[Coral-List] Sunscreen & coral

Reynertson, Kurt [CPCUS] KReynert at its.jnj.com
Wed Feb 13 00:19:07 UTC 2019

Hello Coral-listers,

I'm a long-time reader who has never posted. This topic, however, is fascinating to me both from a scientific and policy angle. My disclaimer: I am posting as an interested scientist, and not as a representative of where I work. 

I have read the primary literature on this topic with careful attention. What I fail to understand is how everyone assumes that "oxybenzone and octinoxate kill coral" based on the 2 papers in the primarily literature (1, 2).

Do these 2 papers really represent a weight of evidence? I think that is what Terry Hughes was addressing in the Conversation post. 

Paper 1: The Danovaro paper places coral fragments in plastic bags and treats them to extremely high concentrations of sunscreen formulations (10 - 100 uL/L). It's not exactly clear what is really being tested, as the methods are not adequately described. And it seems that the stress of placing a sensitive organism in a plastic bag is more than unusual. Coral toxicologists I've talked to dismiss the relative significance of this paper. 

Paper 2: The Downs paper is primarily based on cell culture studies. Cell culture has utility in science, but is NEVER used for environmental risk assessments. So the "toxicity" is questionable. The planulae assay is potentially more relevant, but has numerous methodological issues, including a lack of proper controls, the use of DMSO as a cosolvent, and test concentrations several orders of magnitude higher than what's been found by most of the monitoring studies. There’s no validation of the method for in situ coral, which are especially sensitive to fluctuations in light, temperature, salinity, etc. The monitoring portion of the paper is based on single samples taken from 5 sites in the US Virgin Islands and 7 sites Hawaii (most were below the LOQ). No replicates or blanks reported, and the analytical methods are lacking. Also: oxtinoxate is not even part of this study.
That's it. From a risk assessment standpoint, both studies would be assigned a Klimish score of 3, meaning they cannot be used for regulatory purposes. [FYI, Two more papers were published last month (3,4). They also lack some critical controls and still put these ingredients in the "low risk category."] That does not feel like a solid weight of evidence. If we are to accept this as a standard for banning a chemical, then there are many thousands of chemicals we should ban at the same time, including many of the "reef-safe" UV filters. There are certainly more than 2 papers on coral toxicity from titanium and zinc, and yet everyone seems to readily accept these ingredients are "reef-safe" in the same breath as they damn oxybenzone.

In fact, there's no regulatory or scientific criteria for "reef-safe." It's an opportunistic marketing term. What makes a sunscreen reef-safe anyway? I wish someone could explain that to me in scientific terms.

So should all sunscreen be banned based on the precautionary principle? The dermatologists and skin cancer experts do not think so. UV radiation is a Group 1 carcinogen, on par with smoking, and the WHO says that 4/5 of skin cancers are considered preventable. Hence the policy discussion.

P.S., These 2 ingredients are approved for use by heath agencies and regulatory bodies worldwide. Oxybenzone is NOT banned in Europe as someone suggested (5).

1) Danovaro, et al. (2008) Sunscreens cause coral bleaching by promoting viral infections. Environmental Health Perspectives. 116: 441-447.
2) Downs, et al. (2016) Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Arch Envtl 
3) He, et al. 2019. Comparative toxicities of four benzophenone ultraviolet filters to two life stages of two coral species. Science of the Total Environment 651: 2391-2399.
4) He, et al. 2019. Toxicological effects of two organic ultraviolet filters and a related commercial sunscreen product in adult corals. Environmental Pollution 245: 462-471.
5) EU Cosmetic Regulation http://data.europa.eu/eli/reg/2009/1223/2016-08-12

Kurt Reynertson, PhD

More information about the Coral-List mailing list