Water Pollution
Water pollution
Water is one of the most vital natural resources on earth and has been around for a long time. In fact, the same water which we drink has been around in one form or the other since the time of the dinosaurs.
The earth has more than two-thirds of its surface covered with water. This translates to just over 1 octillion litres (1,260,000,000,000,000,000,000 litres) of water distributed in the oceans, rivers, lakes and streams.
That is a lot of water, however, less than 0.3% is accessible for human consumption. As commercialization and industrialization have progressed, that number continues to dwindle down. Furthermore, inefficient and outdated practices, lack of awareness and a plethora of other circumstances have led to water pollution.
Also Read: How Can We Conserve Water?
What is Water Pollution?
Water pollution can be defined as the contamination of water bodies. Water pollution is caused when water bodies such as rivers, lakes, oceans, groundwater and aquifers get contaminated with industrial and agricultural effluents.
When water gets polluted, it adversely affects all lifeforms that directly or indirectly depend on this source. The effects of water contamination can be felt for years to come.
Also Refer: Types of Pollution
Sources Of Water Pollution
The key causative of water pollution in India are:
- Urbanization.
- Deforestation.
- Industrial effluents.
- Social and Religious Practices.
- Use of Detergents and Fertilizers.
- Agricultural run-offs- Use of insecticides and pesticides.
Water Pollution – A Modern Epidemic
One of the primary causes of water pollution is the contamination of water bodies by toxic chemicals. As seen in the example mentioned above, the dumped plastic bottles, tins, water cans and other wastes pollute the water bodies. These result in water pollution, which harms not just humans, but the whole ecosystem. Toxins drained from these pollutants, travel up to the food chain and eventually affect humans. In most cases, the outcome is destructive to only the local population and species, but it can have an impact on a global scale too.
Nearly 6 billion kilograms of garbage is dumped every year in the oceans. Apart from industrial effluents and untreated sewage, other forms of unwanted materials are dumped into various water bodies. These can range from nuclear waste to oil spills – the latter of which can render vast areas uninhabitable.
Effects Of Water Pollution
The effect of water pollution depends upon the type of pollutants and their concentration. Also, the location of water bodies is an important factor to determine the levels of pollution.
- Water bodies in the vicinity of urban areas are extremely polluted. This is the result of dumping garbage and toxic chemicals by industrial and commercial establishments.
- Water pollution drastically affects aquatic life. It affects their metabolism, and behaviour, and causes illness and eventual death. Dioxin is a chemical that causes a lot of problems from reproduction to uncontrolled cell growth or cancer. This chemical is bioaccumulated in fish, chicken and meat. Chemicals such as this travel up the food chain before entering the human body.
- The effect of water pollution can have a huge impact on the food chain. It disrupts the food chain. Cadmium and lead are some toxic substances, these pollutants upon entering the food chain through animals (fish when consumed by animals, humans) can continue to disrupt at higher levels.
- Humans are affected by pollution and can contract diseases such as hepatitis through faecal matter in water sources. Poor drinking water treatment and unfit water can always cause an outbreak of infectious diseases such as cholera, etc.
- The ecosystem can be critically affected, modified and destructured because of water pollution.
Minamata Incident
The Minamata Incident marked one of the worst cases of water pollution
In 1932, a factory in Minamata City, Japan began dumping its industrial effluent – Methylmercury, into the surrounding bay and the sea. Methylmercury is incredibly toxic to humans and animals alike, causing a wide range of neurological disorders.
Its ill effects were not immediately noticeable. However, this all changed as methylmercury started to bioaccumulate inside shellfish and fish in Minamata Bay. These affected organisms were then caught and consumed by the local population. Soon, the ill effects of methylmercury were becoming apparent.
Initially, animals such as cats and dogs were affected by this. The city’s cats would often convulse and make strange noises before dying – hence, the term “dancing cat disease” was coined. Soon, the same symptoms were observed in people, though the cause was not apparent at the time.
Other affected people showed symptoms of acute mercury poisoning such as ataxia, muscle weakness, loss of motor coordination, damage to speech and hearing etc. In severe cases, paralysis occurred, which was followed by coma and death. These diseases and deaths continued for almost 36 years before they could be officially acknowledged by the government and the organisation.
Since then, various control measures for water pollution have been adopted by the government of Japan to curb such environmental disasters in the future.
Pollution of the Ganges
Some rivers, lakes, and groundwater are rendered unfit for usage. In India, the River Ganges is the sixth most polluted river in the world. This is unsurprising as hundreds of industries nearby release their effluents into the river. Furthermore, religious activities such as burials and cremations near the shore contribute to pollution. Apart from the ecological implications, this river poses a serious health risks as it can cause diseases like typhoid and cholera.
