The Ocean's Pollution: Sources And Solutions

Oceans cover 70% of the Earth's surface and play a vital role in the health and well-being of our planet. However, human activities have led to significant ocean pollution, threatening the marine environment and human health. One of the primary sources of ocean pollution is plastic waste, which enters the oceans through rivers, maritime transport, and improper waste disposal on beaches and inland. Other sources include industrial waste, sewage, oil spills, and agricultural runoff. The accumulation of pollutants in the ocean leads to increased ocean temperatures, ocean acidification, and the ingestion of microplastics by marine life, posing risks to marine ecosystems and human health.

Rivers, maritime transport, and beach rubbish

Rivers are a major source of plastic waste in the oceans. Research suggests that over 1000 rivers are accountable for nearly 80% of global annual riverine plastic emissions, which range between 0.8 and 2.7 million metric tons per year. The remaining 20% of plastic emissions are distributed over 30,000 rivers. The River Yangtsé in Asia is the most polluting river, depositing 330 million kilograms of waste into the sea annually. Other highly polluting rivers include the Ganges in Asia, which carries 120 million kilograms of plastic waste into the sea each year, and the Nile and Amazon, which are among the handful of large continental rivers that transport 90% of river-borne plastic waste into the oceans.

Rivers in tropical regions continuously disgorge plastic into the sea, while rivers in temperate regions typically flush most plastic during a single month, usually in August, or during events such as flash floods. Small rivers that flow through densely populated urban areas, rather than the largest rivers, are the main distributors of plastic waste. For example, the 16-mile-long Pasig River in the Philippines has displaced the 3,915-mile-long Yangtze as the most polluted river by plastics.

Maritime transport is another significant contributor to plastic pollution in the oceans. A recent study published in Nature magazine found that waste originating from boats is responsible for almost half of the pollution in the North Pacific Garbage Patch. The Great Pacific Garbage Patch is the largest garbage patch in the world, measuring 1.6 million square kilometers and weighing 80,000 tonnes.

Beach rubbish is also a major source of plastic pollution in the oceans. Littering, inadequate waste management, and industrial activities contribute to plastic waste on beaches, which is then directly or indirectly dumped into the oceans. A 2019 survey found that thousands of tiny industrial plastic pellets were contaminating the UK's coastlines, affecting nearly three-quarters of its beaches annually. Globally, nearly 400 tonnes of plastic waste is generated every year, of which only about 9% is recycled, leading to most of the waste being dumped, incinerated, or discarded in the environment.

Industrial waste and fossil fuels

Oceans, which make up 70% of the Earth's surface, are incredibly polluted. Industrial waste and fossil fuels are major contributors to this crisis. Industrial waste can be both hazardous and non-hazardous. Hazardous waste includes ammonia, solvents, and petroleum. When these chemicals are released into the environment, they cause significant water pollution. For example, pollutants like total organic carbon (TOC) and compounds containing nitrogen and phosphorus can lead to eutrophication, which often results in the death of a body of water. Eutrophication occurs when a body of water becomes enriched with nutrients and minerals, promoting the growth of toxic algae and plants that increase carbon dioxide levels in the water. This, in turn, leads to decreased sunlight and hypoxia (lack of oxygen), which is detrimental to aquatic life.

In addition to industrial waste, fossil fuels also play a significant role in polluting the oceans. The burning of fossil fuels, such as coal, oil, and gas, releases carbon dioxide into the atmosphere, contributing to global warming and ocean temperature rise. This has multiple effects on marine life. Firstly, it causes glaciers and permafrost to melt, releasing contaminants trapped in the ice. Secondly, it increases the amount and diversity of disease-causing marine microorganisms. As carbon dioxide levels rise in the atmosphere, the ocean absorbs more, leading to ocean acidification, which is harmful to coral reefs and calcium-containing creatures like plankton. Ocean acidification can also make certain heavy metals and compounds more dangerous.

Furthermore, the extraction, transportation, and refining of fossil fuels carry the risk of oil spills, which have devastating consequences for marine life and ecosystems. Oil spills can destroy habitats, erode shorelines, and result in beach, park, and fishery closures. Additionally, fossil fuels are the source of most plastics, with over 99% of plastics being made from them. Plastic pollution in the ocean is a significant issue, with microplastics finding their way into the water through rivers, wind, and rain. These microplastics can then be ingested by marine life, polluting the food chain.

To address these issues, it is crucial to reduce carbon dioxide emissions and transition to cleaner energy sources. The EU has implemented a "Zero Pollution Action Plan" to reduce water pollution, and other regions should follow suit with similar initiatives. Proper waste management and responsible industrial practices are also essential to minimizing the impact of industrial waste and fossil fuels on ocean pollution.

Sewage and septic systems

Sewage is one of the largest contributors to marine pollution. Over 80% of global sewage is dumped into the seas without adequate treatment. Sewage contains a wide array of pollutants that are harmful to ocean health and public health. These include water, nutrients, organic matter, bacteria, viruses, parasites, endocrine disruptors, suspended solids, micro and macro plastics, microfibers, industrial chemicals, slaughterhouse wastes, sediments, and heavy metals.

