Water Pollution: What's Harming Our Local Waterways?

Water pollution is a pressing issue that poses a threat to human health, the environment, and the economy. It occurs when harmful substances, such as chemicals, waste, and microorganisms, contaminate bodies of water, degrading water quality and rendering it unsafe for human use and harmful to the environment. The main sources of water pollution include toxic waste, petroleum, oil spills, sewage, agricultural runoff, industrial waste, and plastic pollution. These pollutants enter water sources through direct inputs from factories, sewage treatment plants, or accidental spills, as well as through indirect sources like farming activities and pollutants released into the air. With less than 1% of accessible freshwater on Earth, addressing water pollution is crucial to safeguard human health, protect ecosystems, and ensure sustainable economic development.

Industrial and mining activities

Industrial activities are a significant source of water pollution, with harmful chemicals and heavy metals finding their way into our waterways. This includes emissions of nitrogen, which cause eutrophication, a process where water bodies are essentially lifeless due to harmful algal blooms that can produce neurotoxins, affecting wildlife and humans. Other industrial pollutants include total organic carbon (TOC), phosphorus, and heavy metals such as cadmium, lead, mercury, and nickel. These contaminants have detrimental effects on the environment and human health, including aquatic life.

The manufacturing sector, a key driver of economic growth, also contributes to water pollution. The use of chemicals and other toxic substances in industrial processes can contaminate nearby water sources, degrading water quality and rendering it unsafe for human consumption or ecological use. Furthermore, industrial waste emissions, including municipal waste, account for a significant proportion of toxins found in water bodies.

Mining activities, a crucial component of industrial development, have significant environmental consequences. The extraction of critical minerals like lithium and cobalt, essential for renewable energy technologies, can strain water supplies and lead to water pollution. Mining processes require substantial water usage, and the resulting waste can contaminate nearby water sources with residual minerals and chemicals.

In regions with already high water stress, increased mining activity can further deplete limited freshwater supplies. Additionally, mining operations generate massive amounts of waste rock and tailings, which can contain acid-generating sulphides, heavy metals, and other contaminants. Improper storage or disposal of these by-products can result in acid mine drainage, polluting waterways with toxic metals and compounds.

Furthermore, the heavy use of water in ore processing and the discharge of mine effluent contribute to water pollution. The environmental legacy of mining activities, often undertaken with little regard for ecological preservation, has led to long-term challenges in maintaining uncontaminated water sources. As a result, the management of water pollution from mine waste can be necessary for decades or even centuries after a mine's closure.

Sewage and wastewater treatment

Domestic sewage, despite being mostly water by weight, contains impurities such as putrescible organic materials, plant nutrients, and disease-causing microbes. Industrial wastewater often includes specific chemical compounds, and storm sewage can carry high levels of suspended solids. When sewage enters water bodies, it consumes oxygen as microorganisms decompose the organic materials, leading to oxygen depletion that harms aquatic life.

Wastewater treatment facilities aim to remove pollutants before releasing the water into local water bodies. However, the treatment process itself can impact water quality. For example, high levels of oxygen-demanding wastes in sewage can deplete oxygen in the water, causing the death of aquatic species. Additionally, treated wastewater can become a source of nitrogen and phosphorus pollution, with some plants being more effective at removing these nutrients than others.

To address these challenges, it is crucial to invest in upgrading and optimizing wastewater infrastructure. This includes implementing innovative practices, such as diverting waste into valuable resources and adopting new technologies to improve nutrient removal. Additionally, preventing stormwater from entering sewers in the first place through natural solutions like planting trees, restoring wetlands, and creating green roofs can effectively expand sewer system capacity.

While progress has been made since the passing of the Clean Water Act in 1972, aging and poorly planned infrastructure remains an issue. Upgrading the nation's wastewater infrastructure will require significant investments and time. In the meantime, strong notification programs are necessary to alert the public about sewage contamination in waterways, protecting their health and galvanizing support for solutions to reduce sewage pollution.

Farming and fossil fuel power plants

Farming practices have a significant impact on water quality. Agriculture accounts for 70% of water withdrawals worldwide, and farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into water bodies. Increased use of nitrogen-based fertilizers and pesticides can drain into nearby water bodies, causing nutrient overload and stimulating algal blooms. These blooms can affect the health of streams and reservoirs, increase drinking water treatment costs, and harm aquatic life and fish-eating wildlife. Pesticides are also widespread in surface water and groundwater, with at least one type of pesticide found in 94% of water samples and over 90% of fish samples from US streams.

Additionally, the expansion of irrigation practices has exacerbated the issue by increasing the transfer of agricultural pollution to water bodies. The growing demand for livestock and aquaculture has further contributed to water quality issues, with fish excreta and uneaten feed diminishing water quality. The increased use of antibiotics and other veterinary medicines in livestock farming has led to the emergence of a new class of agricultural pollutants, which can move from farms into drinking water sources and ecosystems.