Pollution of the Ganges is also driving some of the distinct fauna to extinction. The Ganges River shark is a critically endangered species that belong to the order Carcharhiniformes. The Ganges River dolphin is another endangered species of dolphin that is found in the tributaries of the Ganges and Brahmaputra rivers.
As per a survey, by the end of 2026, around 4 billion people will face a shortage of water. Presently, around 1.2 billion people worldwide do not have access to clean, potable water and proper sanitation. It is also projected that nearly 1000 children die every year in India due to water-related issues. Groundwater is an important source of water, but unfortunately, even that is susceptible to pollution. Hence, water pollution is quite an important social issue that needs to be addressed promptly.
Control Measures of Water Pollution
Water pollution, to a larger extent, can be controlled by a variety of methods. Rather than releasing sewage waste into water bodies, it is better to treat them before discharge. Practising this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself. If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields.
A very special plant, the Water Hyacinth can absorb dissolved toxic chemicals such as cadmium and other such elements. Establishing these in regions prone to such kinds of pollutants will reduce the adverse effects to a large extent.
Some chemical methods that help in the control of water pollution are precipitation, the ion exchange process, reverse osmosis, and coagulation. As an individual, reusing, reducing, and recycling wherever possible will advance a long way in overcoming the effects of water pollution.
Water Pollution
Water pollution is the contamination of water sources by substances which make the water unusable for drinking, cooking, cleaning, swimming, and other activities. Pollutants include chemicals, trash, bacteria, and parasites. All forms of pollution eventually make their way to water. Air pollution settles onto lakes and oceans. Land pollution can seep into an underground stream, then to a river, and finally to the ocean. Thus, waste dumped in a vacant lot can eventually pollute a water supply.
| Vocabulary |
Concentration | The amount of a substance in the water. Part per Million (PPM) means there is 1 drop of chemical mixed in with (diluted in) 1,000,000 drops of water. This is the same as 1 drop in a bathtub of water. Part per Billion (PPB)would be the same as 1 drop of chemical in a swimming pool full of water. |
Effluent | Chemicals or other waste from factories which is dumped into the environment. |
Eutrophication | Plants and very small animals in lakes and ponds grow so fast that they use up all the oxygen in the water, causing everything else to suffocate.It is caused by too many nutrients in the water. |
Filtration | Removal of particles and tiny organisms by forcing the water through materials that have very small holes. |
Nutrients | Substances which plants and animals use for food, including fertilizers from farms and sewage. Too many nutrients in water can cause eutrophication. |
Sewage | The wastewater from bathrooms and factories, usually containing biological contaminants. |
Toxic | Poisonous. Acute toxicity is when the substance has poisonous effects in a short time (hours to days). Chronic toxicity is when an organism is exposed to a chemical in low doses over a long period of time. Toxic effects may occur after years, often as a disease like cancer. |
Watershed | An area which contains all the water systems (rivers, lakes, reservoirs, and underground water sources, etc.) formed by the runoff of rain and snow from the land, streets, and mountains in a particular region.The water eventually flows into the ocean. |
| Diseases, Medical Problems |
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Water pollutants may cause disease or act as poisons. Bacteria and parasites in poorly treated sewage may enter drinking water supplies and cause digestive problems such as cholera and diarrhea. Hazardous chemicals, pesticides, and herbicides from industries, farms, homes and golf courses can cause acute toxicity and immediate death, or chronic toxicity that can lead to neurological problems or cancers. Many water pollutants enter our bodies when we use water for drinking and food preparation. The pollutants enter the digestive tract. From there, they can reach other organs in the body and cause various illnesses. Chemicals come in contact with the skin from washing clothes, or from swimming in polluted water and may lead to skin irritations. Hazardous chemicals in water systems can also affect the animals and plants which live there. Sometimes these organisms will survive with the chemicals in their systems, only to be eaten by humans who may then become mildly ill or develop stronger toxic symptoms. The animals and plants themselves may die or not reproduce properly.
| What You Can Do? |
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Avoid pouring chemicals down the drain: Use fewer chemicals and cleaners around the home. Not only will you cut down on indoor air pollution, but also on the amount of chemicals entering the water system. If necessary, use biodegradable cleaners. Do not pour oil or other chemicals into the drainage system on the street.
Have your water checked for lead contamination: Many homes have lead pipes or lead around connections on the pipes which carry water to their homes. Since this lead may enter your drinking water and cause medical problems in young children, you might want to have the water tested. If lead is present, installing a filter may solve the problem.
