Sewage Crisis: Water Pollution's Unseen Danger

Untreated sewage is a pressing issue that poses a significant threat to both human health and the environment. Sewage pollution, which refers to water-carried waste, has contaminated many rivers, streams, and oceans, leading to harmful consequences for the ecosystems and human communities that rely on these water sources. The discharge of untreated sewage into water bodies can occur due to infrastructure failures, overflows, or illegal practices, resulting in the spread of diseases, disruption of ecosystems, and adverse effects on human health. This issue demands urgent attention and collaboration between conservation and public health sectors to implement effective solutions.

Sewage contains bacteria, viruses and parasites that cause diseases like cholera and typhoid

Untreated sewage is a major cause of water pollution, with far-reaching consequences for both human health and the environment. Sewage contains harmful bacteria, viruses, and parasites that can cause serious diseases, including cholera and typhoid.

Cholera is a waterborne disease caused by the ingestion of food or water contaminated with the Vibrio cholerae bacterium. It typically spreads in areas with inadequate sanitation and can cause severe diarrhea and dehydration, leading to death if left untreated. In 2008, a cholera epidemic broke out in Zimbabwe, spreading to neighboring countries due to poor sanitation and limited access to clean water.

Typhoid fever, on the other hand, is caused by the Salmonella typhi (S. typhi) bacterium, which is shed in the stools of infected individuals. It can be transmitted through contaminated food or water, and symptoms include high fever, weakness, stomach pains, headache, and loss of appetite. While antibiotics are effective in treating typhoid, those who do not receive treatment face a high risk of complications and death.

In addition to cholera and typhoid, untreated sewage can harbor other dangerous pathogens, such as E. coli, hepatitis A, and various parasites. These pathogens can contaminate water sources, leading to outbreaks of gastroenteritis, dysentery, and other waterborne illnesses. According to the World Health Organization (WHO), unsafe water, inadequate sanitation, and poor hygiene result in 1.5 million preventable deaths annually.

The impact of sewage pollution extends beyond human health. It also disrupts aquatic ecosystems, encouraging the growth of algae, which blocks light needed for photosynthesis and leads to oxygen depletion, ultimately killing fish and other organisms. Sewage can also attract fish with its warmer temperatures, only to expose them to high levels of contaminants, making it an "ecological trap."

Sewage overflows and leaks cause untreated sewage to enter rivers and other water sources

Sewage overflows and leaks are a major cause of water pollution, with untreated sewage entering rivers and other water sources. This has been a long-standing issue, with a 1998 study published in the International Journal of Epidemiology attributing one-third of all reported gastroenteritis cases and two-thirds of all ear infections to water pollution. Sewage overflows can occur due to various factors, including infrastructure failures, heavy rainfall, and insufficient wastewater treatment systems. The consequences of sewage overflows can be dire, leading to water pollution and posing significant risks to both human health and the environment.

Sewage overflows often result from ageing and failing infrastructure. In many cities, sewer systems are nearing 100 years old and are unable to cope with increasing populations and the impacts of climate change. This leads to frequent failures, such as line breaks and pump failures, resulting in sewage spills. For example, in Florida, the Department of Environmental Protection reported nearly 14,000 sewage spills over five years, releasing over 1.6 billion gallons of sewage.

In addition to infrastructure failures, heavy rainfall and stormwater can overwhelm sewer systems, causing overflows. During storms, excess water can rush into sewers, leading to overflows and the discharge of untreated sewage into nearby water bodies. This problem can be mitigated by investing in natural infrastructure, such as planting trees, restoring wetlands, and creating green roofs, which help absorb and filter stormwater, reducing the risk of sewer overflows.

Untreated sewage released into water sources can have severe environmental impacts. Sewage contains high levels of nutrients, such as nitrogen and phosphorus, which can fuel the growth of algae. Algal blooms can block light, hindering photosynthesis in aquatic plants, and when the plants and algae die, they are consumed by bacteria, reducing oxygen levels in the water. This oxygen depletion, known as eutrophication, can lead to the death of fish and other aquatic organisms, disrupting the entire ecosystem.

Furthermore, untreated sewage can spread diseases and pathogens, posing a significant risk to human health. It can contain harmful bacteria, viruses, and parasites, leading to gastrointestinal illnesses, skin and eye infections, and even life-threatening diseases such as cholera, typhoid, and hepatitis A. The World Health Organization (WHO) estimates that 1.5 million preventable deaths occur annually due to unsafe water, inadequate sanitation, and hygiene-related issues.

