Water Sources: Polluted, Affected, And Toxic

Water is essential for life, but it is also highly susceptible to pollution. Water pollution occurs when substances like chemicals, waste, and microorganisms contaminate water bodies, degrading water quality and harming humans, wildlife, and the environment. Major sources of water pollution include industrial waste, agricultural runoff, plastic pollution, sewage, and solid waste disposal. These pollutants can originate from factories, agricultural sites, improper waste management, and even natural sources like mercury from the Earth's crust. The consequences of water pollution are severe, impacting health, ecosystems, and economies, with the United Nations reporting more annual deaths from polluted water than all forms of violence combined.

Industrial waste

The production of all kinds of industrial goods generates wastewater that can be contaminated with toxic substances. The composition of industrial wastewater depends on its origin from production. In the course of production, this water becomes polluted and must be treated before being discharged into public supply networks. Many of the hazardous substances from industry are difficult to biodegrade and therefore accumulate in water sediments. The polluted water from rivers and the contaminants from the water sediments can get into the groundwater, and thus into the drinking water.

In Europe, there have been strict limits for decades that industries must observe when discharging wastewater into public networks. However, in some areas of the world, wastewater is discharged untreated into nearby public waters. In the United States, industrial waste has contaminated drinking water, with a News21 analysis of EPA data showing that the drinking water of more than 244 million people contains contaminants that can be linked to industrial practices.

Sources of toxic chemicals include improperly disposed of wastewater from industrial plants and chemical process facilities, as well as surface runoff containing pesticides used on agricultural areas and suburban lawns. Dry cleaning fluids have contaminated groundwater supplies in all areas of the United States, with PCE (perchloroethylene or tetrachloroethylene) being a suspected carcinogen that must be removed from water.

Agricultural chemicals

Agriculture is the world's largest user of freshwater and a major cause of surface and groundwater degradation through erosion and chemical runoff. The associated agrofood-processing industry is a significant source of organic pollution. Aquaculture has been recognised as a major problem in freshwater, estuarine and coastal environments, leading to eutrophication and ecosystem damage.

Agricultural runoff is the leading cause of water quality impacts to rivers and streams, the third leading source for lakes, and the second-largest source of impairments to wetlands. About half a million tons of pesticides, 12 million tons of nitrogen, and 4 million tons of phosphorus fertilizer are applied annually to crops in the continental United States. Soil erosion, nutrient loss, bacteria from livestock manure, and pesticides constitute the primary stressors to water quality. Rainfall and snowmelt transport the majority of these pollutants to surface waters, but other factors, such as cattle loafing in stream corridors, can also contribute.

Excess nitrogen and phosphorus from chemical fertilizers and animal manure can be washed from farm fields and into waterways during rain and snowmelt events, and can also leach through the soil and into groundwater over time. High levels of nitrogen and phosphorus can cause eutrophication of water bodies, leading to hypoxia ("dead zones") and a decrease in aquatic life. Excess nutrients can also cause harmful algal blooms (HABs) in freshwater systems, which can produce toxins harmful to wildlife and humans.

Sewage and wastewater

Wastewater, which includes sewage, is a leading cause of water pollution in rivers, reservoirs, lakes, and seas, introducing a range of contaminants. These water bodies are inundated with chemicals, waste, plastics, and other pollutants from sewage and wastewater. Sewage systems, particularly older ones found in many developed countries, struggle to manage the volume of wastewater and can become overwhelmed, resulting in the release of untreated wastewater. For example, in the United States, sewage treatment systems discharge over 850 billion gallons of untreated wastewater annually, according to EPA estimates.

The impact of sewage and wastewater pollution extends beyond the contamination of water sources. It poses risks to human health, with approximately 3.5 million Americans experiencing health issues such as skin rashes, pink eye, respiratory infections, and hepatitis due to sewage-laden coastal waters. Additionally, wastewater pollution disrupts ecosystems and food webs, affecting biodiversity and the health of aquatic environments.

Furthermore, sewage and wastewater contain valuable nutrients and freshwater, emphasizing the importance of perceiving them as resources rather than solely pollutants. This shift in perspective is crucial for achieving a sustainable "circular economy." While technology plays a role in addressing sewage and wastewater issues, it is also essential to acknowledge that a significant mindset change is required to embrace a comprehensive suite of solutions.

Oil spills

Oil on the ocean surface prevents sufficient sunlight from penetrating and reduces dissolved oxygen levels. This lack of sunlight can kill plants growing in the water, and the reduction in oxygen levels can harm aquatic life. Oil also ruins the insulating and waterproofing properties of feathers and fur, causing oil-coated birds and marine mammals to die from hypothermia. Ingesting oil is toxic to affected animals, and the damage to their habitats and reproductive rates can slow the long-term recovery of animal populations.

There are several methods to clean up oil spills, depending on the type and amount of oil spilled, the water location, and local weather conditions. Floating booms can be placed around the spill to contain it and reduce its spread. Skimming involves physically separating the oil from the water and placing it into collection tanks. Sorbents such as straw, volcanic ash, or polyester-derived plastic shavings can absorb the oil from the water. Chemical surfactants and solvents may also be used to accelerate the dispersion of the oil into the sea.

Solid waste

Municipal solid waste (MSW) is of particular concern. MSW disposal methods are often not well-planned globally, and wastes are often disposed of in water bodies in low-lying areas. Solid waste from hospitals, industrial estates, and other harmful sources can severely impact the health of workers and the general public when not properly separated and treated.

Additionally, many solid wastes, such as plastics and electronic waste, can break down and leach harmful chemicals into the water, becoming a source of toxic or hazardous waste. This can have detrimental effects on human health and the environment, as contaminated groundwater can lead to diseases and harm aquatic ecosystems.

To address solid waste pollution, promoting awareness about the importance of groundwater protection and proper waste disposal practices is essential. This includes encouraging responsible chemical usage and supporting sustainable practices to preserve groundwater integrity and reduce the impact of solid waste on water sources.

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