Do not pollute outdoor water sources: Do not pour oil or other chemicals into the drainage system on the street. A little oil can kill many plants and animals. Do not litter, especially near water. Litter may be eaten as food by animals and cause harm to them. Do not use pesticides on lawns, or use only organic ones. Later pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses.[1]: 6 Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants are introduced into these water bodies. Water pollution can be attributed to one of four sources: sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater.[2] It can be grouped into surface water pollution (either fresh water pollution or marine pollution) or groundwater pollution. For example, releasing inadequately treated wastewater into natural waters can lead to degradation of these aquatic ecosystems. Water pollution can also lead to water-borne diseases for people using polluted water for drinking, bathing, washing or irrigation.[3] Water pollution reduces the ability of the body of water to provide the ecosystem services (such as drinking water) that it would otherwise provide.
Sources of water pollution are either point sources or non-point sources. Point sources have one identifiable cause, such as a storm drain, a wastewater treatment plant or an oil spill. Non-point sources are more diffuse, such as agricultural runoff.[4] Pollution is the result of the cumulative effect over time. Pollution may take the form of toxic substances (e.g., oil, metals, plastics, pesticides, persistent organic pollutants, industrial waste products), stressful conditions (e.g., changes of pH, hypoxia or anoxia, increased temperatures, excessive turbidity, unpleasant taste or odor, and changes of salinity), or pathogenic organisms. Contaminants may include organic and inorganic substances. Heat can also be a pollutant, and this is called thermal pollution. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers.
Control of water pollution requires appropriate infrastructure and management plans as well as legislation. Technology solutions can include improving sanitation, sewage treatment, industrial wastewater treatment, agricultural wastewater treatment, erosion control, sediment control and control of urban runoff (including stormwater management). Effective control of urban runoff includes reducing speed and quantity of flow.
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Definition
A practical definition of water pollution is: "Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses".[1]: 6 Therefore, pollution is associated with concepts attributed to humans, namely the negative alterations and the uses of the water body. Water is typically referred to as polluted when it is impaired by anthropogenic contaminants. Due to these contaminants it either does not support a human use, such as drinking water, or undergoes a marked shift in its ability to support its biotic communities, such as fish.
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Contaminants
Contaminants with an origin in sewage
The following compounds can all reach water bodies via raw sewage or even treated sewage discharges:
- Disinfection by-products found in chemically disinfected drinking water (whilst these chemicals can be a pollutant in the water distribution network, they are fairly volatile and therefore not usually found in environmental waters).[5]
- Hormones (from animal husbandry and residue from human hormonal contraception methods) and synthetic materials such as phthalates that mimic hormones in their action. These can have adverse impacts even at very low concentrations on the natural biota and potentially on humans if the water is treated and utilized for drinking water.[6][7][8]
- insecticides and herbicides, often from agricultural run-off.
If the water pollution stems from sewage (municipal wastewater), the main pollutants are: suspended solids, biodegradable organic matter, nutrients and pathogenic (disease-causing) organisms.[1]: 6
| Pollutant | Main representative parameter | Possible effect of the pollutant |
|---|---|---|
| Suspended solids | Total suspended solids |
|
| Biodegradable organic matter | Biological oxygen demand |
|
| Nutrients |
| |
| Pathogens |
| Waterborne diseases |
| Non-biodegradable organic matter |
|
|
| Inorganic dissolved solids |
|
Pathogens
The major groups of pathogenic organisms are: (a) bacteria, (b) viruses, (c) protozoans and (d) helminths.[1]: 47 In practice, indicator organisms are used to investigate pathogenic pollution of water because the detection of pathogenic organisms in water sample is difficult and costly, because of their low concentrations. The indicators (bacterial indicator) of fecal contamination of water samples most commonly used are: total coliforms (TC), fecal coliforms (FC) or thermotolerant coliforms, escherichia coli (EC).[1]: 47
Pathogens can produce waterborne diseases in either human or animal hosts.[10] Some microorganisms sometimes found in contaminated surface waters that have caused human health problems include: Burkholderia pseudomallei, Cryptosporidium parvum, Giardia lamblia, Salmonella, norovirus and other viruses, parasitic worms including the Schistosoma type.[11]
The source of high levels of pathogens in water bodies can be from human feces (due to open defecation), sewage, blackwater, manure that has found its way into the water body. The cause for this can be lack of sanitation or poorly functioning on-site sanitation systems (septic tanks, pit latrines), sewage treatment plants without disinfection steps, sanitary sewer overflows and combined sewer overflows (CSOs)[12] during storm events and intensive agriculture (poorly managed livestock operations).
Organic compounds
Organic substances that enter water bodies are often toxic.[13]: 229
- Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from oil spills or storm water runoff[14]
- Volatile organic compounds, such as improperly stored industrial solvents. Problematic species are organochlorides such as polychlorinated biphenyl (PCBs) and trichloroethylene, a common solvent.
Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants.[15][16]
Inorganic contaminants
Inorganic water pollutants include for example:
- Ammonia from food processing waste
- Heavy metals from motor vehicles (via urban storm water runoff)[14][17] and acid mine drainage
- Nitrates and phosphates, from sewage and agriculture (see nutrient pollution)
- Silt (sediment) in runoff from construction sites or sewage, logging, slash and burn practices or land clearing sites.
- Salt: Freshwater salinization is the process of salty runoff contaminating freshwater ecosystems.[18] Human-induced salinization is termed as secondary salinization, with the use of de-icing road salts as the most common form of runoff.[19][20]
Pharmaceutical pollutants
The environmental effect of pharmaceuticals and personal care products (PPCPs) is being investigated since at least the 1990s. PPCPs include substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. More than twenty million tons of PPCPs are produced every year.[21] The European Union has declared pharmaceutical residues with the potential of contamination of water and soil to be "priority substances".[3]
PPCPs have been detected in water bodies throughout the world. More research is needed to evaluate the risks of toxicity, persistence, and bioaccumulation, but the current state of research shows that personal care products impact over the environment and other species, such as coral reefs[22][23][24] and fish.[25][26] PPCPs encompass environmental persistent pharmaceutical pollutants (EPPPs) and are one type of persistent organic pollutants. They are not removed in conventional sewage treatment plants but require a fourth treatment stage which not many plants have.[21]
In 2022, the most comprehensive study of pharmaceutical pollution of the world's rivers found that it threatens "environmental and/or human health in more than a quarter of the studied locations". It investigated 1,052 sampling sites along 258 rivers in 104 countries, representing the river pollution of 470 million people. It found that "the most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing" and lists the most frequently detected and concentrated pharmaceuticals.[27][28]- Environmental persistent pharmaceutical pollutants, which can include various pharmaceutical drugs and their metabolites (see also drug pollution), such as antidepressant drugs, antibiotics or the contraceptive pill.
- Metabolites of illicit drugs (see also wastewater epidemiology), for example methamphetamine and ecstasy.[29][30]
When discussing the issues that can arise due to water pollution, there are three major areas to consider:
- Health: According to the United Nations, every year there are more deaths caused by polluted water than all types of violence combined, including war. Waste from humans and animals that contaminates water carries bacteria and viruses that cause the spread of diseases such as typhoid, cholera and giardia.
- Environment: All the species in an ecosystem rely on each other in order to survive. Outside substances, such as pollutants found in wastewater, can disrupt the complicated relationships between species that an ecosystem needs in order to thrive.
- Economy: Polluted water can have many negative effects on the economy. It directly impacts sectors such as commercial fishing, recreational businesses, tourism and even property values, all of which rely heavily on clean water. Polluted drinking water can also cause treatment costs to rise, which in turn makes the cost of drinking water rise as well.
Solid waste and plastics
Solid waste can enter water bodies through untreated sewage, combined sewer overflows, urban runoff, people discarding garbage into the environment, wind carrying municipal solid waste from landfills and so forth. This results in macroscopic pollution– large visible items polluting the water– but also microplastics pollution that is not directly visible. The terms marine debris and marine plastic pollution are used in the context of pollution of oceans.
Microplastics persist in the environment at high levels, particularly in aquatic and marine ecosystems, where they cause water pollution.[31] 35% of all ocean microplastics come from textiles/clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process.[32]
Types of surface water pollution
Surface water pollution includes pollution of rivers, lakes and oceans. A subset of surface water pollution is marine pollution which affects the oceans. Nutrient pollution refers to contamination by excessive inputs of nutrients.
Globally, about 4.5 billion people do not have safely managed sanitation as of 2017, according to an estimate by the Joint Monitoring Programme for Water Supply and Sanitation.[33] Lack of access to sanitation is concerning and often leads to water pollution, e.g. via the practice of open defecation: during rain events or floods, the human feces are moved from the ground where they were deposited into surface waters. Simple pit latrines may also get flooded during rain events.
Combatting Water Pollution
Water pollution is a major issue across the world and is caused by many contributing factors. It can greatly disrupt entire ecosystems and be extremely harmful to our health and economy. Water is an extremely valuable resource, and proper water treatment policies and management are imperative in the fight to keep the world’s water supply clean.
There are numerous ways that each of us can help reduce water pollution, and the Natural Resources Defense Council has outlined a few, including:
- Don’t flush trash. Being mindful not to flush non-degradable products, such as plastic, down your toilet is one small but great way to stop contributing to the problem and start becoming part of the solution.
- Pick up after your pets. Waste from animals is full of bacteria, and if not disposed of properly, that bacteria can find its way into the water supply through storm drains and runoff. The recommended disposal method is to use a bag made from recycled plastic to throw it in the trash.
