Water Pollution

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Water Pollution

Introduction

Water pollution refers to the presence of compounds that decrease the quality of fresh or marine water. This is a broad definition that takes into account a variety of water sources including lakes, streams, rivers, oceans, and groundwater. As well, the sources of water pollution can be natural, such as animal waste, or more commonly, due to human activity.

There are many causes of human-mediated water pollution, including runoff of pesticides, herbicides, and feces from agricultural land; runoff of gasoline and other chemicals from concrete in urban settings; and household chemicals discarded by flushing down the toilet (such as medicines or household cleaners).

Water pollution is a major global concern. In developing countries, waterborne diseases such as cholera, typhoid fever, and hepatitis A are among the leading causes of illness and death, killing over 3.4 million people every year (including 4,000 children every day), according to the World Health Organization (WHO).

In the environment, water pollution can alter or destroy a watercourse directly by the addition of the pollutants, and indirectly when the pollutant can be used as food source by microorganisms, whose explosive increase in growth and total numbers depletes the water of oxygen.

Historical Background and Scientific Foundations

As humans began to shift from a nomadic way of living to settlements, the communities were virtually always located near water. The importance of clean water to health was recognized thousands of years ago, even if the reason was not understood. For example, in ancient Rome, the Tiber River became so polluted with the direct discharge of human sewage that separate channels were built for drinking water. Throughout the next two millennia, waterborne illness outbreaks occurred; from the descriptions provided, it is likely that many were cholera and typhoid. Even today, cholera remains a problem in areas of the world that do not have access to clean water.

It was not until the 1850s that the connection was made between water contaminated with human feces and disease. Then, during a cholera outbreak in London, physician John Snow (1813–1858) deduced that fecal-contaminated water from a particular well was implicated in the illness. Stopping the use of the well stopped the spread of the disease.

Similarly, in the United States, rivers were used to dispose of human waste for centuries. With the growth of industries, waters also became the disposal system for industrial waste, a practice that continued into the twentieth century. An example is the Cuyahoga River in Cleveland, Ohio, which periodically caught fire from the 1930s into the 1970s due to oil and other flammable industrial waste discharged into the water. Finally, a fire in 1969 that was immortalized in a song (“Burn On”) by American recording artist Randy Newman drew attention to the deplorable condition of the Cuyahoga and other American waterways, which spurred passage of the Clean Water Act in 1972. The legislation banned the release of pollutants in waterways used by craft, although it has subsequently been criticized for a lack of standards of toxicity and difficulty in identifying pollution that does not come from a single source (non-point source pollution).

In the decades of prosperity following World War II (1939–1945), many chemicals were synthesized and commercialized. Antibiotics and DDT, for example, were spectacularly successful at stopping the spread of a variety of diseases (at least until resistance developed). At the same time, these and other compounds were finding

WORDS TO KNOW

AQUIFER: Rock, soil, or sand underground formation that is able to hold and/or transmit water.

COLIFORMS: Bacteria that live in the intestinal tract of warm-blooded animals. The presence of coliforms in water indicates fecal pollution.

DISINFECTION BY-PRODUCT: A compound created by the interaction of a disinfectant chemical and organic compounds in the water.

EUTROPHICATION: The process whereby a body of water becomes rich in dissolved nutrients through natural or man-made processes. This often results in a deficiency of dissolved oxygen, producing an environment that favors plant over animal life.

GROUNDWATER: Fresh water that is present in an underground location.

HYDROLOGY: The study of the distribution, movement, and physical-chemical properties of water in Earth’s atmosphere, surface, and near-surface crust.

RUNOFF: Water that falls as precipitation and then runs over the surface of the land rather than sinking into the ground.

their way into water by runoff. In 1962, the book Silent Spring was published. Written by Rachel Carson, the book was a condemnation of the environmental release of pesticides and especially of DDT.

Preventing Waterborne Disease

Microorganisms are an important source of water pollution. Some microorganisms that are of concern live in the intestinal tract of warm-blooded animals, including humans. Examples of disease-causing (pathogenic) bacteria are Salmonella, Shigella, Vibrio, and Escherichia. With the latter, Escherichia coli 0157:H7 is particularly dangerous. Contamination of drinking water with 0157:H7 can cause severe illness, permanent kidney damage, and even death. In an infamous example, contamination of the municipal water supply of Walkerton, Ontario, Canada, in the summer of 2000 because of runoff from adjacent cattle farms sickened over 2,000 people and killed 7.

