Presentation on theme: "Chapter 14 Water Pollution. Water pollution- the contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human."— Presentation transcript:
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 Deposition Acid Precipitation Created by BURNING COAL which release the primary pollutants: SO 2 & No x These turn into Sulfuric and Nitric acid in the atmosphere (H 2 O and O 2 ) 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 otters 300 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.