- Maintain your car. Antifreeze, oil, coolant and other chemicals can leak out of your car if it’s not properly cared for. Then, rainwater washes those chemicals into the groundwater supply. Regular maintenance can reduce the amount of pollutants emitted by your car, and it enhances the vehicle’s performance as well.
These are just a few ways to start the process of combatting water pollution, and they are contained to the actions you carry out in your home. There are bigger issues that need to be addressed, though, and that’s where leaders come in. Changes to policy and advances in science can help tackle the larger issues contributing to water pollution, such as marine dumping and offshore oil spills. Earning a water resources master’s degree online will prepare you with an advanced understanding of the growing complexity of water issues impacting the state, nation and globe. East Central University’s online M.S. Water Resource Policy and Management trains students for leadership roles that make water policy decisions that impact various communities. Our program integrates knowledge from multiple disciplines to address the complex challenges of water resource decisions and to develop solutions that are socially acceptable, politically and economically viable and environmentally sustainable. Because our program is fully online, you’ll be able to earn your degree on a schedule that works for you
Marine pollution
Nutrient pollution
Thermal pollution
Elevated water temperatures decrease oxygen levels (due to lower levels of dissolved oxygen, as gases are less soluble in warmer liquids), which can kill fish (which may then rot) and alter food chain composition, reduce species biodiversity, and foster invasion by new thermophilic species.[41]: 179 [13]: 375
Biological pollution
The introduction of aquatic invasive organisms is a form of water pollution as well. It causes biological pollution.[42]
Groundwater pollution
In many areas of the world, groundwater pollution poses a hazard to the wellbeing of people and ecosystems. One-quarter of the world's population depends on groundwater for drinking, yet concentrated recharging is known to carry short-lived contaminants into carbonate aquifers and jeopardize the purity of those waters.[44]
Pollution from point sources
Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain.
The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes (see United States regulation of point source water pollution).[45] The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.[46]
Sewage
Sewage typically consists of 99.9% water and 0.1% solids.[47] Sewage contributes many classes of nutrients that lead to eutrophication. It is a major source of phosphate for example.[48] Sewage is often contaminated with diverse compounds found in personal hygiene, cosmetics, pharmaceutical drugs (see also drug pollution), and their metabolites[49][50] Water pollution due to environmental persistent pharmaceutical pollutants can have wide-ranging consequences. When sewers overflow during storm events this can lead to water pollution from untreated sewage. Such events are called sanitary sewer overflows or combined sewer overflows.
Industrial wastewater
Industrial processes that use water also produce wastewater. This is called industrial wastewater. Using the US as an example, the main industrial consumers of water (using over 60% of the total consumption) are power plants, petroleum refineries, iron and steel mills, pulp and paper mills, and food processing industries.[2] Some industries discharge chemical wastes, including solvents and heavy metals (which are toxic) and other harmful pollutants.
Industrial wastewater could add the following pollutants to receiving water bodies if the wastewater is not treated and managed properly:
- Heavy metals, including mercury, lead, and chromium
- Organic matter and nutrients such as food waste: Certain industries (e.g. food processing, slaughterhouse waste, paper fibers, plant material, etc.) discharge high concentrations of biochemical oxygen demand (BOD), ammonia nitrogen and oil and grease.[52]: 180 [13]
- Inorganic particles such as sand, grit, metal particles, rubber residues from tires, ceramics, etc.;
- Toxins such as pesticides, poisons, herbicides, etc.
- Pharmaceuticals, endocrine disrupting compounds, hormones, perfluorinated compounds, siloxanes, drugs of abuse and other hazardous substances [53][54][55]
- Microplastics such as polyethylene and polypropylene beads, polyester and polyamide[56]
- Thermal pollution from power stations and industrial manufacturers
- Radionuclides from uranium mining, processing nuclear fuel, operating nuclear reactors, or disposal of radioactive waste.