The intestinal tract of warm-blooded animals also harbors pathogenic (disease-causing) viruses that can contaminate water, in particular rotavirus, enterovirus, norovirus, and coxsackievirus. A number of protozoan microorganisms can also affect water quality. The two most prominent protozoans are Giardia and Cryptosporidium, which normally live in the intestinal tracts of wild animals such as beaver and deer.

Municipal drinking water is usually treated with disinfectants in order to minimize the risk of microbial contamination. One common disinfectant is chlorine. Other treatments that kill bacteria include the use of a gaseous form of ozone (a compound containing three oxygen atoms, which is also present in Earth’s atmosphere), and exposure of shallow water to ultraviolet light. The ultraviolet radiation breaks apart the bacterial genetic material so much so that it cannot be repaired, and the microbe dies. Filters can also be used in water treatment; they contain openings of some filters that are so tiny that even viruses that are 10 nanometers in diameter are blocked from passing through (a nanometer is one-billionth of a meter).

Water polluted with protozoans can be more difficult to treat, as both Giardia and Cryptosporidium form chlorine-resistant structure cysts that can pass through the water treatment filters. In 1993, the contamination of the water supply of Milwaukee, Wisconsin, sickened over 400,000 people and at least 47 people died.

Non-point Source Pollution

Non-point source pollution enters water from many different sites, rather than from a single site. Examples of non-point source pollution are acid rain and runoff of polluted water from the urban and rural land. The nitrogen and phosphorus in fertilizers can be a source of food to microorganisms such as algae. Their resulting rapid growth and increase in numbers can deplete the oxygen in the water. In some areas of North America, huge factory farms contain tens of thousands of poultry or pigs. The waste material and huge amounts of water used in the farm operation are typically stored in large lagoons. Rupture of a lagoon wall can release the toxic water into nearby watercourses or into the groundwater.

Because of the many possible sites of non-point source pollution, tracking down the origin of the water pollution can be difficult. In contrast, an example of a point source is polluted material flowing from one factory into a river. This type of pollution can be much easier to detect and to stop.

According to the U.S. Environmental Protection Agency (EPA), as of 2008, about 40% of all the U.S. freshwater sources that have been mapped have been so affected by non-point source pollution that they are not safe for swimming or fishing.

There are a variety of organic (carbon-containing) water pollutants in addition to microorganisms. There are many types of chemicals that kill insects (insecticides) and weeds (herbicides). Runoff of moisture from agricultural land or urban lawns can carry these chemicals into streams, rivers, and lakes. Similarly, leakage of industrial chemicals, oil, and gasoline can occur both above the ground and from underground storage tanks. The latter can be especially serious since it may escape detection for a long time, and the pollutant can move outward from the source, even into groundwater.

The treatment of water can generate disinfection byproducts such as trihalomethanes, when chlorine reacts with organic matter. This tends to occur with surface waters, as more organic material can be present in the water. Trihalomethanes are considered a pollutant since they affect the smell and taste of the drinking water.

A more recent concern are the various drugs that people discard by flushing them down the toilet or the ones that can end up in landfills. With the development of technologies that can detect very low levels of drugs (parts per billion, equivalent to a drop of water in an Olympic sized swimming pool), the presence of (as a few examples) cosmetics, detergents, toiletries, painkillers, tranquilizers, anti-depressants, antibiotics, birth control pills, estrogen replacement therapy drugs, chemotherapy drugs, and epilepsy treatment drugs have all been detected in the environment. Some pharmaceuticals and drugs, including caffeine and acetaminophen (Tylenol), have also been detected in drinking water.

Although concentrations of most of these chemicals are not a concern in the short term, it is unknown if longer-term exposure is harmful. In 1999–2000, the most recent survey of the U.S. Geological Survey tested 139 streams from 30 states for 95 contaminants. Some 75% contained two or more of these contaminants, with 13% of the streams containing 20 or more.

Inorganic Pollutants

Inorganic water pollutants include heavy metals, acidic materials, nitrogen and phosphorus that are part of fertilizers, and silt from construction sites and clear-cut lands that is washed into watercourses.

