21 Water Pollution

Overview of Chapter 21 Types of Water Pollution Water Quality Today Municipal Agricultural Industrial Improving Water Quality Laws Controlling Water Pollution © 2012 John Wiley & Sons, Inc. All rights reserved.

Types of Water Pollution Any physical or chemical change in water that adversely affects the health of humans and other organisms Problem in developing countries: lack of disease free. Eight categories Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution © 2012 John Wiley & Sons, Inc. All rights reserved.

Sewage The release of wastewater from drains or sewers Causes 2 serious environmental problems: Enrichment Fertilization of a body of water by high levels nitrogen and phosphorus. Sewage and other organic wastes are measures by biochemical oxygen demand (BOD). Increase in Biological Oxygen Demand (BOD) (in milligrams of dissolved oxygen per liter of water for a specific number of days at a given temperature). A large amount of sewage in water generates a high BOD which robs the water of dissolved oxygen. When dissolved oxygen levels are low, anaerobic microorganism produce compounds with unpleasant orders which deteriorate water quality. As BOD increases, Dissolve Oxygen (DO) decreases © 2012 John Wiley & Sons, Inc. All rights reserved.

Sewage © 2012 John Wiley & Sons, Inc. All rights reserved.

Sewage - Eutrophication Oligotrophic Unenriched, clear water that supports small populations of aquatic organisms © 2012 John Wiley & Sons, Inc. All rights reserved.

Sewage - Eutrophication Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus. The enrichment of water results in an increased photosynthetic productivity. The water in eutrophic lake is a cloudy and usually resembles pea soup b/c of the presence of algae. © 2012 John Wiley & Sons, Inc. All rights reserved.

Disease-causing Agents Disease-causing agents are infectious organism that cause disease; they come from the wastes of infected individuals. Municipal wastewater usually contains many bacteria, viruses, protozoa, parasitic worms and other infectious agents that cause human or animal disease. Infectious organisms that cause diseases Originate in the wastes of infected individuals Common bacterial or viral diseases: Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis © 2012 John Wiley & Sons, Inc. All rights reserved.

Monitoring for Disease from Sewage Monitored by testing for presence of E. coli in the water via a fecal coliform test Small sample of water is passed through a filter to trap all bacteria. The filter is then transferred to a Petri dish that contains agar. Indicates the presence of pathogenic organisms © 2012 John Wiley & Sons, Inc. All rights reserved.

Monitoring for Disease from Sewage When dangerous levels of fecal coliform bacteria are discovered in a stream or other body of water. Important to determine source of contamination. Bacterial source tracking (BST) allows investigators to identify subtle difference in strains of E. coli on the basis of their animal host. © 2012 John Wiley & Sons, Inc. All rights reserved. 10

Sediment Pollution Excessive amounts of suspended soil particles. (clay, silt, sand and gravel are suspended and carried in water.) Sediment pollution occurs when excessive amounts of suspended soil particles eventually settle out and accumulate on the bottom of a body of water. Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction Problems Sediments that settle out of the water and form a layer over coral reefs or shellfish beds can clog the gills and feeding structures of aquatic animals. Limits light penetration Covers aquatic animals and plants Brings insoluble toxins into waterways ( which makes the water turbid so cloudy). This reduces the ability of producers to photosynthesize. Affect water Quality by carrying toxic chemicals both inorganic and organic into the water. © 2012 John Wiley & Sons, Inc. All rights reserved.

© 2012 John Wiley & Sons, Inc. All rights reserved.

Inorganic Plant and Algal Nutrients Nitrogen and phosphorus that stimulate the growth of plants and algae Harmful in large concentrations Sources: Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff Causes: Enrichment, bad odors, and a high BOD © 2012 John Wiley & Sons, Inc. All rights reserved.

Inorganic Plant and Algal Nutrient- The Dead Zone Dead Zone in Gulf of Mexico: nitrogen and phosphorus from the Mississippi River are largely responsible for huge dead zones. Dead zones are a sections of the ocean or a sea in which oxygen has been d depleted to the point that most animals and bacteria cannot survive often caused by runoff of chemical. fertilizers. © 2012 John Wiley & Sons, Inc. All rights reserved.

Organic Compounds Chemicals that contain carbon atoms Natural examples: sugars, amino acids, and oils Human-made examples: pesticides, solvents, industrial chemicals, and plastics © 2012 John Wiley & Sons, Inc. All rights reserved.

Volatile Organic Compounds in Groundwater © 2012 John Wiley & Sons, Inc. All rights reserved.

Inorganic Chemicals Contaminants that contain elements other than carbon Do not degrade easily Lead Found in old paint, industrial pollutants, leaded gasoline. Contaminates water when the water passes through the pipes of older homes that contain lead lined pipes brass fitting containing lead and lead containing material. Exposure can damage the brain nervous system and kidneys. Mercury Mercury is found in increase concentrations in water as result of human activities. Coming from the burning of fossil fuels mainly coal, incineration of garbage, hazardous waste, medical supplies, and dental supplies and raw supplies to make cement. Mercury bioaccumulates in the muscles of top predators of the open ocean. This is found in fish and shellfish. © 2012 John Wiley & Sons, Inc. All rights reserved.

Radioactive Substances Contain atoms of unstable isotopes that spontaneously emit radiation Sources Mining Processing radioactive materials Medical and Research Facilities Nuclear power plants Natural sources © 2012 John Wiley & Sons, Inc. All rights reserved.