- Some industrial discharges include persistent organic pollutants such as per- and polyfluoroalkyl substances (PFAS).[15][16]
Oil spills
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Pollution from nonpoint sources
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Agriculture
Agriculture is a major contributor to water pollution from nonpoint sources. The use of fertilizers as well as surface runoff from farm fields, pastures and feedlots leads to nutrient pollution.[58] In addition to plant-focused agriculture, fish-farming is also a source of pollution. Additionally, agricultural runoff often contains high levels of pesticides.[2]
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Atmospheric contributions (air pollution)
Air deposition is a process whereby air pollutants from industrial or natural sources settle into water bodies. The deposition may lead to polluted water near the source, or at distances up to a few thousand miles away. The most frequently observed water pollutants resulting from industrial air deposition are sulfur compounds, nitrogen compounds, mercury compounds, other heavy metals, and some pesticides and industrial by-products. Natural sources of air deposition include forest fires and microbial activity.[59]
Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids.[60] Some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere. The main source of sulfur and nitrogen compounds that result in acid rain are anthropogenic, but nitrogen oxides can also be produced naturally by lightning strikes and sulphur dioxide is produced by volcanic eruptions.[61] Acid rain can have harmful effects on plants, aquatic ecosystems and infrastructure.[62][63]
Carbon dioxide concentrations in the atmosphere have increased since the 1850s due anthropogenic influences (emissions of greenhouse gases).[64] This leads to ocean acidification and is another form of water pollution from atmospheric contributions.[65]
Sampling, measurements, analysis
Water pollution may be analyzed through several broad categories of methods: physical, chemical and biological. Some methods may be conducted in situ, without sampling, such as temperature. Others involve collection of samples, followed by specialized analytical tests in the laboratory. Standardized, validated analytical test methods, for water and wastewater samples have been published.[66]
Common physical tests of water include temperature, Specific conductance or electrical conductance (EC) or conductivity, solids concentrations (e.g., total suspended solids (TSS)) and turbidity. Water samples may be examined using analytical chemistry methods. Many published test methods are available for both organic and inorganic compounds. Frequently used parameters that are quantified are pH, biochemical oxygen demand (BOD),[67]: 102 chemical oxygen demand (COD),[67]: 104 dissolved oxygen (DO), total hardness, nutrients (nitrogen and phosphorus compounds, e.g. nitrate and orthophosphates), metals (including copper, zinc, cadmium, lead and mercury), oil and grease, total petroleum hydrocarbons (TPH), surfactants and pesticides.
The use of a biomonitor or bioindicator is described as biological monitoring. This refers to the measurement of specific properties of an organism to obtain information on the surrounding physical and chemical environment.[68] Biological testing involves the use of plant, animal or microbial indicators to monitor the health of an aquatic ecosystem. They are any biological species or group of species whose function, population, or status can reveal what degree of ecosystem or environmental integrity is present.[69] One example of a group of bio-indicators are the copepods and other small water crustaceans that are present in many water bodies. Such organisms can be monitored for changes (biochemical, physiological, or behavioral) that may indicate a problem within their ecosystem.
Domestic sewage
Domestic sewage is the primary source of pathogens (disease-causing microorganisms) and putrescible organic substances. Because pathogens are excreted in feces, all sewage from cities and towns is likely to contain pathogens of some type, potentially presenting a direct threat to public health. Putrescible organic matter presents a different sort of threat to water quality. As organics are decomposed naturally in the sewage by bacteria and other microorganisms, the dissolved oxygen content of the water is depleted. This endangers the quality of lakes and streams, where high levels of oxygen are required for fish and other aquatic organisms to survive. Sewage-treatment processes reduce the levels of pathogens and organics in wastewater, but they do not eliminate them completely (see also wastewater treatment).
Domestic sewage is also a major source of plant nutrients, mainly nitrates and phosphates. Excess nitrates and phosphates in water promote the growth of algae, sometimes causing unusually dense and rapid growths known as algal blooms. When the algae die, oxygen dissolved in the water declines because microorganisms use oxygen to digest algae during the process of decomposition (see also biochemical oxygen demand). Anaerobic organisms (organisms that do not require oxygen to live) then metabolize the organic wastes, releasing gases such as methane and hydrogen sulfide, which are harmful to the aerobic (oxygen-requiring) forms of life. The process by which a lake changes from a clean, clear condition—with a relatively low concentration of dissolved nutrients and a balanced aquatic community—to a nutrient-rich, algae-filled state and thence to an oxygen-deficient, waste-filled condition is called eutrophication. Eutrophication is a naturally occurring, slow, and inevitable process. However, when it is accelerated by human activity and water pollution (a phenomenon called cultural eutrophication), it can lead to the premature aging and death of a body of water.
Solid waste
The improper disposal of solid waste is a major source of water pollution. Solid waste includes garbage, rubbish, electronic waste, trash, and construction and demolition waste, all of which are generated by individual, residential, commercial, institutional, and industrial activities. The problem is especially acute in developing countries that may lack infrastructure to properly dispose of solid waste or that may have inadequate resources or regulation to limit improper disposal. In some places solid waste is intentionally dumped into bodies of water. Land pollution can also become water pollution if the trash or other debris is carried by animals, wind, or rainfall to bodies of water. Significant amounts of solid waste pollution in inland bodies of water can also eventually make their way to the ocean. Solid waste pollution is unsightly and damaging to the health of aquatic ecosystems and can harm wildlife directly. Many solid wastes, such as plastics and electronic waste, break down and leach harmful chemicals into the water, making them a source of toxic or hazardous waste
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Toxic waste
Waste is considered toxic if it is poisonous, radioactive, explosive, carcinogenic (causing cancer), mutagenic (causing damage to chromosomes), teratogenic (causing birth defects), or bioaccumulative (that is, increasing in concentration at the higher ends of food chains). Sources of toxic chemicals include improperly disposed wastewater from industrial plants and chemical process facilities (lead, mercury, chromium) as well as surface runoff containing pesticides used on agricultural areas and suburban lawns (chlordane, dieldrin, heptachlor). (For a more-detailed treatment of toxic chemicals, see poison and toxic waste.)
Sediment
Sediment (e.g., silt) resulting from soil erosion or construction activity can be carried into water bodies by surface runoff. Suspended sediment interferes with the penetration of sunlight and upsets the ecological balance of a body of water. Also, it can disrupt the reproductive cycles of fish and other forms of life, and when it settles out of suspension it can smother bottom-dwelling organisms.
Thermal pollution
Heat is considered to be a water pollutant because it decreases the capacity of water to hold dissolved oxygen in solution, and it increases the rate of metabolism of fish. Valuable species of game fish (e.g., trout) cannot survive in water with very low levels of dissolved oxygen. A major source of heat is the practice of discharging cooling water from power plants into rivers; the discharged water may be as much as 15 °C (27 °F) warmer than the naturally occurring water. The rise in water temperatures because of global warming can also be considered a form of thermal pollution.
Petroleum (oil) pollution
Petroleum (oil) pollution occurs when oil from roads and parking lots is carried in surface runoff into water bodies. Accidental oil spills are also a source of oil pollution—as in the devastating spills from the tanker Exxon Valdez (which released more than 260,000 barrels in Alaska’s Prince William Sound in 1989) and from the Deepwater Horizon oil rig (which released more than 4 million barrels of oil into the Gulf of Mexico in 2010). Oil slicks eventually move toward shore, harming aquatic life and damaging recreation areas.
Effects of water pollution on groundwater and oceans
Groundwater—water contained in underground geologic formations called aquifers—is a source of drinking water for many people. For example, about half the people in the United States depend on groundwater for their domestic water supply. Although groundwater may appear crystal clear (due to the natural filtration that occurs as it flows slowly through layers of soil), it may still be polluted by dissolved chemicals and by bacteria and viruses. Sources of chemical contaminants include poorly designed or poorly maintained subsurface sewage-disposal systems (e.g., septic tanks), industrial wastes disposed of in improperly lined or unlined landfills or lagoons, leachates from unlined municipal refuse landfills, mining and petroleum production, and leaking underground storage tanks below gasoline service stations. In coastal areas, increasing withdrawal of groundwater (due to urbanization and industrialization) can cause saltwater intrusion: as the water table drops, seawater is drawn into wells.
Although estuaries and oceans contain vast volumes of water, their natural capacity to absorb pollutants is limited. Contamination from sewage outfall pipes, from dumping of sludge or other wastes, and from oil spills can harm marine life, especially microscopic phytoplankton that serve as food for larger aquatic organisms. Sometimes, unsightly and dangerous waste materials can be washed back to shore, littering beaches with hazardous debris. By 2010, an estimated 4.8 million and 12.7 million tonnes (between 5.3 million and 14 million tons) of plastic debris had been dumped into the oceans annually, and floating plastic waste had accumulated in Earth’s five subtropical gyres that cover 40 percent of the world’s oceans (see also plastic pollution).
Another ocean pollution problem is the seasonal formation of “dead zones” (i.e., hypoxic areas, where dissolved oxygen levels drop so low that most higher forms of aquatic life vanish) in certain coastal areas. The cause is nutrient enrichment from dispersed agricultural runoff and concomitant algal blooms. Dead zones occur worldwide; one of the largest of these (sometimes as large as 22,730 square km [8,776 square miles]) forms annually in the Gulf of Mexico, beginning at the Mississippi River delta.
Water quality standards
Although pure water is rarely found in nature (because of the strong tendency of water to dissolve other substances), the characterization of water quality (i.e., clean or polluted) is a function of the intended use of the water. For example, water that is clean enough for swimming and fishing may not be clean enough for drinking and cooking. Water quality standards (limits on the amount of impurities allowed in water intended for a particular use) provide a legal framework for the prevention of water pollution of all types.
