Chapter 14 Water 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.

LE 15-21 Non-point sources of water pollution Pollutant Farms, lawns, and golf courses Fertilizers, herbicides, and pesticides Animal feedlots (also non-point source) Nutrients, waste, and bacteria Salt on winter roads; oil, grease, and chemicals from urban runoff Residential neighborhoods and urban streets Sewage treatment plants Industrial waste and toxic chemicals Factories and disposal sites Construction sites, and deforested and overgrazed land Eroded soil Oil spills Abandoned mines (also point source) Acid drainage Oil tankers

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 Effect on BOD & pH 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. Also the metabolic by products of photosynthesis increase pH levels in the water. CO2 is being taken in by plants. When the decomposers metabolize the dead algae they release CO2 (H2CO3) into the water which creates carbonic acid which lowers the pH

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.

Interactive animation http://www.gbra.org/septic.swf

SE 15-24 Wastewater treatment Slide 1 Raw sewage enters treatment facility 1 Screens and grit tank Solid objects and grit removed Oils and greases float to the top Solids disposed at landfill 2 Primary clarifier Oils, greases, and solids removed Solids sink to the bottom Gases chemically treated to reduce odor 3 Aeration basin Microbes consume organic matter Some solids returned to seed aeration basin with new microbes 4 Secondary clarifier Remaining oils, greases, and solids removed Sludge sent to anaerobic digester 5 Filtering and disinfection Water filtered with coal and sand, and/or disinfected with chlorine or UV light Gas to generate electricity Biosolids for cropland Effluent discharged into waterways

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. Contamination of water with fecal coliform bacteria. Reside in intestines of humans and animals. Indicator species when testing water quality

Heavy Metals and Other Substances that can threaten human Health and the Environment Lead Arsenic Mercury Acids Synthetic compounds (pesticides, pharmaceuticals, and hormones)

World Mercury Production - burning of coal,production of cement (limestone) Bioaccumulates in food chain & in humans

Acid Mining Drainage Runoff has a low pH Causes Iron to precipitate out from the sediment

Contaminants in U.S. Streams

Endocrine Disruption due to hormones Poison Water video http://www.ted.com/talks/tyrone_hayes_penelope_jagessar_chaffer_the_toxic_baby.html

Oil Pollution Valdez spill video BP spill interactive

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-dispersants Bacteria that are genetically engineered to consume oil- bioaugmentation Industrial vacuums Hose off with hot water on shoreline. The Exxon Valdez oil is still present today on rocks, soil, sediment

OTHER WATER POLLUTANTS Solid waste pollution (garbage) Sediment pollution (sand, silt and clay) through removal of plant material Thermal pollution-warm, filtered water from power plants Noise pollution-disrupts sea animals sonar Perchlorate-rocket fuel-causes thyroid gland issues PCB’s polychlorinated biphenyls from manufacturing of plastics & insulating electrical wires. No longer made in U.S. Carcinogenic G.E. dumping into Hudson River PBDE Polybrominated diphenyl ethers –used as flame retardants children’s clothing, construction materials, furniture Scientists have found in fish, aquatic birds, human breast milk. Can lead to brain damage, especially in children. Banned in Euorope, Washington state & California.

Water Laws First major act 1948-Federal Water Pollution Control Act expaneded into Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”. Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways. If necessary restore the chemical, physical and biological properties of natural water. It does not include groundwater. Controlled by the EPA and state governments.

Water Laws Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water. EPA is responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater. MCL considers the concentration of a compound to cause harm and the feasibility and cost to reduce the compound to such a concentration