Water Pollution's Impact On Aquatic Life

Water pollution is a serious ecological threat that endangers the health of millions of people worldwide. It occurs when harmful substances contaminate bodies of water, such as lakes, rivers, and oceans, degrading water quality and rendering it toxic to humans and the environment. This contamination can come from a variety of sources, including toxic waste, petroleum, and disease-causing microorganisms. Water pollution has devastating impacts on aquatic ecosystems and can also reach groundwater, leading to contaminated water in our households. It affects both wealthy and poor countries, with the United Nations reporting that one in every three people on the planet is affected by this issue.

Human health

Water pollution has a significant impact on human health. According to the World Health Organization (WHO), contaminated water causes around 500,000 diarrhoeal deaths each year. The World Bank's president, David Malpass, has warned of the economic impact of deteriorating water quality, stating that it "stalls economic growth and exacerbates poverty in many countries".

Diarrhea and Dysentery

The most common disease caused by water pollution is diarrhea, which is transmitted by enteroviruses in the aquatic environment. Contaminated drinking water can harbor bacteria, such as those responsible for diarrhea and dysentery. According to the WHO, diarrhea caused by unsafe drinking water, sanitation, and hand hygiene leads to the deaths of about 829,000 people each year, including nearly 300,000 children under the age of five.

Cholera

Water pollution is linked to cholera, with the WHO estimating that contaminated drinking water causes approximately 505,000 cholera deaths each year.

Typhoid and Polio

Water contaminated by sewage can transmit diseases such as typhoid and polio.

Hepatitis A

According to the WHO, about 2 billion people worldwide drink water contaminated by feces, exposing them to diseases such as hepatitis A.

Cancer

Water pollution can also lead to cancer. Arsenic, nitrate, and chromium in drinking water have been linked to skin, kidney, bladder, and lung cancer. Additionally, chlorinated by-products, heavy metals, and herbicides in drinking water are also considered carcinogenic.

Skin Diseases

Exposure to or use of heavily polluted water is associated with a risk of skin diseases. Excessive bacteria in seawater and heavy metals in drinking water are the main pathogenic factors for skin conditions.

Infant Mortality and Child Health

Water pollution is an important cause of infant and child mortality, especially in low- and middle-income countries. Diarrhea in infants and young children can lead to malnutrition and reduced immune resistance, increasing the likelihood of prolonged and recurrent diarrhea. Children exposed to pollution during critical periods of development are also at risk of height loss in adulthood.

Cardiovascular and Kidney Problems

Chemical pollutants in water, such as pesticides, fertilizers, and heavy metals, can cause cardiovascular and kidney problems if ingested.

Other Health Issues

In addition to the diseases mentioned above, water pollution has been linked to a range of other health issues, including gastrointestinal illness, malnutrition, respiratory infections, and altered brain function.

Aquatic ecosystems

Water pollution is a pressing issue that poses a significant threat to aquatic ecosystems. These ecosystems are incredibly diverse, encompassing a wide range of organisms and habitats. The following paragraphs delve into the impacts of water pollution on aquatic life, specifically exploring the consequences for aquatic ecosystems.

One of the most visible impacts of water pollution on aquatic ecosystems is the proliferation of harmful algal blooms. Excess nutrients, particularly nitrogen and phosphorus, from agricultural runoff and sewage, stimulate the growth of algae. While algae are a natural part of aquatic ecosystems, too much can lead to eutrophication. This process depletes oxygen in the water, creating "dead zones" where aquatic life cannot survive. Eutrophication can also lead to the accumulation of toxins that are harmful to both wildlife and humans.

Water pollution also introduces an array of toxic substances into aquatic ecosystems. These toxins include heavy metals, pesticides, and industrial chemicals. These contaminants accumulate in the tissues of aquatic organisms, leading to reduced lifespans and reproductive capabilities. They also bioaccumulate up the food chain, resulting in high concentrations of toxins in top predators like tuna.

