Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557-0258, United States.
Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97333, United States.
Water Res. 2018 Aug 1;139:281-290. doi: 10.1016/j.watres.2018.03.062. Epub 2018 Mar 27.
Both nanoparticulate (nZnO and nTiO) and organic chemical ultraviolet (UV) filters are active ingredients in sunscreen and protect against skin cancer, but limited research exists on the environmental effects of sunscreen release into aquatic systems. To examine the trade-offs of incorporating nanoparticles (NPs) into sunscreens over the past two decades, we targeted endpoints sensitive to the potential risks of different UV filters: solar reactive oxygen production in water and disruption of zebrafish embryo development. First, we developed methodology to extract nanoparticles from sunscreens with organic solvents. Zebrafish embryos exposed to parts-per-million NPs used in sunscreens displayed limited toxicological effects; nZnO particles appeared to be slightly more toxic than nTiO at the highest concentrations. In contrast, seven organic UV filters did not affect zebrafish embryogenesis at or near aqueous solubility. Second, to simulate potent photo-initiated reactions upon release into water, we examined methylene blue (MB) degradation under UV light. nTiO from sunscreen caused 10 times faster MB loss than nZnO and approached the photocatalytic degradation rate of a commercial nTiO photocatalysts (P25). Organic UV filters did not cause measurable MB degradation. Finally, we estimated that between 1 and 10 ppm of sunscreen NPs in surface waters could produce similar steady state hydroxyl radical concentrations as naturally occurring fluvic acids under sunlight irradiation. Incorporation of NPs into sunscreen may increase environmental concentrations of reactive oxygen, albeit to a limited extent, which can influence transformation of dissolved substances and potentially affect ecosystem processes.
纳米颗粒（nZnO 和 nTiO）和有机化学紫外线（UV）过滤器都是防晒霜中的有效成分，可以预防皮肤癌，但关于防晒霜释放到水生系统中对环境的影响的研究有限。为了研究在过去二十年中将纳米颗粒（NPs）纳入防晒霜的利弊权衡，我们针对对不同 UV 过滤器潜在风险敏感的终点：水中的太阳能活性氧产生和斑马鱼胚胎发育的中断。首先，我们开发了用有机溶剂从防晒霜中提取纳米颗粒的方法。暴露于防晒霜中使用的百万分之几的 NPs 的斑马鱼胚胎显示出有限的毒理学效应；在最高浓度下，nZnO 颗粒似乎比 nTiO 略有毒性。相比之下，在水溶解度或接近水溶解度的情况下，七种有机 UV 过滤器不会影响斑马鱼胚胎发生。其次，为了模拟释放到水中后的强光引发反应，我们检查了在紫外光下亚甲基蓝（MB）的降解。防晒霜中的 nTiO 比 nZnO 快 10 倍导致 MB 损失，接近商业 nTiO 光催化剂（P25）的光催化降解速率。有机 UV 过滤器不会导致 MB 可测量的降解。最后，我们估计，在地表水中，1 至 10ppm 的防晒霜 NPs 可能会产生与阳光照射下天然富里酸相似的稳定态羟基自由基浓度。将 NPs 纳入防晒霜可能会增加环境中活性氧的浓度，但程度有限，这会影响溶解物质的转化，并可能影响生态系统过程。
