Emily Driehaus  |  Science Communication Intern

Oxybenzone is a common sunscreen ingredient that has been shown to have negative impacts on human health and the environment. Evidence has shown that it can contaminate drinking water after being washed down the drain while showering off sunscreen. 

What is Oxybenzone?

Oxybenzone is a UV filter used in sunscreen and other cosmetics. It absorbs UV rays from the sun and helps prevent them from penetrating the skin and causing sun damage. While it does help protect our skin against the sun, it has implications for both our health and the environment, particularly aquatic life. 

Oxybenzone and Marine Life

Much of the concern regarding oxybenzone began when researchers noticed damage to coral reefs near beaches with many visitors. As sunscreen gets sloughed off the skin by the water and sand, it can make its way into the ocean and harm aquatic life. Coral reefs are especially susceptible to damage, as oxybenzone can harm normal growth and development, damage DNA and put them at an increased risk of bleaching. 

Health Implications of Oxybenzone

As research into oxybenzone has continued, it has been designated as an endocrine disruptor. Endocrine disruptors interfere with normal hormonal processes in the body and can impact the reproductive system. Most research on oxybenzone in the human body has focused on absorption through the skin rather than ingestion, but more evidence has shown that oxybenzone is present in drinking water, especially in communities near large bodies of water.

How Does Oxybenzone Get Into Drinking Water?

After a day at the beach, most individuals hop in the shower to rinse off the sunscreen and sand that has accumulated on their skin throughout the day. When this water goes down the drain, it goes to wastewater treatment plants to be treated before being released into water sources, which can be used for drinking water. Wastewater treatment plants and drinking water facilities lack the ability to filter out endocrine disruptors like oxybenzone, so it ends up in drinking water consumed by the public. A study looking at oxybenzone in Honolulu tap water showed that individuals consume between 0.8-1.2 micrograms of oxybenzone a day from drinking water. This concentration is not particularly harmful to fully grown adults, but can have a greater impact on children, infants and developing fetuses. 

Regulations on Oxybenzone

The previously mentioned study was submitted as part of testimony on a bill that would ban the sale of sunscreens containing oxybenzone in the state of Hawaii. The bill passed in 2018 and went into effect at the beginning of this year. The city of Key West, Florida has also enacted a ban on sunscreens with oxybenzone in an effort to protect coral reefs. These bans are not without controversy, as skin damage from UV rays can lead to skin cancer and banning sunscreens with oxybenzone leaves individuals in these areas with one less form of sun protection.

What Should I Do if I’m Concerned About Oxybenzone in my Water?

Carbon water filters are able to filter out oxybenzone and other endocrine disruptors. Using sunscreen with ingredients like zinc oxide or titanium dioxide rather than oxybenzone can also reduce your overall exposure. Switching sunscreens will also help protect aquatic life when you swim in bodies of water like lakes or oceans.

**Updated on 3/15/18 to reflect discovery that microplastics were found in over 90% of bottled water

Caitlin M. Cameron, M.S.  |  Contributing Scientist

When people think of plastic waste they likely think of items such as bottles, bags, and straws, but there are smaller objects that inconspicuously threaten habitats and wildlife. Microplastic waste is a monumental problem world-wide, but has received little attention until recently. Microplastic waste endangers both organisms living on land and those in aquatic habitats, and may harm humans. Additionally, microplastics in water interfere with industries like fishing, shipping, and tourism, which suffer at least $13 billion in damages every year from plastic pollution. Microplastics are used in large quantities in many products and are harder to clean up than other plastic materials. This article answers several questions pertaining to microplastics, some of which may surprise consumers.

What Are Microplastics?

