ocean dumping

Preserving our Earth’s oceans is crucial to the survival of millions of marine animals, fish, and plant species. Human life, too, is inextricably linked to the sea through the food and economic opportunity it provides.

However, the accumulation of waste and hazardous materials in the ocean can damage entire habitats and ecosystems. Through widespread water pollution and large amounts of ocean dumping, we are jeopardizing the health of one of our Earth’s most precious resources.

While ocean dumping is not a new concern, awareness is absolutely critical if we can hope to preserve our oceans.

This guide will help you understand this complex issue, and dive into the main causes of ocean dumping around the world. You’ll also learn the many far-reaching effects of ocean dumping, and how you can help curb them.

What is ocean dumping?

It’s important to know what ocean dumping really entails to understand its leading causes and how they impact our planet.

So, what counts as ocean dumping?

Ocean dumping is defined as the deliberate disposal of hazardous wastes at sea from vessels, aircraft, platforms, or other human-made structures.

In fact, in the U.S., dredged material is the primary substance dumped into the ocean, at about 80% with several million tons being dumped into the seas each year. So, where does this hazardous substance come from?

Dredged material is sediment excavated or otherwise removed from the bottoms of ocean waters to maintain navigation channels and docks. This sediment is removed from our waterways to support a network of coastal ports and harbors for commercial, transportation, national defense, and recreational purposes.

About 20 to 22% of dredged material is dumped into the ocean, and about 10% of all dredged material is polluted with heavy metals such as cadmium, mercury, and chromium, as well as hydrocarbons like heavy oils, nutrients (including phosphorus and nitrogen), and organochlorines from pesticides.

In addition, radioactive wastes from worldwide nuclear power plants also find their way into our oceans. There is growing evidence that both short and long-lived radioactive elements can be absorbed by phytoplankton, zooplankton, kelp, and other marine life and then be transmitted up the food chain to fish, marine mammals, and humans.

Other materials disposed of in the ocean include human remains for burial at sea, vessels, man-made ice piers in Antarctica, and fish wastes.

What are the main causes of ocean dumping?

The hazardous waste dumped into the ocean comes from several different sources, but they all relate to human activity. Whether accidental oil spills or mining activities, manmade vessels are undoubtedly causing the most damage to the ocean.

Direct dumping of wastes in the ocean

While a large number of individuals are responsible for directly dumping garbage into the ocean – on average, a half of a kilogram – the majority of direct ocean dumping is done by commercial vessels and large-scale operations.

Earthworks found that each year, mining companies dump more than 220 million tons of waste rock and tailing, the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore, into our oceans and rivers.

Oil spillages from offshore rigs

Oil spills are some of the primary causes of hazardous materials being dumped in the ocean around the world. While often not intentional, these fuel spillages cause untold damage to marine and human life.

Oil leaks and spills happen in many ways, whether it be by accident while mining oil from the Earth or from oil rig malfunctions. When oil spills occur, they often kill thousands of marine life species at once.

oil spill around a sinking ship
Oil spills cause significant damage to marine life and the ocean ecosystem
Source: Flickr / NOAA Images

Many newsworthy disastrous accidental oil spills come to mind, like the 1991 Gulf War oil spill that resulted in 240 million gallons of oil being intentionally spilled along the Gulf Coast. The effects of this incident lasted over a year after the original spill: oil continued to spill out of contaminated coastal sediments for over a year after the war.

However, this was not an isolated incident – there have been at least 44 major oil spills since 1969 in the U.S., and every year, it is estimated that more than 1 million gallons of oil contaminate our oceans.

Oil spills harm animals, humans, and plants in two primary ways:

  • Fouling or oiling. This occurs when oil physically harms a plant or animal and impacts their chance of survival. For example, oil can coat a bird’s wings and leave it unable to fly or strip away the insulating properties of a sea otter’s fur, putting it at risk of hypothermia.
  • Oil toxicity. Oil consists of many different toxic compounds that can cause severe health problems like heart damage, stunted growth, immune system damage, and even death.

