Water Pollution: The Most Common Ways Our Water Gets Contaminated

Water pollution is a pressing issue that affects millions of people worldwide, with one in three people on the planet lacking access to clean drinking water. While water pollution can sometimes be caused by nature, such as when mercury filters from the Earth's crust, the most common cause is human activity. There are various ways in which water gets polluted, but the most popular way is through agricultural runoff, which is the leading cause of water pollution globally.

Industrial and municipal wastewater

Industrial wastewater is wastewater that is discharged from industrial and commercial sources. It may contain pollutants that can affect the quality of the receiving waters or interfere with publicly owned treatment works (POTWs) that receive those discharges. The main industries contributing to wastewater pollutants include chemical, electric power, food processing, iron and steel, mining, nuclear, automotive, and paper and pulp. For example, the production of 70 million cars globally each year contributes over 34 trillion liters of wastewater.

The treatment of industrial wastewater is critical due to its potential to impact the environment and public health. With increasing population and industrial activity, there is a need for increased levels of treatment before discharging municipal and industrial wastewater. The United Nations Sustainable Development Goals (UN SDGs) have set targets for improved water quality, integrated water resource management, improved water use efficiency, and restored water-related ecosystems.

Municipal wastewater refers to wastewater from municipal and domestic sources. Municipal and industrial wastewater were previously combined and sent for treatment via a single drain, but this led to health hazards for humans and marine life, and the segregation of the two was required. Municipal wastewater can be a valuable source of energy and nutrients if treated efficiently. For example, sludge from municipal wastewater can be used to extract energy and bio-solids for agricultural use.

The management of industrial and municipal wastewater is a complex task that requires tailoring treatment methods to the specific characteristics of the water source, pollutant types, geographical location, budget, and available technology. Some of the challenges include high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), high total suspended or dissolved solids, and high nitrate and phosphate levels.

Furthermore, some industrial and municipal facilities generate large volumes of wastewater, which may require the implementation of zero-liquid discharge systems to adjust chemical volumes, recover liquid waste for reuse, treat valuable byproducts, and produce dry/solid cake for disposal. The treatment of wastewater has become more challenging due to changing regulations, increasing population, and the presence of modern-day contaminants such as microplastics, PFAS, and pharmaceuticals.

Oil spills

The oil industry, including drilling, transportation, and storage, is a significant contributor to the risk of oil spills. Oil spills can result from the release of crude oil from tankers, offshore platforms, drilling rigs, and wells. They can also involve spills of refined petroleum products, such as gasoline and diesel fuel, as well as heavier fuels used by large ships. The transportation and storage of oil are inherently subject to leakage, which can have devastating impacts on our water resources.

Cleanup and recovery from an oil spill are challenging and can take weeks, months, or even years. The process depends on various factors, including the type of oil spilled, the temperature of the water, and the types of shorelines and beaches involved. Physical cleanups are also very expensive, and even with advanced technology, it is impossible to remove 100% of the spilled oil. After the Exxon Valdez oil spill in 1989, it was found that the cleanup efforts caused more damage than the oil spill itself in certain sensitive habitats.

Notable examples of major oil spills include the Deepwater Horizon spill in 2010, the Exxon Valdez spill in 1989, and the Ixtoc I spill. While technologies for drilling in deep water have improved, oil companies are moving to more challenging drilling sites, and there is no clear trend in the frequency of offshore oil platform spills. The increasing complexity of drilling sites and the inherent risks associated with oil transportation and storage highlight the urgency of addressing oil spills as a significant cause of water pollution.

Agricultural runoff

Water pollution is a pressing issue that endangers the health of millions of people and ecosystems around the world. One of the most common ways water gets polluted is through agricultural runoff, which is the leading cause of water quality issues in rivers and streams. This type of pollution occurs when contaminants from agricultural activities, such as pesticides, fertilizers, and manure, make their way into nearby water sources.