The term “microplastics” is used to describe particles that are made of nondegradable plastic, smaller than five millimeters long, and cannot dissolve in water. Several sources are responsible for creating microplastics: mechanical forces, sunlight, and weather wear down and fracture large plastic containers; plastic pellets used for manufacturing; and the small, manufactured plastic beads used in health and beauty products. Known as “microbeads”, these tiny pollutants may be as small as one micrometer (1 μm), making them completely invisible to the naked eye. An estimated eight trillion microbeads enter aquatic environments every day, which is equivalent to lining up microbeads side by side and covering more than 300 tennis courts daily!  A 2015 study estimated between 15 trillion and 51 trillion microplastic particles had accumulated in world oceans. Microplastics are entering aquatic environments in copious amounts, and coupled with the small size of these particles, environmentalists are struggling to develop methods to successfully clean up these particles.

Where Do Microplastics Come From?

Microbeads, the manufactured plastic beads that are added as exfoliates, have been replacing natural ingredients in personal care products for the last fifty years. Face wash, skin scrub, hand soap, makeup, shampoo and conditioner, hair dye, sunscreen, baby care products, cleaner, nail polish, deodorant, and toothpaste are just a few of the consumer goods that contain microplastics (including microbeads). These particles can account for up to 90 percent of the ingredients in certain cosmetic products. An even less talked about source of microplastics is nylon and polyester clothing. Laundering nylon and polyester clothing causes tiny bits of plastic to wash down the drain and eventually empty into lakes, streams, and oceans. One study found that as many as 700,000 tiny synthetic fibers (i.e., pieces of nylon or polyester) washed down the drain after one cycle in the washing machine, while a study conducted using four different types of synthetic fleece jackets revealed that every time a synthetic fleece jacket was washed, 1.7 grams of microfibers were washed down the drain.

Why Do We Care About Microplastics?

Microplastics in water have the potential to pose an environmental hazard from the moment they enter bodies of water. Fish and other aquatic wildlife ingest microplastics, which may irritate or damage their digestive system. If microplastics are not excreted and instead accumulate in the gut, the animal may mistakenly believe it is full of nutritious food instead of harmful plastic, resulting in malnutrition or starvation. Microplastics may also affect the feeding behavior, predator avoidance capabilities, and cell function in some vertebrates and invertebrates as well as alter sediment composition. Microplastics also serve as a vessel, carrying pollutants like pesticides and manufactured chemicals such as BPA, DDT, and PCB’s, which may be ingested or filtered by animals. Crustaceans and other filter feeders may also experience a decrease in reproductive success due to the consumption of microplastics. Filter-feeding organisms play an important role in creating a healthy food web, and microplastics may adversely affect the biology and physiology of these animals and any animal who consumes them.

It’s not just wildlife that is threatened by plastics in our water bodies. Evidence suggests that humans who eat seafood are also consuming the plastic particles that fish and shellfish already ingested. In 2014, researchers purchased fish and shellfish from Indonesian and American markets that were selling seafood for human consumption to assess the number of plastic pieces in the animals’ guts. In Indonesia and the United States, approximately one out of every four fish contained small plastic or fibrous debris while one out of every three shellfish sampled in the United States contained some sort of small debris in their guts. While it seems apparent that aquatic wildlife are not the only organisms to consume plastic particles, the effects of microplastic consumption on human health are not yet clear.

What Is Unknown About Microplastics?

A lot. Research on plastic pollution, which includes the study of microplastics, is still a relatively new field, so a great deal is still unknown with regards to microplastics and their effects on aquatic organisms, habitats, and human health. Scientists are still identifying how best to quantify the number of microplastics (in all size ranges) that enter aquatic environments, which organisms consume and accumulate particles, and whether the affected animals harm the predators (including humans) that eat them. In other words, the extent of damage that microplastics are causing to habitats and species at all levels of the food chain need to be studied in much more detail.

What Is Being Done To Learn More?

Researchers are working to answer many unknowns: the extent of microplastics in the ocean; how microplastics uptake in the food web; if pollutants transfer to animals from microplastic particles; and the potential impacts on the conservation and health of aquatic plants and animals. A collaborative effort between researchers at the University of Washington Tacoma and the National Oceanic and Atmospheric Administration’s (NOAA) Marine Debris Program has led to the establishment of a reliable method to use weight to quantify the amount of microplastics in sand, sediment, or a water sample. Similarly, many nonprofit organizations were formed to investigate microplastic pollution and its effects on wildlife and human health.

