Water Pollution's Impact: Illnesses And Their Causes

Water pollution is the release of harmful substances into bodies of water, making it unsafe for human use and disrupting aquatic ecosystems. It is caused by a range of contaminants, including toxic waste, petroleum, pesticides, heavy metals, and disease-causing microorganisms. These contaminants can originate from various sources, such as industrial waste, sewage, oil spills, and agricultural runoff. The impact of water pollution on human health is significant, leading to various illnesses and diseases. Diarrhea, caused by waterborne pathogens, is the most common disease associated with water pollution. Other illnesses include cholera, dysentery, hepatitis, typhoid, polio, skin diseases, malnutrition, and even cancer. In addition, water pollution can result in gastrointestinal illnesses, nervous system disorders, and reproductive issues. The World Health Organization (WHO) estimates that 80% of diseases and 50% of child deaths worldwide are linked to poor drinking water quality.

Diarrhoea and other gastrointestinal issues

Diarrhoea is the most widely known disease linked to contaminated water. It is a common symptom of gastrointestinal issues and is the most common disease caused by water pollution. It is a leading cause of illness and death in young children. According to the World Health Organization (WHO), 80% of the world's diseases and 50% of child deaths are related to poor drinking water quality. Diarrhoea is largely preventable, and the deaths of 395,000 children under the age of five could be avoided each year if risk factors were addressed.

Observational studies examining the association between water quality and diarrhoea have had mixed results. While some studies have found no clear relationship, others have found a significant association between poor water quality and diarrhoea, particularly when using Escherichia coli as an indicator of microbial water quality. However, it is important to note that water quality indicators can be too variable and unspecific to adequately characterise exposure to poor-quality water.

In addition to diarrhoea, gastrointestinal issues caused by water pollution can include vomiting and acute gastrointestinal illness (AGI). These illnesses are often caused by pathogens from external sources, such as sewage, and children are at the highest risk. Safety measures such as flushing pipes may not be sufficient to reduce all microbial risks, and additional measures should be considered to ensure the safety of drinking water.

The mechanisms underlying the association between contaminated water and gastrointestinal issues are still being explored. One potential mechanism involves the content and ratios of micro-elements in contaminated water, such as chlorides, nitrates, phosphates, and heavy metals, which can affect gastrointestinal health and function. Another factor may be the presence of specific pathogens in the water, such as Escherichia coli or enteroviruses, which can cause diarrhoea and other gastrointestinal problems.

To prevent diarrhoeal and other gastrointestinal diseases, it is crucial to ensure access to safe and sufficient water, improve water supply and sanitation, and implement effective water treatment and storage practices. These measures can reduce the transmission of diseases and improve overall public health.

Cholera and other bacterial infections

Cholera is a disease caused by the bacterium Vibrio cholerae, which can be found in soil, food, or water that has been contaminated with infected human faeces. It is transmitted by the consumption of contaminated water or food, especially in areas of poor sanitation and water treatment. Cholera is characterised by severe watery diarrhoea, and can lead to dehydration and renal failure in serious cases, and can even be fatal. The bacterium produces cholera toxin (CT), which affects the cells of the gastrointestinal tract, causing the loss of large quantities of fluid (up to one litre per hour).

Cholera was prevalent in the 1800s but has since become rare in developed countries due to proper sewage treatment and clean drinking water. However, it remains a significant health threat in over 47 countries, with approximately 2.9 million cases and 95,000 deaths annually. The highest burden is in Bangladesh, with around 100,000 cases and 4,500 deaths each year. Cholera outbreaks are common in developing countries, where sewage disposal and water treatment facilities are often inadequate.

In addition to cholera, other bacterial infections caused by water pollution include typhoid fever and bacillary dysentery. These diseases are transmitted through the consumption of water or food contaminated with faeces. Salmonella and shigellosis are also waterborne bacterial gastrointestinal diseases, mainly transmitted through contaminated water and food.

Waterborne bacterial infections are a serious global health issue, particularly in regions with inadequate sanitation and water treatment infrastructure. The impact of water pollution on human health is significant, and improving water quality is crucial to reducing its adverse effects.

Parasitic worms and diseases

One of the most prevalent parasitic infections transmitted through contaminated water is schistosomiasis, caused by a small parasitic worm that can remain dormant in the body for years while damaging internal organs. In 2021, over 251.4 million people required preventative treatment for schistosomiasis. Another common parasite found in water sources is cryptosporidium, which causes cryptosporidiosis, resulting in stomach cramps, diarrhoea, and vomiting. Cryptosporidium is a microscopic parasite that can be found in water contaminated with human or animal faeces and can survive for extended periods in the environment.

Giardia is another significant cause of waterborne diseases, including giardiasis, which is characterised by stomach cramps, bloating, nausea, and diarrhoea. Giardia parasites are microscopic and can be found worldwide, particularly in areas with inadequate sanitation and unsafe water. They can contaminate natural surface waters, public water supplies, swimming pools, and wells. The parasite is transmitted when contaminated water is ingested, and it then lives and reproduces in the intestines, causing intestinal problems that may persist even after the parasites are gone.