The clean-up efforts that attempt to rectify these oil spillages are typically costly and unable to truly resolve the disastrous effects of fuel spilling into ocean water. In fact, clean-ups can never remove 100% of the oil released into the ocean.

Pollutant runoff from land

All of the Earth’s waters, including our oceans, are connected through the water cycle. This means that all pollutants from land-based activities that result in soil or air pollution eventually end up contaminating our oceans.

Primarily, contaminants are transported through land runoff.

When it rains, runoff or stormwater travels off of roofs and driveways onto our streets, where it picks up fertilizer, oil, pesticides, dirt, bacteria, and other pollutants as it makes its way through storm drains and ditches to our streams, rivers, lakes, and the ocean.

There are several key contributors to these pollutants that are released into our oceans: agricultural and industrial operations and improperly managed sewage.


As a result of improperly managed large-scale agricultural operations, pollutants like sediment, nutrients, pathogens, pesticides, metals, and salts are released into the Earth’s soil and water through runoff.

tractor pesticides on a field
Large-scale agriculture seems impossible without harmful pollutants like pesticides and fertilizers

According to the United States Geological Survey, about half a million tons of pesticides, 12 million tons of nitrogen, and 4 million tons of phosphorus fertilizer are applied annually to crops in the continental U.S.

These chemicals, in turn, pass through every component of the water system, including our air, soil, streams, and wetlands, and can often end up being dumped in our oceans. 

Industrial operations at sites around the world are major causes of water pollution. Because many industrial sites produce toxic chemical waste and pollutants, these materials can easily sink into soil and waters that lead directly to oceans or lakes.

Improperly managed sewage

Wastewater from bathrooms, factories, and commercial activities usually contains biological contaminants like bacteria and pathogens.

Despite the many wastewater treatment plants that operate around the U.S. and the world, these systems are often aging. They cannot handle increased capacity: sewage treatment systems release more than 850 billion gallons of untreated wastewater and runoff yearly.

oil spills into a sewer drain
Car oil spills end up in the sewer system, and, if managed improperly, can pollute the environment

Even when used water is treated, damaging contaminants can remain and still cause harm when released into larger causes of water like our oceans.

Lack of regulation and education

Countries around the world, including the U.S., have a long history of dumping toxic waste into our oceans with the false belief that if these toxic materials were released far enough away, they would not affect us or marine life at all.

Trash, radioactive wastes, munitions, chemical and industrial wastes and more were simply disposed of in the ocean, with little to no concern for the negative impacts. This trend was based on the false assumption that marine waters had an unlimited capacity to mix and disperse wastes, according to the U.S. Environmental Protection Agency (EPA). 

The 1960s and 1970s saw millions of tons of waste dumped into the ocean, and the numbers from 1970 are shocking:

  • 38 million tons of dredged material (34 percent of which was polluted)
  • 4.5 million tons of industrial waste
  • 4.5 million tons of sewage sludge (significantly contaminated with heavy metals)
  • 0.5 million tons of construction and demolition debris

In addition, EPA records indicate that more than 55,000 containers of radioactive waste were dumped at three ocean sites in the Pacific Ocean between 1946 and 1970.

You may be thinking: why was all of this harmful ocean dumping allowed to continue?

In the U.S, in particular, there was no federal regulation that regulated ocean dumping at all. One such policy, however, was only enacted in 1972.

The Marine Protection, Research and Sanctuaries Act (MPRSA) says that the U.S. is responsible for regulating the dumping of all materials which would adversely affect human health, welfare or amenities, the marine environment, ecological systems, or economic potentialities.

Regulations like MPRSA and others set forth by governing bodies worldwide have, unfortunately, been unable to do enough to eliminate all ocean dumping on a global scale.

Regulating ocean dumping is a challenging task for governments – reporting, compliance, and enforcement challenges persist, and some countries are not able to succeed because of economic or developmental constraints.