What is Being Done To Fix The Problem?

In recent years, preventing microplastics from entering waterways has received international attention. Important work is ongoing to develop ways to minimize the amount of microplastics going down drains and clean up plastic already polluting bodies of water. Additionally, nonprofit organizations, government agencies, and universities are working together to evidence and encourage lawmakers to pass legislation requiring companies to use fewer microplastic ingredients in their products. Several states in the U.S. and countries around the world have banned the manufacture and sale of one-time use plastic products, which will reduce the number of plastic items in a landfill that will eventually become microplastic pieces. Many nonprofit organizations work tirelessly to combat the world’s plastics problem. The Ocean Cleanup Project recently developed a new method to remove 70,000 metric tons of plastic from the sea within ten years. Other efforts include collaborations between nonprofits and clothing manufacturers to create clothing and footwear made entirely out of plastic debris. On a global scale, the United Nations held an environmental assembly for the first time in 2014 involving more than 150 governments who are concerned about the effects of microplastic pollution in water bodies around the globe. The United Nations Environment Programme (UNEP) was tasked with studying aspects of microplastic debris in marine environments worldwide and developing methods for reducing the number of sources of microplastics. UNEP also works to mitigate the global impacts that microplastics have on habitats, marine flora and fauna, and humans. Closer to home, former President Barack Obama signed the Microbead-Free Waters Act, which banned the use of microbeads in all personal care products manufactured after 2015. This Act was a respectable first step in eliminating the use of microplastics while also increasing public awareness and prompting some corporate action. However, it contains language that leaves room for the use of microbeads in items that are not considered “personal care” or “rinse-off products” like deodorants, nail polish, or cleansers. It also contains loose definitions of the terms “plastic” and “biodegradable”, which allows companies to produce plastic products that biodegrade only slightly (not fully) over a short period of time.

In the short term, focusing on improving wastewater management facilities and their ability to prevent smaller plastic debris from reaching the water has been considered a decent first step. Perhaps more important for long-term success would be a shift in the way we think about all plastic, regardless of size. Treating plastic as a valuable, limited resource like water instead of an inexhaustible resource that can be discarded after one use would ultimately lead to a reduction in the amount of microplastics in water bodies. If companies redesigned products to be more ecofriendly, contain less synthetic material, and use safer chemicals and consumers used these products more responsibly, we will reduce the potential for health threats posed by microplastics.

Other Articles We Think You'll Enjoy

Editor's Note: We've been writing more articles about organic chemicals like endocrine disruptors, methylated mercury, so we've been getting a lot of questions about how people become exposed to these chemicals. Even though these questions deal more with food than drinking water, we though that it'd be worthwhile to spend some time on an article explaining how this happens.

What is Bioaccumulation?

Bioaccumulation refers to the process of toxic chemicals building up inside of an organism’s body. This happens when a chemical is consumed or absorbed, and the body cannot catabolize or excrete it quickly enough. Mercury is a well-known chemical that will bioaccumulate in humans. We commonly hear about mercury exposure resulting from eating fish such as tuna (or other large predatory fish). However, mercury as well as many other harmful chemicals can also be found in drinking water supplies across the United States.

Chemicals that tend to bioaccumulate are stored in cells and not exposed to direct physical or biochemical degradation. These chemicals can collect and hide-out, particularly within adipose tissue (fat cells). Fatty mammary tissue often contains the highest concentrations of toxic chemicals. These chemicals in our mammary tissue are then passed along to infants when nursing.

What is Biomagnification?

Biomagnification refers to the process of toxic chemicals increasing in concentration as they move throughout a food chain. Bioaccumulation and biomagnification often work hand-in-hand; one animal accumulates chemicals in the body (bioaccumulation) and then a larger predator consumes that smaller animal such that the chemical is passed along to the predator. The chemical “magnifies” as the resulting concentrations increase in the predator because it likely consumes large quantities of that particular prey throughout its lifetime (biomagnification). As top-level predators in our own food chain, humans tend to collect high concentrations of toxic chemicals in our bodies.

