Water Pollution

Case Study—Lake Washington (Living in the Environment, Miller) pg. 528 Case Study—Lake Washington (Living in the Environment, Miller) pg. 528

It is a hard truth to swallow, but nature does not care if we live or die. We cannot survive without the oceans, for example, but they can do just fine without us. It is a hard truth to swallow, but nature does not care if we live or die. We cannot survive without the oceans, for example, but they can do just fine without us. --Roger Rosenblatt

Hydrologic Cycle

Transformation Processes Transformation Processes –Evaporation from surface water storage from surface water storage –Transpiration release of water from plants release of water from plants –Condensation clouds clouds –Precipitation Rain, snow, sleet, hail, etc. Rain, snow, sleet, hail, etc.

Hydrologic Cycle Transfer Processes Transfer Processes –Percolation (Infiltration) When water seeps through the soil into the ground When water seeps through the soil into the ground –Results in ground water (wells) –Run off When water runs off the surface When water runs off the surface –Can flow to rivers, lakes, and/or oceans –Happens when soil is saturated or –Happens when there is a barrier  Eg. Asphalt

Human Impact on the Hydrologic Cycle Increase level of surface run off due to the building of roads, parking lots, and structures. Increase level of surface run off due to the building of roads, parking lots, and structures. –Ground water table is decreasing—less fresh water available for consumption Pollution of fresh water Pollution of fresh water

Biochemical Oxygen Demand Dissolved organic matter is a significant water pollution problem because it decays in the water. Dissolved organic matter is a significant water pollution problem because it decays in the water.

Biochemical Oxygen Demand Biochemical oxygen demand (BOD) is the amount of oxygen required to decay a certain amount of organic matter. Biochemical oxygen demand (BOD) is the amount of oxygen required to decay a certain amount of organic matter. –If too much organic matter is added, all available oxygen will be used up. –Anaerobic bacteria begins to break down waste, producing a foul odor

Biochemical Oxygen Demand Effect of organic wastes on dissolved oxygen.

Biochemical Oxygen Demand Nutrients can also be a pollution problem. Nutrients can also be a pollution problem. –Eutrophication is excessive growth of algae and aquatic plants due to added nutrients. –Particulate matter can also affect quality. Particles alter the clarity of the water. Particles alter the clarity of the water. They cover spawning sites. They cover spawning sites. They act as abrasives that injure organisms They act as abrasives that injure organisms They carry toxic materials. They carry toxic materials.

Testing for Eutrophication and BOD By testing the Dissolved Oxygen (DO) in the water, one can infer how much BOD and eutrophication is in the water which indicates the health of the body of water By testing the Dissolved Oxygen (DO) in the water, one can infer how much BOD and eutrophication is in the water which indicates the health of the body of water –This is a kind of indirect measurement of pollution. –Must take into account water velocity as well.

Sources of Water Pollution A point source is a source of pollution readily located and identified. A point source is a source of pollution readily located and identified. –Municipal and industrial waste discharge pipes. Example: Wastewater treatment plants Example: Wastewater treatment plants

Sources of Water Pollution Nonpoint sources are more difficult to identify and control. Nonpoint sources are more difficult to identify and control. –Diffuse pollutants from agricultural land and urban paved surfaces come from nonpoint sources. –Acid rain

How You Can Help Individuals can protect surface and ground waters from nonpoint pollution: Individuals can protect surface and ground waters from nonpoint pollution: –Use less toxic or nontoxic alternatives to commonly used home chemicals. –Buy chemicals only in the amount you intend to use, and apply them only as directed. More is not better. –Take unwanted household chemicals to hazardous waste collection centers. Do not pour them down the drain.

How You Can Help –Never pour unwanted chemicals on the ground. –Use water-based products whenever possible. whenever possible. –When landscaping your yard, select native plants that have low requirements for water, fertilizers, and pesticides. –Test your soil before applying fertilizers.

Kinds and Sources of Water Pollution Municipal Water Pollution Municipal Water Pollution –Waste from homes consists primarily of organic matter from garbage, organic matter from garbage, food preparation, food preparation, cleaning of clothes and dishes, cleaning of clothes and dishes, –At one time, many detergents contained phosphates, which contributed to eutrophication.  These have been eliminated from most major detergents since and human waste. and human waste. –Fecal coliform bacteria is a generic term for bacteria found in the intestines of warm-blooded animals, such as Escherichia coli and Streptococcus faecalis.

