How Plastic Is Causing a Wave of Cancer at Sea

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How Plastic Is Causing a Wave of Cancer at Sea

By Karina Jimenez

There’s a war raging at sea. It is not between battleships, planes, and aircraft carriers. It is not between predator and prey in the marine food chain.  

Instead, marine life has found itself in a battle for survival. A battle against cancer in the sea. One within a war that is quietly yet increasingly happening beneath the ocean’s surface.

Though humans are the cause, we can also be the solution if we act now.

Tumors in Sea Animals

All living things consist of cells. Cancer is the uncontrolled dividing and growth of cells. When a mass of cells grows unchecked they form tumors or big lumps in the bodies of organisms.

Tumors steal nutrients from healthy cells, disrupting the normal functions of the body.

Humans are familiar with hearing about cancer in other humans. But the truth is, sea life is also falling victim to cancer.

The photos of fish with bulging bellies. Disfigured sea lions and turtles with malformed fins are becoming more frequent.

These grotesque pictures firmly put in view what is happening in our oceans.

The shifting chemical makeup of the vast sea is making an unhealthy environment. Now the sea creatures who live in the sea are getting sick as a result.

Seafood lovers and divers might be the first to defend the ocean. Next would be the sea animals who call it home. But the health of the oceans should be on everyone’s mind.

The oceans help keep the weather balanced. They keep the air moving, and terrestrial ecosystems healthy and thriving.

The connection between the oceans and terrestrial life depends on balance in the sea.

When cancer begins to affect the health of the oceans and the animals who live there, we are all affected.

This is why in modern times we need to think in terms of “One World Ocean” and not many smaller oceans.

Cancer in Sharks and Other Marine Life

For a long time, people thought that sharks couldn’t get cancer. As a result, sharks were hunted for their cartilage with the belief that it could cure cancer in humans.

Shark hunters spread this belief to make a quick profit. But the truth is sharks can develop cancerous tumors as well.

For the last 150 years, scientists have had evidence of sharks having tumors. Recently, a photo of a great white shark in Australia with a large tumor on its lower jaw surfaced. It brought the matter to everyone’s attention once again.

It is estimated that 100 million sharks are killed globally each year by humans. That’s a lot of sharks!

Many times they are indirectly caught and killed by humans. They can be caught in gillnets. These are large nets that trap sea creatures indiscriminately.

Sharks are accidentally caught in trawls as well. Trawls are similar to gillnets but are dragged along the ocean floor.

Sharks are also threatened by the use of longlines. Longlines are fishing lines with thousands of baited hooks. The average longline is 28 miles long!

In addition, the habitat of sharks is crumbling as the chemical make-up of our One World Ocean is changing.

In many of these situations, humans don’t intend for sharks to get captured. However, sharks are often targeted directly in the fishing industry too.

Overfishing is a massive contribution to declining shark populations. People indiscriminately kill sharks for their fins. The do this in order to provide consumers with the ever-popular shark-fin soup.

Fishermen also harvest shark cartilage to sell for medicinal reasons. There are many who want shark cartilage for its healing properties. Traditional Chinese medicine teaches that shark cartilage can help fight cancer.

Other schools of thought maintain that cartilage cannot cure cancer. Regardless, the overfishing of sharks continues, which is driving some species towards extinction.

More alarming is the fact that cancer in sharks is becoming more common. It is often the result of humans carelessly discarding plastics and chemical waste.

Creatures of the ocean have simple defense mechanisms against aquatic pollutants. They have cellular pumps called efflux transporters that help remove toxins from their bodies.

These pumps can become inundated by the large amounts of toxins floating in the oceans. When this happens, the pumps are rendered ineffective. When toxins cannot be removed, DNA damage can occur. This causes cancer in fish and sharks alike.

What is the relationship between plastic and chemical waste causing cancer in the ocean?

Cancer-Causing Pollutants

You have seen it. Plastic floating along with the current of the river. Or perhaps you have seen a plastic bottle stuck at the mouth of a storm drain. Plastics that enter our waterways eventually reach the ocean. They are slowly broken down to microplastic shreds. Sunlight and knocking into hard or abrasive surfaces in waterways causes this.

These bits and pieces of plastic act like magnets and attract chemicals in the water. In 1979 legislation in the U.S was passed to ban one of these chemicals – Polychlorinated Biphenyl. However, today it still poses a threat to marine life.

