Water PollutionChapter 11, section 3

Underlying causes of water pollution:1. industrialization2. rapid human population growth

Point Pollution

Definition: pollution discharged from a single sourceExamples: water discharged by industries, waste treatment

plants, leaking underground storage tanks

Nonpoint Pollution

Definition: pollution that comes from many different sources and is hard to identify

Examples: water runoff from streets, chemicals added to lawns and crops, feces from cattle, oil and gas from personal water craft

Water pollution sources

Pollutant Types and Sources:1. Pesticides

Older pesticides:• Arsenic• Chlorinated hydrocarbons Ex:

DDT, now banned in U.S.

Many work by inhibiting the activity of the enzyme acetycholinesterase, thus affecting the nervous system

Pollutant Types and Sources: Pesticides

Newer, less dangerous pesticides:• Pyrethrins commonly used insecticide now –

- derived from plants, non-persistent and biodegradable- still, very toxic to insects, pets and fish, less so to birds

• Atrazine –commonly used herbicide in U.S., banned in Europe• Glyphosate – brand name Roundup, herbicide

Biological Magnification– accumulation of pollutants at successive levels of the food chain

Pollutant Types and Sources: Pesticides

Federal Insecticide, Fungicide, and Rodenticide Act (or FIFRA) –

• U.S. law that regulates pesticide use• All pesticides must be registered• Pesticides must be tested and approved

before they are registered• Only a few pesticides are available

to the general public

Pollutant Types and Sources:2. Fertilizers – natural and man-made

Artificial eutrophication – addition of nutrients due to human activities 1. synthetic fertilizers added to agriculture, gardens, golf courses, etc.2. contamination by human and animal wastes3. addition of detergents that contain phosphates

Steps: nutrient influx

algal bloom algal death and decomposition

oxygen depletion (hypoxia) death of aquatic organisms

Eutrophication of mangrove swamp in Florida

• Eutrophication of the Gulf of Mexico – The Dead Zone

• Seasonal – starts in spring with the beginning of the growing season in the central U.S. and fades in the winter

Pollutant Types and Sources:3. Petroleum products

• Major oil spills have a huge impact on an area, such as the Exxon Valdez accident in Prince William Sound in 1989 and the BP Horizon spill in the Gulf of Mexico in 2010

• effects on wildlife: ingest toxins, hypothermia, inability to fly or catch food

Oil Spills are difficult to clean up – three methods are:1. Mechanical methods – booms, skimmers, absorbent devices2. Chemical methods – coagulating agents, dispersing agents,

fire3. Biological methods – oil-eating bacteria consume the oil;

called bioremediation

PREVENTION IS BEST!!!

• Land-based activities contribute oil pollution to the ocean, too• When people change oil in their cars and do not dispose of it

properly, it can pollute water• Oil that leaks from cars in parking lots washes into water

when it rains

Pollutant Types and Sources:4. Mining pollution

• The process of mining exposes dangerous materials, such as heavy metals and sulfur compounds, to rainfall; the result is the leaching of these materials into waterways (“acid mine drainage”)

• Very low pH can result• May leach copper, iron, lead, mercury• Piles of mining waste are called

tailings; they also leach toxic materials

• Sometimes toxic chemicals, such as cyanide, are used in the process of extracting ores, such as gold

• Example: Iron Mountain Mine, CA, closed in 1963 but still pollutes water

Pollutant Types and Sources:5. Sediment

• Results from erosion due to clear cutting, poor agricultural practices, construction, etc.

• Too much sediment can have a negative effect on aquatic life

• Silt fencing – contains sediment near construction sites, keeps it out of waterways and storm drains

Pollutant Types and Sources:6. Chemical and industrial processes

Industry uses water to carry away wastes that may contain a variety of toxic materials

Effluent – term for the industrial waste water that is dumped into the environment

EPA list of drinking water contaminantshttp://www.epa.gov/safewater/contaminants/index.html

Mercury – can come from industrial discharge, but also unlined landfills, mining, household chemicals

Mercury is a potent neurotoxin and can cause learning disabilities in children. Other symptoms include skin damage, memory loss, kidney problems, edema.

http://www.mercury-poisoning-symptoms.com/products.htm

• Radioactive water pollution – comes from nuclear plant operations, mining of uranium and thorium, use of radioactive materials in industry, medicine and science

• Savannah River Plant, SC – refined nuclear materials for use in weapons, radioactive materials are present in the surrounding area now due to effluents from the plant, Savannah River Ecology Lab studies effects of radiation on wildlife

• PCBs – polychlorinated biphenols– Used in electrical transformers, capacitors and

other equipment– Carcinogenic (cancer-causing)– Endocrine disruptor – mess up hormones– Biomagnifies and can be consumed via

contaminated fish– An example of a persistent organic pollutant (POP)

banned by Stockholm Convention– Case study: Anniston – high levels of PCBs due to

chemical plant discharging wastes into water supplies, 1920s-1970s, run by Monsanto

• Video link: http://www.youtube.com/watch?v=yrGzfhXwdyc&safety_mode=true&persist_safety_mode=1

