Laundering clothes may send indoor pollutants outdoors | Science News for Students

Laundering clothes may send indoor pollutants outdoors

Clothing acts like sponges for pollutants — and doing laundry can ‘squeeze’ those pollutants back out of it again
Sep 23, 2016 — 11:13 am EST

Washing may release any indoor pollutants that clothes picked up. Some of the gaseous pollutants may go down the drain with the wash water — or get released outdoors via the dryer vent.

Denisenko / iStockphoto

Many items in homes, schools and businesses give off air pollutants, some of which may pose a risk to health. Those chemicals can be absorbed by clothing. And later, those pollutants can go down the drain with the wash water. Or they may even be sent into the air through a dryer’s vent. That's the finding of a new study.

Flame retardants make products  such as plastics and fabrics resistant to burning in a fire. Plasticizers are chemicals added to vinyl and certain other plastics to make them soft or flexible. Both types of chemicals have lots of beneficial uses. But research suggests each may be toxic if released into the environment. And both can leach from products into the air.

"People had looked at these chemicals in dust,” notes Miriam Diamond. She is an environmental scientist at the University of Toronto in Canada. But no one had looked at clothing as a possible environmental sponge for these compounds. So Diamond designed a study to learn if clothing might collect flame retardants and plasticizers from indoor air.

It made sense to her that they might. After all, she points out, even after walking away from a stovetop where you cooked an onion, “you smell of onions.” That’s because your clothes had absorbed some of the chemicals spewed into the air by the cooking veggies. Knowing that clothes can pick up kitchen chemicals, she was curious what other compounds fabric might collect from the air.

So she and her colleagues ran some tests — and were surprised by what they found.

What they learned

The researchers left two types of fabric in an office at the university for 30 days. One was made of cotton. The other was made of polyester. After the month was up, they measured the chemicals in these fabrics. Then they laundered the fabric and measured again. The researchers compared these results to chemicals they measured in the same type fabric that had not been exposed to the office air.

Clothes can pick up indoor pollutants while hanging in a closet, thrown over the back of a chair or strewn across the floor.
KhongkitWiriyachan / iStockphoto

The fabric had been hung in special frames in the office. But nothing else was changed there. The researchers wanted to know what might be found in ordinary indoor air, Diamond explains. Many everyday items contain flame retardants and plasticizers. So the researchers looked for them.

Fabrics can be made from a complex mix of chemicals. What that mix consists of determines which air pollutants the fabric will catch and hold onto, Diamond says. In the new tests, each fabric picked up both flame retardants and plasticizers. But cotton fibers appeared better than polyester’s at collecting pollutants.

Cotton absorbed almost twice as much of some flame retardants as did the polyester. And the cotton absorbed as least five times as much of some plasticizers as did the polyester.

Both fabrics lost a good deal of the chemicals during washing and drying. But how much washed out depended on the pollutant.

Certain flame retardants came out of fabric faster than others. This included those made with chlorine and phosphate. An older type clung to cotton and polyester even through the wash. These are brominated flame retardants. But both fabrics shed far more of a type of flame retardants known as organophosphate esters (Or-GAN-oh-FOS-fayt ES-terz). This type “just floated away in the laundry,” says Diamond. The finding helps explain why these chemicals are now showing up in the wastewaters that enter a town's water-treatment plants.

The new findings appeared August 10 in Environmental Science & Technology.

Probing that ‘sponge’ effect

These data “certainly demonstrate that clothing could be absorbing these chemicals over time,” says Heather Stapleton. She works at Duke University in Durham, N.C. She is an environmental chemist. And she has conducted many studies on flame retardants and their effects in the environment.

“Most of our research has focused on where these chemicals are being used in the home,” Stapleton says. These new data provide valuable clues about how those chemicals may be moving from the home and out into the environment. The new testing also “has provided some good insight into exposure pathways,” she adds. By that she means it points to where and how people may be exposed to these chemicals.

Indeed, the new data raise questions about how these fabrics might affect people, says Diamond. That’s because our skin makes contact with those spongelike fabrics that are soaking up pollutants.

Next, Diamond and her team will be working to pinpoint the indoor sources of the chemicals that collected in the fabrics she tested.

But there’s also another question Stapleton would like to see studied: How might the fabrics’ spongelike accumulation of pollutants affect the ability of these chemicals to enter the body. Clearly, she says, “There’s still a lot we need to know.”

Power Words

(for more about Power Words, click here)

chemical     A substance formed from two or more atoms that unite (become bonded together) in a fixed proportion and structure. For example, water is a chemical made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O. Chemical can also be an adjective that describes properties of materials that are the result of various reactions between different compounds.

chlorine     A chemical element with the scientific symbol Cl. It is sometimes used to clean water. Compounds that contain chlorine are called chlorides.

compound     (often used as a synonym for chemical) A compound is a substance formed from two or more chemical elements united in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O.

contaminant     Pollutant; a chemical, biological or other substance that is unwanted or unnatural in an environment such as water, soil, air, or food. Some contaminants may be harmful in the amounts at which they occur or if they are allowed to build up in the body over time.

environment     The sum of all of the things that exist around some organism or the process and the condition those things create for that organism or process. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature, humidity and placement of components in some electronics system or product.

fabric     Any flexible material that is woven, knitted or can be fused into a sheet by heat.

fiber     Something whose shape resembles a thread or filament of some kind. (in nutrition) Components of many fibrous plant-based foods. These so-called non-digestible fiber tends to come from cellulose, lignin, and pectin — all plant constituents that resist breakdown by the body’s digestive enzymes.

flame retardants     Chemical coatings added to products, such as pyjamas, plastics, foam and furniture, to suppress or delay how fast they might burn in a fire.

insight     The ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.

leach     (in geology and chemistry) The process by which water (often in the form of rain) removes soluble minerals or other chemicals from a solid, such as rock, sand, soil or ash.

molecule     An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

phosphate     A chemical containing one atom of phosphorus and four atoms of oxygen. It is a component of bones, hard white tooth enamel, and some minerals such as apatite.

plastic     Any of a series of materials that are easily deformable; or synthetic materials that have been made from polymers (long strings of some building-block molecule) that tend to be lightweight, inexpensive and resistant to degradation.

plasticizer     Any of several chemicals added to certain synthetic materials to make them soft and/or pliable.

pollutant     A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

polyester     A synthetic material used chiefly to make fabrics. The actual chemical name for the material used is polyethylene terephthalate.

risk     The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.

toxic     Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.

wastewater     Any water that has been used for some purpose (such as cleaning) and no longer is clean or safe enough for use without some type of treatment. Examples include the water that goes down the kitchen sink or bathtub or water that has been used in manufacturing some product, such as a dyed fabric.


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Journal: A. Saini​ ​et​ ​al.​ From clothing to laundry water: Investigating the fate of phthalates, brominated flame retardants, and organophosphate esters.​ ​​Environmental Science & Technology.​ ​​Published online ​August 10, 2016. doi:​​ 10.1021/acs.est.6b02038.

Journal: E.D. Schreder and M.J. La Guardia. Flame retardant transfers from U.S. households (dust and laundry wastewater) to the aquatic environment. Environmental Science & Technology. Vol. 48, October 7, 2014. doi: 10.1021/es502227h.

Journal: H. Stapleton et al. Detection of organophosphate flame retardants in furniture foam and U.S. house dust. Environmental Science & Technology. Vol. 43, October 1, 2009. doi: 10.1021/es9014019.

Further Reading

E. Sohn. “Our plastic world.” Science News for Students. September 26, 2008.