Human Activities: Polluting Our Waterways

Water pollution is a pressing issue that poses a significant threat to both human health and the environment. It occurs when harmful substances contaminate bodies of water, degrading water quality and rendering it unsafe for human use and detrimental to aquatic ecosystems. Human activities play a pivotal role in water pollution, encompassing a range of factors from industrial waste to agricultural runoff and sewage systems. These human-induced contaminants introduce toxic chemicals, bacteria, and pathogens into water sources, leading to dire consequences for human health, aquatic life, and the economy.

Industrial waste

When industrial waste is not treated properly or not treated at all, it can easily pollute freshwater systems. Most major industries have treatment facilities for industrial effluents, but small-scale industries often cannot afford the necessary investments in pollution control equipment. Technologies have been developed to address solid waste and other environmental and recycling problems, but proper waste management systems are not always in place.

Sewage and wastewater

Inadequate wastewater treatment facilities and poor sewage systems are prevalent issues. In the Bahamas, for example, only 15.6% of the population has access to sewage collection services, and 44% of sewage treatment plants are in poor condition. In Haiti, there are no sewage collection services, and a large portion of the population uses latrines and septic tanks, with 80-90% of the solids dumped illegally into rivers and seas. This results in elevated levels of pathogenic microorganisms, such as viruses and bacteria, which can lead to health issues and even deaths.

Sewage-related debris, such as tissue paper, wipes, condoms, and sanitary products, can also cause blockages and flooding, further polluting the environment. Additionally, sewage and wastewater can introduce a range of toxic contaminants, including pharmaceuticals, microplastics, heavy metals, and endocrine disruptors, which threaten food and water security and harm marine species.

The discharge of untreated sewage into water bodies is a significant concern. For instance, along the Colombian Caribbean coast, 472,653 cubic meters of untreated sewage is discharged into the sea daily, leading to mass fish mortalities and eutrophication. Eutrophication, caused by sewage and fertilizer runoff, has also impacted the coral reefs in Barbados, changing the species composition of the corals.

Furthermore, sewage and wastewater can contribute to habitat loss and extinction. Studies have linked wastewater pollution to seagrass die-offs, harmful algal blooms, and weakened reefs. Ignoring this issue has led to closed beaches, collapsed fisheries, and harmful algal blooms, as seen in Long Island due to nitrogen pollution from untreated sewage.

Oil spills

The consequences of oil spills are far-reaching and impact both the environment and human society. Oil spills can harm sea creatures by ruining their insulating and waterproofing abilities, making them more vulnerable to temperature changes and reducing their buoyancy in the water. Ingesting oil can be toxic to these animals, and the damage to their habitats can slow the long-term recovery of their populations. Oil spills also damage plant life, with saltwater marshes and mangroves being particularly vulnerable.

The economic impact of oil spills is significant. Oil-coated beaches and populated shorelines can severely affect tourism and commerce. Power plants and other utilities that rely on or discharge seawater may also be disrupted. The cleanup and recovery process after an oil spill is challenging and expensive, and it can take weeks, months, or even years to complete. Physical cleanups are costly, and the methods used must be carefully chosen to avoid causing further harm.

To address the problem of oil spills, it is crucial to improve waste management systems and enforce regulations to prevent the negligent release of petroleum products into the environment. By reducing the frequency and impact of oil spills, we can mitigate their ecological, economic, and societal consequences.

Pesticides and fertilisers

Pesticides are materials intended to control, prevent, kill, reduce, or repel pests. They can be made from natural ingredients or synthetic chemicals. All pesticides are toxic to some degree, and their overuse or misuse can harm the environment and human health.

Pesticides can contaminate water in several ways. Firstly, they are often applied directly to agricultural land, non-crop land, and urban areas, and can subsequently seep into the groundwater. This can occur through applications onto crop fields, seepage of contaminated surface water, accidental spills and leaks, improper disposal, or injection waste material into wells. Pesticides can also enter water sources through storm drains, indoor drains, and irrigation, wind, or rain, which can carry them from hard surfaces like sidewalks and driveways into nearby waterways.

The use of pesticides has helped make the United States the world's largest producer of food. However, it has also been associated with adverse effects on the environment and human health. Pesticides can be transported by water, contaminating other locations and causing health problems. They can also alter the genetic characteristics of frogs, with even low doses causing male frogs to develop female organs.

Fertilisers can also contaminate water sources. They can enter storm drains, indoor drains, and groundwater through improper disposal and runoff. Like pesticides, they often end up in drainage points that flow directly into rivers, streams, lakes, and oceans. Fertilisers can be deadly to aquatic organisms, especially tiny creatures known as aquatic invertebrates. When these invertebrates are killed, it affects the entire aquatic food chain.

To prevent pesticides and fertilisers from polluting waterways, it is important to apply them under the right weather conditions, such as calm weather with wind speeds below 10 mph and no rain or snow forecast. Additionally, limiting the use of highly toxic pesticides like pyrethroids, organophosphates, and fipronil can help minimise their impact on water sources.

Radioactive waste

Radioactive contamination of water sources has serious consequences for both marine life and humans. Radioactive isotopes can move up the food chain, being ingested by seaweed, plankton, and mollusks, and then transferred to fish, which are in turn eaten by larger fish. Radioactive iodine, for example, is taken up by the thyroid in humans and marine mammals and can have adverse health effects.

The impact of radioactive pollution on marine life and humans is not always immediately apparent and can be difficult to study. For instance, while the Soviets dumped large quantities of radioactive material into the Arctic Ocean, it has not been definitively shown to have caused widespread harm to marine life, possibly due to the containment vessels around the dumped reactors preventing the escape of radiation. However, some die-offs of marine life in the Barents Sea and White Sea have been attributed by Russian scientists to pollution or nuclear contamination.

To prevent radioactive contamination of water sources, drinking water suppliers engage in various practices. These include identifying the path that water travels to reach the drinking water system to determine areas where drinking water could become contaminated, preparing for emergencies such as floods or spills, and participating in voluntary programs that help keep contaminants out of drinking water. Public drinking water systems also regularly test and filter out contaminants, including radionuclides, to ensure that the water meets all federal, state, and local drinking water standards.

Frequently asked questions