Featured,  Science,  Sustainability,  Toxic Exposure,  Water Pollution

Nanoparticles and Sunscreen Products: Toxicity to Sea Life in Coastal Waters

By Roberta Attanasio

The debate on the safety of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles contained in sunscreen products is still on. Some scientists have raised concerns about the negative impact that these tiny particles — generally between one and 100 nanometers (between one and 100 billionths of a meter) across — may have on human health. Due to their small size, nanoparticles might do harm to humans by seeping through the skin and into the bloodstream. A few months ago, despite the widespread safety concerns, Paul Wright (a toxicology expert at RMIT University) told The Guardian that sunscreen nanoparticles don’t get past the outermost dead layer of human skin cells. In contrast, Paul Westerhoff (a professor at Arizona State University’s School of Sustainable Engineering and the Built Environment) told The New York Times that the products have not been thoroughly studied and are minimally regulated — he concluded: “I’m just saying we need to figure out if we should worry.”

We need to figure out if we should worry not only in terms of human health, but also in terms of toxicity to the environment.

Photo Credit: Frank Kovalchek, licensed under CC BY 2.0

About a year ago, Antonio Tovar-Sánchez (Department of Global Change Research, Mediterranean Institute for Advanced Studies, Esporles, Balearic Island, Spain) and collaborators reported the potential effects of commercial sunscreens released in nearshore waters by beachgoers. The researchers sampled surface nearshore waters of three beaches around Majorca Island and demonstrated that sunscreen products are a significant source of organic and inorganic chemicals that reach the sea with potential ecological consequences on the coastal marine ecosystem, inhibiting the growth of some species of marine phytoplankton or adding essential micronutrients that may stimulate the growth of others.

In a new study published July 28, 2014 (Sunscreens as a Source of Hydrogen Peroxide Production in Coastal Waters), Antonio Tovar-Sánchez and his collaborator David Sánchez-Quiles show that titanium dioxide and zinc oxide nanoparticles — when exposed to solar radiation —  produce significant amounts of hydrogen peroxide (H2O2), a strong oxidizing agent able to generates high levels of stress on phytoplankton, the microscopic organisms that feed marine animals, from small fish to shrimp to whales.. 

The researchers went to Majorca Island’s Palmira beach on the Mediterranean along with about 10,000 beachgoers, a small portion of the more than 200 million tourists that flock to Mediterranean shores every year. Based on lab tests, seawater sampling and tourism data, they concluded that titanium dioxide nanoparticles contained in sunscreen products are largely responsible for a dramatic summertime spike in hydrogen peroxide levels in coastal waters. 

The researchers point out, in a press release, that other than staying indoors, slathering on sunscreen is currently the best way to protect the skin from the sun’s harmful rays. However, when sunbathers splash into the ocean to cool off, some of their lotions and creams get rinsed into the water, react with ultraviolet light from the sun and form new compounds (such as hydrogen peroxide) that could be toxic.

Back in 2010, Johannes Jacobs and collaborators argued that the marketing of sunscreens containing titanium dioxide nanoparticles constitutes a morally unacceptable societal experiment  — it is a large scale societal experiment due to the introduction of the technology before the hazards of the technology can be fully assessed and it is morally unacceptable as it violates four reasonable moral conditions for societal experimentation.  They proposed a set of actions to move towards acceptability:

  • Closing the existing information gap.
  • Setup of monitoring tools and gathering data from the conducted societal experiment.
  • Start continuous evaluation of available quantitative risk and benefits.
  • Ongoing engineering design for safety.
  • Altering legislation so that it incorporates the experimental nature of introducing novel technologies into society.

Sadly, not much has been done by regulators during the past years as it relates to the proposed set of actions. Although the new study on the release of hydrogen peroxide at levels hazardous for sea life in coastal waters helps to attenuate the information gap, much more research must be carried out in a timely fashion to address the concerns raised by the widespread use of sunscreen products containing titanium dioxide nanoparticles.   


  • Ray Kinney

    Nanosized TiO2 Exposure Resulted in Neurotoxicity via Impairing NMDA Receptor-mediated Postsynaptic Signaling Cascade in Mice
    Lei Sheng
    Given the paper above:
    If nano TiO2 sunscreen is slathered on by hundreds of swiming pool recreating children
    elevate the water in contaminant, are we sure ENOUGH that internal body exposure is not elevating to harmful levels by some route, percutaneous or otherwise? We better be REAL Sure! Neuroexcitotoxic pathology in many very serious diseases is currently looking at Lead, BMAA, MSG, etc. as possibly being accumulative in neuron damage via impairment of NMDA receptor regulation (for ALS, PD, MS and others).
    Are we sure we are looking closely enough to clear sunscreen use???

  • Simon Suarez

    Sally, there is a difference between designing precautions and implementing them. I’m not sure there is much interest in protecting the environment from these nanoparticles of dubious safety. Plus, as another commenter (Ray) mentions, we don’t know much about nanoparticles toxicology. Then, how can we have proper precautions in place? I doubt we do.

  • Ray Kinney

    Sunscreen-derived metal nanoparticle pollution is one thing, but just wait until the industry produces vast quantities of products containing even more toxic nanometals such as lead and cadmium, small enough to stay suspended for hundreds of miles in our waters… to expose fish gill and gut (and human drinking water). Toxicity might take an exponential jump in exposure potential, and pathogenic risk. Who is going to fund pointedly investigative research enough that the threat of industrial profit biases are tempered enough to provide for better societal wellbeing? Lead and cadmium health degradation is already on a vast scale, from legacy, and current product dispersal and subsequent degradation forming pollution.Nanoscale metals need very careful assessment. IMHO

    • sally white

      I thought lead and cadmium nanoparticles are used mostly for semiconductor applications. How would they get in the water unless there is a huge disrespect of precautions to avoid dispersal in the environment? I trust that precautions are in place to keep them out of the way.

      • Ray Kinney

        I seriously doubt that lead and cadmium nanoparticles will be restricted only to semiconductor use in the future. And, I seriously doubt that there are adequate precautions…. and ‘disrespect of precautions’has not been uncommon in our current state of contaminant dispersal. Who is going to assure that precautions are in place…. and adequate, the same entities that are currently massively polluting for profit? Also, zinc used as nanoparticles in sunscreen, widely dispersed in aquatic habitats,very likely is toxic to the populations of salmon we are working very hard to recover. Are we really so sure we are not poisoning human populations with any of this technology? ‘Disrespect of precautions’ is common. I don’t think that we know enough about nanoparticle toxicology yet to begin to have confidence that our precautions will remain adequate. IMHO

  • Jean Russeau

    I like you brought up the “societal experiment”, this is something that is not discussed as it should. While we read about the dangers, or potential dangers, of nanoparticles in sunblocks and cosmetics of all sorts, we fail to understand why nanoparticles are in there, even though their safety has not been approved. We all serve as guinea pigs, and once we guinea pigs get sick because of these ingredients of unproven safety, regulations will be slowly developed and even more slowly implemented. However, first we have to do our job as guinea pigs by involuntarily testing things that we slather on our skin.

    • mgnd88

      The entire world is a huge guinea pig, made up of billions of very small ones. In this case, the case of the study presented in this post, the guinea pigs are the sea creatures, that suffer because of our sunscreens. As you said, humans are guinea pigs too, and so I wonder if the hydrogen peroxide that comes from these nanoparticles is bad for the sea life as well as for us, may be less as we don’t stay in the water that long. But think of the creatures that live there, breathe in there, eat in there, etc. etc.

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