How Human Activities Pollute Waterways

Water pollution is the contamination of water bodies, including lakes, rivers, oceans, and groundwater, with harmful substances that degrade aquatic ecosystems and render the water unfit for human use. This pollution primarily arises from human activities, with sewage discharges, industrial waste, agricultural runoff, and urban stormwater runoff being the most significant contributors. These sources introduce contaminants such as chemicals, nutrients, heavy metals, and pathogens into water bodies, leading to adverse effects on both the environment and human health. The impact of water pollution is widespread, causing approximately 1.8 million deaths in 2015 and threatening the drinking water sources of a quarter of the world's population.

Oil spills and leaks

One of the most notable oil spills in history was the Deepwater Horizon/BP spill in the Gulf of Mexico in 2010, which resulted in a controlled in-situ burn of surface oil. Another significant incident was the Exxon Valdez oil spill in 1989, where it was found that the use of high-pressure, hot-water hoses to clean up beaches caused more damage than the oil alone. This led to the Oil Pollution Act of 1990, which established that those responsible for oil spills can be held accountable for the costs of cleanup and restoration.

The magnitude of the impact of oil spills and leaks on water pollution is evident in the statistics. For example, in 1969, a blowout on an offshore platform off the coast of Santa Barbara, California, resulted in over four million gallons of oil being spilled. These types of point source pollution, which also include wastewater discharged by manufacturers, oil refineries, and wastewater treatment facilities, can have far-reaching effects, affecting miles of waterways and oceans.

The environmental and ecological consequences of oil spills and leaks can be devastating. Oil spills can contaminate water sources, killing marine life and causing illnesses in people who come into contact with the polluted water. The clean-up process must also be carefully managed, as some methods can cause further damage to sensitive habitats. Additionally, oil spills can contribute to carbon pollution in the ocean, which already absorbs a significant portion of man-made carbon emissions.

Agricultural runoff

Agriculture is the leading cause of water degradation worldwide. The agricultural sector is the biggest consumer of freshwater resources, with farming and livestock production using about 70% of the world's surface water supplies.

Pollutants from agricultural operations can enter groundwater and degrade sources of drinking water. Bacteria and nutrients from livestock and poultry manure can cause beach and shellfish bed closures and affect drinking water supplies. Pesticide runoff to streams can also pose risks to aquatic life, fish-eating wildlife, and drinking water supplies.

To minimize the risks of agricultural runoff, farmers can adopt soil and water conservation practices to reduce the runoff of sediment, nutrients, bacteria, pesticides, and other pollutants from their operations. Storing livestock manure in lagoons, covered stockpiles, or protected upland areas can help to reduce runoff risks. Implementing carefully tailored systems of conservation practices through an agricultural conservation systems approach can also help to control multiple pollutants.

Industrial and municipal wastewater

Industrial wastewater is a major contributor to water pollution. The escalating global population has led to a higher demand for goods, resulting in rapid industrialization. This, in turn, has increased the number of industrial setups and the amount of industrial waste generated. Industrial wastewater can contain non-biodegradable waste such as heavy metals, pesticides, and plastics, as well as biodegradable compounds like paper, leather, and wool. It can be toxic, reactive, carcinogenic, or ignitable. If not properly treated, discharging this waste into water bodies can have dire environmental and health consequences.

The Environmental Protection Agency (EPA) in the United States is responsible for monitoring water quality and regulating point source pollution, which includes wastewater discharged by manufacturers, refineries, and treatment facilities. While the EPA has made strides in improving wastewater treatment, with billions invested in upgrading plants, there is still a significant amount of pollution from industrial sources. In 2018, the EPA estimated that nearly 11,000 industrial facilities and municipal wastewater treatment plants had illegally dumped pollutants into nearby water bodies.

Mining operations, for example, can generate large amounts of wastewater, impacting surface and groundwater quality and drinking water supplies. Shale gas extraction is another industry that produces wastewater with high concentrations of dissolved solids, radionuclides, metals, and other drilling pollutants. The casual disposal of industrial wastewater used in irrigation can also cause damage to crop quality and enter the food chain.

Municipal wastewater treatment plants also play a role in polluting waterways. In the United States, hundreds of municipalities have combined sewer systems that mix sewage and stormwater in the same pipes. During heavy rainfall or snowmelt, these systems can discharge untreated sewage into nearby water bodies, posing serious health risks due to the presence of bacteria, solids, toxic chemicals, and other pollutants.

To address the issues caused by industrial and municipal wastewater, proper treatment and management strategies are crucial. The toxicity of the wastewater must be neutralized through physical, chemical, and biological means to ensure it can be safely recycled for water conservation. Several countries are developing policies and programs to control water quality, setting standards for the acceptable levels of pollutants in specific water bodies.

Solid debris and plastic pollution

Solid debris, including litter, trash, and construction debris, finds its way into waterways through various means. Land-based sources, such as construction sites, ports, marinas, and industrial facilities, often generate solid waste that is not properly managed or contained. This waste can be blown into waterways or washed in through storm drains and sewers, eventually making its way into rivers, estuaries, and oceans.

Plastic pollution is a growing concern, with plastics being the most common form of marine debris. Plastic debris comes from a variety of land and ocean-based sources, including discarded fishing gear, food containers, packaging, and single-use disposable products. Once in the water, plastic does not fully biodegrade and can have detrimental effects on marine life. Seabirds, fish, and marine mammals often ingest plastic debris, mistaking it for food. Over time, plastics can break down into smaller pieces, known as microplastics, which are then consumed by smaller organisms, leading to a buildup of plastic pollutants in the food chain.

The impact of plastic pollution extends beyond the immediate harm to aquatic life. Plastics in the ocean act as a transport mechanism for invasive species and accumulate pollutants such as persistent organic pollutants, which can be absorbed by marine life. This further endangers marine ecosystems and can potentially impact human health if contaminated seafood is consumed.

The problem of solid debris and plastic pollution in waterways is widespread and requires a multifaceted approach to address it effectively. Public education, improved waste management practices, and the reduction of disposable product usage can all play a role in mitigating this issue. Additionally, increasing research efforts and global knowledge about plastic pollution in freshwater ecosystems is crucial to develop targeted solutions.

Radioactive and nuclear waste

Radioactive contamination is more prevalent in groundwater than surface water. The dumping of radioactive waste into surface water bodies causes water pollution. This has been seen at the Fukushima plant, and also at the Indian Point nuclear power plant on the banks of the Hudson River, where leaks of toxic, radioactive water have contaminated the local soil, groundwater, and the Hudson River itself.

Nuclear waste is not the only way that radioactivity can pollute water sources. The application of radioactive elements in nuclear weapons, X-rays, and medical equipment like MRI machines also exposes humans to radioactivity.

There is hope that the development of new technologies, such as nuclear fusion, could slash the generation of nuclear waste in the future. There is also room for improvement in existing nuclear facilities to help minimise waste generation, for example, by forcing radioactive byproducts to decay faster.

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