Our lakes and rivers are probably cleaner than they were 50 years ago. Our oceans have probably become more polluted between all the plastic and oil that we have spilled in them. Water pollution remains a problem. Here are some of the causes of water pollution.
In some cases, it might seem that prevention of water pollution is out of our hands. We can easily think that industry and government bear all the responsibility for it. But in most cases, we have an influence. In some cases, our homes are a leading source of water pollution. Hundreds of millions of homes either contributing to water pollution or seeking to avoid it have a huge impact.
Water pollution from agriculture
Agriculture accounts for 70% of the world’s withdrawals of water. And so it is among the leading causes of water pollution. Farms pollute water bodies through the discharge of fertilizers, pesticides, herbicides, drug residues, manure, and more.
In most developed countries, and in many emerging nations, agricultural pollution contaminates water more than population or industry. Nitrite from agriculture is now the most common chemical contaminant of groundwater.
Among other things, agriculture causes eutrophication. That is, the water contains such a heavy concentration of nutrients that it encourages too much algae growth in the water. Animal life dies from lack of oxygen.
Prevention of water pollution from agriculture
Our lawns, gardens, parks, and golf courses don’t count as agriculture, but they add to the burden on our waterways when we overuse chemical fertilizers and pesticides. Especially if the way we water them causes excessive runoff.
As individual households, we can’t solve agricultural water pollution, but we can avoid contributing to it. Prefer natural fertilizers, such as Milorganite—composted sewage sludge from Milwaukee. (Any other wastewater system can compost and sell sludge, but they can’t use Milwaukee’s trademark.)
Water pollution from oil spills
Oil spills may be one of the first causes of water pollution that comes to mind for many people. Big oil spills, such as Deep Water Horizon or Exxon Valdez, remain in our consciousness for a long time. And indeed, they are the most serious spills simply because of the concentration of oil in a small area.
But oil that goes down the drain accounts for about six times more over the years. Routine leakage from ships and boats puts still more oil in the water.
To begin with, oil travels from place to place in tanker ships, trucks, railroads, and pipelines. And it gets transferred from one mode of transportation to another many times from the oil well to the end user.
Leaks frequently happen in the transportation chain. And it’s impossible to clean them up without a lot of it washing into storm drains.
Since oil is organic, bacteria will eventually biodegrade it. In the meantime, the oil kills plants and animals, either by coating them, depriving them of air, or poisoning them. It also pollutes drinking water.
Quite apart from the problems caused by oil drilling and coal mining, burning these fuels adds to water pollution. They release nitrogen oxides into the atmosphere. The nitrogen oxides return to land and water in the form of acid rain. The excess nitrogen contributes to harmful algae blooms. The excess acidity is toxic to aquatic life.
Prevention of water pollution from oil spills
For ordinary citizens, preventing water pollution from oil includes handling it intelligently and taking good care of machinery. We can also take steps to conserve energy in our homes, which includes buying Energy Star appliances, and to save gas when we drive.
When a car or truck has an oil leak, oil drips on streets and highways. Lawnmowers, boats, and other machines that use oil and gasoline also leak. Boats leak directly into a lake. The other leaks get washed into storm sewers by rainwater.
Routine maintenance of equipment on land, sea, or air also leaks oil.
And then there are the morons who change the oil in their cars themselves and dump the used oil down a drain. Oh, and other morons who dump paint.
With luck, wastewater treatment plants can remove the oil, but they have to do something with the sludge. The oil doesn’t just go away.
Water pollution from mining
Mining requires, and sullies, lots of water to process ore. After mines close, they fill up with water. Whether working, closed, or abandoned, mining causes water pollution. Until recent decades, the mining industry didn’t care about water quality. Most people, far removed from mines, didn’t notice.
As mining becomes more mechanized, it can process more ore and surrounding rock than ever before. And technology enables mines to process low-grade ore that was never profitable before. These technological advances negate many of the improvements that came with environmental regulation and corporate environmental commitment.
In the process of digging any kind of ore out of the ground, miners must remove large quantities of other rock. Producing one ton of copper can entail 99 tons of waste. The ratio of gold to waste is even less.
Mine wastes produce water pollution from four basic sources: sulfuric acid, heavy metal contamination, processing chemicals, and erosion plus sedimentation. Dealing with polluted water that has accumulated in abandoned mines is fraught with danger.
In 2015, the EPA was working to drain water that had collected in the closed Gold King Mine near Silverton, Colorado.
Its contractors inadvertently destroyed a plug that had been constructed years earlier to contain the water in the mine. Three million gallons of heavily polluted water flowed into the scenic Animas River.
Prevention of water pollution from mining
Since few if any readers of this post have any responsibility for mine safety, there doesn’t seem to be much point in describing how to mitigate water pollution from mines.
We can, however, try to recycle as much metal as possible to cut down on the demand for newly mined metal. Unfortunately, given how much we use batteries, lithium recycling is not yet economically viable. Just be sure not to put any dead batteries in the trash.
Water pollution from radioactive waste
Radioactivity may be one of the least obvious causes of water pollution. Nuclear wastes have found their way into waterways as long as we’ve been dealing with nuclear energy. Deliberate dumping accounts for a lot of it.
Nothing, however, created more water pollution from radiation than the destruction of the Fukushima nuclear plant in 2011. Many point to that disaster as a caution of the inherent dangers of nuclear energy. Actually, it illustrates an even more insidious problem.
The engineers who designed the plant knew that it sat near a fault line. So they took care to design a facility that could withstand a major earthquake. They neglected to consider that earthquakes often trigger tsunamis. So they built a major nuclear complex near the coast with no protection against tsunamis at all.
If they had designed tsunami protection as well as earthquake protection, the plant might still be operating normally. As it is, we’ll never know how well they planned the earthquake protection.