What are Persistent Bioaccumulative Toxics (PBTs)?

PBTs are a particular group of chemicals that threaten the health of humans and the environment. Examples include methylmercury, polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethane (DDT), and dioxins. PBTs are considered extremely dangerous to both humans and wildlife because they remain in the environment for a very long time without breaking down, then bioaccumulate and biomagnify in ecosystems (including ours).

PBTs can also travel long distances and move between air, water, and land. DDT, a notorious environmental pollutant, was developed as a synthetic insecticide in the 1940s. Sprayed over crops, DDT would then wash into water supplies and contaminate lakes, ponds, streams, rivers, and oceans. Small organisms such as plankton and algae absorb DDT through the water. Smaller fish then consume the contaminated algae and plankton. Larger predatory fish then consume the smaller fish. Eventually, large predatory birds or humans eat the contaminated fish. Despite being banned in the United States over 40 years ago, DDT is still found in soil and water supplies today. In addition, humans contain the highest concentrations of DDT when compared to other organisms.

How Does This Impact Human Health?

Exposure to PBTs has been linked to a wide range of toxic effects in humans and wildlife. Some of those adverse effects include but are not limited to disruption of the nervous and endocrine systems, reproductive and developmental problems, immune system suppression, and cancer.

How Can I Minimize Exposure To PBTs?

1. Avoid eating species of fish that are long-lived and high on the food chain such as tuna, marlin, shark, swordfish, king mackerel, and tilefish.
2. Use a high quality water filter that removes PBTs (e.g. DDT, Dioxins, BPA, Phthalates) from contaminated drinking water before the chemicals get a chance to accumulate in you.

More Articles We Think You'll Love:

Stephanie Angione, Ph.D.  |  Scientific Contributor

Pesticides are chemicals used to kill environmental pests including insects, weeds, fungi and rodents. These are commonly divided into insecticides (used to specifically target and kill insects) and herbicides (used to kill undesirable plants or “weeds”). The most widely used agricultural pesticides are herbicides, which account for 40% of all pesticide use in the US. In typical agriculture, pesticides are applied to crops in order to provide protection against destructive insects and invasive weeds or fungi. By design, pesticides kill or deter pests and thus are toxic to their intended target organisms. Additionally, many pesticides are toxic to humans, and organochlorine pesticides are 9 of the 12 most toxic organic chemicals, as outlined by the Stockholm Convention in 2001.

Which Pesticides Are Most Commonly Found In US Water Systems?

The most comprehensive information available about pesticide occurrence at the national level is part of a 10-year program by the National Water-Quality Assessment (NAWQA), part of the US Geological Survey (USGS). It provides information about pesticide concentrations in streams and groundwater from data collected between 1991-2001.

Major findings of this study are that pesticides exist in both streams and groundwater throughout the US, in both urban and rural areas, but seldom occur at concentrations that will affect human health. Of the water systems studied, pesticides were found 90% of the time in streams throughout the US in urban and agricultural areas. Groundwater sources were less affected by pesticide contamination, with shallow groundwater sources in agricultural and urban areas having pesticides 61% and 55% of the time respectively.

The most commonly detected pesticides in stream water include five agricultural herbicides, atrazine, metolachlor, cyanazine and acetochlor and five non-agricultural herbicides in urban areas, including simazine, prometon, tebuthiuron, 2,4-D and diuron and three insecticides – diazinon, chlorpyrifos and carbaryl (Figure 1).

Figure 1: Percentage of samples found with pesticide contamination in agricultural and urban stream water (upper) and groundwater (lower).

Additionally, pesticides detected the most frequently in fish and streambed sediment were organochloride pesticides and degradation products (Figure 2). Organochlorides were used heavily in the 1950s and 1960s and were largely abandoned by the 1980s. However these compounds including DDT are very persistent in soils, sediments and animals, and were thus found at high levels in stream sources.

