Fancy soap, liquid soap, shower gel, or shampoo, we all use them. No matter what cosmetics we use while taking a shower, all of them end up running down the pipes directly into the drain. Then, they travel to the sewage treatment plant, where the wastewater is processed and clarified.
Unfortunately, a large part of the wastewater polluted with soaps, gels, or other cosmetic products finds its way into the natural environment, resulting in significant pollution. Here we take a closer look at what pollutants, originating from soaps and other hygiene products, can be found in the environment.
Somewhere, over the ocean
Summer, Holidays by the sea means sun, water, waves, and for some of us – sunbathing. Long-term exposure to sunlight requires proper skin protection, like wearing sunscreen with a UV filter. Sunscreens are the best example of chemicals that go directly into the sea, river, or lake while we swim. They contain substances that absorb or reflect ultraviolet radiation from the sunlight, like organic and inorganic compounds, and those can become serious aquatic pollutants [1, 4].
Some of the most environmentally harmful chemicals in sunscreens include oxybenzone, benzophenone-1, benzophenone-8, 4-methyl benzylidene camphor, 3-benzylidene camphor, nanostructural zinc oxide, octinoxate, and octocrylene [5], and that is just a beginning of a very long list of harmful compounds in cosmetics. These substances have a negative influence on the aquatic environment: coral reefs, fish, and others are highly vulnerable to exposure.
These chemicals affect zooplankton and other animals. Even though fish and chips might be one of the world’s most famous dishes, it turns out that not all fish are that healthy; Experiments have shown that fish that come in direct contact with these substances may yield offspring with significant developmental defects.
UV filters found in sunscreen have also been found to cause the dying off of animals living in aquatic systems; among these, oxybenzone is at the most significant fault. It disturbs the hormonal activity of corals and fish, making their reproduction impossible. Even minimal oxybenzone concentrations, in the order equivalent to 1 droplet dissolved in 6.5 Olympic swimming pools, are harmful.
Oxybenzone also has a negative influence on plankton being food for fishes. If it is harmful to fishes, it is also toxic for us. What about the following ones? Benzophenone-8, benzophenone-3, and benzophenone-1 work similar to the endocrine disruptor affecting the hormonal system [6]. Moreover, benzophenones are carcinogens, so they can also lead to cancer tissue development [7].
Another compound widely used in UV-filters, the 4-methyl benzylidene camphor, is also recognized as endocrine disruptors. It is one of the most commonly detected compounds in freshwater fish tissues. It was found that it also affects brain tissues of animals living in water polluted by that compound [8]. Its derivative 3-benzylidene camphor has such toxic effects on the living organisms banned in European Unions for use in cosmetics [9].
Next, a dangerous compound is zinc oxide (ZnO). Its powder is used in UV filters, while particles and tiny nanoparticles may dissolve in the seawater, aggregate, or sediment. Its toxicity is quite different from compounds mentioned above, while still, it is dangerous. It can generate reactive oxygen species that affect organisms living in aquatic systems [10]. Last, but not least – octinoxate and octocrylene reveal neurologic toxicity and hormonal disruption [11, 12].
Not only UV-filters
What about other chemical substances in cosmetics that get easily to the water? Whatever we use to treat our skin, sooner or later, get to the drains and environment. For many years parabens (widely used in creams or other cosmetics) were said to have low toxicity. Unfortunately, the truth is far from that.
Parabens may affect fetus development, causing reddening of the skin and allergic reactions in both animals and humans. The structure of these compounds is similar to our hormones, so once they interact with our skin, they easily cross biological barriers. They interact with the body acting as hormones negatively influencing the hormonal system and causing several health problems [1, 2].
Parabens are not the only example of compounds that still can be found in cosmetics. The next one is triclosan, used as an antibacterial agent. Formerly, triclosan was said to be non-toxic, and it was widely added to hand soaps, shampoos, or even kinds of toothpaste. Later, it turned out that it is dangerous to humans and the environment. A high concentration of triclosan in water has a toxic influence on many types of seaweed and crustaceans. This impacts their structure and functioning and can lead to an imbalance in aquatic ecosystems [1].
The list of environmentally harmful compounds is longer than we can even imagine [13]. Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are used as preservatives and antioxidants in cosmetics, such as lipsticks and moisturizing creams. In higher concentrations, they may be toxic (e.g., on the kidneys, liver) and allergic (skin irritation) to both animals and humans [14].
Dibutyl phthalate (DBP) is mainly an ingredient in nail polishes, nail polish remover, and hairsprays. Due to its cytotoxicity, it is recently prohibited in the European Union, while still can be found in many cosmetics[15]. Diethanolamine (DEA) is a foaming agent used in cleansing cosmetics like shampoos, soaps, and bath lotions. DEA can cause skin irritation and can react with some chemicals forming carcinogens.
All these substances mentioned above harm the aquatic environment – they can cause changes in the behavior and growth of fish, disturb the development of animal and plant plankton, and lead to the death of species living in water [13].
There is more…
Do you like peelings and scrubs? Sometimes abrasive granules in these cosmetics are made with synthetic materials like plastics. They can release many substances like pigments and plasticizers that can be harmful. Due to their wide use in cosmetics, they get to rivers, seas, oceans. Moreover, recently microplastics (tiny pieces of plastic lower than 5 mm) were found in Mount Everest and the North Pole. That is not the end; microplastic granules are eaten by fishes or other aquatic animals, affecting their health [1, 3].
Summary
Cosmetics get quickly into the soil, rivers, oceans, and even into drinking water affecting natural habitat and wildlife. Despite the growing popularity of eco-friendly and organic cosmetics, the cosmetics market is full of many harmful compounds. Whenever we use sunscreens, lotions, or make-up cosmetics, let’s keep in mind that swimming is not a good idea. Thus, all of them would be rinsed out from the skin directly to the environment.
This article is a joint work of Jakub Hilus (3rd High school named Adama Mickiewicza in Katowice), Weronika Urba?ska (Department of Environmental Engineering, Wroc?aw University of Science and Technology), Agnieszka Pregowska (Institute of Fundamental Technology Research, Polish Academy of Sciences), and Magdalena Osial (Faculty of Chemistry, University of Warsaw) as a Science Embassy Project. Photo Credit – A. Pregowska & M. Osial
References
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