Water Pollution Chapter 20

Water Pollution Comes from Point Sources Any chemical, biological, or physical change in water quality that harms living organisms or makes water unsuitable for desired uses. Point sources Located at specific places Easy to identify, monitor, and regulate Examples: Ditches, sewer lines, drain pipes, oil tankers, undergound mines

Point Source of Polluted Water in Gargas, France

Water Pollution Comes from Nonpoint Sources Broad, diffuse areas from which pollutants enter bodies of surface water or air Difficult to identify and control Expensive to clean up Examples Runoff (chemical or biological) from feedlots, cropland, lawns, golf courses, logged forests, urban streets & parking lots (THINK BIG AREA)

Nonpoint Sediment from Unprotected Farmland Flows into Streams

Biggest Sources of Water Pollution Agriculture activities ***Sediment eroded from agricultural land*** Fertilizers and pesticides Bacteria from livestock and food processing wastes Industrial facilities Organic and inorganic chemicals Mining Sediment from eroding soil Toxic chemicals

Waste water runoff from strip mining flowing into the Ohio River

Other Sources of Water Pollution Parking lots Build up of toxins on surface Human-made materials E.g., plastics – release polymers as they break down Climate change due to global warming will affect precipitation and change amounts of pollutants washing into the hydrological cycle

Major Water Pollutants Have Harmful Effects Infectious disease organisms: contaminated drinking water Over 500 disease-causing agents can be spread through water vectors The World Health Organization (WHO) 3.2 Million people die every year from water diseases or clean water shortages (most under 5) In the developing world, diarrheal diseases kill a child under 5 every 18 SECONDS 1.2 Billion people (1 out of 6) worldwide have no access to clean drinking water

Major Water Pollutants and Their Sources

Common Diseases Transmitted to Humans through Contaminated Drinking Water

Testing Water for Pollutants Variety of tests to determine water quality: Coliform bacteria: Escherichia coli, significant levels Chemical analysis of Fecal Coliform (per 100 mL) For drinking = NO colonies For swimming < 200 colonies Raw sewage contains several million colonies Level of dissolved oxygen (DO) Can indicate the presence of oxygen demanding bacteria – a sign that the water is polluted by potentially disease causing agents

Water Quality as Measured by Dissolved Oxygen Content in Parts per Million

Testing Water for Pollutants Indicator species Examples: cattails, mussels Genetic engineering Bacteria and yeast glow in the presence of a particular toxic chemical Measuring sediment Color and turbidity of the water Turbidity – cloudiness of the water

Threats to Streams Streams can cleanse themselves if we do not overload them Dilution is a natural recovery process Hindered by drought, damming, water diversion (reduces flow) Biodegradation of wastes by bacteria takes time – and cannot break down non-degradable pollutants (like mercury or DDT) Oxygen sag curve shows the demands of oxygen-demanding wastes on a stream or river that has been polluted

Stream Pollution in Developed Countries 1970s: Water pollution control laws Must eliminate or reduce point source discharge Successful water clean-up stories Ohio Cuyahoga River, U.S. Thames River, Great Britain Room for improvement – large fish kills Contamination of toxic inorganic and organic chemicals by industries and mines Malfunctioning or overloaded sewage treatment plants Runoff from agriculture/feedlots (fertilizer, pesticides, manure)

Cuyahoga River Fire, 1969

Global Outlook: Stream Pollution in Developing Countries Half of the world’s 500 rivers are polluted Most of these are in developing countries Cannot afford waste treatment Cannot enforce water pollution laws Untreated sewage Developing countries dump 80-90% of waste raw Industrial waste Pollutes 2/3 of India’s rivers China’s rivers 1/3 unsafe for agricultural & industrial use 300 million people without access to drinkable H20

Natural Capital Degradation: Highly Polluted River in China

Trash Truck Disposing of Garbage into a River in Peru

Low Water Flow and Too Little Mixing Makes Lakes Vulnerable to Water Pollution Less effective at diluting pollutants than streams Stratified layers Little vertical mixing Little of no water flow

Cultural Eutrophication Is Too Much of a Good Thing Natural nutrient enrichment of a lake over time Oligotrophic lake Low nutrients, clear water Cultural eutrophication Accelerated nutrient enrichment due to human activites involving mostly nitrate- and phosphate- containing effluents Sources: feedlots, farmland, suburban yards, mining sites, untreated sewage

How Cultural Eutrophication Happens During hot weather or droughts More nutrients Algal blooms Algal death Increased bacteria – decomposing Fish die (suffocation) Anaerobic bacteria take over producing hydrogen sulfide and methane

Cultural Eutrophication Is Too Much of a Good Thing (3) Prevent or reduce cultural eutrophication Remove nitrates and phosphates Diversion of lake water Clean up lakes Remove excess weeds Use herbicides and algaecides; down-side? Pump in air

Case Study: Pollution in the Great Lakes (1) 1960s: Many areas with cultural eutrophication 1972: Canada and the United States: Great Lakes pollution control program What was done? Problems still exist Raw sewage Nonpoint runoff of pesticides and fertilizers Biological pollution Atmospheric deposition of pesticides and Hg

Case Study: Pollution in the Great Lakes (2) 2007 State of the Great Lakes report New pollutants found Wetland loss and degradation; significance? Declining of some native species Native carnivorous fish species declining What should be done?

