A Review of Toxic Chemicals in Cosmetics That Harm the Environment and Mankind

Cosmetic pollution can occur at various stages in the life cycle of cosmetic products. During production, the manufacturing process may generate wastewater or air emissions that contain toxic substances. When consumers use these products, the chemicals can enter the environment through various pathways, such as washing down the drain or being absorbed into the skin and later released into the environment. Finally, when these products are disposed of, they can accumulate in landfills or water bodies, contributing to long-term pollution.

The impacts of cosmetic pollution can be significant. For example, chemicals such as microplastics, parabens and phthalates have been found in water bodies and can harm aquatic life. These chemicals can also accumulate in the food chain, potentially affecting human health. Additionally, the use of cosmetics can contribute to air pollution, which can exacerbate respiratory and other health problems.

Overall, cosmetic pollution is an important issue that requires greater attention from both consumers and manufacturers to reduce the environmental and human health impacts of these products.

Studying cosmetic pollution is important for several reasons. First, the widespread use of cosmetics and personal care products has led to the release of a large number of chemicals into the environment. These chemicals can have negative impacts on ecosystems, wildlife and human health. By studying cosmetic pollution, researchers can better understand the extent and severity of the problem and develop strategies to mitigate its impacts.

Second, the cosmetics industry is a large and growing market, with an increasing number of products being developed and marketed globally. Understanding the environmental and health impacts of these products is crucial for ensuring sustainable production and consumption practices.

Third, cosmetic pollution is a complex issue that requires a multidisciplinary approach to address. Researchers from a range of fields, including environmental science, chemistry, toxicology and public health, are needed to understand the various pathways through which cosmetic pollution occurs and to develop effective solutions to minimise its impacts.

Finally, addressing cosmetic pollution requires a coordinated effort from multiple stakeholders, including government agencies, industry and consumers. By studying cosmetic pollution, researchers can inform policies and regulations that promote sustainable production and consumption practices, and help raise awareness among consumers about the environmental and health impacts of their personal care choices.

A literature search was conducted. The search was carried out on electronic databases such as PubMed and Google Scholar. The results included 25 references, which were research studies, news reports and cosmetics committee reports.

Heavy metals are used in various cosmetic products as colourants and pigments. Thiomersal is widely used in the manufacture of mascara. In 2008, Minnesota in the United States became the first state to ban the intentional use of mercury in cosmetics.¹ The results of a study showed that the range of Pb levels for lipsticks is higher than that for local eyeliners. Comparable amounts of Pb were found in the local eyeliners and pencils. The World Health Organization review on mercury in skin-lightening products revealed that mercury is a common ingredient found in skin-lightening soaps and creams as well as in other cosmetics, such as eye make-up, cleansing products and mascara. A study investigated the levels of heavy metals, including lead, cadmium, arsenic and mercury, in hair samples of children in Riyadh, Saudi Arabia. The researchers found that certain cosmetics, such as kohl and henna, contributed to the presence of these heavy metals in the hair samples. In another study, various cosmetic products, including lipsticks, eyeliners and face powders, were analysed for the presence of heavy metals. The researchers detected lead, cadmium, arsenic and other metals in some of the tested cosmetics, emphasising the importance of monitoring and regulating heavy metal concentrations in these products.² A further study investigated the presence of heavy metals, phthalates and bisphenol A in various cosmetic products available on the Korean market. The researchers found that some cosmetics contained lead, arsenic, mercury and other heavy metals, highlighting the potential exposure of consumers to these contaminants.

Parabens are preservatives added to cosmetics. They have a broad spectrum of activity against various yeasts, moulds and bacteria. Although many regulatory authorities in European and other countries have imposed stricter regulations on the use of parabens as preservatives in cosmetics, they are still used extensively in the cosmetic industry. Among the parabens, propylparaben and methylparaben are the most frequently identified paraben compounds in surface waters owing to their frequent utilisation in cosmetics. Parabens undergo biodegradation to produce chlorinated by-products.³

Microplastics are used in cosmetics for scrubbing, for exfoliation or simply for visual aesthetic purposes. Various abrasive products, such as toothpaste, cleansers, and body and face scrubs, utilise microplastics to remove dead skin cells. A study reported that 93% of the microplastics used in cosmetics are for decorative purposes.

