Water Cycle: Pollutants' Intrusion And Their Harmful Effects

Water is an essential resource that supports all life on Earth. However, modernisation and industrialisation have harmed the quality and availability of water. Water pollution occurs when harmful substances contaminate a body of water, degrading water quality and rendering it toxic to humans or the environment. This widespread problem jeopardises our health and is responsible for more deaths each year than war and all other forms of violence combined. Water pollution can be caused by various sources, including point sources such as industrial waste discharge and city sewage systems, as well as dispersed sources like agricultural runoff and oil spills. These pollutants can have detrimental effects on the environment and public health, and it is crucial to address them to protect our water resources.

Industrial waste

Hazardous waste may result from manufacturing or other industrial processes, and it can be toxic, ignitable, corrosive or reactive. Certain commercial products, such as cleaning fluids, paints or pesticides, can also be defined as hazardous waste. If improperly managed, this waste can have dangerous consequences for both human health and the environment. For example, high levels of toxic contaminants has been found in humans and animals that are continually exposed to waste streams, such as farm workers and oil and gas workers.

The production of industrial goods generates wastewater that can be contaminated with toxic substances. These include organic compounds (such as solvents), metals, nutrients or radioactive material. If this wastewater is discharged without treatment, it can contaminate groundwater and surface water bodies, including lakes, streams, rivers and coastal waters. This, in turn, can have serious impacts on human health and the environment. For example, drinking water sources and irrigation water used for farming may be affected, and aquatic life can be destroyed and its reproductive ability reduced.

In Europe, there are strict limits that industries must observe when discharging wastewater, and it must be treated before being discharged into the sewage system or rivers. However, in emerging countries such as China, India, Africa and South America, environmental policies are not as stringent, and the illegal discharge of wastewater from industry is common. Similarly, in the USA, there are laws against water pollution, but they do not cover all types of industrial wastewater pollution.

Sewage systems

Another way sewage systems can pollute water is through the release of untreated sewage into rivers and streams. This can occur due to leaks, flooding, or overflows in the sewer system. In the US, for example, over 860 billion gallons of untreated sewage escape from sewer systems each year, polluting nearby bodies of water. This not only harms aquatic life but also poses a significant risk to human health, as people may come into contact with contaminated water during swimming, boating, or fishing.

The items that people flush down their toilets can also cause sewage systems to pollute water sources. Flushing items such as wipes, nappies, or cotton buds can cause drains to block and lead to flooding. Additionally, pouring cooking fats, oils, and grease down the drain can result in clogs as these substances harden and stick to the inside of drains and sewers.

Misconnections in plumbing can also lead to sewage pollution. A misconnection occurs when the drainage from a building is connected to the wrong sewer network, resulting in the pollution of waterways.

Furthermore, even properly treated sewage can have negative impacts on the environment. For instance, microscopic plastic fibres released from certain clothes during washing can pass through wastewater treatment plants and enter marine ecosystems, causing harm to animals and disrupting the food chain.

Stormwater runoff

During this process, stormwater often picks up various pollutants, including motor oils, fertilizers, pesticides, and even pet waste. This type of pollution is known as non-point source pollution, and it is a major problem in urban and suburban areas. Non-point source pollution has no single, identifiable source, making it challenging to regulate. However, it accounts for a significant portion of the pollution in creeks, streams, rivers, and bodies of water like Puget Sound in Washington State.

The impacts of stormwater runoff are far-reaching. In Washington, stormwater pollution has contributed to the closure of thousands of acres of shellfish growing beaches. It can also lead to swimming beach closures and contaminate drinking water supplies. Poorly managed stormwater can cause flooding, harming streams, wetlands, and wildlife habitats. Additionally, it can result in water shortages, especially in areas with a high proportion of impervious surfaces that prevent water infiltration.

To address stormwater runoff, individuals and communities can take several actions. Maintaining vehicles and properly disposing of fluids, such as oil and antifreeze, is crucial. Washing cars at commercial car washes or on lawns instead of in streets or driveways can also help. Reducing the use of fertilizers, pesticides, and herbicides, and opting for organic alternatives, is another effective measure. Additionally, removing impervious surfaces and increasing vegetated land cover can help mitigate the impacts of stormwater runoff.

By implementing these measures and supporting stormwater management programs, communities can minimize the negative effects of stormwater runoff, protect natural resources, and enhance the resilience of their local water systems.

Oil spills

Furthermore, oil spills can have long-lasting effects on ecosystems, with some marine life populations unable to recover even a decade later. For example, bottlenose dolphin populations in the Gulf of Mexico failed to recover due to increased reproduction failure following the Deepwater Horizon spill in 2010.

Agricultural pollution

Agriculture is a leading cause of water pollution, and the sector is the biggest consumer of global freshwater resources. Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into water bodies.

Agricultural land can cause water pollution in several ways. Firstly, irrigation can lead to increased evaporation from the soil, which can increase the amount of water vapour in the atmosphere and alter precipitation patterns. This can lead to more precipitation in areas downstream from the agricultural land. Irrigation is also a major source of pollution, as contaminated water is used to irrigate crops, leading to contaminated food products. Poorly managed animal feeding operations, overgrazing, and overworking the land can all contribute to agricultural runoff, which can pollute water sources with pesticides, fertilisers, bacteria, viruses, and other chemicals.

Agricultural practices can have negative impacts on water quality if they are not done properly. For example, elevating concentrations of nutrients, fecal coliforms, and sediment loads can occur due to poor management of animal waste, leading to eutrophication of water bodies and damaging aquatic ecosystems. The intensive use of pesticides and chemical fertilisers in crop production also contributes to water pollution.

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