NSCI 102 Ch 20

Three other sources of water pollution

Fertilizers, pesticides, and bacteria from livestock and food-processing wastes.

Major sources of groundwater contamination

Fertilizers, pesticides, gasoline, and organic solvents.

Economic and environmental implications of using bottled water

- A bottle of water costs between 240 and 10,000 times as much as the same volume of tap water. - A 2018 study showed that 93% of bottles were contaminated with microplastics. Bottled water is less regulated than tap water and the EPA contamination standards that apply to public water supplies do not apply to bottled water. - Many of the billions of discarded bottles end up in landfills, where they can remain for hundreds of years. Those that are burned in incinerators without high-tech pollution controls release some of their harmful chemicals into the atmosphere. In addition, millions of discarded water bottles get scattered on the land and end up in rivers, lakes, and oceans. - It takes huge amounts of energy to manufacture bottled water and to transport it across countries and around the world, as well as to refrigerate much of it in stores. Toxic gases and liquids are released during the manufacture of plastic water bottles, and greenhouse gases and other air pollutants are emitted by the fossil fuels burned to make them and to deliver bottled water to suppliers.

Areas where there is room for improvement of U.S. water quality

- About 40% of the nation's surveyed streams, lakes, and estuaries are still too polluted for swimming or fishing. - Runoff of animal wastes from hog, poultry, and cattle feedlots and meat processing facilities pollutes 70% of U.S. rivers. - Tens of thousands of gasoline storage tanks in 43 states are leaking. - Since 2003, 20% of U.S. water treatment systems have violated the Safe Drinking Water Act by releasing sewage and chemicals such as arsenic and radioactive uranium into U.S. surface waters. - A study showed that water samples from 139 streams in 30 states contained measurable levels of drugs used for birth control and for reducing pain and depression.

Five major sources of ocean pollution in coastal areas

- Cities, toxic metals and oil from streets and parking lots pollute waters, and sewage adds nitrogen/phosphorous - Farms, runoff of pesticides, and fertilizers add toxins and nitrogen/phosphorous - Industries, nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals flow into bays and estuaries - Toxic sediments, chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders - Construction sites, sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight

3 ways that the U.S. Safe Drinking Water Act could be strengthened

- Combine many of the drinking water treatment systems that serve fewer than 3,300 people with nearby larger systems to make it easier for these smaller systems to meet federal standards. - Strengthen and enforce requirements concerning public notification of violations of drinking water standards. - Ban the use of toxic lead in new plumbing pipes, faucets, and fixtures and remove existing lead pipes.

5 U.S. laws that have helped to control pollution of surface waters in the United States

- Federal Water Pollution Control Act of 1972, which was amended in 1977 and renamed the Clean Water Act (CWA). Two-thirds of the nation's lakes, rivers, and coastal waters were unsafe for fishing and swimming, and the key goal of the CWA was to make them safe. - 1972 Marine Protection, Research, and Sanctuaries Act, amended in 1988. It empowered the EPA to regulate the dumping of untreated sewage and toxic chemicals into U.S. waters. - 1975 Safe Drinking Water Act (SDWA), amended in 1996. Its goals are to protect surface and groundwater used as sources of drinking water and to establish national drinking water standards for key pollutants. - 1987 Water Quality Act, which requires the EPA to set standards for allowed levels of 100 key water pollutants. It requires polluters to get permits that limit the amounts of these various pollutants that they can discharge into aquatic systems. - 1990 Oil Pollution Act. It has the goal of protecting U.S. waterways from oil pollution.

