Chapter 14Water Pollution

Water Pollution

Water pollution- the contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities and that negatively affect organisms.

Point sources- distinct locations that pump waste into a waterway.

Nonpoint sources- diffuse areas such as an entire farming region that pollutes a waterway.

Human Wastewater

Water produced by human activities such as human sewage from toilets and gray water from bathing and washing clothes or dishes.

Three reasons scientists are concerned about human wastewater:

Oxygen-demanding wastes like bacteria that put a large demand for oxygen in the water

Nutrients that are released from wastewater decomposition can make the water more fertile causing eutrophication

Wastewater can carry a wide variety of disease-causing organisms.

Biochemical Oxygen Demand (BOD)

BOD- the amount of oxygen a quantity of water uses over a period of time at a specific temperature.

Lower BOD values indicate the water is less polluted and higher BOD values indicate it is more polluted by wastewater.

Eutrophication Eutrophication is an

abundance of fertility to a body of water.

Eutrophication is caused by an increase in nutrients, such as fertilizers.

Eutrophication can cause a rapid growth of algae which eventually dies, causing the microbes to increase the BOD.

Eutrophication in the Great Lakes

Mississippi River Delta

Common Diseases from Human Wastewater

Cholera

Typhoid fever

Stomach flu

Diarrhea

Hepatitis

Treatments for Human and Animal Wastewater

Septic systems- a large container that receives wastewater from the house.

Treatments for Human and Animal Wastewater

Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes.

Treatments for Human and Animal Wastewater

Manure lagoons- large, human-made ponds line with rubber to prevent the manure from leaking into the groundwater. After the manure is broken down by bacteria, it is spread onto fields as fertilizers.

Heavy Metals and Other Substances that can threaten human Health and the

Environment

Lead

Arsenic

Mercury

Acids

Synthetic compounds (pesticides, pharmaceuticals, and hormones)

Lead•Pipes and fittings in old homes

•Can leach into drinking water

•Causes neural and renal damage (nervous system & Kidneys)

•Pregnant women, children and unborn babies are at the most risk

•Change your pipes!

Arsenic • Naturally found in rocks and dissolves into groundwater

• Mining can increase arsenic levels because it helps to break up rocks. Also used as a wood preservative.

• Carcinogenic (causes cancer): skin, lungs, kidneys and bladder. Takes ~ 10yr for symptoms to develop.

• 50µg/L was set as the acceptable dose 1947-1999. National academy of the sciences wants it to be 5µg/L, lumber and mining companies compromised and EPA set 10µg/L limit

• Can be removed by filtration, distillation and reverse osmosis

• Upper midwest has the biggest issues with arsenic contamination.

Mercury-sources, stats &

trasition

• Released from coal burning power plants, petroleum exploration and manufacturing cement.

• Asia accounts for 54% global of mercury production. (28% from China)

• Inorganic mercury is not harmful. Bacteria change inorganic mercury into Methaylmercury. Methylemercury is VERY harmful.

• Bioaccumulates up the food chain posing a threat to human health.

Human and Environmental Impacts

• Exposure to methylmercury (eating shellfish and fish) can cause:

• Damage to the central nervous system

• Bad for children and embryos

• Decreases Biodiversity in aquatic ecosystems

• Poisons fish

World Mercury Production-from human activities

•Only way to reduce Mercury is to try and

reduce GLOBAL mercury production.

•Mercury can be carried in clouds, travel for

thousands of miles and be deposited with the

rain or snow. •We get the mercury

from Asia and it poses a serious threat to the

Great Lakes.

Acid deposition

•Wet-acid deposition,

rain and snow

•Dry-acid deposition, gasses and particles on plants, soil

and in water

Wet-Acid DepositionAcid Precipitation

•Created by BURNING COAL which release the primary pollutants: SO2

& Nox

•These turn into Sulfuric and Nitric acid in the atmosphere (H2O and O2) hence ‘acid rain’ (and snow!)

•Lowers the pH of bodies of water to below 5

•Reduces Biodiversity

•Coal plants can use scrubbers to filter out the particulate matter and other air pollutants that can lead to acid deposition.

Synthetic organic compounds- pesticides &

‘inert’ ingredients

•Nonpoint source pollution

•Fertilizers contribute nutrients to aquatic systems (even organics) Causing cultural eutrification.

•Pesticides are nonspecific and can kill beneficial species: Amphibians, fish, predators of the pest, bioaccumulation.

• DDT – Banned in1972 in the US

•Used in the developing world to control Malaria

Organic compounds- Pharmaceuticals & Hormones

•Leads to mutations•Male frogs producing Ova instead of sperm

USGS survey results of 139 streams in the

US

Military & Industrial Compounds

• Perchlorates- Additive in rocket fuel, leaches into ground water. Causes Thyroid problems in humans.

• Cuyahoga river, OH

• PCB’s – plastics

• GE dumped in the Hudson river 1947-1977

• PBDE’s – flame retardant

Oil Pollution •5,000 offshore oil platforms in

the US •~146,000Kg (322,000 lbs)

of leaks

•3,000 more platforms worldwide •.3-1.4 million kg (.6 million-3.1 million lbs)

of leaks

Largest Global Oil Spills • 2010-Deep water

horizon- A pipe broke ~1 mile below the

surface= 780 million L (206 million gal) •Env. effects- ???

•1989- Exxon Valdez- Tanker ran ashore in

AK= 41 million L (11 million gal) •Env. effects- 250,000 birds

2,800 sea otters300 seals & 22 killer whales

Ways to Remediate Oil Pollution

Containment using booms to keep the floating oil from spreading.

Chemicals that help break up the oil, making it disperse before it hits the shoreline.

Bacteria that are genetically engineered to consume oil

Other Water Pollutants Solid waste pollution (garbage)

Sediment pollution (sand, silt and clay)

Thermal pollution

Noise pollution

•There is a plastic ‘island’ the size of Texas floating in the pacific ocean.

•

Water Laws

Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlbife and recreation in and on the water”.

Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways.

Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water.

It is responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater.