Everything You Need to Know About Ocean Pollution

Ocean Health Guide Part 1: What Pollutes Our Oceans and Why?

As a local dive shop, we are very invested in the health of our oceans here at Dive Maui. We are constantly looking into our own practices and how we can best improve them for the betterment of both our clients and conservation purposes. We’ve come a long way, but there is further still to go.

Luckily, we aren’t alone in our passion for protecting our precious marine environments, as we constantly are surprised at the curiosity that our clientele has shown when it comes to ocean conservation. But, at this point you’re probably asking yourself, what are the main sources of pollution and what pollutants should I be aware of?

Unfortunately, the most common sources of pollution are man-made such as sewage dumping, land runoff, or industrial chemical waste. Other issues include the incursion of noise pollution and litter into our waterways.

So, if you’re ready to learn more about ocean pollution and its impacts, be sure to read on as we dive into all the details next!

What is the Ocean’s Biggest Source of Pollution?

Our oceans suffer from a variety of ills. Some pollutants are easily identified, such as plastic waste, others, such as sound pollution, can be no less pernicious but are nonetheless often more difficult to identify.

Some of the most common sources of ocean pollution include:

Sewage Dumping

In many locations—even the famed Mediterranean—raw sewage is still released untreated straight into waterways. This has a disastrous impact on our oceans. The practice of dumping sewage can see everything from human waste to industrial byproducts discharged into rivers and streams that will eventually flow into the sea. The result changes the water in ways that can degrade the quality of life for both aquatic plants and animals.


Runoff From Land

Just as raw sewage can introduce a variety of pollutants into our oceans, so too can runoff from land. This typically occurs when rain or wind picks up man-made contaminants as it flows overland towards a culvert or stream, eventually joining the water cycle—and spreading harmful pollution in the process. 

One common example of this would be the detrimental effect that road salt can have on the amount of chloride in nearby bodies of water like streams or lakes during the winter. This isn’t a trivial issue, as chloride is toxic and will permanently pollute water. And lest you think this has no potential impact on you, the implications for drinking water supplies can be frightening.


Chemical Pollutants

Industrial discharge of pollutants has been a reality for our oceans for decades. And even if polluting originated long in the past, the consequences for the present may still be continuing. Just look at the recent discovery of a cache of barrels of DDT off the coast of California’s Santa Catalina Island for an illustration of the unknowable potential depth of this problem.

And chemical pollutants can also be a primary contributor to issues such as the eutrophication of the oceans, which occurs when substances such as nitrogen-rich fertilizers change water quality to promote explosive and deadly algae blooms.


Noise Pollution

Everyone is aware that sound is greatly affected by water. Less commonly considered is the impact that human activity can have on marine life via this noise pollution. Yet, human noise pollution can greatly impact the ability of animals such as whales and dolphins to communicate. 

To be certain, these are highly social animals who find it just as hard to converse near sources of underwater noise pollution as you would standing under a Boeing 747. If you’d like to learn more about why sound is so important in the ocean, this article from NOAA does a good job of explaining the basics.



The amount of litter that finds its way into our oceans is almost unfathomable. In fact, getting a good idea of the problem can be difficult, as numbers are hard to pin down. A recent study estimated that 192 coastal countries introduce anywhere between 4.8 and 12.7 million metric tons of plastic waste into our oceans alone—a number that is only thought to have increased in the interim. We will look at what this category of pollutant is typically comprised of in more detail next.


What are the Most Common Ocean Pollutants?

One of the most common pollutants found in ocean environments is litter. And 80% of all trash found in water can be traced to a land-based source. You may have noticed that things around your own town seem a little dirtier lately. Detritus and debris large and small have recently been found illegally dumped at higher numbers and even smaller trash, such as food wrappers and masks, seems to have multiplied. 

And you don’t need to be near an ocean to notice what appears to be an uptick in the amount of trash, as the problem can be found nearly nationwide. If you think the streets have seen more trash, just imagine how our oceans are faring. A 2020 survey from Keep America Beautiful detailed an estimated there 26 billion pieces of litter along the country’s waterways alone.

Even before recent events, the U.S. has had a woefully inefficient waste management system, one that relies on landfills or shipping refuse overseas. And while pinpointing how human refuse ends up in our oceans is a notoriously tricky task, it seems obvious that carting garbage barges all across the seven seas must at least somewhat contribute to the problem.

Besides general trash, such as cigarette butts, plastic bags, fishing lines, food containers, and beverage bottles, other common ocean pollutants include:

  • Detergents
  • Fertilizers
  • Oil
  • Industrial Chemicals
  • Human Waste
  • Pharmaceuticals
  • Sunscreen
  • Algae Blooms


Caring For Our Oceans is Our Full-Time Job

Now that we know a little bit more about ocean pollution, it is time to consider steps we can all take to help tackle this problem. This is something we spend a lot of time thinking about here at Dive Maui (we consider it an important part of our job) and the topic will be the focus of our next article, part two in the series, which we hope you keep an eye out for.

Until the next time we see you on the island, as always, thank you for reading and Aloha!


Dive Maui / Hawaiian Rafting Adventures

1223 Front Street
Lahaina, Maui, Hawaii 96761
Tel: (808) 661-7333


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