Things that individuals can do to help reduce water pollution

- Fertilize gardens and yard plants with manure or compost instead of commercial inorganic fertilizer - Minimize the use of pesticides, especially near bodies of water - Prevent yard wastes from entering storm drains - Do not use water fresheners in toilets - Do not pour harmful chemicals down the drain or onto the ground

5 ways to prevent groundwater contamination

- Find substitutes for toxic chemicals - Keep toxic chemicals out of the environment - Require leak detectors on underground tanks - Ban hazardous waste disposal in landfills and injection wells - Store harmful liquids in aboveground tanks with leak detection and collection systems

3 ways to provide safe drinking water in poor countries

- In tropical countries that lack centralized water treatment systems, the WHO urges people to purify drinking water by exposing a clear plastic bottle filled with contaminated water to intense sunlight. The sun's heat and ultraviolet (UV) rays can kill infectious microbes in as little as 3 hours. - LifeStraw™, an inexpensive, portable water filter that eliminates many viruses and parasites from water that is drawn through it. - Bottled water

The use of living machines to treat sewage

- It begins when sewage flows into a passive solar greenhouse or outdoor site containing rows of large open tanks populated by an increasingly complex series of organisms. In the first set of tanks, algae and microorganisms decompose organic wastes, with sunlight speeding up the process. Water hyacinths, cattails, bulrushes, and other aquatic plants growing in the tanks take up the resulting nutrients. - After flowing though several of these natural purification tanks, the water passes through an artificial marsh made of sand, gravel, and bulrushes, which filter out algae and remaining organic waste. Some of the plants also remove toxic metals such as lead and mercury and secrete natural antibiotic compounds that kill pathogens. - Next, the water flows into aquarium tanks, where snails and zooplankton consume microorganisms and are in turn consumed by crayfish, tilapia, and other fish that can be eaten or sold as bait. After 10 days, the clear water flows into a second artificial marsh for final filtering and cleansing. The water can be made pure enough to drink by treating it with ultraviolet light or by passing the water through an ozone generator, usually immersed out of sight in an attractive pond or wetland habitat.

Ways to prevent or reduce water pollution

- Prevent groundwater contamination - Reduce nonpoint runoff - Work with nature to treat sewage and reuse treated wastewater - Find substitutes for toxic pollutants - Refuse, reduce, reuse, recycle

3 ways to clean up groundwater contamination

- Pump to surface, clean, and return to aquifer (very expensive) - Inject microorganisms to clean up contamination (less expensive but still costly) - Pump nanoparticles of inorganic compounds to remove pollutants (still being developed)

Suggestions for improving conventional sewage treatment

- Require industries and businesses to remove toxic and hazardous wastes from water sent to municipal sewage treatment plants. - Use Norwegian thermal hydrolysis (pressure cooker) system to convert the sludge from treated sewage into electricity—turning poop into power.

Methods (chemical and biological) that can be used to measure water quality

- Scientists use chemical analysis to determine the presence and concentrations of specific organic chemicals in polluted water. They also monitor water pollution by using living organisms as indicator species. - Scientists measure the amount of sediment in polluted water by evaporating the water in a sample and weighing the resulting sediment. They also use instruments called colorimeters to measure specific wavelengths of light shined through a water sample to determine the concentrations of water pollutants in the water.

6 ways to prevent coastal ocean water pollution

- Separate sewage and stormwater lines - Require secondary treatment of coastal sewage - Use wetlands and other natural methods to treat sewage - Ban dumping of wastes and sewage by ships in coastal waters - Strictly regulate coastal development, oil drilling, and oil shipping - Require double hulls for oil tankers

Why lakes cannot cleanse themselves as readily as streams do

- They often contain stratified layers that undergo little mixing - They have low flow rates or no flow at all. The flushing and changing of water in lakes and large artificial reservoirs can take from 1 to 100 years, compared with several days to several weeks for streams.

Secondary sewage treatment

A biological process in which oxygen is added to the sewage in an aeration tank to encourage aerobic bacteria to decompose as much as 90% of dissolved and biodegradable, oxygen-demanding organic wastes.

Plans for improving sanitation in less-developed countries

A company, working in less-developed countries, takes waste from pit latrines and septic tanks and converts it into a renewable solid fuel that can replace coal as an energy resource.

Primary sewage treatment

A physical process that uses screens and a grit tank to remove large floating objects and to allow solids such as sand and rock to settle out. Then the waste stream flows into a primary settling tank where suspended solids settle out as sludge.

