Microplastics are one of the chief environmental concerns today. Whether microplastics contaminate food, water, or even air, they have made their way to all parts of the globe and pose a threat to any living creatures that consume them. With plastic use continuing to increase with seemingly little change on the horizon, groundwater has become an alarming victim of contamination. Fortunately, water filtration systems exist that can remove the threat of microplastics from drinking water. Below you can find information on what microplastics are, how they get into groundwater, and how to remove them from your drinking water.
What are microplastics?
Microplastics are pieces of plastic debris that are smaller than 5 millimeters and larger than 100 nanometers (0.0001 millimeters). They result from plastic products that break down over time and products that intentionally contain microplastics. Some of these products include synthetic clothing, facial scrubs, tires, tea bags, sparkly toothpaste, and paint. Certain foods and beverages are also victims of microplastic contamination. These include fruits and vegetables, beer, fish, and bottled water. Plastics are the most common debris found in the oceans and Great Lakes, and they do not disappear quickly. Most plastics do not biodegrade. Rather, they only break down into smaller pieces. This makes microplastics particularly harmful to life because they do not exit the body easily.
How do microplastics get into water?
Microplastics can make their way into drinking water in any of the following ways:
- Surface run-off
- Wastewater effluent
- Degraded plastic waste
- Atmospheric deposition
- Plastic used to store water
Run-off and wastewater effluent are the most common sources of microplastic contamination in the United States. Because plastics do not biodegrade and become smaller over time, they can find their way to groundwater through soil once they break down to a small enough size. A study published by the National Groundwater Association discovered microplastics in two aquifers in Illinois at a concentration of 15.2 particles per liter.
Are microplastics dangerous?
Yes, microplastics are dangerous to both our bodies and the environment. Plastic products can take dozens, hundreds, or even thousands of years to decompose depending on the type of plastic the products contain. Microplastics have found their way to every region of the globe, even uninhabited zones. In June 2022, scientists discovered microplastics in freshly fallen snow in Antarctica for the first time. Because of their prevalence, microplastics have most likely found their way into your body already.
Microplastic effects on humans
Studies, such as this review study by the Italian National Research Council, have shown that microplastics damage cells and cause inflammatory and immune reactions within the body. They can also induce symptoms such as obesity, reproductive harm, and increased cancer risk. These side effects are present at levels of microplastic contamination achieved by consuming food, drinking water, and inhaling air. The effect of microplastics on the human body is a new phenomenon, so the science behind how they affect health is not certain. Researchers are currently working to discover the long-term effects of microplastic consumption on the human body. However, filtering microplastics out of water is still suggested when possible, as doing so can greatly reduce microplastic intake and, consequently, benefit your health.
How to test water for microplastics
Currently, there is no method for an average consumer to test water for microplastics at home. However, there are options to ship water to a laboratory for testing, but this process is expensive and will almost certainly confirm that microplastics are present in your water to some degree. As microplastic contamination becomes more common, regulations regarding microplastics in water will likely be put in place. In September 2022, California became the first state to require microplastic testing in drinking water sources. This quarterly testing will begin in the fall of 2023 and may cause other states to follow suit.
Are microplastics in bottled water?
Yes, microplastics have been discovered in more than 90% of samples in common bottled water brands. A sustainability researcher at Penn State Behrend conducted a study on microplastic contamination in bottled water. In this study, bottled water was found to contain an alarming amount of microplastics. On average, the bottled water in this study and similar university studies contained 325 plastic particles per liter of water. One bottle of Nestle Pure Life contained levels as high as 10,000 particles per liter. After this research was published, the World Health Organization announced that they would review the safety concerns regarding bottled water.
How to remove microplastics from drinking water
To remove microplastics from drinking water, the best home filtration options are reverse osmosis, distillation, and ultrafiltration. Microplastics range between 100 nanometers and 5 millimeters in size, so a filter’s micron rating must be able to filter out contaminants between 100 nanometers and 5 millimeters to effectively reduce levels of microplastics of all sizes. One micron is 1000 nanometers, so a filter must have a micron rating of 0.1 to remove contaminants 100 nanometers in size. Both reverse osmosis and ultrafiltration systems possess a micron rating capable of filtering contaminants of less than 100 nanometers in size, while water distillers separate microplastics from water during the distillation process.