A well-known inorganic water pollutant is Dichloro-Diphenyl-Trichloroethane (DDT). DDT exposure causes adverse effects in humans, animals, and birds in the short-term and more chronically. Possible longer-term effects include difficulties in reproduction, altered development of a fetus, and both liver and lung cancer. Prior to the ban on DDT use in the United States, bald eagle populations had declined to levels that threatened the species due to the accumulation of the pesticide in the bird’s tissue, which caused production of eggs with thinner, more fragile shells. As the compound has gradually declined in the environment in the decades following the ban, bald eagle populations have rebounded.

One major reason for the chronic effects of DDT is bioaccumulation, the accumulation of a compound in tissues of one species that is passed on to species higher in the food chain. As a result, creatures including the bald eagle ingest a much higher level of the toxin than they otherwise would and store the poison in fatty tissues, where it can persist.

The structure of DDT also makes it difficult to degrade. It can persist in water for months. Degradation is not a solution, since two breakdown products also persist in the environment and can cause adverse effects.

Compounds that can leak out of landfills can also degrade slowly, as do petroleum and petroleum-based products; polychlorinated biphenyls (PCBs); dioxins and polyaromatic hydrocarbons (PAHs); metals such as lead, mercury, and cadmium; and some kinds of radioisotopes. As an example, one of the considerations in selecting Yucca Mountain in Nevada as an underground garbage site for radioactive waste was the geology of the volcanic rock, which lacked cracks that could allow the waste to move from the site of storage in the event of a leak, and the fact that groundwater was very far beneath the storage area. Thus, the likelihood of radioactive contamination of the groundwater would be remote. This is good, since radioisotopes can have a half-life (the time for half the radioactivity to be degraded) of thousands of years, which would irreversibly contaminate water. Although the concern over water pollution may have been met, other concerns have pushed back the planned 1998 opening to 2017.

Water pollution due to chemicals is an inevitable consequence of modern society. Chemicals are used for a variety of everyday activities; only a very few examples are dishwashing, house cleaning, lawn care, and interior and exterior painting. Environment Canada estimates that 100,000 chemicals are commonly used.

Some such as pesticides, PCBs (which were used as a coolants in electrical transformers), and polychlorinated phenols (PCPs; which are present in wood preservatives) are toxic even when present in very low amounts. While PCBs were banned in the 1970s because of their environmental toxicity, they can still be found in older transformers. These compounds are designed and used because of their toxicity and long-lasting property—the same properties that make them so detrimental to the environment.

Acid rain is a serious form of water pollution, particularly in the northeastern United States. The term comes from the presence of nitric and sulfuric acids in the atmosphere close to the surface. Acid rain can be produced naturally, but the majority is generated by human activities, mainly from electricity generation that relies on the burning of fossil fuels such as coal. The burning releases sulfur dioxide and nitrogen oxides, which react with atmospheric water, oxygen, and other compounds to form a mild solution containing the nitric and sulfuric acids. The small droplets can stay suspended in the air and can be blown for hundreds of miles. As time goes on, the continued deposition of the droplets in water sources makes the water more acidic, which can kill vegetation and fish. As species lower in the food chain are affected, the entire ecosystem of a lake can be affected. In areas where acid rain is especially pronounced, the result can be lakes that are devoid of life. A lake that has been affected by acid rain can be sparkling clear in appearance. This beauty is deceptive, since the reason the water is so clear is that there is no microscopic of other life present.

In contrast, the phenomenon of eutrophication occurs because of the opposite reason; the presence of too much life. The overgrowth of the many organisms depletes the oxygen from the water. Although eutrophication is a natural process, it is greatly accelerated by pollution with compounds such as nitrogen and phosphorus, which are components of fertilizer. Drainage of fertilizer from surrounding land into a waterway boosts the amount of nutrients in the water, which can cause the explosive growth of microorganisms. The oxygen-starved water becomes inhospitable for fish. In turn, the decay of the dead fish uses up even more oxygen.

Impacts and Issues

One recent example of the effects of eutrophication and of the recovery that is possible even in severely polluted water is Lake Erie. In the 1960s, the addition of nitrogen and phosphorus to Lake Erie, the shallowest of the five Great Lakes, had depleted the oxygen to such an extent that massive deaths of fish were occurring. In 1972, legislation banning the use of phosphate in laundry detergent was passed. This reduced the amount of phosphorus entering Lake Erie by about 90%. The quality of the water recovered. In 2008, Lake Erie supports an abundance of life.