Polychlorinated Biphenyl (PCB) was used to manufacture many household appliances. It was used worldwide and now can be found all over the globe.

This is an alarming discovery as PCBs have been shown to directly cause cancer in marine life. They eat microplastics contaminated with it thinking the microplastics are food.

The problem continues to be magnified by our inclination to buy and live with all things plastic. Plastic is a cheap and convenient way for getting many things done. Its overuse is driving a wave of cancer through the ocean’s ecosystem.

Another chemical, Dichloro-Diphenyl-Trichloroethane (DDT), is an insecticide that has proliferated. It was widely used from the 1940s to the 1970s. It was useful for agricultural purposes and to fight against malaria in humans. It is toxic to humans, sea animals, and other wildlife.

DDT is most harmful to creatures that live higher up on the food chain. As they dine on prey from lower in the food chain, the presence of DDT in their bodies gets more concentrated.

A scientist of environmental health at San Diego State School of Public Health, Euhna Hoh, investigated. She tested eight dolphins that washed up on the shores of California. She was surprised to see they had high levels of DDT and wondered where such an enormous source of the chemical could be coming from.

According to an article in the LA times, there is a massive dumping site for DDT near San Catalina Island. Estimates of the amount of DDT go from 870 to 1,450 tons.

When DDT was banned in 1972, Montrose — the chemical’s producer — started dumping the chemical into the shallow waters near Catalina. Workers cut into the barrels to make them sink allowing the DDT to seep out.

The article goes on to explain that the result is a DDT dumping site so deep it outmatches superfund sites in the New York and Boston Harbors. The site is also incredibly toxic; some samples are 40 times more concentrated than the superfund site in nearby Palo Verde.

“Nobody in their worst nightmares ever thought there would be half a million barrels of DDT waste dumped into the ocean off of L.A. County’s coast, ” says Mark Gold, a marine scientist who fought against DDT dumping.

An uncontained and unknown amount of DDT on the ocean floor is great cause for concern as more sea creatures ingest pieces of plastic contaminated with the chemical.

DDT will slowly degrade over time. This provides a small glimmer of hope for the future. PCBs on the other hand are a massive problem. You can read more about the dumping near Catalina in our post How Barrel After Barrel of DDT Ended Up On the Ocean Floor.

It has been found in all corners of the world and is soaked up by the 8 million tons of plastic that is deposited into the oceans each year.

The question is not if we should remove the plastic in the ocean, it is now whether it is even possible. The amount of plastic in the ocean is so large and the ocean itself is so vast no one really knows how or where to start.

But the good news is there’s a way to stop the problem from its source and stop cancer from entering the ocean in the first place.

How You Can Help Stop Plastic Pollution

Humans who have cancer have the benefit of being able to receive life-saving treatments. Sea life, on the other hand, is more likely to succumb to the effects of cancer.

For the animals in our oceans, the next step is simple. We need to fight the issue at its source by preventing plastic from flowing into the oceans in the first place.

It all starts with you.

There are many ways you can help keep sea life healthy and cancer-free.

You can stop the spread of cancer in the sea by reducing the use of plastic in your home. Instead of using plastic bags at the grocery store, take reusable bags.

Reduce the use of plastic water bottles by bringing water from home in reusable water bottles.

In short, avoid using plastic items that can only be used one time.

Donating to Ocean Blue Project is also an amazing way to support keeping the oceans healthy. Ocean Blue Project removes 1 pound of plastic for every dollar donated.

These are small financial investments that will make a big impact and greatly reduce the need and use of plastic.

More solutions to stopping the spread of cancer require nothing more than a few moments of your time.

It can be as simple as picking up plastic debris and tossing it into a nearby trash can. Or you can join cleanups organized by your community to clear out plastic along the rivers or ocean beaches. Don’t have a cleanup in your area? Ocean Blue Project will guide you about how to organize one.

Taking time to become informed and spreading the word about organizations like Ocean Blue Project can make a huge difference as well.

Our One World Ocean is a beautiful and mysterious place. It may seem like a distant world, but more now than ever we are seeing how connected we are to it. And how much we depend on its deep blue waters.

Each one of us can make these small changes to reduce the use of plastic. We do it not only for the health of the creatures in the ocean but for the health and safety of everyone.


Author Bio: Karina was born and raised in the Pacific Northwest. She loves hiking, kayaking and going to the beach at the Oregon Coast.