July 31, 2022

The environmental impact of UV filters

Thanks to rising consumer awareness of sun-induced health risks, as well as efforts from authorities and the industry to develop and promote efficient sun protection, the use of sun protection products is expanding. These important products protect the skin from the detrimental effects of UV radiation, including sunburn, premature skin aging and skin cancer. At the same time, the increased concentration of UV filters in facial care, hand care and full body sunscreens has increased scrutiny on their environmental impact, especially on aquatic organisms.

Some UV filters that are used globally in high amounts – such as octocrylene (OCR; PARSOL® 340) and butyl-methoxydibenzoylmethane (BMDBM; PARSOL® 1789) – have been detected in monitoring studies in both freshwater and marine environments. Due to the global and broad usage, these products are highlighted frequently in the public press, increasing the pressure felt by consumers to find the right balance between protecting the environment and protecting themselves against harmful UV light.

A recent independent review ¹ prepared by environmental experts from ECT Oekotoxikologie (ECT) and published in the leading journal, Science of the Total Environment, now offers a different, more positive perspective on the potential environmental impact of these two UV filters.

The comprehensive review is the product of almost three years of consortium work initiated by the German Cosmetic, Toiletry, Perfumery and Detergent Association (IKW) and funded by a small group of IKW members and UV filter suppliers, including dsm-firmenich. It analyses a multitude of studies addressing the environmental profile of OCR and BMDBM and concludes that the available evidence suggests that neither OCR nor BMDBM fulfils the Persistent, Bioaccumulative and Toxic (PBT) criteria according to EU REACH.

Environmental profile of OCR and BMDBM – filtering fact from fiction

To establish the environmental profile of the two filters within the aquatic environment, the ECT investigators carried out an extensive literature review and meta-analysis of data covering various parameters for both OCR and BMDBM, such as environmental fate and occurrence, bioaccumulation and ecotoxicity (including endocrine effects).

This included evaluating multiple open access publications and data provided by sponsors of the project in the context of regulatory requirements, as well as establishing criteria for the assessment of the quality and relevance of the studies and data.

Based on reliable data at the different endpoints covered in the review, the authors concluded that“neither OCR nor BMDBM fulfils the PBT or vPvB [very persistent, very bioaccumulative] criteria according to EU REACH”.

Here we aim to distil the information in the comprehensive review, to provide you with some key take-aways on the two UV filters.

Bioaccumulation in aquatic organisms

OCR: Data from fish bioconcentration and biomagnification studies indicate that OCR is not bioaccumulative according to EU REACH. The reliable fish bioconcentration factor (BCF) was well below the threshold value of 2000 for the B-criterion.

BMDBM: The available data do not enable a definitive conclusion on the bioaccumulation potential of BMDBM, highlighting an avenue for future study.

Aquatic toxicity testing

OCR: The ECT investigators concluded that “OCR concentrations up to the limit of water solubility were not toxic to microorganisms, algae, corals and adult ﬁsh, and not acutely toxic to daphnids”.

In coral, for example, no effects were observed on coral survival, coral bleaching and zooxanthellae density for species such as Seriatopora caliendrum and Pocillopora damicornis. Other coral effects were only recorded at concentrations considerably above the limit of water solubility. Similarly, in fish, saturated OCR solutions exhibited no acute toxicity to fish species such as zebrafish, and long-term exposure to the UV filter did not impact survival of adult fish such as three-spined sticklebacks.

However, based on the result of a chronic daphnid test, OCR was found to fulﬁl the toxicity criterion according to EU REACH. As a consequence, OCR is currently classified as Aquatic Chronic 1 (H410) to meet the requirements of product safety.

BMDBM: The ECT investigators concluded that “concentrations up to the water solubility limit were shown to be non-toxic to microorganisms, algae, daphnids and corals, and not acutely toxic to ﬁsh. Based on these data, no hazard was identiﬁed for BMDBM”.

Within its water solubility range, the UV filter did not show acute fish toxicity. The results of a chronic fish test performed under EU REACH that were not available at the time of publication also confirmed that BMDBM does not present an environmental hazard. As a result, PARSOL® 1789’s previously assigned environmental self-classification (as ‘safety net’ H413) could be revoked, such that it would no longer have to be classified under this category.

Endocrine activity

Data on endocrine activity from in vitro and in vivo fish screening tests were also assessed due to the potential of endocrine disruption leading to adverse effects on growth, development and functioning, and the overall response to stressors in the environment.

It was found that in “various in vitro assays, the endocrine activity of OCR and BMDBM was only recorded at concentrations substantially above the water solubility limit”, screening tests in fish did “not provide evidence of endocrine effects for the two UV filters”.

Reflecting reality

When evaluating the reliability of ecotoxicity studies, the authors of the review often found the quality of the aquatic toxicity data questionable; several limitations and confounding factors were identified. For instance, in many cases, effects were only seen at concentrations significantly exceeding the water solubility limit of the tested UV filter; no information was provided on preparation of testing solutions and nominal substance concentrations lacked verification by chemical analysis; and/or too high solvent concentrations were used.

These issues can result in overestimation of toxicity or may have physical impacts on the organisms exposed to the substances during testing. Where high concentrations were used, it may not be valid to extrapolate the results to suggest toxicity at lower concentrations of the dissolved substance in a risk assessment context. As a result, many of the publicly available studies on aquatic toxicity were rejected from the review due to quality limitations.

Another factor to consider regarding exposure is that measured concentrations of OCR and BMDBM in the aquatic environment varied widely depending on location and on season (reflecting varied sunscreen use across consumers). Use of local, regional, and seasonal data going forward could therefore help to refine the environmental risk assessment of UV filters.

A shared vision for UV filters

In summary, the ECT review is a key example of a great, industry-led collaborative effort to investigate extensive and conflicting evidence to fully understand the environmental safety and sustainability of two crucial UV filters. The ultimate aim is to ensure that both industry and consumers have access to the most accurate available information.

The review showcases positive and promising data around the environmental profile of both OCR and BMDBM, while also highlighting the limitations of some of the studies that have contributed to the concern amongst industry and consumers. While continued assessment of OCR, BMDBM and other UV filters used in sunscreen products is necessary and ongoing to build a full picture of the impact on the aquatic ecosystem and wider environment, the review indicates that consumers may not have to compromise while using sunscreen to protect themselves against the detrimental effects of UV radiation.

As a responsible, purpose-led company, we at DSM have an obligation to help find the best balance between the environmental and health arguments surrounding UV filters. As well as supporting the ECT review, we are working across many other avenues to improve the quality of scientific data on the potential environmental impact of UV filters so that we can remain eco-conscious and sustainable, while also keeping discussions based on facts, rather than emotion, perception or even false claims.

References

1. Duis, K. et al. Review of the environmental fate and effects of two UV filter substances used in cosmetic products. Sci. Total Environ. 808, 151931 (2022); https://doi.org/10.1016/j.scitotenv.2021.151931