The Great Lakes of North America

Case Study: India’s Ganges River: Religion, Poverty, Population Growth, and Health (1) Holy river: religious customs Pollution Sewage Human remains Painted statues Government intervention Waste treatment plants Crematoriums Snapping turtles

India’s Ganges River

Ground Water Cannot Cleanse Itself Very Well Source of drinking water for ½ of US and 95% rural areas Common pollutants Fertilizers and pesticides Gasoline Organic solvents Pollutants dispersed in a widening plume

Ground Water Cannot Cleanse Itself Very Well Slower chemical reactions in groundwater due to Slow flow (less than 1 ft per day): contaminants not diluted Less dissolved oxygen Fewer decomposing bacteria How long will it take to cleans itself of Slowly degradable wastes (like DDT) Take decades to thousands of years Nondegradable wastes (like lead and arsenic) Permanent pollution

Groundwater Pollution Is a Serious Threat China: many contaminated or overexploited aquifers 9 out of 10 U.S.: FDA reports of toxins found in many aquifers EPA survey of 26,000 industrial waste ponds and lagoons found that 1/3 had no liners 2/3 of America’s liquid hazardous wastes are injected into disposal wells and leak into aquifers EPA has cleaned up 350,000 of 460,000 underground tanks

What’s in those leaky tanks? What about leaking underground storage tanks: Gasoline Oil Methyl tertiary butyl ether (MTBE) A suspected carcinogen Nitrate ions Can cause cancer or “blue baby syndrome” Bottom Line: Wastes we think we have thrown away or stored safely can escape and come back to haunt us 33

Case Study: A Natural Threat from Arsenic in Groundwater Source of As in the groundwater Natural AND human (mining) Human health hazards: cancer Skin Lungs Bladder Northern Chile – 3 to 14 times higher cancer rates than normal

There Are Many Ways to Purify Drinking Water Reservoirs and purification plants Improve quality by letting suspended matter settle Protecting watersheds is cheaper than treating Process sewer water to drinking water El Paso, TX gets 40% of its water this way Works well, but expensive & people think its gross Expose clear plastic containers to sunlight (UV) Takes 3 hours to kill bacteria Has decreased childhood diarrhea by 30-40% Nanofilters The LifeStraw

The LifeStraw: Personal Water Purification Device

Case Study: Protecting Watersheds Instead of Building Water Purification Plants New York City water Reservoirs in the Catskill Mountains Protect the watershed instead of water purification plants Spent $1.5 billion on revegetation & protection Purification would cost $6 billion plus $300 million per year in filtration cost

Using Laws to Protect Drinking Water Quality 1974: U.S. Safe Drinking Water Act Sets maximum contaminant levels for any pollutants that affect human health The BAD news 5.6 million Americans drink water that does not meet EPA safety standards for 1 or more pollutants 1 in 5 American’s drink water from a plant that has violated one or more safety standards during the year

Using Laws to Protect Drinking Water Quality Health scientists say strengthen the law More notification for violations Ban lead in plumbing pipes Still allowed to sell plumbing line w/ 10% lead as “lead-free” Water-polluting companies: weaken the law Want “waivers” to violate standards when it is too expensive to comply Want to eliminate national tests and reduce notifications (usually you’re parents get one every year from your water utility company) 39

Is Bottled Water the Answer? U.S.: some of the cleanest drinking water Bottled water ¼ is regular tap water 40% is contaminated by bacteria Costs 240 to 100,000 times more than tap water Fuel cost to manufacture the plastic bottles Recycling of the plastic Consumers spend $1-2 billion in US Growing back-to-the-tap movement If you’re worried have an INDEPENDENT test

Ocean Pollution Is a Growing and Poorly Understood Problem (1) Coasts bear the brunt 40% of the world’s population live on or near the coast Of the world’s 15 largest metropolitan areas – 14 are on the coast 2006 Study by UN EP: State of the Marine Environment 80% of marine pollution originates on land Sewage

Ocean Pollution: Cruise Ships Cruise line pollution: what is being dumped? Human waste Dry cleaning solutions Garbage Used oil It is illegal in US waters, but most do it at night Solution: tourists are picking cruise lines based on ship waste management Outside of US waters, it is up to each ship’s country of origin – most are flagged from nations without strict employment or environmental laws

