Human Waste: A Water Pollution Crisis

Water pollution is a serious global issue that poses a significant threat to human health and the environment. One of the main sources of water pollution is human waste, which can have detrimental effects on aquatic ecosystems and human well-being.

Human waste, also known as sewage or wastewater, refers to water that has been used in domestic, commercial, agricultural, or industrial activities. It includes water from toilets, sinks, showers, and other sources. Unfortunately, a significant portion of this wastewater is discharged back into natural water bodies without proper treatment. According to the United Nations, more than 80% of the world's wastewater is released into the environment untreated, with the figure exceeding 95% in some least-developed countries.

When human waste is released into rivers, lakes, or oceans, it introduces a range of contaminants, including harmful chemicals, pathogens, and nutrients. These contaminants can have severe ecological and health impacts. For example, human waste can contain high levels of nitrogen and phosphorus, which promote the growth of algae, leading to algal blooms that disrupt the natural balance of ecosystems and create dead zones where oxygen levels are too low to support life.

In addition to ecological consequences, human waste pollution also poses risks to human health. Untreated wastewater can contain disease-causing bacteria and viruses, leading to waterborne illnesses such as cholera, dysentery, and typhoid. It can also introduce chemical toxins, such as heavy metals and pesticides, into the water supply, which can accumulate in the food chain and have detrimental effects on human health, including cancer, hormonal disruptions, and altered brain function.

To address the issue of human waste pollution, it is crucial to improve wastewater treatment infrastructure and reduce the discharge of untreated sewage into natural water bodies. This includes investing in treatment facilities, promoting sustainable waste management practices, and enforcing regulations to hold polluters accountable. Additionally, individuals can play a role by reducing their plastic consumption, properly disposing of chemicals and medications, and supporting policies that protect and invest in water infrastructure.

Sewage and wastewater

Wastewater contains harmful bacteria and viruses, which can cause serious illnesses such as cholera, typhoid, dysentery, hepatitis A, and polio. According to the World Health Organization, approximately 1.4 million people die each year due to poor sanitation, poor hygiene, or unsafe drinking water. Sewage and wastewater can also cause gastrointestinal illnesses, skin infections, and other potentially life-threatening conditions.

The release of untreated sewage into water bodies can lead to water quality degradation, harming aquatic ecosystems and making the water unsafe for human and animal use. Nutrient-rich sewage can cause eutrophication, leading to excessive growth of algae, which depletes oxygen in water bodies and results in fish die-offs. Sewage pollution also negatively impacts coral reefs, which are vital for maintaining marine biodiversity.

In addition to health risks, sewage pollution has economic consequences, particularly in the tourism industry. For example, sewage-polluted beaches can deter visitors, affecting local industries that rely on tourism revenue and impacting job security.

Furthermore, sewage systems often suffer from leaks and spills, allowing untreated sewage to seep directly into the environment and contaminate water sources. This infiltration of sewage into groundwater and other water sources leads to contamination, endangering human and animal health and requiring costly water treatment processes.

To prevent sewage pollution, proper maintenance of septic systems and disposal of waste are crucial. Reducing water usage and improving wastewater treatment processes are also essential to minimizing the impact of sewage and wastewater on water pollution.

Microplastics

The toxicity of a plastic particle is largely dependent on its size, shape, composition, and ability to bind with other chemicals present in the ecosystem. The larger, more rigid particles can lodge in the gut of consumers resulting in intestinal blockage whereas smaller (nano) particles and fibres can cause metabolic, behavioural, and developmental impacts following ingestion.

The small size of microplastics allows plastic fragments to become airborne, which leads to an increased risk of exposure through inhalation. Contact with skin may also be a route of exposure to microplastics, as some nanoplastics are small enough to be absorbed by the skin.

The different shapes, sizes, and makeup of microplastics influence the amount of chemical toxins and microbes, such as bacteria and viruses, that can adhere to their surface. As a result, the hazards associated with microplastics are broad because they are unique to the particle shape, size, and composition.

Nonpoint source pollution

• Urban and suburban areas: Contaminated stormwater washed off of parking lots, roads, and highways is called urban runoff. This runoff is often classified as a type of non-point source pollution.
• Agricultural operations: Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer, animal manure, or spraying of municipal or industrial wastewater. Nutrient pollution such as nitrates can harm aquatic environments by lowering levels of oxygen, which can induce algal blooms and eutrophication.
• Atmospheric deposition: Atmospheric deposition is a source of inorganic and organic constituents because these constituents are transported from sources of air pollution to receptors on the ground.
• Highway runoff: Harned (1988) estimated that runoff loads were composed of atmospheric fallout (9%), vehicle deposition (25%) and highway maintenance materials (67%).
• Forestry and mining operations: Forestry operations reduce the number of trees in a given area, thus reducing the oxygen levels in that area as well. Mining operations can also cause chemical reactions with the air and newly exposed rock to create acidic runoff.
• Marinas and boating activities: Chemicals used for boat maintenance, like paint, solvents, and oils find their way into water through runoff. Spilling fuels or leaking them directly into the water from boats also contributes to nonpoint source pollution.

Eutrophication

Causes of Eutrophication

Effects of Eutrophication

• Increased biomass of phytoplankton
• Changes in macrophyte species composition and biomass
• Dissolved oxygen depletion
• Increased incidences of fish kills
• Loss of desirable fish species
• Decreased biodiversity
• New species invasion
• Harmful algal blooms
• Economic impacts
• Human health effects

Preventing and Reversing Eutrophication

To prevent and reverse eutrophication, we can minimise point source pollution from sewage and agriculture, as well as other nonpoint pollution sources. Introducing bacteria and algae-inhibiting organisms such as shellfish and seaweed can also help reduce nitrogen pollution, controlling the growth of cyanobacteria, the main source of harmful algae blooms.

Industrial wastewater

Sources of Industrial Wastewater

Effects of Industrial Wastewater on the Environment

Effects of Industrial Wastewater on Human Health

The toxins in industrial wastewater can cause acute poisoning, immune system suppression, and reproductive failure. According to the World Health Organization (WHO), around 80% of diseases are waterborne. Industrial wastewater can contain heavy metals, which can cause teratogenic and carcinogenic effects, as well as oxidative stress, organ damage, nervous system impairments, and reduced growth and development. Phenolic compounds, commonly found in wastewater from oil refineries and bulk drug manufacturing industries, can cause reflex loss, sweating, low body temperature, cyanosis, decreased respiration, and respiratory failure.

Treatment of Industrial Wastewater

The treatment of industrial wastewater is complex and often requires industry-specific solutions. Various technologies and strategies are being developed and employed to remove contaminants from wastewater. This includes methods such as adsorption, membrane filtration, electrodialysis, and photocatalysis for the removal of heavy metals, and electrochemical processes for the removal of phenolic compounds.

Preventing Industrial Wastewater Pollution

To prevent water pollution from industrial waste, it is essential to implement appropriate environmental legislation and adopt sustainable industrial wastewater recycling systems. This may involve identifying water streams generated in production and having them analysed by a professional laboratory to determine the most suitable treatment methods. By recycling and reusing wastewater, companies can reduce their environmental impact and improve sustainability.

Frequently asked questions