Chapter 14. Water Pollution

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1 Chapter 14 Water Pollution

2 The Chesapeake Bay Chesapeake Bay largest estuary in the US Pollutants: Excess nitrogen and phosphorus From 3 major sources: Consequence of increased nutrients Sediment increase Causes: Anthropogenic chemicals, including: Pesticides Pharmaceutical drugs Trying to clean the CB massive size = monumental effort

3 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 Ex : Nonpoint sources- diffuse areas that pollutes a waterway Ex:

4 Types of Pollutants Human wastewater Inorganic substances (ie. heavy metals) Organic compounds Synthetic organic compounds Oil Nonchemical pollutants

5 Human Wastewater Water produced by human activities such as: Can be difficult to prevent human wastewater from contaminating human drinking water bc

6 Three reasons scientists are concerned about human wastewater: Oxygen-demanding wastes are broken down by 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

7 Oxygen Demand Oxygen demanding waste organic matter that enters a body of water and feeds the growth of bacteria (decomposers) BOD (biological oxygen demand)- the amount of oxygen a quantity of water uses over a period of time at a specific temperature Dead zones areas where this is so little oxygen, there is so little life

8 Nutrient Release Nutrients (ie phosphorus, nitrogen) present from human wastewater Eutrophication increase in fertility of a body of water Cultural eutrophication due to anthropogenic inputs of nutrients Ex: Dead Zone in the Gulf of Mexico

9 Why is eutrophication a bad thing? Sewage Explosion in algal, bacteria & Enrichment decomposer populations Fish kills Biological oxygen demand (BOD) Oxygen levels in water

10 Disease-causing Organisms Pathogens illness-causing viruses, bacteria and parasites Illnesses include: Indicator species organism that indicates whether or not disease-causing pathogens are likely to be present Fecal coliform bacteria group of generally harmless microorganisms that live in the intestines of humans and other animals

11 Treatments for Human and Animal Wastewater Septic systems- a large container that receives wastewater from the house Consists of a septic tank and leach field Septic tank Leach field Environmental advantages to septic system: Downside:

12 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 Primary treatment Secondary treatment Problems high amounts of nitrogen and phosphorus can cause eutrophication

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14 What is removed

15 Treatments for Human and Animal Wastewater Manure lagoons- large, human-made ponds line with rubber to prevent the manure from leaking into the groundwater Risks:

16 Heavy Metals and Other Substances Lead Arsenic Mercury Acids Synthetic compounds Pesticides Pharmaceuticals Hormones

17 Lead Heavy metal Rarely found in natural sources of drinking water Sources: Most at risk fetuses and infants Risks: In mid-1990 s- 10% + municipal water supplies contained lead levels that exceeded max permitted by Safe Drinking Water Act

18 Arsenic Occurs naturally in Earth s crust, can dissolve into groundwater Human activities (ie mining) can increase Can be removed via: Problems associated with: Many people suffer from arsenic poisoning with no other options

19 Mercury Image mercury releases from different regions of world Comes from: Inorganic mercury (Hg) not dangerous Bacteria (in wetlands and lakes) convert Hg into methylmercury Methylmercury is highly dangerous to humans Most at risk developing embryos and young children Can cause:

20 Acid Deposition and Acid Mine Drainage Acid deposition acids deposited on Earth, reducing the ph of bodies of water to below 5 Wet deposition vs. Dry deposition What s being done to prevent? Acid mine drainage resulting from underground mines that fill with water once abandoned Lower ph = harmful metal ions become water soluble What can be done? Problem

21 Synthetic Organic Compounds Synthetic human made Includes: Pesticides can be detrimental to the environment Concerns : Pharmaceuticals/hormones Military compounds from manufacturing, testing, dismantling rockets Industrial cleaners PCBs used in manufacturing plastics and insulating electrical transformers until 1979 PBDEs flame retardants

22 Oil Pollution Petroleum products highly toxic to many marine organisms, birds, mammals Very difficult to remove Sources: Drilling for undersea oil using offshore platforms Spills from oil tankers Natural seeps

23 Ways to Remediate Oil Pollution Where does oil accumulate? So how do we clean up surface oil? Containment using booms to keep the floating oil from spreading Dispersants - chemicals that help break up the oil Bacteria that are genetically engineered to consume oil But what about underwater plumes? Treatment of rocky coastlines:

24 Other Water Pollutants Solid waste pollution (garbage) Sediment pollution (sand, silt and clay) Thermal pollution Noise pollution

25 Solid Waste Pollution Garbage - discarded materials from homes and industries that do not pose a toxic hazard to humans/other organisms 1997 scientists discovered the Great Pacific Garbage Patch More of a problem in developing countries Coal ash and coal lag Contains harmful chemicals (lead, mercury, arsenic)

26 Sediment Pollution Sediment particles of sand, silt, clay Carried by moving water natural process Sediment pollution increased movement of sediment due to human activities Resulting from activities that loosen soil Accounts for ~70% of sediment in waterways Effects?

27 Thermal Pollution Substantial change in water temperature Can be increase or decrease, most commonly is increase Methods to reduce thermal pollution: Thermal shock dramatic change in temperature causing death to many species

28 Noise Pollution Sound emitted by ships/submarines interfere with animal communication Esp sonar

29 Water Laws Clean Water Act- (1972) supports the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water Originated as the Federal Water Pollution Control Act of 1948 Issued water quality standards that defined acceptable limits of various pollutants in U.S. waterways

30 Water Laws Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water Responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater MCLs are subjective and subject to political pressure

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32 We still have work to do