Groundwater pollution represents an even more serious threat to human health, because the pollutant can remain in the water; water contaminated with a radioactive substance, for example, can be unusable for

IN CONTEXT: WATER POLLUTION IMPACTS ON MICROORGANISMS

There is a microbiological aspect of water pollution that experts fear reduces our ability to treat some bacterial infections: the presence in water of agents used to treat bacteria in other environments. For example, in the household a number of disinfectant compounds are routinely employed in the cleaning of household surfaces. In the hospital, the use of antibiotics to kill bacteria is an everyday occurrence. Such materials have been detected in water both before and after municipal wastewater treatment. The health effect of these compounds is not known at the present time. However, by analogy with other systems, the low concentration of such compounds might provide selective pressure for the development of resistant bacterial populations.

thousands of years. In the United States, about half the population relies on groundwater as a drinking water source, for industrial purposes, or for crop irrigation.

Pollution of groundwater is not rare. For example, the EPA has records of over 400,000 cases of petroleum-based fuel spills from underground storage tanks. Although detection and remediation of groundwater pollution is a priority in the United States as mandated by the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, which is also known as the Superfund), it is often a less important priority in developing countries where resources are limited. Developing countries also bear the brunt of waterborne diseases, due to the presence of pathogenic bacteria and viruses in water.

Recent studies indicate that global warming might create a more favorable environment for V cholerae, the bacteria that causes cholera, and increase the incidence of the disease in vulnerable areas. A majority of cholera deaths occur in children under five years of age. Aside from the human tragedy of this loss, the effect on the economy is felt for decades. The World Health Organization has estimated that, in the poorest of developing nations, every dollar spent to remedy water pollution and inadequate sanitation would produce an economic return of $3 to $34.

The United Nations has set a goal of reducing by half the number of people who do not have access to safe drinking water and adequate sanitation by the year 2015. This goal will require the participation of developed countries and comes at a time when the changing global climate is beginning to affect the availability of water, and the prevalence of waterborne microbial diseases such as malaria and cholera.

Primary Source Connection

The Water Quality Act of 1965 and the amendments that became law in 1977 represent two of several initiatives by the U.S. government to protect and ensure the quality of surface and ground waters.

Legislative concern over water quality began in 1948, with the passage of the Water Pollution Control Act. The act was essentially an adoption of principles to be followed in the pursuit of water quality. It was the Water Quality Act of 1965 that put some legislative teeth to these principles.

The 1965 legislation directed the states to develop water-quality standards. A federally directed initiative was deemed necessary since many watersheds and waterways crossed state boundaries. By the early 1970s, water quality standards had been developed and enacted by all the states. Since then, revisions have occurred to reflect changing scientific information and new testing procedures.

THE WATER QUALITY ACT OF 1965

An Act

To amend the Federal Water Pollution Control Act to establish a Federal Water Pollution Control Administration, to provide grants for research and development, to increase grants for construction of sewage treatment works, to require establishment of water quality criteria, and for other purposes.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That (a) (1) section 1 of the Federal Water Pollution Control Act (33 U.S.C. 466) is amended by inserting after the words “Section 1.” a new subsection (a) as follows:

(a) The purpose of this Act is to enhance the quality and value of our water resources and to establish a national policy for the prevention, control, and abatement of water pollution.

Federal Water Pollution Control Administration

Sec. 2. Effective ninety days after the date of enactment of this section there is created within the Department of Health, Education, and Welfare a Federal Water Pollution Control Administration (hereinafter in this Act referred to as the “Administration”).

Grants for Research and Development

Sec. 6. (a) The Secretary is authorized to make grants to any State, municipality, or intermunicipal or interstate agency for the purpose of assisting in the development of any project which will demonstrate a new or improved method of controlling the discharge into any waters of untreated or inadequately treated sewage or other waste from sewers which carry storm water or both storm water and sewage or other wastes, and for the purpose of reports, plans, and specifications in connection therewith. The Secretary is authorized to provide for the conduct of research and demonstrations relating to new or improved methods of controlling the discharge into any waters of untreated or inadequately treated sewage or other waste from sewers which carry storm water or both storm water and sewage or other wastes, by contract with public or private agencies and institutions and with individuals without regard to sections 3648 and 3709 of the Revised Statutes, except that not to exceed 25 per centum of the total amount appropriated under authority of this section for any fiscal year may be expended under authority of this sentence during such fiscal year.