There are several types of water quality standards. Stream standards are those that classify streams, rivers, and lakes on the basis of their maximum beneficial use; they set allowable levels of specific substances or qualities (e.g., dissolved oxygen, turbidity, pH) allowed in those bodies of water, based on their given classification. Effluent (water outflow) standards set specific limits on the levels of contaminants (e.g., biochemical oxygen demand, suspended solids, nitrogen) allowed in the final discharges from wastewater-treatment plants. Drinking-water standards include limits on the levels of specific contaminants allowed in potable water delivered to homes for domestic use. In the United States, the Clean Water Act and its amendments regulate water quality and set minimum standards for waste discharges for each industry as well as regulations for specific problems such as toxic chemicals and oil spills. In the European Union, water quality is governed by the Water Framework Directive, the Drinking Water Directive, and other laws
Impacts
Ecosystems
Water pollution is a major global environmental problem because it can result in the degradation of all aquatic ecosystems – fresh, coastal, and ocean waters.[70] The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical changes such as elevated temperature. While many of the chemicals and substances that are regulated may be naturally occurring (calcium, sodium, iron, manganese, etc.) the concentration usually determines what is a natural component of water and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna. Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species.[71]
Public health and waterborne diseases
A study published in 2017 stated that "polluted water spread gastrointestinal diseases and parasitic infections and killed 1.8 million people" (these are also referred to as waterborne diseases).[72]
Eutrophication from nitrogen pollution
Nitrogen pollution (a form of water pollution where excessive amounts of nutrients are added to a water body), can cause eutrophication, especially in lakes. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur, affecting fish and other animal populations.[1]: 131
The following are some negatives ways that water pollution can directly affect human health.
Ingesting microplastics
A person may ingest microplastics via drinking water or through eating contaminated seafood. At Tokyo Bay in 2016, scientists examined 64 anchovies for microplastic consumption —
People have also discovered them within salt, beer, and other food items.
Studies show microplastics may cause oxidative stress, inflammatory reactions, and metabolic disorders in humans. However, further research is needed to confirm these effects.
Consuming water contaminated by sewage
The WHO note that, globally, around
According to the UN, every year, approximately 297,000 children under five die from diseases linked to poor sanitation, poor hygiene, or unsafe drinking water.
Drinking water containing chemical waste
Chemical pollutants, such as pesticides, fertilizers, and heavy metals can cause serious health problems if ingested.
In 2014, residents in Flint, Michigan, experienced water contamination due to inadequate testing and treatment of their water supply. The contaminated water caused rashes, hair loss, and itchy skin. Lead levels in the bloodstream of children who drank the water doubled.
A person who ingests chemical toxins in their water can be at risk of:
- cancer
- hormone disruption
- altered brain function
damage to immune and reproductive systems- cardiovascular and kidney problems
Swimming in contaminated water can also trigger:
- rashes
- pink eye
- respiratory infections
- hepatitis
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A person who wishes to reduce water pollution can help by:
- reducing plastic usage and recycling plastics when possible
- disposing of household chemicals properly
- keeping up with the maintenance of their vehicle to ensure it is not leaking harmful substances
- avoiding using pesticides
- making sure to clean up dog waste
- making sustainable choices regarding food and drinks
- considering going vegan or vegetarian
Water pollution is a serious environmental issue that can be caused by many contaminants. Human health can be affected by consuming, entering, or washing in polluted water.
There are various ways to help to limit water pollution. If a person experiences any effects of water pollution, they should speak to their doctor.
References
- ^ a b c d e f g h Von Sperling, Marcos (2007). "Wastewater Characteristics, Treatment and Disposal". IWA Publishing. 6. doi:10.2166/9781780402086. ISBN 978-1-78040-208-6.
Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License - ^ a b c Eckenfelder Jr WW (2000). Kirk‐Othmer Encyclopedia of Chemical Technology. John Wiley & Sons. doi:10.1002/0471238961.1615121205031105.a01. ISBN 978-0-471-48494-3.
- ^ "Water Pollution". Environmental Health Education Program. Cambridge, MA: Harvard T.H. Chan School of Public Health. July 23, 2013. Archived from the original on September 18, 2021. Retrieved September 18, 2021.
- ^ Moss B (February 2008). "Water pollution by agriculture". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 363 (1491): 659–666. doi:10.1098/rstb.2007.2176. PMC 2610176. PMID 17666391.
- ^ Alexandrou L, Meehan BJ, Jones OA (October 2018). "Regulated and emerging disinfection by-products in recycled waters". The Science of the Total Environment. 637–638: 1607–1616. Bibcode:2018ScTEn.637.1607A. doi:10.1016/j.scitotenv.2018.04.391. PMID 29925195. S2CID 49355478.
- ^ "Environment Agency (archive) – Persistent, bioaccumulative and toxic PBT substances". Environment Agency (UK). Archived from the original on August 4, 2006. Retrieved November 14, 2012.
- ^ Natural Environmental Research Council – River sewage pollution found to be disrupting fish hormones Archived April 27, 2015, at the Wayback Machine. Planetearth.nerc.ac.uk. Retrieved on 2012-12-19.
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