Mining activities

Mining activities have impacted thousands of miles of streams and rivers throughout the eastern and western U.S. (and the world) due to active and historic mining of iron, copper, lead, gold, platinum, silver, and other materials.

In the ocean, waste from these mining activities can contain up to three dozen dangerous chemicals that eventually make their way into marine life and people that eat fish. It’s not hard to imagine what disastrous effects these polluted fish could have – both on land and in the sea.

an illustration of the deep-sea mining
A schematic of manganese nodules mining on the deep sea floor.
Deep-sea mining has a range of negative impacts that disrupt aquatic life.
Source: Wikimedia / MimiDeepSea

But how do these chemicals make their way into oceans?

When drill mining occurs on land, especially near rivers and streams, metal ores are often deposited in these waterways, eventually leading to the ocean. This trend has led to large concentrations of contamination in certain bodies of water, so much so that they are no longer fit for swimming, eating, or drinking.

In addition, as more and more raw materials are needed for technologies such as electric vehicle batteries, many corporations are considering deep-sea mining for resources like lithium, manganese, nickel, and cobalt.

However, experts warn that this mining activity is sure to destroy marine habitats with noise pollution and contribute to ocean dumping with sediment plumes and chemicals.

How does ocean dumping affect our health and our environment?

Ocean dumping from any source is a critical danger to human and marine health and makes it difficult to preserve and protect our environment.

Because the ocean is a complex, connected system of plants, crustaceans, mammals, fish, and more, there is no element of the seas that a not impacted by ocean dumping, water pollution, and air pollution.

Each element of the ocean’s ecosystem feeds the others: from the plants that feed fish, to the fish that feed mammals. Not to mention the humans around the world that rely on the ocean’s marine life to eat and sustain a living.

So, how exactly does ocean dumping impact the environment? Let’s dive in.

Ocean dumping has a detrimental effect on the world’s marine life

The Safe Water Drinking Foundation notes that the ocean is an interwoven ecosystem in which every biotic and abiotic factor influences the other. When one habitat is rendered toxic from chemicals and pollution, all other marine systems that rely on it are unable to survive.

For example, many marine species such as sea turtles, fish, shrimp, crabs, and others rely on seagrass for survival. However, today, seagrass is being lost at a fast rate: one study estimated that a football field-sized area of seagrass is lost every half hour, whether it is torn out by dredging and choked by polluted runoff.

The loss of such an important food source is incredibly alarming and is already having impacts on marine life today: fish and mammals are forced to migrate and seek out other food sources.

The disposal of trash such as plastic and metal are also negatively impacting marine life. Waste can trap, harm, and kill animals and fish when they become entangled.

grey fish caught in a plastic glove
Single-use plastic ends up in the ocean water killing fish and other marine inhabitants

In addition to waste, chemicals like household cleaners are harming the world’s marine life as well. Roughly two thirds of the world’s marine life have been threatened with chemicals humans throw down the drain every day.

When ocean dumping harms marine life and damages their habitats, food sources, and waters, several other effects occur:

  • Coral reefs are destroyed
  • Ecological imbalance
  • Loss of biodiversity in the ocean
  • Human livelihoods are lost or hindered

It’s clear that continuously depositing hazardous wastes into our oceans is already causing irreparable damage to marine ecosystems around the world.

Ocean dumping depletes oxygen levels in seawater

Another direct impact of ocean dumping is the deoxygenation of our oceans: according to the IUCN, the oxygen content of the ocean has declined by around 2% since the middle of the 20th century overall, while the volume of ocean waters wholly depleted of oxygen has quadrupled since the 1960s.

Hazardous wastes from ocean dumping and water pollution leads to lower oxygen levels in the sea. Less oxygen affects the health of marine life and plants that they depend on.

Aside from potentially eradicating marine species, there are several other dire consequences that result from the decline of oxygen in the ocean:

Adverse effects on human health

The ocean is home to a vastly complex interconnected ecosystem, but humans also play a role in this system. Our activities, whether on land, in the air, or in the sea, affect the oceans’ health and, in turn, our lives.