Figure 2: Percentage of samples of fish tissue containing organochlorine pesticides and degradation products in agricultural and urban streambeds

Despite the widespread existence of pesticides in water systems, levels of pesticides only exceeded human health benchmarks in about 10% of agricultural streams, and 7% of urban streams studied. It should be noted that for public water supply intakes that withdraw water from streams in the US, only 12% are from an agricultural land-use areas, and only 1% from an urban land-use areas. As for groundwater, only 1% of wells sampled had pesticide levels above human health benchmarks.

As for the pesticides present at these excessive concentrations, the most commonly found were atrazine, cyanazine, diazinon and dieldrin. Notably, stream contamination was commonly atrazine and cyanazine and well contamination was dieldrin, which is no longer used but is a known persistent pollutant.

While the compounds discussed above were detected the most frequently in the study period from 1992-2001, pesticide usage changes as new pesticides are developed. A new study of streams sampled in the US in 2015 by the USGS indicates the existence of the relatively new class of pesticides- neonicotinoids, in US water systems. The study found at least one neonicotinoid detected in 53% of all samples, with imidacloprid detected the most frequently (37%). Guidelines on the effects of neonicotinoids in humans and safe levels of exposure have not yet been systematically investigated.

In addition, a 2022 study revealed that very high levels of PFAS were detected in 6 of 10 varieties of pesticides commonly used in rural and agricultural environments. 

For more information on tracking of common pollutants and pesticides in drinking water, the USGS has an interactive map to examine levels of pesticides nationwide.

How Is Pesticide Contamination Regulated?

The EPA regulates pesticides nationally under the Federal Insecticide, Fungicide and Rodenticide Act to protect human health and the environment. Aside from the 141 banned and severely restricted pesticides, the EPA has set limits on the allowable amount of pesticides in food and drinking water. Many pesticides including alachlor, atrazine, carbofuran, chlordane, 2,4-D, glyphosate, heptachlor, and simazine are included in the national primary drinking water standards that outline the maximum contaminant level for each compound. Public water suppliers are required to maintain levels below the maximum contaminant level for all compounds listed. The EPA has also established 394 human health benchmarks for pesticides that are registered for use on food crops but are not regulated under the national primary drinking water standards.

How Do I Find Out If My Drinking Water Is Contaminated With Pesticides?

If you are concerned about the effects of pesticides in your drinking water and are served by a public water system, your local water supplier is required to issue a Consumer Confidence Report that lists contaminant levels in the water supply. If you have a private well, a laboratory can test your drinking water.

Although the EPA regulates many pesticides as drinking water contaminants, there are many that are not. Additionally, levels of pesticide contamination can vary widely depending on the agricultural season and pesticides can be used in water systems to control pests like mosquitos.

If you get water from a household well, the local health department should have information about ground water quality and contaminants of concern, but it is often a good idea to have your water tested by a certified laboratory for contaminants. The EPA’s Safe Drinking Water Hotline (800-426-4791) can provide additional resources in your local area. It is also important to consider the proper use of pesticides at home if you have a private well, as pesticide runoff can contribute to well contamination.

How Do I Remove Pesticides From Drinking Water?

A home water filtration system can remove pesticides from drinking water that may not fall under EPA regulation. Water filter systems that use activated carbon as part of the filtration media blend or reverse osmosis can be effective in removing pesticides from water. Contrary to what some people tell you, boiling/freezing water does NOT remove pesticides from drinking water!

Do You Have More Questions About Pesticides In Drinking Water?

At Hydroviv, we make it our business to help you better understand your water. As always, feel free to take advantage of our “help no matter what” approach to technical support! Our Water Nerds will work to answer your questions, even if you have no intention of purchasing one of our water filters. Reach out by dropping us an email (hello@hydroviv.com) or through our live chat. You can also find us on Instagram, Twitter or Facebook!