Filtering microplastics with reverse osmosis
Reverse osmosis (RO) systems are efficient at reducing high levels of microplastics, as well as most other contaminants, in water. Standard reverse osmosis systems utilize three phases in the filtration process, while some systems contain four or five stages. In an RO system, water begins by traveling through a sediment filter. As the name suggests, this phase reduces levels of large contaminants, such as dirt, sand, rust, and other microscopic particles. Not only does this filter the water, but it also prevents these contaminants from damaging the reverse osmosis membrane in later stages. After the sediment filter, the water is subjected to an activated carbon filter. This stage removes contaminants that cause water to taste and smell unpleasant, such as chlorine. The final step of a three-stage reverse osmosis system is the reverse osmosis membrane. Here, water is placed under pressure as it passes through a semi-permeable membrane. This stage is where most contaminants are eliminated from the water. The RO membrane contains tiny pores (0.001 microns) that allow water to pass through while washing away minute contaminants, such as microplastics, down the drain. Some reverse osmosis systems contain a carbon post-filter that polishes the final product to ensure its clarity. A remineralizing filter can also be added to an RO system to reintroduce beneficial minerals that were lost in the filtration process.
Advantages of reverse osmosis for microplastics
- Reduces levels of most contaminants
- Long lifespan
- Fewer maintenance costs than ultrafiltration
Disadvantages of reverse osmosis for microplastics
- Produces wastewater
- Complex installation
- Slower filter speed than ultrafiltration
- Requires water pressure
Removing microplastics with water distillation
Water distillers are not a filter in the traditional sense. Instead of passing water through a filter media, they boil water, collect the resulting steam at the top of the distiller, and cool it back down to liquid form. Because water evaporates at a lower temperature than most contaminants, including microplastics, distilled water provides the purest water available. For some applications, laboratories and hospitals require distilled water to be used to ensure contaminated water does not compromise the result of the test or procedure. Water distillers require a constant energy source to operate, and they purify water at a much slower rate than traditional filters.
Advantages of water distillation for microplastics
- Simple countertop installation
- Removes almost all impurities from water
- More expensive than point-of-use RO and ultrafiltration systems
Disadvantages of water distillation for microplastics
- Uses electricity
- Slower than reverse osmosis and ultrafiltration
- Can only be used for drinking water
Filtering microplastics with ultrafiltration
An ultrafiltration system filters water through a .02 micron membrane. This micron rating is small enough to effectively reduce levels of microplastics of all sizes. Unlike reverse osmosis, which forces water through the outside of the membrane, ultrafiltration systems filter water through the inside of the membrane. Also unlike RO systems, ultrafiltration does not dispose wastewater during the filtration process. In areas where water restrictions are in place due to drought, such as California, ultrafiltration is a common choice over reverse osmosis. Ultrafiltration does not remove as many contaminants as reverse osmosis systems do, but it does reduce levels of bacteria, viruses, lead, copper, cysts, and other contaminants. Some users may prefer the taste of water filtered via ultrafiltration because minerals are not removed from the final product.
Advantages of ultrafiltration for microplastics
- Fast filter speeds (1 gallon per minute)
- Maintains beneficial minerals in final product
- Simple installation
- Works at low water pressure
- Produces no wastewater
Disadvantages of ultrafiltration for microplastics
- Short lifespan
- Higher maintenance costs that RO and water distillation
- Removes fewer contaminants than RO and water distillation
Do ceramic filters remove microplastics?
A ceramic filter with a micron rating of less than 2.5 can reduce levels of microplastics in water. The smaller the micron rating, the more effective the filter will be at filtering out microplastics. If microplastics are a point of concern in your water, reverse osmosis, water distillation, and ultrafiltration are more effective alternatives to ceramic filters.
Do refrigerator filters remove microplastics?
Most refrigerator filters use an activated carbon core that reduces contaminants in water via adsorption. The average micron rating of a refrigerator filter is 20, but some options offer a much lower rating. A filter with a 5 micron rating, for example, will remove some microplastics from water and not others. Reverse osmosis is much more effective at removing microplastics and nanoplastics than a refrigerator filter, so you should not rely on a refrigerator filter for such a task.