Kinds and Sources of Water Pollution Other Municipal Other Municipal –Pharmaceuticals, –hormones, –detergent metabolites, –insecticides, –fire retardants, –and plasticizers, –among other chemicals, also found in municipal water discharge.

Kinds and Sources of Water Pollution In a study of 139 streams throughout the Untied States, the U.S. Geological Survey (USGS) found one or more chemicals in 80% of sampled streams. In a study of 139 streams throughout the Untied States, the U.S. Geological Survey (USGS) found one or more chemicals in 80% of sampled streams. –These chemicals largely escape regulation and are not removed by municipal wastewater treatment.

Kinds and Sources of Water Pollution Agricultural activities are the primary cause of water pollution. Agricultural activities are the primary cause of water pollution. –Excessive fertilizer use may lead to eutrophication in many aquatic habitats. –Runoff from animal feedlots carries nutrients, organic matter, and bacteria.

Kinds and Sources of Water Pollution Agricultural runoff from large, open expanses is major source of water pollution, but can be controlled: Agricultural runoff from large, open expanses is major source of water pollution, but can be controlled: –Leave conservation buffer. –Keep soil covered with crop. –Control amount and timing of fertilizer application. fertilizer application.

Kinds and Sources of Water Pollution Factories and industrial complexes frequently dispose of waste in municipal sewage systems. Factories and industrial complexes frequently dispose of waste in municipal sewage systems. –Sulphur –Lead –Mercury –Nitrates and phosphates

Kinds and Sources of Water Pollution Mining is a special source of industrial water pollution. Mining is a special source of industrial water pollution. –Chemical run-off is released into streams. –Water draining from mines is highly acidic.

Kinds and Sources of Water Pollution Thermal pollution occurs when industry withdraws water from a source, uses it for cooling purposes, and returns heated water to its original source. Thermal pollution occurs when industry withdraws water from a source, uses it for cooling purposes, and returns heated water to its original source. –Steam from steam turbines must be condensed into water after leaving turbine for maximum efficiency. –An increase in temperature, even a few degrees, may significantly alter some aquatic ecosystems.

Kinds and Sources of Water Pollution Today in the industrialized world, most cooling water is not released in such a way that aquatic ecosystems are endangered. Today in the industrialized world, most cooling water is not released in such a way that aquatic ecosystems are endangered.

Kinds and Sources of Water Pollution Other methods of discharging heated water include: Other methods of discharging heated water include: –Large, shallow cooling ponds Heat dissipated from pond. Heat dissipated from pond. –Heated water sprayed into air and cooled by evaporation.

Kinds and Sources of Water Pollution Marine pollution has many sources, including accidents. Marine pollution has many sources, including accidents. The Exxon Valdez ran aground in Prince William Sound, Alaska, in 1989 and spilled 42 million liters (11 million gallons) of oil. The Exxon Valdez ran aground in Prince William Sound, Alaska, in 1989 and spilled 42 million liters (11 million gallons) of oil. –This affected nearly 930 miles of coastline. –Economic impact on the local economy was severe.

Kinds and Sources of Water Pollution BP Gulf of Mexico spill BP Gulf of Mexico spill in 2010

Kinds and Sources of Water Pollution Tanker accidents are spectacular, but more oil is released as a result of small, regular releases from other sources. Tanker accidents are spectacular, but more oil is released as a result of small, regular releases from other sources. –Two-thirds of all human-caused marine oil is from: Street runoff. Street runoff. Improper disposal of lubricating oil. Improper disposal of lubricating oil. Intentional oil discharges during tanker Intentional oil discharges during tanker loading and unloading.

Kinds and Sources of Water Pollution An international agreement was reached in 1992 that declared new oil tankers must be double-hulled. An international agreement was reached in 1992 that declared new oil tankers must be double-hulled. –Currently 25% of all tankers double-hulled

Kinds and Sources of Water Pollution Major sources of groundwater pollution include: Major sources of groundwater pollution include: –Agricultural products Pesticides Pesticides –Underground storage tanks Leakage Leakage –Landfills Approximately 90% of North American landfills have no liners to stop leakage. Approximately 90% of North American landfills have no liners to stop leakage. 96% do not have systems to collect leachate that seeps from the landfill. 96% do not have systems to collect leachate that seeps from the landfill.

Kinds and Sources of Water Pollution –Septic tanks There are over 20 million septic tanks in U.S.; about one-third are operating improperly. There are over 20 million septic tanks in U.S.; about one-third are operating improperly.

Kinds and Sources of Water Pollution Sources of groundwater contamination