AP Environmental Science

"Water and air, the two essential fluids on which all life depends, have become global garbage cans." — Jacques Cousteau

Fun (or not so fun) Facts: 40% of America’s rivers and 46% of America’s lakes are too polluted for fishing, swimming or aquatic life 2/3 of US estuaries and bays are degraded by eutrophication ( remember N and P!) Pollution of drinking water is a problem for about half of the world's population. Each year there are about 250 million cases of water-related diseases, with roughly 5 to 10 million deaths

Fun (or not so fun) Facts Bangladesh has some of the most polluted groundwater in the world. Arsenic ~ 85% of the total area of the country has contaminated groundwater >1.2 million Bangladeshis exposed to arsenic poisoning Asian rivers are the most polluted in the world. three times more bacteria from human waste as the global average 20 times more lead than rivers in industrialized countries

Clean Water v Dirty Water (physical/chemical characteristics) Physical Turbidity Chemical DO pH

What sources can you think of that cause water pollution? Self –Directed Learning Hint: Jot your answer to these reflection questions! Reflecting on what you already know about a subject before encountering new information will help you store it better.

Some sources of water pollution… Industry Agriculture (huge source) Oil spills Household chemicals Urban runoff Forestry After clear cutting, dirt is free to run into nearby water Mining In the case of gold mining, cyanide is intentionally poured on piles of mined rock to chemically extract the gold from the ore. Some of the cyanide ultimately finds its way into nearby water. How many of these were you able to guess before hand?

Point vs. Non-point sources Non-point source pollution- results from the combining of many sources over large areas Ex: fertilizer runoff, sewer system discharge, urban street runoff Point source pollution- can be traced to one source Ex: industrial discharge

Major Water Pollutants: The following slides go into more detail about each of these…

1. Infectious Agents (Pathogens) Enter the water supply through human or animal waste Over 1 billion people don’t have access to safe drinking water supplies Diseases: Dysentary Cholera Typhoid Hepatitis A

2. Nutrient Pollution Excess nutrients such as sewage, food waste, nitrogen or phosphorus fertilizers Leads to increased demand for oxygen, which then lowers the dissolved oxygen content of water. These are sometimes called “dead zones” because fish and other animals suffer from the lack of oxygen. Eutrophication  enrichment of waters with nutrients

3. Organic Chemicals Most organic water pollutants are synthetic chemicals created for human activities. These include pesticides, solvents, industrial chemicals, and plastics. Some organic compounds enter water sources directly or through seepage from landfills, through agrichemical runoff, or by leaching into groundwater. Poorly managed landfills are a source of toxic leachate Organic pollutants often take many years to break down

4. Oil Pollution Oil pollution is particularly acute in harbors and shipping lanes. Oil damages aquatic systems because it spreads over water surfaces forming a film. It also coats organism and is toxic when ingested.

5. Inorganic Pollutants ‣ Inorganic chemical pollutants include mercury, lead, road salt, and acid drainage. Most are toxic to aquatic organisms and their presence may make water unsuitable for drinking and other uses. Inorganic chemicals enter water courses from industrial plants, mines, irrigation runoff, oil drilling, and municipal storm drainage. Mine drainage into a river, UK Over irrigating can lead to pesticide runoff (Toxins from unit 5!)

6. Sediment Pollution ‣ Sediment pollution comes from agricultural land, forest soils exposed by logging, overgrazed rangelands, strip mining, and construction. Suspended sediments increase turbidity and reduce light penetration. When they settle out, they smother aquatic organisms and reduce available habitat. Increased sediment loads may choke waterways and cause sediment buildup behind dams and in reservoirs. Stream erosion and sediment runoff Earthworks and quarrying increase sediment runoff

7. Thermal Pollution Thermal pollution of waterways is a common consequence of thermal power generation and water cooled industrial processes. Upstream, water is withdrawn, used for cooling, and then released downstream as a (heated) thermal plume. Restrictions are placed on the percentage of water removed for cooling and the temperature of the release water. However, the increased thermal load reduces oxygen levels and may compromise sensitive species. Richard Allan Brendan Hicks Water from a thermal power station is released over steps to increase cooling rate. Upstream of a thermal power station