UV filters protect the skin from the damage caused by UV rays. UV filters are present in 20% of sunscreen products. These UV filters are of two types: organic and inorganic. They undergo photolysis to generate reactive oxygen species. Currently, the most commonly detected organic filters in sediment are octocrylene (OC), ethylhexyl methoxycinnamate (EHMC), octyl dimethyl-p-aminobenzoic acid (OD-PABA), butyl methoxydibenzoylmethane (BMDM) and benzophenone derivatives.³ The inorganic filters used are zinc oxide and titanium dioxide.

Triclosan (TCS) is a lipid-soluble antimicrobial used not only in cosmetics but also in different types of packaged products. Triclosan and triclocarban are commonly used antimicrobial agents found in antibacterial soaps and detergents, toothpaste and tooth-whitening products, antiperspirants, deodorants, shaving products, creams and colour cosmetics.⁴

Hydroquinone is a bleaching agent. The popularity and use of hydroquinone as a skin-lightening agent have been on the rise. Various surveys and studies have been conducted in a wide range of geographical locations, such as Kampala and Korea, to investigate the use of hydroquinone as a skin-lightening agent.

1,4-Dioxane is an organic compound that works as an emulsifier in cosmeceutical products. It is used to give a fine texture to foaming products such as shampoos, shaving creams and body washes.⁴

A survey conducted in Nigeria investigated the effects of chronic use of skin-lightening creams. It was reported that, over the period, a third of respondents experienced yellowing of the skin, while other respondents reported thinning of the skin, stretch marks and rashes. Amongst them, a major part of the respondents reported worsening of their existing conditions.¹

A study conducted in Dhaka, Bangladesh, reported that the heavy metals used in skin fairness creams, such as cadmium, chromium, lead and mercury, exceeded the regulatory limits.⁵

Heavy metals are easily absorbed through dermal and mucosal exposure as well as through inhalation. Heavy metals are carcinogenic, though not in trace amounts. Chronic deposition of heavy metals causes their accumulation in the body beyond the permissible amount.

Heavy metals used in eyeshadows and mascara can bind to the retinal epithelium over long-term exposure.

UV filters, which form 20% of sunscreen products, are emerging pollutants. The recommended application of sunscreens on beaches causes their wash-off during recreational activities, which adds to marine pollution. Organic UV filters later undergo photodegradation and generate reactive oxygen species. The by-products of this degradation have oestrogenic activity, which disrupts the sexual outcome of marine fishes. On the other hand, inorganic UV filters accumulate and generate hydrogen peroxide. Hydrogen peroxide has a bleaching effect on coral reefs and human skin.³ Traces of organic UV filters were detected in human breast milk samples in 75% of cases, demonstrating significant exposure of suckling neonates.

Parabens used as preservatives are linked to endocrine-disrupting and carcinogenic activity; however, there is currently no scientific evidence supporting this. Nevertheless, various in vitro studies show that parabens stimulate the epidermal growth factor responsible for carcinoma. The authors of a study indicated that there has been a substantial increase in the amount of parabens in water resources, which clearly shows that the use of parabens has increased over the years, even though wastewater treatment plants are efficient in treating parabens.

Plastic microbeads used in cosmetics are insoluble in water as well as non-biodegradable. It has been observed that microplastics easily escape sewage treatment. They are small and thus cannot be trapped.

These plastic microbeads further add to plastic in landfills. Plastic microbeads are made up of low-density and high-density plastics; the former remains in the marine sediment and the latter floats on water. As there is no effective method of removing them from the environment completely, there are reports of their consumption by aquatic animals.⁶

Owing to its broad-spectrum activity, triclosan is widely used in cosmetics. However, studies indicate it to be amongst the topmost emerging pollutants. A study conducted in Japan stated that rivers of that region contain triclosan at levels of nanograms per litre. Moreover, chlorinated water in swimming pools converts it into a yet more toxic chlorinated derivative. Triclosan has high lipophilicity and, owing to this, bioaccumulates in algae and other aquatic organisms. Exposure to TCS can produce negative effects on human health, including thyroid function impairment, endocrine disruption, oxidative stress and liver carcinogenesis.⁶

There has been elevated usage of skin-lightening creams in the last decade, and most of them contain hydroquinone as their active ingredient. Hydroquinone has varied side effects depending on the sensitivity of the skin and the term of exposure. Yellowing and discolouration of the skin have been reported.¹ Hydroquinone is toxic to animals, as it retards their growth and causes irreversible oxidative damage.

