prevented by better managing farms and forests

Thermal pollution

When human activities raise water temperature, the ability of water to hold dissolved oxygen decreases

Rushing water from dams being opened can cool water temperatures, favoring invasive species that are better adapted to temperature change over native species

Groundwater pollution

Groundwater is regularly polluted by industry and agriculture

Heavy metals to petroleum products can leach through soil and seal into aquifers

Retains its contaminants until they decompose, much harder to control

Leaking of radioactive compounds from underground is also a source of pollution

Ex: DDT was banned 35 years ago but is stills found in US aquifers

Legislative/Regulatory efforts help reduce pollution

Federal water pollution control act of 1972 (amended and renamed the clean water act in 1977)

Made it illegal to discharge pollution without a permit

Set standards for contaminant levels in surface waters

In the past 10 years the laws become more lax, New York Times revealed in 2009 that violations of the clean water act are reaching over 100 thousand violations a year

Treatment of our drinking water

Technological advances as well as government regulation have helped improve our control on pollution

Before water goes to our tap it it:

Treated with chemicals to remove particulate matter

Passed through filters of sand, gravel, and charcoal

and /or disinfected with small amounts of an agent such as chlorine

U.S EPA set standards for over 90 drinking water contaminants

Wastewater

Treating wastewater is now a mainstream practice

Wastewater includes water that carries sewage:

Water from showers

Sinks

Washing machines

Dishwashers

Large amounts of wastewater can harm ecosystems and pose health threats

This is why they started treatment

Septic systems are the most popular method of wastewater disposal

In septic systems wastewater runs from the house to an underground septic tank

Inside the septic tank solids and oils separate from water

The water is then taken to a landfill

Primary treatment: the physical removal of contaminants in setting tanks or clarifiers, removes 60% of solids

Secondary treatments: water is stirred and aerated so the aerobic bacteria degrade organic pollutants

Constructed wetlands can aid treatment

Natural wetlands are filtering and purifying water

After realizing this engineers have been constructing new wetlands to clense wastewater

Conclusion

Citizen action, government legislation and regulation, new technologies, economic incentives, and public education are all helping us to confront a rising challenge of our ecosystems