US Beaches U.S. coastal waters Beach goers Raw sewage Sewage and agricultural runoff: NO3- and PO43- Beach goers Ear infections, sore throats, eye irritation, respiratory diseases, gastrointestinal disease 1 in 4 beaches is “unsuitable” for swimming 44

Pollution effects Harmful algal blooms Oxygen-depleted zones Red, brown or green tides Cause airborne toxins to be release killing birds, marine mammals Poisons seafood Reduces Tourism Oxygen-depleted zones “Dead Zones” Nitrates and Phosphates 45

A Red Tide

Science Focus: Oxygen Depletion in the Northern Gulf Of Mexico Severe cultural eutrophication Mississippi watershed drains 2/3 of the US land Oxygen-depleted zone Overfertilized coastal area Preventive measures Reduce fertilizer use (or use below ground) Improve flood prevention Replanting vegetation Will it reach a tipping point?

A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms

Ocean Oil Pollution Sources Largest source of ocean oil pollution Urban and industrial runoff from land 1989: Exxon Valdez, oil tanker ran aground in Prince William Sound, Alaska Price to clean up - $2.5 billion ($4 billion after lawsuits) 2002: Prestige, oil tanker, sank off the coast of Spain Leaked oil for 2 years (twice the amount of the Valdez)

Ocean Oil Pollution Problems Volatile organic hydrocarbons Kill many aquatic organisms Especially vulnerable larval forms Tar-like globs on the ocean’s surface Coat animals Loss of buoyancy and death results from drowning Heavy oil components sink Affect the bottom dwellers (clams, crabs, oysters)

Recovery from Oil Spills Faster recovery from crude oil than refined oil Crude oil: 3 years Refined oil: 10-20 years Economic impact to tourism Cleanup procedures Floating booms, skimmer boats, absorbent bacteria Only gets 15% of oil Methods of preventing oil spills Use double hulls

Reduce Surface Water Pollution from Agriculture Reduce erosion Keep cropland covered with vegetation Reduce the amount of fertilizers Especially on sloped land Plant buffer zones of vegetation Use organic farming techniques Use pesticides prudently Control runoff Tougher pollution regulations for livestock operations Deal better with animal waste

Case Study: The U.S. Experience with Reducing Point-Source Pollution Numerous improvements in water quality # of people served by community H2O meeting federal health standards went from 79% to 94% Some lakes and streams are not safe for swimming or fishing From 36% to 60% High levels of Hg, pesticides, and other toxic materials in fish Treated wastewater still produces algal blooms

Dealing with Sewage to Reduce Water Pollution Septic tank system Underground tank for treating wastewater from a home in rural and suburban areas. Bacteria in the tank decompose organic wastes, and the sludge settles to the bottom of the tank. The effluent flows out of the tank into the ground through a field of drainpipes. Issues: Settling tank must be pumped every few years Not maintained can cause sewage to back-up into the home or pollute nearby groundwater Chemicals can kill the bacteria

Solutions: Septic Tank System

Dealing with Sewage to Reduce Water Pollution Wastewater or sewage treatment plants STEP 1: Primary sewage treatment Physical process Goal: Removal of solids Screens, grit chamber, settling tanks Result: 60% reduction in suspended solids & 30 to 40% reduction in oxygen-demanding waste DOES NOT REMOVE: Pathogens, phosphates, nitrates, salts, radioisotopes, pesticides 57

Solutions: Primary and Secondary Sewage Treatment 58

Dealing with Sewage to Reduce Water Pollution Wastewater or sewage treatment plants STEP 2: Secondary sewage treatment Biological process Goal: remove oxygen demanding waste Result: 90% of dissolved and biodegradable wastes are removed, 70% of toxic metals, phosphorous and 50% of nitrogen DOES NOT REMOVE: Most isotopes Persistent organic substances (pesticides) Pathogens 59

Solutions: Primary and Secondary Sewage Treatment 60

Dealing with Sewage to Reduce Water Pollution Wastewater or sewage treatment plants STEP 3: Tertiary or advance sewage treatment Chemical Goal: remove specific pollutants VERY HIGH COST, not widely used BEFORE DISCHARGE (LAST STEP) Bleaching or chlorination to remove color and disease-causing bacteria Result: very successful, but carries some risk from the chemicals (cancer, miscarriage, endocrine disruptors) DOES NOT REMOVE: some viruses 61

Solutions: Primary and Secondary Sewage Treatment

Sewage Treatment in the US Law requires primary and secondary treatment You can exempt secondary if it is an “excessive financial burden” Separate pipes for sewage and storm runoff Reduces cost of treating waste water (less of it) More expensive to install Health risks of swimming in water with blended sewage wastes

We Can Improve Conventional Sewage Treatment Use composting toilet systems Now waterless and odorless (?) Wetland-based sewage treatment systems Ideal for some developing countries

Options!

Solutions: Water Pollution, Methods for Preventing and Reducing Water Pollution

What Can You Do? Water Pollution, Ways to Help Reduce Water Pollution