Data for: Are UV filters better together? A comparison of the toxicity of individual ultraviolet filters and off-the-shelf sunscreens to Daphnia magna

Organic ultraviolet filters (UVFs) are known to contaminate many aquatic
ecosystems, with much environmental contamination attributed to the use of
UVF-containing skin care products such as sunscreens during aquatic
recreation. Most studies addressing the impact of sunscreen contamination
have focused on the effects of UVFs under the assumption that they are the
primary contaminants of concern from sunscreen pollution; however, the
extent to which the toxicity of UVFs is representative of the
environmental impacts of the whole sunscreen mixture is unknown. To
address this knowledge gap, this study compared the mixture toxicity of
five off-the-shelf sunscreen spray products containing the UVFs
avobenzone, homosalate, octisalate, octocrylene, and oxybenzone to the
toxicity of each UVF in isolation to the freshwater invertebrate Daphnia
magna. It was found that sunscreen toxicity was not proportional to their
total UVF content, as the sunscreen containing the fewest UVFs was
approximately equivalent to the sunscreen with the most UVFs, causing ≥90
% mortality and inhibiting all daphnid reproduction over 21 d exposures.
Sunscreen toxicity was typically lower than expected when compared to the
toxicity of each individual UVF within the mixture, as some sunscreens
causing ≤20 % mortality contained octocrylene and/or oxybenzone at
concentrations exceeding those which caused 90 % mortality during exposure
to the UVF alone. Despite sunscreens causing large impairments in
reproduction, growth, and metabolism, poor correlations existed between
the severity of most sublethal endpoints with respect to the measured UVF
content of each sunscreen. Overall, these results indicate that potential
antagonistic relationships between sunscreen ingredients can greatly
reduce the toxicity of UVFs, creating more uncertainty regarding the level
of threat that UVFs pose to the environment as a result of sunscreen
contamination.