1,4-Dioxane is employed in most cosmeceutical foaming products. Reports state that overexposure to this particular molecule causes genotoxicity and various types of cancer. In a study, it was found that mice exposed to 1,4-dioxane-containing water developed skin cell carcinoma and hepatocellular carcinoma.³

In the above discussion, the use and harmfulness of cosmetic ingredients have been emphasised. However, the fact that the cosmetic industry is growing and expanding implies that the burden of environmental and human toxicity will be ever-increasing. The development of sustainable cosmetic products can pave a pathway for the future cosmetic industry and cosmeceutical researchers.

Sustainable cosmetics prioritise the use of natural and organic ingredients that are responsibly sourced, ensuring minimal harm to ecosystems and promoting biodiversity. They also focus on using renewable resources and reducing the consumption of non-renewable materials. In addition, sustainable cosmetics emphasise eco-friendly packaging, such as recyclable or biodegradable materials, to minimise waste and reduce pollution.

Furthermore, sustainable cosmetics promote ethical practices throughout the supply chain, including fair trade, cruelty-free testing and responsible manufacturing processes. They prioritise transparency and consumer education, providing clear information about ingredients, sourcing and manufacturing practices. The adoption of sustainable cosmetics supports a more conscious and responsible approach to personal care, aligning with the principles of environmental conservation and social well-being. By choosing sustainable cosmetics, consumers contribute to the preservation of natural resources, the reduction of waste, and support for ethical and socially responsible initiatives within the beauty industry.

Sustainable cosmetic products are derived from natural ingredients, and the life cycle of such a product is environmentally friendly. The raw material is extracted from natural resources and then transformed into a product that is well tolerated by humans.

Owing to the wide variety of natural cosmetic products available in tropical Asian countries such as India, Sri Lanka and Vietnam, researchers can work on quality control parameters of these materials to develop a sustainable yet reliable quality product.

Bom et al. listed various natural plants and their extracts, together with their cosmeceutical uses. The authors looked into each category of cosmeceutical and suggested natural alternatives. The multifunctional capabilities of these natural products add more benefits for the consumer; for example, rice and walnuts should be used for exfoliation instead of plastic microbeads. There are various ingredients, such as carrot seed oil, that can be used to prevent sun damage instead of UV filters.⁷

However, the efficiency and sustainability of these natural ingredients are to be assessed so as to develop a product that is sustainable throughout its life cycle.

Considering the shift towards green consumerism and a sustainable lifestyle, sustainable cosmetics could play a pivotal role in this era. Sustainable cosmetics can reduce cosmetic environmental pollution.

In a study of Sri Lankan herbal cosmetic ingredients, Nadeeshani Dilhara Gamage et al. found that herbal cosmetics have considerable potential for serving the purpose of varied cosmeceutical requirements. The authors also explained the growing demand for herbal cosmetics in Western countries.⁸

The cosmetic industry is growing, and so is the need to look into the damage caused by it. Consumers as well as the environment are at high risk from increasing cosmetic pollution. Analytical studies should be carried out to assess pollutant levels in natural water bodies and sediments. Systematic surveys should be carried out to understand the usage of, and level of exposure to, cosmeceuticals. There should be mandatory adherence to the restriction levels imposed by regulatory authorities concerning the use of heavy metals and preservatives. Simultaneously, alternative research should be carried out to work on the quality, efficiency and sustainability parameters of naturally occurring cosmeceutical ingredients. Sustainable cosmetics have the potential to benefit consumers, industries and the environment. They also offer enormous scope for cosmeceutical formulation scientists in developing and analysing sustainable cosmetics.