Rivers: Polluted And Plundered

Rivers are a source of life, providing drinking water, irrigation, and income for millions of people worldwide. However, human activities have severely polluted these vital waterways with chemicals, waste, plastics, and other pollutants. This widespread problem of river pollution is endangering the health of both humans and aquatic ecosystems, and it is primarily caused by sewage, industrial waste, agricultural runoff, and plastic pollution. With less than 1% of Earth's freshwater accessible, addressing river pollution is crucial to ensure the availability of clean water for current and future generations.

Industrial and sewage waste

The impact of industrial wastewater on freshwater ecosystems is profound. When industries discharge untreated wastewater, the high levels of pollutants can severely affect key parameters such as oxygen demand and suspended solids, making it difficult for aquatic life to survive. The self-purification processes of rivers slow down, and the community structure within the river can change dramatically.

Sewage pollution, also known as municipal wastewater, is another critical concern. Sewage can contain human waste, household chemicals, personal hygiene products, pharmaceuticals, and other contaminants that can endanger human health and the environment. According to the United Nations, more than 80% of the world's wastewater flows back into the environment without proper treatment, and this figure exceeds 95% in some least-developed countries. In the United States, despite wastewater treatment facilities reducing pollutants through processing, the nation's aging and overwhelmed sewage systems still release over 850 billion gallons of untreated wastewater annually.

The consequences of sewage pollution are dire. Waterborne pathogens, including disease-causing bacteria and viruses from human and animal waste, can lead to illnesses such as cholera, giardia, and typhoid. Legionnaires' disease, a severe form of pneumonia, is another example of the health risks posed by contaminated water sources. To protect public health and the environment, it is essential to treat sewage and industrial wastewater effectively before discharge.

Furthermore, the development of large towns and urban sprawl near freshwater sources contributes to the problem. Poorly planned infrastructure can increase stormwater surges into sewers, exacerbating the pollution discharged into rivers and other water bodies. Implementing solutions such as natural areas, street-side swales, pervious concrete sidewalks, and green roofs can help manage stormwater and reduce sewer overflows.

Agricultural chemicals

Groundwater can become polluted when contaminants such as pesticides and fertilizers make their way into an aquifer, rendering it unsafe for human use. Pesticides like atrazine are commonly used in agriculture and are often detected in surface water. Exploding demand for food with high environmental footprints, such as meat from industrial farms, is contributing to unsustainable agricultural intensification and water-quality degradation. This intensive agriculture relies heavily on pesticides and chemicals, which can find their way into rivers and other water bodies.

The GLRI Edge-of-Field Monitoring project aims to identify and reduce agricultural sources of excess nutrients that threaten the health of the Great Lakes. Simple techniques such as riparian buffer strips or constructed wetlands can help reduce pollutants entering surface water bodies. Integrated farming systems, where waste from one enterprise becomes inputs for another, can also help optimize resource use and reduce pollution.

In some developing countries, the construction of large towns close to freshwater sources results in untreated water being cycled back into the water system. This chemical runoff from the midwestern US flows into the Gulf of Mexico, contributing to the Dead Zone. Our rivers are drowning in chemicals, waste, plastic, and other pollutants, posing a significant threat to human health and the environment.

Plastic and other pollutants

Other pollutants, such as chemicals, waste, and microorganisms, also play a significant role in river pollution. Chemical pollution can come from agricultural runoff, industrial discharge, and improper disposal of chemicals. These chemicals can include pesticides, fertilizers, and pharmaceuticals, which can contaminate rivers and pose a risk to both human and animal health.

Industrial waste and sewage are also major sources of river pollution. Untreated sewage can contain high levels of bacteria, viruses, and parasites, which can be harmful to human health. In developing countries, the lack of proper wastewater treatment infrastructure can lead to polluted water being released back into rivers and other water bodies.

Additionally, stormwater runoff can carry pollutants such as oil, heavy metals, and sediment into rivers. Green infrastructure practices, such as rainwater collection and filtration, can help mitigate this issue by reducing the amount of polluted stormwater entering rivers.

River pollution has severe environmental, health, and economic impacts. It can lead to the extinction of fish species, damage to plant life, and the contamination of drinking water sources. The health risks associated with polluted water include waterborne diseases such as diarrhoea, cholera, dysentery, typhoid, and poliomyelitis. The World Bank has also highlighted the economic consequences of deteriorating water quality, which can stall economic growth and exacerbate poverty.

Mismanaged wastewater

Rivers are a source of freshwater, which covers less than 1% of the Earth's freshwater. Yet, rivers, reservoirs, lakes, and seas are increasingly being polluted by chemicals, waste, plastic, and other harmful substances. This widespread problem of water pollution is detrimental to human health and the environment.

In developing countries, the construction of large towns close to freshwater sources poses a challenge. The wastewater from homes and industries is often not properly treated, leading to the release of untreated sewage into rivers and other water bodies. This is a major concern as untreated sewage contains harmful pathogens and bacteria that can cause various diseases.

The agricultural sector is also a significant contributor to water pollution. Fertilizers, pesticides, and animal waste from farms wash into rivers and streams during rainfall, leading to nutrient pollution. This excess of nitrogen and phosphorus can cause algal blooms, which are toxic to both humans and wildlife.

Additionally, plastic waste is another critical factor in river pollution. Mismanaged plastic waste has been found to strongly correlate with the presence of macroplastics in rivers. This includes items such as water sachets, which are commonly found in river catchments.

The problem of mismanaged wastewater is not limited to developing countries. In the United States, for example, wastewater treatment facilities process a significant amount of wastewater daily. However, due to aging infrastructure and overwhelmed systems, they also release a substantial amount of untreated wastewater into waterways each year.

Climate change

One of the primary ways climate change is exacerbating river pollution is through the increase in extreme weather events, such as floods and droughts. Floods can overwhelm sewer systems, causing raw sewage and polluted stormwater to be discharged into nearby rivers and streams. In the case of droughts, lower water levels mean there is less water to dilute pollutants, leading to higher concentrations of contaminants.

The combination of higher temperatures and increased nutrient pollution from agricultural runoff can also lead to more frequent and severe algal blooms. These blooms can reduce dissolved oxygen levels in the water, causing fish kills and damaging aquatic ecosystems. Climate change is also increasing evaporation rates from reservoirs and lakes, further reducing water availability and potentially concentrating pollutants.

The impacts of climate change on water pollution have far-reaching consequences for communities and ecosystems. It threatens public health, weakens economies, and decreases the quality of life in many places. It is crucial that communities take steps to safeguard their water supplies and address aging infrastructure to mitigate the effects of climate change on their water resources.

Frequently asked questions