UV filter
One of the major applications of UV filters is their use as sunscreens to protect skin from sunburn and other sun/UV related damage.
UV filters span[clarification needed] the color spectrum and are used for a wide variety of applications.
Hoods can counteract this, as they offer some protection against impact and shade optical elements, thus preventing lens flare.
Also, quality UV filters offer some protection against lens contamination while minimizing the inherent additional distortion.
Since excessive UV radiation can cause sunburn, photoaging, and skin cancer, care products such as sunscreen usually include a classification for the specific wavelengths they filter.
UV-absorbing compounds are used not only in sunscreen, but also in other personal care products, such as lipstick, shampoo, hair spray, body wash, toilet soap, and insect repellent.
[2][3] Reflection and scattering are accomplished by inorganic physical UV filters, such as titanium dioxide (TiO2) and zinc oxide (ZnO).
[5] Several UV filters have been detected at ppb or ppt levels[vague] in surface water and wastewater, with maximum concentrations in the summertime.
[7][8] Because most UV filters are lipophilic, they tend to bioaccumulate in aquatic environments and food chains originating from them.
Confirming bioaccumulation, several studies have shown the presence of UV filters in aquatic organisms.
The 4-methyl-benzylidene camphor was detected in the muscle tissue of trout in Swiss and German waters, while traces of Ethylhexyl methoxycinnamate and octocrylene were found in shellfish in the Mediterranean and Atlantic coasts of France.
[9][10] Furthermore, eighteen organic sunscreens were found in sediments of Japanese rivers and lakes, at concentrations ranging from 2 to about 3000 ng/g.
[12] Also, Goksøyr et al. (2009) reported concentrations of organic UV-filters in open waters of the Pacific Ocean, providing evidence of the persistence and wide dispersion of these components in the marine environment.
Some studies have recorded increased hydrogen peroxide or H2O2 levels in beaches directly attributable to UV filter transformation.
Among the UV filters that result in coral bleaching according to studies are Ethylhexyl methoxycinnamate, benzophenone-3, and 4-methyl benzylidene camphor, even in very low concentrations.
In the presence of other UV filters, Benzotriazole, and humic acids, Benzophenone -3 degradation was observed through the loss of hydroxyl and benzoyl functional groups resulting in the formation of 2,4 dimethyl anisole.
Octyl methoxycinnamate (OMC) can undergo photoisomerization, photodegradation, and photodimerization to obtain several dimers and cyclodimers isomers.
The major sources of BP-3 are reported to be human recreational activities and wastewater treatment plant (WWTP) effluents.
[citation needed] The photochemical fate of PABA may be impacted by water constituents, e.g., NO3−, dissolved organic matter (DOM), and HCO3−.
However, in the presence of free radical scavengers such as carbonate forms and natural organic matter (NOM), the photodegradation of PABA decreased.
In sunscreen formulations, avobenzone exists predominantly in the enol form, which has a maximum absorption at wavelengths ranging from 350 to 365 nm depending on the solvent used.
The double bond of the enolic form was shown to be more reactive in conditions of aquatic chlorination than the aromatic ring.
However, it has some side effects, including its ability to produce reactive oxygen species (ROS) and penetrate the human skin after exposure to UV light.
Prenatal exposure to EHMC can affect both the reproductive and neurological development in the offspring of rats, which can be a cause for concern because humans are routinely exposed to this compound through the use of sunscreens and other cosmetics.
