Water Contamination: Understanding The Diverse Sources

Water contamination is a pressing issue that affects billions of people worldwide. In 2022, approximately 2.2 billion people lacked access to safely managed drinking water services, exposing them to potential health risks and diseases. Contaminated water sources can be attributed to both natural and human-made factors, with the latter being the primary cause. Human activities such as industrial waste disposal, agricultural practices, ageing infrastructure, and sewage treatment can introduce harmful chemicals, heavy metals, pathogens, and microorganisms into water supplies. Natural sources of contamination include geological features like rocks and soil containing chemicals, as well as natural disasters such as storms, earthquakes, and volcanic eruptions. Additionally, water contamination knows no borders, as transboundary pollution occurs when contaminated water from one country spills into the waters of another.

Industrial waste and urbanisation

Industrial Waste

Industrial waste encompasses a range of harmful substances released into water bodies, primarily through improper dumping and waste disposal practices. These contaminants include heavy metals, toxic chemicals, organic pollutants, and hazardous waste generated during manufacturing, mining, and chemical processes. The food products industry and small-scale industries also contribute to water pollution, often due to a lack of treatment facilities for their industrial effluents.

The impact of industrial waste on water quality is severe and long-lasting. It renders water unfit for drinking, recreation, agriculture, and industrial use. The presence of toxic chemicals and heavy metals in water sources poses a direct threat to human health, with contaminants found in high levels in both animals and humans, particularly those working in industries that expose them to such waste. Additionally, contaminated water destroys aquatic life and reduces their reproductive abilities, further disrupting ecosystems.

Urbanisation

Urbanisation, the process of people living in concentrated groups, has profound effects on water bodies and systems. The removal of trees and vegetation during urban development leads to increased storm runoff, erosion, and sedimentation in streams. Urban areas also generate large amounts of wastewater, which, if not properly treated, can discharge toxins and pollutants into local water bodies.

The impact of urbanisation on water quality is evident in the increased pollution of urban creeks and streams, often teeming with life, that weave through cities and towns. Unsanitary conditions in neighbourhoods without adequate water and sanitation services pose a constant threat of waterborne disease outbreaks, such as cholera, which can rapidly spread through densely populated urban areas.

Addressing the Issues

Addressing water contamination due to industrial waste and urbanisation requires a multifaceted approach. Governments and industries must prioritise sustainable waste management practices, strict regulation and treatment of industrial effluents, and the adoption of technologies for solid waste management and recycling. Additionally, investing in safe wastewater treatment and sanitation services in urban areas is crucial for protecting public and environmental health.

Agricultural activities

One major way is through the use of pesticides and fertilizers. When pesticides are applied to crops, some of the chemicals can drift and be carried by wind or rain into nearby water bodies, a process known as pesticide drift. The overuse or misuse of pesticides and fertilizers can result in these chemicals being washed into water bodies during rainfall or irrigation

Natural events

Natural Disasters and Weather Events

Severe weather events, such as tornadoes, hurricanes, floods, and storms, can cause the overflow of sewage systems and wastewater treatment plants, leading to the discharge of untreated sewage and pollutants into water bodies. These events can also damage industrial facilities, resulting in the accidental release of toxic chemicals and hazardous substances that can contaminate nearby water sources. Additionally, heavy rainfall or snowmelt can cause water run-off, washing microorganisms, sediment, and pollutants into water systems and contaminating private wells.

Geological Factors

The natural presence of certain chemicals and minerals in groundwater can pose health risks. For example, high levels of fluoride in groundwater, while beneficial for preventing tooth decay, can lead to skeletal fluorosis and dental fluorosis if consumed in excess. Radionuclides, which are naturally occurring radioactive substances, can also contaminate groundwater and private wells, posing risks of toxic kidney effects and increased cancer risk. Arsenic, a toxic chemical, can be present in drinking water due to natural mineral deposits, and lead can leach into water supplies from natural sources or through contact with plumbing components.

Natural Runoff and Erosion

Natural runoff from rainfall or snowmelt can carry pollutants, such as pesticides and fertilizers, into water bodies. This nonpoint source pollution is challenging to regulate as it originates from various diffuse sources, including agricultural activities and stormwater runoff. Soil erosion caused by natural events, such as heavy rainfall or flooding, can contribute to water contamination by carrying sediment, chemicals, and pollutants into nearby water sources.

Aquifer Intrusion

Saltwater intrusion into coastal aquifers can occur when freshwater is extracted from the aquifer in large quantities. This process can contaminate the groundwater and render it unsuitable for drinking or agricultural use.

Natural Microorganisms

The presence of certain microorganisms in water sources can have adverse effects on human health. Bacteria, viruses, and parasites, which are naturally occurring, can contaminate water supplies through human sewage, animal waste, or runoff. These microorganisms can lead to gastrointestinal illnesses and infections, with serious consequences for public health, especially in areas with inadequate sanitation and hygiene practices.

Sewage and wastewater

Diseases and Health Risks

Human sewage is a major source of harmful microorganisms, including bacteria, viruses, and parasites, which can cause various diseases and infections. For example, cryptosporidiosis, commonly known as "Crypto", is a waterborne disease caused by a parasite found in contaminated water. It leads to diarrhoea, stomach cramps, nausea, and fever. Viral gastroenteritis, or the "stomach flu", is another infection caused by viruses transmitted through contaminated water, resulting in watery diarrhoea, vomiting, and abdominal cramps.

Additionally, sewage and wastewater can contain high levels of nitrate and nitrite, which are particularly dangerous for infants. This can lead to methemoglobinemia, or "blue baby syndrome", a condition that affects an infant's ability to carry oxygen in their blood, potentially resulting in death within a few days.

Environmental Impacts

Causes of Sewage and Wastewater Contamination

The contamination of water by sewage and wastewater can occur due to various factors, including:

• Poorly designed or failing sewage systems: Ineffective septic systems can result in leakage of untreated sewage into water sources, causing contamination.
• Excess wastewater and high contaminant concentrations: When the amount of wastewater exceeds the capacity of the treatment process, it can lead to the escape of untreated water into land or surface water.
• Insufficient treatment time: If wastewater does not spend enough time undergoing filtration and biological processes, contaminant levels may remain high, leading to water system contamination.
• Natural disasters: Events like earthquakes or floods can cause sewer leaks, allowing sewage to enter groundwater directly.

Chemical contaminants

Another source of chemical contamination is sewage, which can contain a range of chemicals, bacteria, viruses, and other contaminants. Sewage can enter water sources through sewage treatment plant discharges and septic systems. Inadequate sewage treatment can result in the presence of harmful microorganisms, such as bacteria, viruses, and parasites, which can cause gastrointestinal illnesses, skin infections, and respiratory diseases.

Natural events, such as storms, earthquakes, and volcanic eruptions, can also contribute to water contamination. However, human actions can indirectly accentuate these events, such as increased storm intensity due to climate change or landslides caused by improper land use.

Some specific examples of chemical contaminants include nitrate and nitrite, which are present in chemical fertilizers, human sewage, and animal waste. High levels of nitrate and nitrite in drinking water can be dangerous, particularly for infants, as they interfere with the blood's ability to carry oxygen. Radionuclides, which are naturally present in some groundwater sources, can also contaminate private wells and have toxic effects on the kidneys and increase the risk of cancer.

It is important to address water contamination to protect human health and the environment. Preventing pollution is more cost-effective than continuously removing contaminants from water sources.

Frequently asked questions