Microplastics, resulting from the breakdown of plastic pollution, are another significant concern for aquatic ecosystems. These tiny plastic fragments are ingested by a wide range of marine organisms, from zooplankton to large marine predators. The presence of microplastics in the food chain can have detrimental effects on the health and survival of these organisms, with potential consequences for humans who consume seafood.

Oil spills and pollution from the shipping industry also wreak havoc on aquatic ecosystems. Oil slicks harm aquatic life and damage coastal habitats. Additionally, the regular operations of the shipping industry contribute to water pollution through legal and illegal discharges, further endangering marine life.

The introduction of invasive species is another indirect consequence of water pollution. When non-native species are introduced into aquatic ecosystems, they can outcompete native species, disrupting the natural balance and leading to a loss of biodiversity.

The impacts of water pollution on aquatic ecosystems are far-reaching and interconnected. The loss of a single species can have cascading effects throughout the food web, affecting numerous other organisms. Additionally, the degradation of aquatic ecosystems can have economic repercussions, impacting industries such as fishing and tourism.

Groundwater

Sources of Groundwater Contamination

• On-site sanitation systems: Pit latrines and septic tanks can contaminate groundwater with pathogens and nitrate if they are not properly designed, located, or maintained.
• Sewage and sewage sludge: Untreated or partially treated sewage can contain pathogens, nutrients, and heavy metals that can seep into groundwater systems.
• Fertilizers and pesticides: Excessive use of fertilizers and pesticides can lead to groundwater pollution. Nitrogen-containing fertilizers, in particular, can leach into groundwater, causing health problems in some low-income countries.
• Commercial and industrial leaks: Various inorganic and organic pollutants can leak into groundwater from commercial and industrial activities, including ore mining, metal processing, and chemical spills.
• Hydraulic fracturing ("fracking"): While fracking can be done without significantly impacting groundwater, there have been cases where improper handling or technical failures have led to groundwater contamination.
• Landfills: Old landfills that lack a protective bottom layer, or landfills with cracks in this layer, can allow contaminants such as battery acid, paint, and household cleaners to seep into groundwater.
• Storage tanks: Above-ground or underground storage tanks containing gasoline, oil, chemicals, or other liquids can corrode or crack over time, leading to leaks that contaminate groundwater.
• Atmospheric contaminants: As groundwater is part of the hydrologic cycle, it can be affected by contaminants in the atmosphere or other bodies of surface water.

Health Effects of Contaminated Groundwater

Drinking contaminated groundwater can have serious health consequences. Here are some of the potential health effects:

• Diseases: Contamination from septic tank waste can cause diseases such as hepatitis and dysentery.
• Poisoning: Toxins that have leached into well water supplies can lead to poisoning.
• Cancer: Exposure to polluted groundwater over the long term has been linked to an increased risk of certain types of cancer.
• Other health issues: Contaminated groundwater can also cause neurological, reproductive, dermal, and cognitive issues, as well as developmental problems in children.

Marine life

Water pollution is a pressing global issue that affects all marine life, from microscopic zooplankton to marine mammals like whales. The delicate balance of aquatic ecosystems is disrupted by contaminants such as heavy metals, oil spills, pesticides, and plastic waste. The presence of these pollutants in the water has detrimental effects on the health and survival of marine organisms, causing physical harm, reducing oxygen levels, and destroying habitats.

Physical Harm to Marine Life

Contaminants like heavy metals, oil spills, and pesticides can cause direct physical harm to fish and other aquatic organisms. These toxic substances can be ingested by marine life, leading to deformities such as gill damage, fin and tail rot, reproductive problems, and even death. Oil spills can strand and kill many marine species, including fish and birds. The 2021 oil spill off the coast of Los Angeles resulted in the death of countless fish and birds and the closure of 15 miles of beach.

Reduction in Oxygen Levels

Water pollution can also lead to a reduction in oxygen levels in aquatic ecosystems. Certain pollutants, such as nitrogen and phosphorus, often found in agricultural runoff, can promote excessive algae growth. When the algae die and decompose, they consume large amounts of oxygen, creating 'dead zones' where fish and other marine life suffocate due to the lack of oxygen. These dead zones can have devastating effects on marine populations and disrupt the natural balance of ecosystems.