Pollutant Types and Sources:7. Plastic

• Not biodegradable• Can be ingested by animals or

trap them• Introduces toxins to food chain• The Great Pacific Garbage

Patch is in the North Pacific Gyre (or vortex) – plastic photodegrades into smaller and smaller particles, floats near the surface

• https://www.youtube.com/watch?v=Co43TXJXryI

Pollutant Types and Sources:8. Personal care products, cleaning

products, and pharmaceuticals• Everything we wash or flush down the drain

goes to our water treatment plants which clean our water; most are not equipped to filter out these chemicals

• Examples of things found in drinking water:– Antibiotics– Hormones– Anti-epilepsy drugs– Ibuprofen

Pollutant Types and Sources:9. Pathogens

Pathogens are organisms that cause disease, including bacteria, viruses and worms

Sources – nonpoint, such as runoff from farms, overburdened water treatment plants, unprocessed human waste

Especially a problem in developing countries

Examples – E. coli and cholera

Pollutant Types and Sources:10. Air Pollution

Chemicals are released from industries and cars; this air pollution gets washed out of the air by rain and can be deposited in aquatic ecosystems

Mercury can contaminate fishSulfur dioxide and nitric oxides can cause acidification of lake water and

leaching of minerals from the ground, sometimes causing toxic effects

Pollutant Types and Sources:11. Carbon dioxide

Burning fossil fuels (gasoline, coal, natural gas) releases CO2Increased CO2 in the atmosphere results in more CO2 dissolved

in the ocean, this makes the ocean more acidic – this is called ocean acidification (lowers the pH of the ocean)

Carbonic acid causes damage to sea creatures that are made of calcium carbonate, such as corals and animals with shells

Pollutant Types and Sources:12. Heat

Thermal Pollution - temperature increase in a body of water caused by human activities that has a negative effect on the organisms that live there

Warm water holds less oxygen than colder water

This coal-fired power plant in Westport, Ky., emits steam and small amounts of pollutants. Thermal pollution is abated by the use of the large cooling tower. Companies are increasingly taking climate change and possible future carbon regulations into consideration, and designing their programs, including power plants, around such regulations. Photograph is copyright Michael Collier, courtesy of Earth Science World Image Bank.

Groundwater Pollution: A Special Problem

Groundwater is increasingly contaminated, but is hidden from view

Sources – chemicals that percolate through the soil to the aquifer, leaking underground tanks

Remain polluted for very long time because recharge slowly, pollution can cling to aquifer materials, low oxygen levels

Indicators of water quality

• Scientists measure properties of water to characterize its quality– Biological indicators: presence of fecal coliform

bacteria and other disease-causing organisms– Chemical indicators: pH, nutrient concentration,

taste, odor, hardness, dissolved oxygen– Physical indicators: turbidity, color, temperature

Federal Water Pollution Laws1972 Clean Water ActGoal: reduce pollution discharge to zero by 1985, set the federal

government (not the states) in charge of water pollution regulation with the Environmental Protection Agency (EPA)

Cuyahoga River fires – 1969, the river was so polluted that the materials on the surface caught fire, burned for days, shocked the nation

http://www.mappamundi.com/mp3/burn.mp3

Federal Water Pollution Laws

1972, 1988 (amended) Marine Protection, Research and Sanctuaries Act, also known as the Ocean Dumping Act

Goal: control dumping of sewage and toxic chemicals into U.S. ocean waters (must have a permit, no medical waste allowed), established marine preserves (sanctuaries)

Federal Water Pollution Laws

1975, 1996 (amended) Safe Drinking Water Act Goal: to protect groundwater and surface

waters that are used for drinking water

1990 Oil Pollution Act – followed Exxon Valdez accident

Goal: to protect U.S. waterways from oil spills by requiring double hulls on oil tankers by 2015

Wastewater

• Wastewater = water that has been used by people in some way– Sewage, showers, sinks, manufacturing, storm

water runoff

• Septic systems = the most popular method of wastewater disposal in rural areas– Underground septic tanks separate solids and oils

from wastewater– The water drains into a drain field, where

microbes decompose the water– Solid waste needs to be periodically pumped and

landfilled

• In populated areas, sewer systems carry wastewater – Physical, chemical, and biological water treatment

• Primary treatment = the physical removal of contaminants in settling tanks (clarifiers)

• Secondary treatment = water is stirred and aerated so aerobic bacteria degrade organic pollutants– Water treated with chlorine is piped into rivers or

the ocean– Some reclaimed water is used for irrigation, lawns,

or industry

• Natural and artificial wetlands can cleanse wastewater– After primary treatment at a conventional facility,

water is pumped into the wetland– Microbes decompose the remaining pollutants– Cleansed water is released into waterways or

percolated underground• Constructed wetlands serve as havens for

wildlife and areas for human recreation– More than 500 artificially constructed or restored

wetlands exist in the U.S.

Bottled waterReasons to give up bottled

water:1. It is not a good value2. It is not necessarily

healthier than tap water3. It produces a lot of

nonbiodegradable waste

Bottled water

4. It takes energy to produce the product in the first place, even if the bottle is recycled

5. The safety of plastics is questionable - bisphenol A (BPA) and phthalates have been proven toxic to people, some companies won’t use them anymore (ex: Nalgene)