Water Pollution Chapter 11, section 3. Underlying causes of water pollution: 1. industrialization 2....
-
Upload
allan-morris -
Category
Documents
-
view
219 -
download
0
Transcript of Water Pollution Chapter 11, section 3. Underlying causes of water pollution: 1. industrialization 2....
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.
• 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)