Our oceans provide for families and communities worldwide: today, 10-12% of the world’s population – 870 million people – depend on fisheries and aquaculture careers.

In addition, over three billion people worldwide rely on wild-caught or farmed fish from the ocean as a significant source of protein. Both of these critical elements of human life are impacted by pollutants spread by ocean dumping.

Hazardous wastes move up the marine food chain until the fish that end up in our farmers’ markets and grocery stores are eventually contaminated. Fish can no longer be caught and sold when marine habitats are no longer safe for consumption. Billions of lives are in danger of being negatively affected.

In addition, research has found that the decrease in oxygen in the oceans from pollution has a direct impact on photosynthetic marine bacteria that produce the oxygen we breathe in. The bacteria, Prochlorococcus, is not only critical to the marine food web but also is responsible for up to 10% of total global oxygen production.

What can we do to prevent ocean dumping?

Ocean dumping is clearly a danger to human and marine life around the world. Though some regulations are in place, ocean dumping is still taking place on a large scale, and more must be done to prevent it from happening.

Luckily, there are a few tactics that the world’s leaders and individuals can adopt to prevent ocean dumping from further damaging our environment.

Raise awareness and educate

Education about ocean dumping is crucial for everyone to understand the urgency of its effects. Whether it be through educational books, online resources, or community events, the importance of preserving our oceans cannot be understated.

As an individual, you can work to amplify anti-ocean dumping campaigns such as ‘Ditch Ocean Dumping’ on social media and support the work of environmental advocates through donations or volunteering.

Dispelling misinformation about marine life and the environment can also help more people understand the direct impact of depositing harmful wastes into our seas.

awareness sign on beach
Raising awareness about the problem is essential to prevent ocean pollution


Around the world, there is a lot of room for improvement when it comes to fully curbing illegal and harmful ocean dumping and ensuring that the effects of ocean dumping are widely known. Some regulations are enacted that aim to stop ocean dumping, but not all countries have such rules, and enforcement is uneven worldwide.

In the U.S., The Marine Protection, Research and Sanctuaries Act (MPRSA), also known as the Ocean Dumping Act, regulates the disposition of any material in the ocean, unless expressly excluded under the MPRSA.

The London Convention, and later The London Protocol, is one example of legislation enacted on a global scale. In 1996 the protocol was updated to prohibit all dumping of wastes, including those from land-based mining operations.

However, as sensible as this protocol sounds, some countries have still not ratified the London Protocol or simply do not have any regulations regarding ocean dumping.

Globally, the more countries that participate in and implement these agreements will ensure that less ocean dumping occurs. You can help curb ocean dumping by advocating for your local area and country to comply with these regulations.


Divestment has proven to be a successful method for change in movements throughout history, and many are calling for investors to withdraw their investments from companies that utilize fossil fuels or operate in unethical ways.

Financial institutions are already using their influence to help protect our oceans by divesting their money in those who dump hazardous wastes. For example, major Norwegian asset manager Storebrand divested from Chinese firm China Metallurgical Group Corporation over ocean dumping at one of their mines in Papua New Guinea.

Earthworks has also highlighted other financial institutions that have issued new policies that prohibit or severely restrict the financing of submarine mine waste disposal. Some of these companies include Standard Chartered, Citigroup, and Credit Suisse.

Final thoughts on ocean dumping

Large-scale human activities like mining, dredging, and accidental oil spills primarily cause ocean dumping. These operations directly deposit hazardous materials into the ocean or waterways that make their way into the ocean.

Ocean currents carry toxic materials far from the original dumping location, spreading negative effects like deoxygenation throughout the entire marine ecosystem.

Through education, awareness, and increased action on a global scale, we can make a difference in preserving our oceans. The majority of our planet is made up of water – so why shouldn’t we protect it like we try to preserve our species and environment on land?

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