Sediment is another leading pollutant in rivers and streams, and while concentrations have decreased in over half of the assessed sites across the contiguous US, increases have occurred in less than 25% of the sites. To mitigate water pollution from farming, various measures can be implemented, such as establishing protection zones along watercourses and buffer zones around farms, improving irrigation schemes, and adopting off-farm techniques like riparian buffer strips.

Fossil fuel power plants also contribute significantly to water pollution. The burning of fossil fuels releases nitrogen oxides, sulfur dioxide, particulate matter, carbon monoxide, and mercury into the atmosphere, leading to smog, acid rain, and respiratory issues. These pollutants eventually find their way into water sources, causing further harm. Oil spills and fracking fluids from fossil fuel extraction and transportation can contaminate groundwater and drinking water, with toxic substances like arsenic, lead, chlorine, and mercury posing significant risks. Ocean acidification, caused by the absorption of carbon dioxide from the atmosphere, is another consequence of fossil fuel use, threatening marine life.

Additionally, mining and drilling for fossil fuels destroy animal habitats, and the increased carbon dioxide levels in the ocean lead to a more acidic environment. According to the National Oceanic and Atmospheric Administration (NOAA), the ocean absorbs about 30% of the CO2 released into the atmosphere, resulting in a 30% increase in ocean acidity since the Industrial Revolution. This has far-reaching consequences for marine ecosystems and the planet's overall health.

Oil spills and leaks

The transportation and transfer of oil increase the risk of oil spills. Up to 15 transfers may be required between ocean tankers, pipelines, trains, and trucks. As the number of transfers increases, so does the risk of spilling oil. Oil spills can also occur due to operational or human error, unpreparedness, and natural disasters. For example, the Deepwater Horizon and Ixtoc I oil spills took months to stop, with enormous amounts of oil leaked.

Oil spills have severe environmental, economic, and social consequences. They can harm marine life, ruin beaches, and make seafood unsafe to eat. Oil penetrates the structure of the plumage of birds and the fur of mammals, reducing its insulating ability and making them more vulnerable to temperature changes and less buoyant in the water. Oil spills can also cause respiratory and reproductive problems in humans, as well as liver and immune system damage.

Cleanup and recovery from an oil spill are challenging and depend on several factors, including the type of oil spilled, the temperature of the water, and the types of shorelines and beaches involved. Cleanup activities can never remove 100% of the spilled oil, and scientists must ensure their actions do not cause further harm. Oil spills are difficult to clean up, and the process can take weeks, months, or even years.

To prevent oil spills, it is essential to properly dispose of oil, paint, and hazardous chemicals. Oil spills from individual vehicles, lawnmowers, and ships contribute to water pollution and can have detrimental effects on the environment and human health.

Radioactive and toxic waste

Radioactive contamination, also known as radiological pollution, is the presence of radioactive substances in solids, liquids, or gases, including the human body. Radioactive contamination can be caused by both natural and man-made sources. Natural sources include the decay of naturally occurring radionuclides in rock and soil, such as radium, uranium, and radon, which can dissolve in water and contaminate groundwater and surface water. On the other hand, man-made sources of radioactive contamination include nuclear weapon testing, nuclear power plants, and the improper disposal of radioactive waste.

Nuclear weapons testing and nuclear power plants can release radioactive waste into the environment, which can contaminate water sources. For example, the Fukushima nuclear accident in 2011 released radioactive material that contaminated land and water, displacing 110,000 people. Similarly, the Chernobyl disaster released large amounts of radioactive iodine-131, causing severe health risks to the surrounding population.

Improper disposal of radioactive waste is a significant concern. Radioactive waste can persist in the environment for thousands of years, making it a challenging and costly issue to address. The Hanford nuclear weapons production site in Washington, for instance, is facing a $100 billion cleanup of 56 million gallons of radioactive waste, expected to last through 2060.

Radioactive contamination can also occur through atmospheric deposition, where dry and wet deposition carries radioactive nuclei into surface water. Additionally, the use of radioisotopes in industries and scientific laboratories can contribute to water contamination. For example, sewage treatment plants can generate sludge containing radioactive elements, such as 40K and 7Be, which can contaminate surface and groundwater if not properly treated.

The presence of radioactive contaminants in water poses a severe risk to human health. Radioactive elements can accumulate in the body, particularly in certain organs, leading to health issues. The Environmental Working Group estimates that over 170 million Americans are at risk of increased cancer rates due to radioactive elements in their drinking water. Therefore, it is crucial to implement prevention strategies, such as greater monitoring and stronger regulations, to protect water sources from radioactive contamination and safeguard public health.

Frequently asked questions