Can short-term data accurately model long-term environmental exposures? Investigating the multigenerational adaptation potential of Daphnia magna to environmental concentrations of organic ultraviolet filters

Organic ultraviolet filters (UVFs) are contaminants of concern,
ubiquitously found in many aquatic environments due to their use in
personal care products to protect against ultraviolet radiation. Research
regarding the toxicity of UVFs such as avobenzone, octocrylene and
oxybenzone indicates that these chemicals may pose a threat to
invertebrate species; however, minimal long-term studies have been
conducted to determine how these UVFs may affect continuously exposed
populations. The present study modeled the effects of a 5-generation
exposure of Daphnia magna to these UVFs at environmental concentrations.
Avobenzone and octocrylene resulted in minor, transient decreases in
reproduction and wet mass. Oxybenzone exposure resulted in > 40%
mortality, 46% decreased reproduction and 4-fold greater reproductive
failure over the F0 and F1 generations; however, normal function was
largely regained by the F2 generation. These results indicate that Daphnia
are able to acclimate over long-term exposures to concentrations of 6.59
μg/L avobenzone, ~0.6 μg/L octocrylene or 16.5 μg/L oxybenzone. This
suggests that short-term studies indicating high toxicity may not
accurately represent long-term outcomes in wild populations, adding
additional complexity to risk assessment practices at a time when many
regions are considering or implementing UVF bans in order to protect these
most sensitive invertebrate species.