Cultural eutrophication

Accelerated eutrophication from human activities. Human activities increase the input of plant nutrients into lakes near urban or agricultural areas. These inputs involve mostly nitrate- and phosphate-containing effluents from various sources. Some nitrogen also reaches lakes by deposition from the atmosphere.

How can cultural eutrophication be prevented or cleaned up?

Advanced (but expensive) waste treatment processes can remove nitrates and phosphates from wastewater before it enters a body of water. Another option is to mimic the earth's natural cycling of nutrients by recycling the removed nutrients to the soil instead of dumping them into waterways. Other preventive approaches include banning or limiting the use of phosphates in household detergents and other cleaning agents, soil conservation and land-use control to reduce nutrient runoff.

Leading source of water pollution

Agricultural activities, most common pollutant being sediment eroded from cropland.

How streams can cleanse themselves

Because they are flowing, rivers and streams can recover from moderate levels of biodegradable wastes. The wastes are diluted by flowing water and are broken down by bacteria. In a flowing stream, the breakdown of biodegradable wastes by bacteria depletes dissolved oxygen and creates an oxygen sag curve. This reduces or eliminates populations of organisms with high oxygen requirements until the stream is cleansed of oxygen-demanding wastes.

Nonpoint sources

Broad and diffuse areas where rainfall or snowmelt washes pollutants off the land into bodies of surface water. Ex: runoff of eroded soil and chemicals such as fertilizers and pesticides from cropland, animal feedlots, logged forests, construction sites, city streets, parking lots, lawns, and golf courses

How can the growth of ocean garbage patches be prevented?

By reducing the production of solid waste and keeping it out of oceans. This would require sharply reducing unnecessary use of plastic items and greatly increasing plastic recycling. Each of us can avoid using plastic water bottles and other plastic products as much as possible and recycle or dispose of them responsibly.

Progress made in reducing the pollution of the Great Lakes

By the 1960s, many areas of the Great Lakes were suffering from severe cultural eutrophication, huge fish kills, and contamination from bacteria and a variety of toxic industrial wastes. In 1972, the United States and Canada signed the Great Lakes Water Quality Agreement, which is considered a model of international cooperation. This program has helped to cut the number and sizes of algal blooms, raised dissolved oxygen levels, boosted sport and commercial fishing catches in Lake Erie, and allowed most swimming beaches to reopen. Despite this important progress, many problems remain. Increasing nonpoint runoff of pesticides and fertilizers resulting from urban sprawl, fueled by population growth, now surpasses industrial pollution as the greatest threat to the lakes. Between 2010 and 2015, the U.S. Congress provided about $1.3 billion for the Great Lakes Restoration Initiative overseen by the EPA. It has focused on reducing environmental threats such as toxic pollution, cultural eutrophication, loss of wildlife habitat, invasive species, and soil erosion and runoff into the lakes. It also promotes wetlands restoration.

Ways to deal with sewage sludge

Can be disposed of in a landfill or the ocean or applied to cropland, pasture, or rangeland.

How seasonal dead zones form in the Gulf of Mexico

During hot weather or drought, nutrient overload can produce dense growths, or "blooms," of organisms such as algae and cyanobacteria. When the algae die, swelling populations of oxygen-consuming bacteria decompose them. These bacteria deplete dissolved oxygen in the surface layer of water near the shore and in the bottom layer of a lake or coastal area. This lack of oxygen can kill fish, shellfish, and other aerobic aquatic animals that cannot move to safer waters. If excess nutrients continue to flow into a lake, bacteria that do not require oxygen take over and produce gaseous products such as smelly, highly toxic hydrogen sulfide and flammable methane.