Beyond the seawater that engulfed the plant, it was necessary to use vast quantities of water to keep the reactors cool. And that water flowed into the ocean. Atmospheric fallout likewise settled in the water.
Whatever inherent problems nuclear power presents, it’s nothing compared to the inherent problems of human negligence and incompetence.
Meanwhile, different nuclear wastes have different half-lives. Whether short-lived or long-lived elements, however, plankton absorb them. Other marine life eats the plankton. The radioactivity travels up the food chain.
The less spectacular nuclear waste most likely enters freshwater—and groundwater. So far, radioactive water pollution has not contaminated public water supplies. How long will our luck hold?
Water pollution from sewage
Here’s one of the causes of water pollution that is literally at our fingertips. We use water and it flows into sewers and from there to wastewater treatment plants. So it doesn’t have a chance to pollute our lakes and rivers, right?
Every year 860 billion gallons of sewage manages to bypass treatment plants. That’s enough to cover the entire state of Pennsylvania in ankle-deep sewage.
How does this happen?
- Sewers sometimes back up into people’s basements.
- Sewers sometimes overflow into streets or parks and from there into streams.
- Some communities have combined sanitary and storm sewers. Excessive rain can force the wastewater treatment plant to allow some raw sewage to bypass it.
After a while, the stench will dissipate. The germs don’t. People might go swimming in a lake contaminated with raw sewage and never know it. When they get sick in a day or two, they may never realize that the illness came from their swim.
The CDC has estimated that nearly half a million cases of waterborne illnesses came from polluted drinking water between 1985 and 2000. Human sewage has caused most of them.
Many communities had no sewage treatment plants until after the Clean Water Act became law in 1972. By this time, many of the plants built then are reaching the end of their useful lives. Some are even older. We desperately need to upgrade our infrastructure in general and, to minimize water pollution, our sewage infrastructure.
Besides building and repairing wastewater treatment, restoring natural areas and wetlands can take the pressure off. A single tree with a 30-foot crown can soak up enough water to keep 4,600 gallons of it out of the sewers. Wetlands, natural or artificial, can impound even more stormwater. And green roofs prevent the runoff of silt and chemicals.
Prevention of oil pollution from sewage
Perhaps the most important step individual households can take to minimize sewage pollution is to be very careful of what we put in drains or flush down the toilet. And that includes the chemicals we can buy to unclog drains. They’re caustic. And you’re putting those poisons into the sewer. The water in the sewer will dilute them, but they’re still there.
If you don’t have standing water in the drain, try this instead: Dissolve baking soda in very hot water and pour it into the drain; pour some vinegar in behind it. Flush with hot water. Or you can always buy the same kind of snake a plumber would use to clear it. No chemicals at all.
Water pollution from plastic
We can also have a direct effect on one of the most insidious causes of water pollution: the amount of plastic that gets into the oceans. The US is the twelfth leading source of plastic in the oceans. The top five account for about 60% of the plastic trash in the oceans. China itself accounts for about half of that. The US ranks as high as it does because of the combined length of our coastlines.
It helps to realize that plastic can get into the ocean from far inland. Imagine a plastic bottle falling into a small creek in western Idaho. Unless somehow it gets taken out of the water, it will flow from that creek into a larger river and from there through more rivers out to the Pacific Ocean. If the creek is on the other side of the Continental Divide, the bottle will go to the Gulf of Mexico instead.
These statistics, by the way, don’t count pollution from microplastics. We used to buy personal care products with microbeads, but now manufacturing them is illegal.
That leaves us with our laundry. Washing clothes takes small amounts of fabric, microfibers, from each item in the load. Microfibers from natural fabrics biodegrade. Plastic microfibers don’t. And no wastewater treatment plant can remove them. They all flow into the oceans.
Marine animals that feed on plankton eat microplastic but can’t digest it. Marine animals that eat other marine animals eat all the plastic in them, too. Plastic bioaccumulates. That is, animals do not excrete it. Their bodies store it. And humans are at the top of the food chain.
Prevention of water pollution from plastic
So while we can’t do much about the plastic that flows into the ocean from China, Indonesia, or anywhere else in the world, we can work at decreasing the United States’ contribution.
- Use reusable shopping bags and avoid the ones the stores want to give you.
- Reject single-use plastic items, including straws, spoons, razors, and more.
- Prefer any other packaging to plastic whenever possible.
- Buy clothes made of natural fabrics in preference to nylon or polyester.
- Wear clothes more than once before you wash them. Smaller or less frequent loads of laundry release less microplastic.
- Participate fully in your local recycling program, following all the local guidelines.
- Don’t litter. And if you see litter, pick it up and dispose of it properly. Your wordless look of disgust might dissuade someone else from littering, too.
- Participate in creek or beach cleanups. If you’re good at organizing activities, organize a cleanup.
- Do whatever you can to influence others, including all levels of government, to cut down on waste.
Agriculture: cause and victim of water pollution, but change is possible / Food and Agricultural Organization of the United Nations
How sewage pollution ends up in rivers / American Rivers
Mining and water pollution / Safe Drinking Water Foundation
Nutrient pollution, the sources and solutions: fossil fuels / US Environmental Protection Agency.
Oil spills / Save Drinking Water Foundation
Radioactivity in the ocean: diluted, but far from harmless / Elizabeth Grossman, Yale Environment 360. April 7, 2011
Wastewater discharge. Wikimedia Commons
Pig farmer. Some rights reserved by Wisconsin Department of Natural Resources.
Oil slick. Wikimedia Commons
Dan River coal ash spill. Some rights reserved by NC Dept. of Energy and Natural Resources.
Sewer pipe. Some rights reserved by Dominic’s pics.
Plastic on a river bank. Some rights reserved by Horia Varlan