In addition to these, a range of other parasitic worms and diseases are associated with water pollution. For example, hookworms, a type of soil-transmitted helminth, can penetrate the skin and cause infections. Other intestinal parasites, such as helminths and protozoans, have been detected in water sources, posing risks for disease outbreaks. The presence of enteric pathogens in water, such as E. coli, Shigella spp., and Vibrio spp., indicates potential gastrointestinal diseases with bacterial or viral origins.

The impact of parasitic infections from water pollution is significant, contributing to morbidity and mortality, especially in developing countries. The negative health effects of water pollution are widespread, and access to clean drinking water remains a challenge for many. Preventative measures, such as water treatment and improved sanitation, are crucial to reducing the impact of parasitic infections and improving public health.

Cancer and other chronic illnesses

Water pollution is a pressing issue that has severe impacts on human health. It is estimated that more than 50 diseases are caused by poor drinking water quality, and 80% of diseases and 50% of child deaths worldwide are related to it. Waterborne illnesses can range from acute to chronic, with varying degrees of severity and long-term consequences. One of the most well-known and prevalent diseases linked to contaminated water is diarrhea, which is especially dangerous for young children in low-income countries. In addition to diarrhea, water pollution causes gastrointestinal illnesses, skin diseases, malnutrition, and even cancer.

Cancer is a significant concern when it comes to water pollution. Arsenic, a contaminant found in water sources, has been linked to an increased risk of developing various types of cancer, including liver, lung, bladder, and kidney cancer. The evidence for the carcinogenic effects of arsenic is particularly strong, with ingestion of high levels of arsenic being an accepted cause of bladder cancer. Additionally, disinfection byproducts (DBPs) formed when chlorine used for water treatment interacts with organic material in the water, have been associated with an increased risk of bladder and rectal cancer. Studies have found a positive correlation between long-term exposure to high levels of DBPs and rectal and bladder cancer.

Other contaminants in water, such as asbestos, radon, agricultural chemicals, and hazardous waste, also pose potential cancer risks. The use of asbestos in public water supply pipes has been linked to gastrointestinal cancer. Furthermore, the presence of endocrine-disrupting chemicals in water supplies has been suggested as a preventable cause of breast cancer. While the fluoridation of water has been scrutinized, current research suggests it poses little to no cancer risk.

Water pollution has been associated with an increased risk of other chronic illnesses as well. For example, schistosomiasis, a disease caused by parasitic worms contracted through exposure to infested water, affects millions of people annually. Additionally, insects that breed in water, including clean water sources, can transmit diseases such as dengue fever. The impact of water pollution on human health is significant, and it is crucial to address this issue through improved water treatment and sanitation practices to reduce the incidence of waterborne illnesses.

Encephalitis and other mosquito-borne diseases

Encephalitis is a mosquito-borne disease that is often symptomless but can cause coma and paralysis in susceptible individuals. The Culex mosquito, which spreads encephalitis, lays its eggs in polluted water. The best way to avoid mosquito-borne diseases is to reduce exposure to mosquitoes and their bites. This can be done by draining stagnant water, using mosquitofish in standing water, wearing long clothing that covers the skin, using insect repellent, and reducing outdoor activity at dawn and dusk when mosquitoes are most active.

Mosquito-borne encephalitis/encephalomyelitis are viral diseases transmitted to humans and animals by mosquitoes. Encephalitis refers to an inflammation of the brain, while encephalomyelitis refers to an inflammation of the brain and spinal cord. The three most important viruses that can cause mosquito-borne encephalitis/encephalomyelitis in California are West Nile Virus (WNV), Western Equine Encephalitis (WEE), and St. Louis Encephalitis (SLE). These viruses are maintained in nature through a bird-mosquito-bird cycle, with mosquitoes sometimes biting humans and transmitting the viruses to them instead of birds.

Symptoms of mosquito-borne encephalitis/encephalomyelitis can include flu-like symptoms such as fever, headache, nausea, and vomiting, which can last for 5 to 10 days. If the disease progresses, meningitis-like symptoms may occur, and in about 1% of WEE infections, encephalitis can develop, leading to severe inflammation of the brain and possibly requiring hospitalization.

In addition to encephalitis, mosquitoes can transmit a variety of other diseases, including malaria, dengue fever, chikungunya fever, Zika virus fever, yellow fever, West Nile fever, and Japanese encephalitis. These diseases are caused by parasites, viruses, or bacteria and can have serious health impacts, including death.

Water pollution can also contribute to the spread of other mosquito-borne diseases, such as dengue fever. Insects that live or breed in water, including mosquitoes, can carry and transmit diseases. While some mosquitoes breed in dirty water, others breed in clean water, and household drinking water containers can serve as breeding grounds. This highlights the importance of improving water sources and sanitation to reduce the risk of waterborne and mosquito-borne diseases.

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