Gulf of Mexico dead zone Ex

During the spring and summer, nitrate- and phosphate-laden freshwater flowing into the Gulf forms an oxygen-rich layer on top of the Gulf's cooler and denser saltwater. Because there are few storms at this time of year, this sun-heated upper layer of water remains calm and does not mix with the bottom layer of low-oxygen water. The combination of sunlight and large inputs of nitrate and phosphate plant nutrients from fertilizer and sewage into the freshwater layer leads to massive blooms of phytoplankton, mostly blue-green algae. When these algae die, they sink into the saltier water below where they are decomposed by oxygen-consuming bacteria. This reduces the dissolved oxygen content in the deeper water to 2 parts per million or lower. The resulting dead zone disrupts the Gulf's food web, because the die-offs lead to the deaths of seabird and marine mammal species that depend on the dying fish and shellfish for their survival.

Primary cause of the annual dead zone in the Gulf of Mexico

Each spring and summer, huge quantities of nitrogen and phosphorus plant nutrients flow into the Mississippi River, end up in the northern Gulf of Mexico, and overfertilize the coastal waters of the U.S. states of Mississippi, Louisiana, and Texas. This excess of plant nutrients leads to an explosive growth of phytoplankton (mostly algae) that eventually die, sink to the bottom, and are decomposed by hordes of oxygen-consuming bacteria. This depletes most of the dissolved oxygen in the Gulf's bottom layer of water. The resulting massive volume of water with a low dissolved oxygen content is called a dead zone because it contains little or no animal marine life. Its low dissolved oxygen levels drive away faster-swimming fish and other marine organisms and suffocate bottom-dwelling fish, crabs, oysters, and shrimp that cannot move to less polluted areas. Large amounts of sediment, mostly from soil eroded from the Mississippi River basin, can kill bottom-dwelling forms of animal aquatic life.

Ocean garbage patch

Gigantic, slowly rotating masses of plastic and other solid wastes in the middle of the ocean. Many of the small plastic particles degrade into microplastics that can contain potentially hazardous chemicals, including PCBs, DDT, and hormone-mimicking BPA. A major problem is that small and microscopic plastic particles are eaten by hundreds of species of marine fishes, seabirds, sea turtles, and other animals that mistake them for food or ingest them unknowingly. The long-lived toxins in some microplastics can build up to high concentrations in food chains and webs and end up in fish sandwiches and seafood dinners.

The threat of groundwater pollution in China

Groundwater provides about 70% of China's drinking water. According to the Chinese Ministry of Land and Resources, about 90% of China's shallow groundwater is polluted with chemicals such as toxic heavy metals, organic solvents, nitrates, petrochemicals, and pesticides. About 37% of this groundwater is so polluted that it cannot be treated for use as drinking water.

Three human factors that have contributed to the formation of the dead zone

Human activities increase the input of plant nutrients into lakes near urban or agricultural areas. These inputs involve mostly nitrate- and phosphate-containing effluents from various sources. Sources include fertilized farmland, animal feedlots, urban streets and parking lots, fertilized lawns, mining sites, and municipal sewage treatment plants.

The threat of groundwater pollution in the U.S.

In the United States, an EPA survey of 26,000 industrial waste ponds and lagoons found that one-third of them had no liners to prevent toxic liquid wastes from seeping into aquifers. In addition, almost two-thirds of America's liquid hazardous wastes are injected into the ground in disposal wells. Leaking injection pipes and seals in such wells can contaminate aquifers used as sources of drinking water. By 2018, the EPA had cleaned up about 461,000 of the more than 532,000 underground tanks in the United States that were leaking gasoline, diesel fuel, home heating oil, or toxic solvents into groundwater.

Eight major types of water pollutants

Infectious agents (bacteria, viruses, parasites) - causes diseases Oxygen-demanding wastes (biodegradable animal wastes and plant debris) - deplete dissolved oxygen needed by aquatic species Plant nutrients (nitrates and phosphates) - cause excessive growth of algae and other species Organic chemicals (oil, gasoline, plastics, pesticides, cleaning solvents) - add toxins to aquatic systems

The threat of arsenic in groundwater

Long-term exposure to nondegradable arsenic in drinking water is likely to cause hundreds of thousands of premature deaths from cancer of the skin, bladder, and lungs. According to the EPA, some 13 million people in several thousand communities, mostly in the western United States, are exposed to arsenic levels of 3 to 10 ppb in their drinking water.