(b) Federal grants under this section shall be subject to the following limitations: (1) No grant shall be made for any project pursuant to this section unless such project shall have been approved by an appropriate State water pollution control agency or agencies and by the Secretary; (2) no grant shall be made for any project in an amount exceeding 50 per centum of the estimated reasonable cost thereof as determined by the Secretary; (3) no grant shall be made for any project under this section unless the Secretary determines that such project will serve as a useful demonstration of a new or improved method of controlling the discharge into any water of untreated or inadequately treated sewage or other waste from sewers which carry storm water or both storm water and sewage or other wastes.

(c) There are hereby authorized to be appropriated for the fiscal year ending June 30, 1966, and for each of the next three succeeding fiscal years, the sum of $20,000,000 per fiscal year for the purposes of this section. Sums so appropriated shall remain available until expended. No grant or contract shall be made for any project in an amount exceeding 5 per centum of the total amount authorized by this section in any one fiscal year.

(3) Standards of quality established pursuant to this subsection shall be such as to protect the public health or welfare, enhance the quality of water and serve the purposes of this Act. In establishing such standards the Secretary, the Hearing Board, or the appropriate State authority shall take into consideration their use and value for public water supplies, propagation of fish and wildlife, recreational purposes, and agricultural, industrial, and other legitimate uses.

(5) The discharge of matter into such interstate waters or portions thereof, which reduces the quality of such waters below the water quality standards established under this subsection (whether the matter causing or contributing to such reduction is discharged directly into such waters or reaches such waters after discharge into tributaries of such waters), is subject to abatement in accordance with the provisions of paragraph (1) or (2) of subsection (g) of this section, except that at least 180 days before any abatement action is initiated under either paragraph (1) or (2) of subsection (g) as authorized by this subsection, the Secretary shall notify the violators of other interested parties of the violation of such standards. In any suit brought under the provision of this subsection the court shall receive in evidence a transcript of the proceedings of the conference and hearing provided for in this subsection, together with the recommendations of the conference and Hearing Board and the recommendations and standards promulgated by the Secretary, and such additional evidence, including that relating to the alleged violation of the standards, as it deems necessary t a complete review of the standards and to a determination of all other issues relating to the alleged violation. The court, giving due consideration to the practicability and to the physical and economic feasibility of complying with such standards, shall have jurisdiction to enter such judgment and orders enforcing such judgment as the public interest and the equities of the case may require.

(6) Nothing in this subsection shall (A) prevent the application of this section to any case to which subsection (a) of this section would otherwise be applicable, or (B) extend Federal jurisdiction over water not otherwise authorized by this Act.

(7) In connection with any hearings under this section no witness or any other person shall be required to divulge trade secrets or secret processes.

Public Law 89-235

Joint Resolution

Authorizing and requesting the President to extend through 1966 his proclamation of a period to “See the United States,” and for other purposes.

Resolved by the Senate and House of Representatives of the United States of America in Congress assembled, That the president is authorized and requested (1) to extend through 1966 the period designated pursuant to the joint resolution approved August 11, 1964 (Public Law 88-416), as a period to see the United States and its territories; (2) to encourage private industry and interested private organizations to continue their efforts to attract greater numbers of the American people to the scenic, historical, and recreational areas and facilities of the United States of America, its territories and possessions, and the Commonwealth of Puerto Rico; and (3) to issue a proclamation specially inviting citizens of other ceremonials to be celebrated in 1966 in the Unite States of America, its territories and possessions, and the Commonwealth of Puerto Rico.

Sec. 2. The President is authorized to publicize any proclamations issued pursuant to the first section and otherwise to encourage and promote vacation travel within the United States of America, its territories and possessions, and the Commonwealth of Puerto Rico, both by American citizens and by citizens of other countries, through such departments or agencies of the Federal Government as he deems appropriate, in cooperation with State and local agencies and private organizations.

Sec. 3. For the purpose of the extension provided for by this joint resolution, the President is authorized during the period of such extension to exercise the authority conferred by section 3 of the joint resolution approved August 11, 1964 (Public Law 88-416), and for such purpose may extend for such period the appointment of any person serving as National Chairman pursuant to such section.

Approved October 2, 1965.

U.S. Congress

U.S. CONGRESS. “THE WATER QUALITY ACT OF 1965.” 79 STAT. 903, 70 STAT. 498. WASHINGTON, DC: U.S. CONGRESS, OCTOBER 2, 1965.