Eighty percent of pollution to the marine environment comes from the land. One of the biggest sources is called nonpoint source pollution, which occurs as a result of runoff. Nonpoint source pollution includes many small sources, like septic tanks, cars, trucks, and boats, plus larger sources, such as farms, ranches, and forest areas. Millions of motor vehicle engines drop small amounts of oil each day onto roads and parking lots. Much of this, too, makes its way to the sea.

Some water pollution actually starts as air pollution, which settles into waterways and oceans. Dirt can be a pollutant. Top soil or silt from fields or construction sites can run off into waterways, harming fish and wildlife habitats.

Nonpoint source pollution can make river and ocean water unsafe for humans and wildlife. In some areas, this pollution is so bad that it causes beaches to be closed after rainstorms.
More than one-third of the shellfish-growing waters of the United States are adversely affected by coastal pollution.

Correcting the harmful effects of nonpoint source pollution is costly. Each year, millions of dollars are spent to restore and protect areas damaged or endangered by nonpoint source pollutants. NOAA works with the U.S. Environmental Protection Agency, Department of Agriculture, and other federal and state agencies to develop ways to control nonpoint source pollution. These agencies work together to monitor, assess, and limit nonpoint source pollution that may result naturally and by human actions.

Ocean pollution: 11 facts you need to know
The ocean is the origin and the engine of all life on this planet — and it is under threat.

A big part of the problem: pollution.

So how does trash get into the ocean? It’s dumped, pumped, spilled, leaked and even washed out with our laundry. Each year, we expose the world’s waterways to an increasing variety of pollutants — plastic debris, chemical runoff, crude oil and more.

Fortunately, it’s not too late to clean up our act. Share the dirty truth about ocean pollution and help make a difference.

1.Oil spills aren’t the big(gest) problem.

Headline-grabbing oil spills account for just 12 percent of the oil in our oceans. Three times as much oil is carried out to sea via runoff from our roads, rivers, and drainpipes.

2.More plastic than fish.

Eight million metric tons: That’s how much plastic we dump into the oceans each year. That’s about 17.6 billion pounds — or the equivalent of nearly 57,000 blue whales — every single year. By 2050, ocean plastic will outweigh all of the ocean’s fish.

3.Five garbage patches.

There’s so much junk at sea, the debris has formed giant garbage patches. There are five of them around the world, and the largest — the Great Pacific Garbage Patch — includes an estimated 1.8 trillion pieces of trash and covers an area twice the size of Texas.

4.Plastic poses a double danger.

Ocean trash can be broken into smaller pieces — known as microplastic — by sun exposure and wave action, after which it can find its way into the food chain. When it eventually degrades (which takes 400 years for most plastic), the process releases chemicals that further contaminate the sea.

5.China, Indonesia top the trash tally.

More plastic in the ocean comes from China and Indonesia than anywhere else — together, they account for one-third of plastic pollution. In fact, 80 percent of plastic pollution comes from just 20 countries, including the United States.

6.Pollution is in fashion (literally).

With each load of laundry, more than 700,000 synthetic microfibers are washed into our waterways. Unlike natural materials such as cotton or wool, these plasticized fibers do not break down. One study showed that synthetic microfibers make up as much as 85 percent of all beach trash.

7.Most ocean trash sits on the bottom.

As unsightly as ocean pollution is, what we can’t see may be worse: 70 percent of ocean garbage actually sinks to the seafloor, meaning we’re unlikely to ever be able to clean it up.

8.Even nutrients can become harmful.

When dumped at sea in large amounts, agricultural nutrients such as nitrogen can stimulate the explosive growth of algae. When the algae decomposes, oxygen in the surrounding waters is consumed, creating a vast dead zone that can result in mass die-offs of fish and other marine life.

9.The number of dead zones is growing.

In 2004, scientists counted 146 hypoxic zones (areas of such low oxygen concentration that animal life suffocates and dies) in the world’s oceans. By 2008, that number jumped to 405. In 2017, in the Gulf of Mexico, oceanographers detected a dead zone nearly the size of New Jersey — the largest dead zone ever measured.

10.The oceans are losing mussel mass.

One effect of greenhouse emissions is increased ocean acidification, which makes it more difficult for bivalves such as mussels, clams and oysters to form shells, decreasing their likelihood of survival, upsetting the food chain and impacting the multibillion-dollar shellfish industry.

11.We’re making a racket down there.

Noise pollution generated by shipping and military activity can cause cellular damage to a class of invertebrates that includes jellyfish and anemones. These animals are a vital food source for tuna, sharks, sea turtles and other creatures.