Freshwater Pollution

Tuesday 2/4/2014

Warm-up

Define a point and nonpoint source of pollution.

Label if the below examples are point or nonpoint sources of pollution.

1. Smokestack?

2. Urban runoff?

3. A leak from a septic tank?

4. People driving cars?

Disease carrying agents

Fecal coliform bacteria Ex: E. coli A fecal coliform bacteria

test is used to indicate the likely presence of disease-causing bacteria in water.

Ex: cholera, dysentery, giardasis, typhoid fever, etc. (see pg 495)

Dissolved oxygen

Only a few fish species can survive in water less than 4ppm at 20°C.

Pollution of Freshwater Steams

Flowing streams can recover if they are not overloaded and their flows are not reduced

“Dilution is the solution to pollution”

Eutrophication

the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land.

Cultural Eutrophication human activities

accelerate the input of plant nutrients (mostly nitrate and phosphate fertilizers) to a lake. 85% of large lakes near

major population centers in the U.S. have some degree of cultural eutrophication

Oxygen Depletion in the Northern Gulf of Mexico

Chesapeake Bay

Apoxia Hypoxia

Groundwater pollution

Groundwater cannot effectively cleanse itself and dilute and disperse pollutants. Moves very slowly

Groundwater pollutants

Nondegradable wastes (toxic lead, arsenic, flouride) are there permanently.

Slowly degradable wastes (such as DDT) are there for decades.

Coastal and Marine Pollution

Harmful Algal Blooms

Caused by explosive growth of harmful algae from sewage and agricultural runoff.

Red Tide: Specific type of algal bloom caused by red-pigmented algae

Oil pollution

Most ocean oil pollution comes from human activities on land takes about 3 years for many forms of marine

life to recover from large amounts of crude oil (oil directly from ground).

Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover.

Oil Spills: Case Studies

Exxon Valdez Spill Prince William Sound,

Alaska 1989 largest spill ever in

the U.S. until… Deepwater Horizon

Spill Gulf of Mexico, 2010

Offshore drilling can be devastating to marine life

Solution?

The key to reducing nonpoint pollution – most of it from agriculture – is to prevent it from reaching bodies of water Farmers can reduce runoff by planting buffers

and locating feedlots away from steeply sloped land, flood zones, and surface water.

How Would You Vote?

Should we greatly increase efforts to reduce water pollution from nonpoint sources even though this could be quite costly? a. No b. Yes

Explain why some one might vote no, and some one might vote yes.

How Would You Vote?

Should we greatly increase efforts to reduce water pollution from nonpoint sources even though this could be quite costly? a. No. Most farmers and ranchers can't afford

more regulations. b. Yes. Nonpoint source water pollution is a

serious environmental and human health threat.

US Clean Water Act The U.S. Clean

Water Act sets standards for allowed levels of key water pollutants and requires polluters to get permits