How we can use wetlands to treat sewage

More than 800 cities and towns around the world (150 in the United States) mimic nature by using natural or artificially created wetlands to treat sewage as a lower-cost alternative to expensive waste treatment plants. For example, in Arcata, California—a coastal town of almost 18,000 people—scientists and workers created some 65 hectares (160 acres) of wetlands between the town and the adjacent Humboldt Bay. The marshes and ponds, developed on land that was once a dump, act as a natural waste treatment plant. The cost of the project was less than half the estimated price of a conventional treatment plant. This system returns purified water to Humboldt Bay, and the sludge that is removed is processed for use as fertilizer. The marshes and ponds also serve as an Audubon Society bird sanctuary, which provides habitats for thousands of seabirds, otters, and other marine animals.

Eutrophication

Natural nutrient enrichment of a shallow lake, a coastal area at the mouth of a river, or a slow-moving stream. It is caused mostly by runoff of plant nutrients such as nitrates and phosphates from land bordering such bodies of water.

Why groundwater cannot cleanse itself very well

Once a pollutant from a leaking underground storage tank or other source contaminates groundwater, it fills the aquifer's porous layers of sand, gravel, or bedrock. Removing such contaminants from groundwater is difficult and costly. Groundwater flows so slowly that contaminants are not effectively diluted and dispersed. In addition, groundwater usually has much lower concentrations of dissolved oxygen (which helps decompose some biodegradable contaminants) and smaller populations of decomposing bacteria. The usually cold temperature of groundwater slows down chemical reactions that decompose wastes.

How should oil spill accidents be prevented in the future?

One of the best ways to prevent tanker spills is to use oil tankers with double hulls. Stricter safety standards and inspections could reduce oil well blowouts at sea. In addition, businesses, institutions, and citizens living in coastal areas must take care to prevent leaks and spillage of even the smallest amounts of oil and oil products such as paint thinners and gasoline.

Effects of annual oxygen depletion in the Gulf of Mexico

Oxygen-depleted zones represent a disruption of the nitrogen cycle primarily by human activities. This is because great quantities of nitrogen from nitrate fertilizers are added to these aquatic systems faster than the nitrogen cycle can remove them. Thus, producing crops to feed livestock and people and ethanol to fuel cars in the Mississippi basin disrupts coastal aquatic life and seafood production in the Gulf of Mexico.

Stream pollutants in more-developed countries

Pollutants come from homes, industries, and mining operations. Also, hurricanes can lead to water pollution.

Stream pollutants in less-developed countries

Pollutants come from untreated sewage, industrial wastes, and discarded trash.

What causes harmful algal bloom and what are their effects?

Runoff of sewage and agricultural wastes flowing into coastal waters introduces large quantities of nitrate and phosphate plant nutrients that can cause explosive growths of harmful algae and lead to dead zones. These harmful algal blooms release waterborne and airborne toxins that can poison seafood, damage fisheries, kill some fish-eating birds, and reduce tourism. They occur annually in at least 400 oxygen-depleted or dead zones around the world.

Point sources

Single identifiable source that discharges pollutants into bodies of surface water at specific locations often through drain pipes, ditches, or sewer lines. Ex: factories, sewage treatment plants (which remove some, but not all, pollutants), open-pit mines, oil wells, and oil tankers

The status of ocean dumping and oil spills in the ocean

Studies show urban and industrial runoff from land is the largest source of ocean oil pollution. Most of this comes from leaks in pipelines, refineries, and other oil-handling and storage facilities and from oil and oil products that are intentionally dumped or accidentally spilled or leaked onto the land or into sewers by homeowners and industries.

How public drinking water is purified

Surface water withdrawn for use as drinking water is typically stored in a reservoir for several days. This improves clarity and taste by increasing dissolved oxygen content and allowing suspended matter to settle. The water is then pumped to a purification plant and treated to meet government drinking water standards. In areas with pure groundwater or surface water sources, little treatment is necessary. Several major U.S. cities, including New York City, Boston, Seattle, and Portland, Oregon, have avoided building expensive drinking water treatment facilities. Instead, they have invested in protecting the forests and wetlands in the watersheds that provide their water supplies. Existing technology can convert sewer water into pure drinking water.