Thermal Pollution Nonchemical water pollution. Occurs when heated water produced during industrial processes is released into waterways. Usually occurs when cold water is removed from a natural supply, used to absorb heat as part of some industrial process, and then returned as heated water back to the natural supply. © 2012 John Wiley & Sons, Inc. All rights reserved.

Thermal Pollution Organisms affected Temperature affects reproductive cycles, digestion rates, and respiration rates Warm water holds less DO than cold water so it increase respiration rate which then suffocate. Thermal shock- A phenomenon which, dramatic change in temperature can kill many species, © 2012 John Wiley & Sons, Inc. All rights reserved. 20

Two Types of Water Pollution Point Source Pollution Water pollution that can be traced to a specific origin. Distinct locations such as particular factory that pumps its waste into a nearby stream or a sewage treatment plant that discharges it wastewater from a pipe in an ocean. Non-point Source Pollution Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry Diffuse, but its cumulative effect is very large Example: Entire farming region, suburban community with many lawns and septic system or storm runoff from parking lots. It is important to differentiate between the 2 types of pollution sources because the distinction can help in controlling polluants inputs to waterways. © 2012 John Wiley & Sons, Inc. All rights reserved.

Water Pollution from Agriculture Agriculture is leading source of water pollution in US Animal wastes and plants residues have high BOD Chemical pesticides can leach into groundwater Almost all streams and rivers are polluted with agricultural pesticides 72% of water pollution in rivers is from agriculture © 2012 John Wiley & Sons, Inc. All rights reserved.

Municipal Water Pollution © 2012 John Wiley & Sons, Inc. All rights reserved.

Industrial Wastes in Water Different industries generate different pollutants Food processing plants - high BOD Paper mills - High BOD and toxic compounds Many industries recover toxins before they go into the waste stream © 2012 John Wiley & Sons, Inc. All rights reserved.

Case-In-Point Green Chemistry- Sources of synthetic pollutants in water © 2012 John Wiley & Sons, Inc. All rights reserved.

Groundwater Pollution © 2012 John Wiley & Sons, Inc. All rights reserved.

Water Pollution in Other Countries Lake Maracaibo, Venezuela 10,000 drill platform oil wells tap lake bottom Leak oil into lake Agricultural wastes from local fields Until recently, raw human waste polluted the lake © 2012 John Wiley & Sons, Inc. All rights reserved.

Water Pollution in Other Countries Po River, Italy Similar to Mississippi River Pollutants: Sewage, industrial wastes, sediment ~17 million Italians depend on the river for drinking water Cleanup will require a national management plan and may take decades © 2012 John Wiley & Sons, Inc. All rights reserved.

Water Pollution in Other Countries Ganges River, India Used for bathing and washing clothing Sewage and industrial waste discharged into river Ganga Action Plan initiated by government Construction of 29 sewage treatment plants © 2012 John Wiley & Sons, Inc. All rights reserved.

Purification of Drinking Water © 2012 John Wiley & Sons, Inc. All rights reserved.

Purification of Drinking Water In US most municipal water supplies are treated Collected from water or reservoir Treated Treated water distributed to customers Sewer lines bring sewage to treatment plant Sewage treated at sewage treatment plant © 2012 John Wiley & Sons, Inc. All rights reserved.

Purification of Drinking Water Chlorine Dilemma Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects Peru stopped using chlorine 1991 - huge cholera epidemic that infected 300,000 people Fluoridation 70% of US drinking water is fluoridated Prevents tooth decay Once believed to be linked to cancer, kidney disease - current studies do not show this © 2012 John Wiley & Sons, Inc. All rights reserved.

Municipal Sewage Treatment Primary treatment Removing suspended and floating particles by mechanical processes Secondary treatment Treating wastewater biologically to decompose suspended organic material; reduces BOD © 2012 John Wiley & Sons, Inc. All rights reserved.

Secondary Treatment Most common treatment, activated sludge. Wastewater from primary sedimentation tank enters the tank Then enters the final sedimentation tank Sludge settles out Some activated sludge used again in aeration Most of the sludge transported to digester Wastewater from final tank is disinfected w/ chlorine and discharged

Secondary Treatment Secondary treatment removes ~90% of BOD Sludge from the digester is dried and disposed of in a landfill, burn, anaerobic digestion, or applied to improve soil.

Municipal Sewage Treatment © 2012 John Wiley & Sons, Inc. All rights reserved.

Municipal Sewage Treatment Sewage Sludge Solids remaining after primary and secondary sewage treatment has been completed Tertiary treatment Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments Reduce phosphorus and nitrogen © 2012 John Wiley & Sons, Inc. All rights reserved.

Municipal Sewage Treatment © 2012 John Wiley & Sons, Inc. All rights reserved.

Individual Septic System- Septic Tank © 2012 John Wiley & Sons, Inc. All rights reserved.

Individual Septic System- Drain Field © 2012 John Wiley & Sons, Inc. All rights reserved.

Laws Controlling Water Pollution Citizen Watchdogs to Monitor Pollution 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. 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. © 2012 John Wiley & Sons, Inc. All rights reserved.

Laws that Protect Groundwater Safe Drinking Water Act National Pollutant Discharge Elimination System (NPDES) Resource, Conservation and Recovery Act © 2012 John Wiley & Sons, Inc. All rights reserved.