Sewage enters the ocean in a variety of ways. The largest volume of waste discharged into the oceans is sewage, which enters the ocean readily in areas without adequate sanitation and wastewater treatment facilities. However, sewage can also easily be discharged where treatment facilities do exist due to aging infrastructure, facility malfunctions, and heavy rains that overwhelm systems and lead to combined sewer overflows. Sewage can also discharge directly from sewage treatment plants via outfalls (treated or untreated), as it is at many wastewater treatment plants along all coastal regions in the United States.

Sewage can be discharged directly into upstream ecosystems like streams, rivers, wetlands, and estuaries before ultimately reaching the coast and ocean. It can be indirectly washed into rivers via runoff or stormwater or released directly into the ocean, which is often the case in low-income cities and towns where open sewers are the norm. In some cities, expansion of the sewage systems is necessary to prevent flooding, which results in sewage and wastewater flowing into the sea.

The tremendous volume of sewage discharged into the ocean kills marine life, degrades critical habitats, and harms the ecosystems upon which humans depend, while remaining a threat to human health. Sewage pollution can cause eutrophication due to nutrient overload that depletes oxygen, kills marine flora and fauna, and disrupts ecological processes. It can also cause harmful algal blooms that produce toxins or physical material that kill marine life, close beaches, and can cause human disease through direct exposure and the consumption of contaminated seafood. Sewage pollution can also cause physical and biological damage to coral reefs, seagrasses, and salt marshes, increasing the risk of disease and local acidification.

Sunscreen and other topicals

Sunscreen and other topical products contribute significantly to ocean pollution. When swimmers jump into the ocean, some of the sunscreen they've applied washes off into the water. It is estimated that roughly 4,000 to 6,000 tons of sunscreen enter oceans worldwide every year, with higher concentrations in shallow areas popular with swimmers.

The key to sunscreen's sun-blocking power is a list of molecules that either absorb or repel ultraviolet (UV) rays. Most sunscreens contain molecules that protect against skin cancer-causing UVA rays and sunburn-causing UVB rays. However, some of these molecules, such as oxybenzone, octinoxate, avobenzone, Benzophenone-1, Benzophenone-8, OD-PABA, 4-Methylbenzylidene camphor, 3-Benzylidene camphor, nano-Titanium dioxide, nano-Zinc oxide, and Octocrylene, have been found to be harmful to marine life.

For example, oxybenzone can cause deformities in coral larvae and baby corals, damage coral DNA, and impair the growth of green algae, an essential part of the food web. Octinoxate degrades into a chemical called benzophenone, a known carcinogen and hormone disruptor. Additionally, evidence shows that sunscreen pollution can have major impacts on the entire ecosystem, affecting corals, fish, mammals, and even at-risk species like the Hawaiian green sea turtle.

To reduce the impact of sunscreen on the ocean, people can opt for reef-friendly sunscreens that contain physical blockers like zinc oxide and titanium dioxide instead of synthetic UV-absorbing compounds. Protective clothing, such as UV-rated swim shirts or rash guards, and avoiding peak sunlight hours can also help keep harmful chemicals out of the ocean.

Other topical products, such as insect repellents, can also contribute to ocean pollution when they wash off into the water. While this may be unintentional, it can still affect marine life and ecosystems. Therefore, it is essential to be mindful of the ingredients in topical products and their potential impact on the environment.

Littering and inadequate waste management

Marine litter or debris is any persistent, manufactured or processed solid material that is discarded, disposed of, or abandoned in the marine and coastal environment. Solid waste on beaches and in the ocean is a significant issue, causing public concern regarding recreational use and impacting the tourism industry.

Littering is a prevalent issue, especially in regions lacking proper waste management infrastructure. According to the UN Environment Programme, approximately two billion people worldwide lack access to solid waste collection services. This lack of infrastructure leads to uncontrolled dumping of waste, with plastic waste being a significant contributor to ocean pollution. Plastic waste can come from a variety of sources, including industrial processes, general littering, and inadequate waste management.

Inadequate waste management systems play a significant role in the pollution of oceans. This can be due to a lack of priority given to solid waste management compared to other national needs, resulting in citizens disposing of waste in gullies and along riverbanks. Rivers are a significant factor in carrying plastic waste to the sea, with the five most polluted rivers contributing millions of kilograms of waste to the ocean annually. In addition, waste left on beaches, such as plastic water bottles and food packaging, can be carried by wind and waves into the ocean, breaking down into microplastics that form floating islands of trash.

The implementation of waste management programs can be challenging due to the lack of infrastructure in some regions, insufficient funding, and inadequate public awareness and education on proper waste management. However, successful waste management programs in some European and developing countries have reduced ocean pollution by encouraging recycling and proper disposal methods.

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