Destruction of Habitats

Pollution can also indirectly impact marine life by damaging their environments. Contaminants can promote the growth of fungus, bacteria, and algae, which can overtake and impede the growth of naturally occurring plants that marine life depends on for survival. Additionally, the existence of large algae or moss mats can block sunlight and nutrients from reaching plants and fish below, hindering their growth and survival.

Plastic Pollution

Plastic waste is a significant pollutant in marine environments. It is long-lasting, with plastic items taking hundreds of years to decompose. Marine animals can become entangled in plastic debris, and some may even mistake plastic bags for food and ingest them. Plastics can also attract other contaminants, making them even more dangerous when ingested by marine life. Microplastics, which are tiny particles resulting from the breakdown of larger plastics, have been found in a range of marine species, including plankton and whales. As smaller organisms that consume microplastics are eaten by larger animals, the toxic chemicals migrate up the food chain, eventually reaching humans.

Impact on Coral Reefs

Wastewater pollution, which includes sewage and agricultural runoff, has detrimental effects on coral reefs. It increases corals' exposure to disease-causing pathogens, leading to coral diseases such as white pox and black band disease. Nutrient pollution, particularly from agricultural runoff, can also cause coral bleaching, decreased coral reproductivity, reduced coral skeletal integrity, and a decline in coral cover and biodiversity.

The economy

Water pollution has a significant impact on the economy, affecting various sectors and resulting in substantial costs and losses. Here are some ways in which water pollution influences the economy:

Impact on Economic Growth

Water pollution has a direct bearing on economic growth, particularly in regions downstream of polluted rivers. According to a study by Russ et al., when rivers become moderately polluted, growth downstream is reduced by 1.4%. This reduction in growth increases to 2% when rivers become heavily polluted. The impact is even higher for middle-income countries, with growth reductions of 1.77% and 2.5% for moderate and heavy pollution, respectively. These findings highlight that the costs of environmental degradation may be severely underestimated, and pollution levels are often above efficient thresholds.

Tourism and Recreation

Water pollution, especially in the form of nutrient pollution and harmful algal blooms, takes a toll on the tourism and recreation industries. The presence of algal blooms can deter tourists and negatively impact activities such as fishing and boating. The tourism industry loses an estimated $1 billion annually due to water pollution, primarily through losses in fishing and boating activities. Additionally, airborne nutrient pollution can affect visibility at outdoor destinations like national parks, further diminishing their appeal to tourists.

Commercial Fishing and Shellfish Industries

Water pollution, particularly from harmful algal blooms, can kill fish and contaminate shellfish, resulting in significant losses for the fishing and shellfish industries. Annual losses to these industries from nutrient pollution are estimated in the tens of millions of dollars. This, in turn, affects the economies of coastal communities and regions that depend on these industries.

Real Estate and Property Values

Water pollution can also influence property values, particularly for waterfront properties. The unpleasant sight and odour of algal blooms can lead to a decline in waterfront property values. On the other hand, clean water can increase the value of nearby homes by up to 25%.

Treatment Costs

Water pollution increases the cost of treating drinking water. For example, the presence of nitrates and algal blooms can significantly increase treatment costs. In Minnesota, nitrate-removal systems caused supply costs to rise from 5-10 cents per 1000 gallons to over $4 per 1000 gallons. Investing in protecting water sources can lead to significant savings in water treatment costs.

Agriculture and Food Production

Water pollution can impact the agriculture sector, reducing the quality and quantity of food produced. Contaminants from agriculture, such as fertilizers, animal waste, and pesticides, can wash into waterways during rainfall, leading to water pollution and affecting crop yields. This, in turn, can have economic repercussions for farmers and the wider economy, especially in countries where agriculture is a significant contributor to GDP.

In summary, water pollution has far-reaching consequences for the economy, affecting multiple sectors and resulting in financial losses, reduced economic growth, and increased costs for treatment and remediation. Addressing water pollution is crucial for sustainable economic development and the well-being of communities and industries that rely on clean water.

Frequently asked questions