Sewage encourages algal blooms, which can lead to the deaths of many species

Sewage contains fats and oils, pharmaceuticals, synthetic hormones, pollutants, and nutrients such as nitrogen and phosphorus. These nutrients feed algal growth, causing algal blooms. While algal blooms can sometimes be natural phenomena, their frequency, duration, and intensity are increased by nutrient pollution. An overabundance of nitrogen and phosphorus can cause significant imbalances in the water body's ecology.

Algal blooms can have a drastic impact on the rest of the ecosystem. They can block out the light that plants need for photosynthesis, causing them to die. As the dead plants and algae are eaten by bacteria, oxygen in the water is reduced, killing fish and other organisms. This depletion of oxygen particularly affects freshwater insects, many of which spend large parts of their development in rivers.

The presence of certain types of algae can also directly affect native aquatic organisms, livestock, pets, and people who come into contact with the toxins. Blue-green algal blooms or scums can cause vomiting and diarrhea in humans, and can be fatal to dogs and livestock.

The impact of sewage spills on algal blooms can be seen in the River Way in 2014, where mayflies were wiped out. While ecosystems can recover if they are not overwhelmed, chronic pollution can cause real problems.

Sewage contains microscopic plastic fibres that can harm animals and damage the food chain

Untreated sewage is a major cause of water pollution, with human waste and chemicals contaminating rivers, streams, and oceans. Sewage contains microscopic plastic fibres that can harm animals and damage the food chain.

Plastic pollution is a pressing issue, with plastic waste ending up in waterways and oceans, where it can cause significant harm to aquatic life. Plastic has been found in the bodies of various animals, from tiny crustaceans to large whales, indicating its widespread presence in the food chain. The plastic fibres in sewage can be consumed by small animals, which are then eaten by larger predators, leading to a buildup of plastic in their systems.

For example, arrow worms, which are transparent torpedo-shaped creatures that hunt for zooplankton, have been recorded consuming plastic microfibers. These microfibers can block their digestive tracts, preventing the intake of real food. As arrow worms are prey for other animals, the plastic is passed up the food chain. This process is known as "trophic transfer."

Another example is the impact of nanoplastics, which are tiny plastic particles that can be generated when larger plastics are broken down by organisms such as Antarctic krill. Nanoplastics can enter the brains of fish through the food chain, leading to abnormal behaviour. In laboratory studies, fish that consumed nanoplastics exhibited slower eating and hyperactive behaviour compared to those that did not.

Furthermore, plastic in the environment tends to bind with pollutants, and these toxins can accumulate in animal fat and tissue through bioaccumulation. This can lead to the transfer of chemicals and toxins to animals higher up in the food chain, causing harm to their health and reproductive capabilities. For instance, plastic additives, such as flame retardants, have been found in the tissues of seabirds, likely ingested through swallowed plastic.

The presence of microscopic plastic fibres in sewage and their impact on the food chain highlights the urgent need to address water pollution and improve wastewater treatment processes to protect both human health and the environment.

Sewage spills and failing wastewater infrastructure threaten coastal water quality

Sewage spills and failing wastewater infrastructure are a major threat to coastal water quality, with serious consequences for both human health and fragile coastal ecosystems. Years of neglect have left wastewater infrastructure in many parts of the world outdated and failing. This has resulted in frequent sewage spills and infrastructure failures, releasing billions of gallons of under-treated or raw sewage into surface waters and oceans every year.

Sewage contains harmful bacteria, viruses, and parasites that can cause various illnesses in humans, including gastrointestinal issues, rashes, skin and eye infections, and flu-like symptoms. In addition, sewage can contain human waste, household chemicals, plastics, and other contaminants that pose a danger to human health. According to the World Health Organization (WHO), unsafe water, inadequate sanitation, and poor hygiene result in 1.5 million preventable deaths annually.

The impact of sewage spills extends beyond human health, significantly affecting coastal ecosystems. Sewage discharges introduce excess nutrients into waterways, promoting the growth of harmful algal blooms. These algal blooms block light necessary for photosynthesis, leading to the decline of aquatic plants and algae, which are then consumed by bacteria. This process reduces oxygen levels in the water, causing the death of fish and other organisms, including freshwater insects such as stoneflies and mayflies.

Mechanical breakdowns, pump failures, and overflowing systems are common causes of sewage spills. Tree roots infiltrating sewer lines, broken and cracked pipes, and corrosion can also lead to blockages and sewage backups. Climate change further exacerbates these issues, with more frequent and intense coastal storms overwhelming wastewater infrastructure. In addition, sea-level rise can cause seawater to infiltrate old pipes, resulting in untreated sewage being discharged into local waterways.

Upgrading and maintaining wastewater infrastructure are crucial to preventing sewage spills and protecting coastal water quality. While investing in such upgrades can be costly, the long-term benefits to human health and the environment are significant. Implementing notification programs to alert the public about sewage contamination in waterways is also essential for minimizing health risks.

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