Water Pollution: Power Sources That Taint Our Oceans

Water pollution is the release of substances into bodies of water that make water unsafe for human use and harm aquatic ecosystems. Power plants are the largest contributors of toxic pollution to water in the US. The wastewater from power plants is pumped directly back into its source, often a river, lake, stream, or ocean. This water is considerably warmer, creating thermal pollution, which can increase the heart rate of sea animals and decrease their fertility. The water is also often dangerously toxic for humans and the environment, containing heavy metals such as lead, arsenic, mercury, and selenium. These pollutants can also end up in our drinking water, making municipal water bills more expensive as water treatment plants may have to spend more to deliver safe water.

Coal-fired power plants

The United States Environmental Protection Agency (EPA) has recognized the impact of coal-fired power plants on water pollution and has set effluent limitation guidelines (ELGs) for the steam electric power industry. These guidelines, issued in 2024, aim to regulate wastewater discharge and protect water resources under the Clean Water Act. The ELGs are based on the performance of demonstrated wastewater treatment technologies and are intended to achieve significant pollutant reductions economically.

However, in 2025, the EPA announced that it would reconsider the 2024 water pollution limits for coal-fired power plants. This decision was made to align with President Trump's "Unleashing American Energy" Executive Order, which aims to ensure reliable and affordable electricity for Americans. While the EPA maintains its commitment to protecting the environment, this deregulatory move has sparked concerns among environmental advocates.

It is worth noting that coal-fired power plants not only pollute water sources but also contribute significantly to air pollution. Fine particulate matter (PM2.5) released into the air from coal-fired power plants has been associated with increased mortality risks. Research has estimated that between 1999 and 2020, approximately 460,000 deaths could have been prevented in the absence of emissions from these power plants. The installation of pollution control technology, such as emissions scrubbers, has been shown to reduce associated deaths.

Oil spills

Accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities are the most common cause of oil spills. Oil tanker accidents can result in the release of large quantities of oil into the ocean, while operational discharges from vessels account for a significant portion of oil spills as well. Natural seeps from seafloor rocks are also a significant source of oil spills, contributing approximately 600,000 tons of oil annually on a global level. However, these natural seeps are considered less problematic because ecosystems have adapted to such regular releases.

While there is no thoroughly satisfactory method for cleaning up major oil spills, responses focus on containing and removing the oil to allow for the resumption of economic activity and the natural recovery of the marine environment.

Thermal pollution

In the United States, about 75 to 80 percent of thermal pollution is generated by power plants, with the remainder coming from industrial sources such as petroleum refineries, pulp and paper mills, chemical plants, steel mills, and smelters. Nuclear power plants are the greatest point source of thermal pollution, requiring 30%–100% more cool water than other power plants. The water used for cooling in power generation from fossil fuels, biomass, or nuclear energy can raise the temperature of the surrounding water bodies, as the water is pulled in to absorb excess heat and is then returned to the source at a higher temperature.

The impact of thermal pollution is more severe in smaller bodies of water, and even a small increase of 1-2 °C in water temperature can be lethal for some sensitive species. It can also affect the growth and reproduction of other aquatic and amphibious organisms. For example, a study of Lake Stechlin in Germany found that after a nuclear power plant was removed, a 2.33 °C increase persisted in surface water during the winter, and a 2.04 °C increase persisted in deep water during the summer. Thermal pollution can also increase the water temperature downstream of power plants, as they receive warmer waters. This has been observed along the Mississippi River.

Climate change can be considered a nonpoint source of thermal pollution, as it affects freshwater habitats extensively. The rise in water temperatures due to global warming is a form of thermal pollution. Additionally, climate change can lead to cold-water thermal pollution by causing glaciers to melt faster.

To reduce thermal pollution, individuals can switch to clean energy sources such as wind and solar power, which do not produce heated wastewater or emit greenhouse gases.

Radioactive waste

The management and disposal of radioactive waste are complex and highly regulated due to the potential risks associated with radiation exposure. In the United States, the Department of Energy (DOE) is responsible for managing much of the nation's radioactive waste. This includes providing repositories for high-level waste, operating the WIPP facility for defence-related transuranic waste, and overseeing the disposal of low-level waste. The Nuclear Regulatory Commission (NRC) and the Conference of Radiation Control Program Directors (CRCPD) also play crucial roles in ensuring the safe handling and transportation of radioactive materials.

While there have been concerns and debates about the potential risks of radioactive waste, particularly in the context of the nuclear industry, it is important to note that there has been no recorded instance of radioactive release causing harm to people, property, or the environment during the transport of nuclear materials. The International Atomic Energy Agency (IAEA) has developed packaging standards to ensure the safe transport of radioactive waste, even under extreme accident conditions. Additionally, the producers of radioactive waste are typically responsible for bearing the costs of disposal, and countries with nuclear power programs make periodic updates to their cost estimates.

Solid waste

Inadequate solid waste management can lead to pollution when trash and debris are directly dumped into water bodies or carried by animals, wind, or rainfall into rivers, lakes, and oceans. This form of pollution is known as "land pollution becoming water pollution." Solid waste, such as plastics and electronic equipment, can break down and leach harmful chemicals into the water, causing toxic contamination.

The agricultural sector, including farming and livestock production, is a significant contributor to solid waste pollution. Fertilizers, pesticides, and animal waste from these operations wash into waterways during rainfall, leading to nutrient pollution and algal blooms that are harmful to both people and wildlife.

To address the issue of solid waste pollution, sludge-to-energy systems have been proposed and implemented in some countries. These systems capture the methane released during the decomposition of organic waste in landfills and use it as a source of energy. This approach not only reduces methane emissions, a potent greenhouse gas, but also provides economic benefits by reducing the reliance on costly and polluting forms of power, such as fossil fuels.

However, the adoption of sludge-to-energy systems is still limited, and improper waste management practices persist. For example, in China, over 70% of municipal solid waste is landfilled or dumped, sometimes illegally. This highlights the need for improved waste management practices and the widespread implementation of sustainable solutions to address solid waste pollution and its impact on water bodies.

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