Pesticides used in agriculture are another major contributor to water pollution. These toxic chemicals can contaminate water sources through runoff, posing risks to aquatic life, fish-eating wildlife, and even drinking water supplies. Pesticides have been linked to various chronic diseases in humans, including endocrine and neurological disorders and cancer. Children are especially vulnerable to the harmful effects of pesticide exposure.

Livestock and poultry manure also play a significant role in agricultural runoff. In the United States, livestock and poultry produce nearly 1.4 billion tons of manure annually, which is often spread on land untreated. When applied in excess, this manure can run off into water sources, leading to contamination. Manure contains high levels of phosphorus, which can harm waterways, and bacteria, which can affect drinking water supplies and lead to beach closures.

To address the issue of agricultural runoff, farmers can adopt best management practices (BMPs) and regenerative agriculture strategies. This includes following fertilizer best practices to reduce nutrient runoff, improving soil health through cover crops, and planting streamside buffer crops to protect water quality. Additionally, landowners can utilize tools such as the Landowner Self-Assessment Tool to assess the risk of water pollution on their properties and implement appropriate solutions. By working together and adopting sustainable practices, we can help ensure clean and safe water for all.

Marine dumping

Before the 1970s, communities worldwide used the ocean as a dumping ground for waste. This practice changed as the harmful impacts of unregulated disposal became better understood. Today, the deliberate disposal of waste into the ocean is governed by international treaties such as the 1972 London Convention and the 1996 London Protocol, which establish global rules and standards for preventing, reducing, and controlling marine pollution. The United States, a Contracting Party to the London Convention, implements its requirements through the Marine Protection, Research, and Sanctuaries Act (MPRSA) of 1972.

The MPRSA plays a crucial role in protecting and preserving ocean and coastal resources by regulating the disposition of materials into the ocean. It evaluates and issues permits for materials disposed of in the ocean, ensuring they do not pose a danger to human health or the environment. The EPA's Headquarters and seven coastal Regional Offices work together to designate and monitor MPRSA ocean sites, evaluate permit inquiries, and provide technical support to other agencies.

Dredging is a significant contributor to marine dumping, accounting for about 80% of all waste dumped into the ocean. Rivers, canals, and harbors are dredged to remove silt and sand buildup or create new waterways. Approximately 20-22% of the dredged material is dumped into the ocean, with the remainder disposed of in other waters, landfills, or used for development. Unfortunately, about 10% of dredged material is polluted with heavy metals, hydrocarbons, nutrients, and pesticides, which have toxic effects on marine organisms and contaminate seafood.

Marine debris, such as plastic bags and fishing gear, poses a severe threat to marine life. Animals like seabirds, turtles, dolphins, and seals can become entangled and suffer injuries, infections, or strangulation. Plastic debris is often ingested by sea turtles, mistaking it for jellyfish, and can lead to starvation or death. Additionally, marine debris can damage boat engines and clog intake valves, propellers, and ports. The long-term effects of nuclear dumping are unknown, but some estimates suggest it could result in up to 1,000 deaths over the next 10,000 years due to evaporated nuclear waste.

Global warming

Secondly, warmer air can hold more moisture, leading to an increase in heavy rainfall and snowstorms. While this can contribute to flooding, which is a form of water pollution in itself, the heavier rainstorms also increase surface runoff. This runoff water strips nutrients from the soil and picks up pollutants, dirt, and other contaminants, flushing them into nearby bodies of water.

Additionally, global warming is linked to increased drought conditions, reducing water availability and affecting both short-term and long-term water sources. This scarcity can also drive overexploitation of groundwater, which is vulnerable to pollution from various sources, including pesticides, fertilizers, and waste from landfills and septic systems. Once contaminated, groundwater can remain unusable for extended periods, and the pollution can spread as it seeps into other water bodies.

The effects of global warming on water quality are far-reaching, impacting drinking water supplies, food production, property values, and more. It is crucial to address these issues through measures such as reducing CO2 emissions, properly treating wastewater, and transitioning to more sustainable practices to mitigate the impact of global warming on water pollution.

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