Pollution of the Great Lakes

The Great Lakes are vulnerable to pollution from point and nonpoint sources. About half of the toxic compounds entering the lakes still come from atmospheric deposition of pesticides, mercury from coal-burning plants, and other toxic chemicals from as far away as Mexico and Russia.

The U.S. laws that protect drinking water quality

The U.S. Safe Drinking Water Act of 1975 (amended in 1996) requires the EPA to establish national drinking water standards, called maximum contaminant levels, for any pollutants that could have adverse effects on human health. Currently, this act strictly limits the levels of 91 potential contaminants in U.S. tap water.

The 2010 BP Deepwater Horizon oil spill

The accident occurred in the Gulf of Mexico, 40 miles off the Louisiana coast, after the wellhead on the ocean bottom ruptured and released oil and natural gas. The resulting fire and explosion killed 11 of the rig's crewmembers and injured 17 more. After burning and belching oil smoke into the air for 36 hours, the rig sank. For 3 months, the ruptured wellhead on the ocean floor released more than 200 million gallons of crude oil before the leaking well was capped. the main causes of the accident were failure of equipment that could have detected the leak earlier, a faulty blowout preventer, failure of several safety valves, and a number of poor decisions made by workers and managers. The oil contaminated the sea floor, some ecologically vital coastal marshes, mangrove forests, sea-grass beds, fish nurseries, and at least three deep coral reefs. The oil spill killed at least 6,100 seabirds and oiled another 2,000. It also killed more than 600 sea turtles and 100 dolphins, and other marine mammals.

How hydraulic fracturing (fracking) can threaten groundwater

The drilling of thousands of new oil and natural gas wells in parts of the United States involving a process called hydraulic fracturing, or fracking. Contamination of groundwater used for drinking water can come from leaky natural gas well pipes and pipe fittings in oil and natural gas wells and from contaminated wastewater brought to the surface during fracking operations and often stored underground in hazardous waste wells.

Sources of oil production in oceans

The most visible human sources of ocean oil pollution include tanker accidents, such as the huge Exxon Valdez oil spill in the U.S. state of Alaska in 1989. Other sources are blowouts at offshore oil drilling rigs, such as that of the BP Deepwater Horizon rig in the Gulf of Mexico in 2010.

How the cleaning process of streams can be overwhelmed

The natural recovery process does not work when a stream is overloaded with biodegradable pollutants or when drought, damming, or water diversion reduces its flow. In addition, this process does not eliminate slowly degradable and non-biodegradable pollutants.

How drinking water was contaminated in Flint, Michigan

The problem began when, in an effort to save money, Flint officials began withdrawing drinking water from the Flint River instead of from Lake Huron. Officials did not take into account that there were at least 20,000 lead pipes connecting the city's main line water pipes (that do not contain lead) to homes, many of them in older and poorer neighborhoods. They also failed to add chemicals to reduce the leaching of lead from pipes exposed to the new and more corrosive water supply.

Waterless composting toilet system

These systems, pioneered several decades ago in Sweden, convert nutrient-rich human fecal matter into humus that can be used as a fertilizer supplement. This process returns plant nutrients in hum an waste to the soil, mimicking the chemical cycling principle of sustainability. On a larger scale, such systems would be cheaper to install and maintain than current sewage systems are, because they do not require vast systems of underground pipes connected to centralized sewage treatment plants. They also save large amounts of water, reduce water bills, and decrease the amount of energy used to pump and purify water.

Tertiary sewage treatment

Uses a series of specialized chemical and physical processes to remove specific pollutants left in the water after primary and secondary treatment. In its most common form, advanced sewage treatment uses special filters to remove phosphates and nitrates from wastewater before it is discharged into surface waters. This third stage would significantly reduce nutrient overload from nitrates and phosphates but is not widely used because of its high cost.