Sunscreens and the Environment

Coral reefs are under threat from multiple stressors. The chief culprit may be climate change, but some argue that sunscreen ingredients also play a role in damaging these vital barrier reefs which occur in more than 100 countries. The New York Chapter of the Society of Cosmetic Chemists (NYSCC) held a one-day symposium in September to highlight the issues and opportunities to protect coral reefs, which are said to contain more than 25% of marine species, according to one expert.

The symposium was organized and chaired by Howard Epstein, PhD. In his opening remarks, Epstein detailed his love of the ocean—a love that dates back to his undergraduate years when he took a scuba diving class.

“Melanoma rates are on the rise. We need sunscreen,” he observed. “But what impact does sunscreen have on coral reefs? That’s why we’re here today.”

A Matter of Opinion?

No one can deny that coral reefs are in trouble—or can they? Dietram Scheufele, PhD, University of Wisconsin-Madison, explained that algorithmically-curated online information is tailored to what we already believe, rather than challenge potential misperceptions. At the same time, the public is battered by information overload every day. To make sense of it all, people have moved from broadcast to narrowcast information consumption. Now, facts fit the individual’s beliefs. And that’s had a destructive impact on society.

“Information by itself doesn’t change hearts and minds,” Scheufele explained. “In today’s environment, heuristics rule. We all use as little information as possible to make decisions.”

In the heuristic technique, problem-solving is accomplished using various shortcuts to produce less than optimal solutions. Unfortunately, as Scheufele pointed out, heuristics become powerful replacements for information and also serve as filters for information. As a result, the same scientific facts can mean different things to different people.

In this environment, how can experts reach consumers with the best science? Scheufele had some suggestions:

• Use strategies tailored toward specific outcomes; such as information, behavior and awareness;
• Use language that minimizes motivated reasoning; that is, speaks to shared, rather than tribal, values;
• Communicate value propositions that address salient public concerns, scientific or not; and
• Appreciate weak ties, especially those algorithmically-curated information ecologies.

The speaker suggested looking outside one’s network to hear other voices and opinions.

“We all have networks,” he concluded. “But the most valuable person in our network is the one who connects us to other networks.”

Pollutants of Concern

Michael T. Connelly, PhD, Smithsonian Tropical Research Institute, told attendees that corals are in a global crisis due to climate change.

“The ocean is hotter, more acidic and less oxygenated, that’s why they bleach,” he explained.

Connelly provided an overview of the main pollutant classes, with a special emphasis on the effects of antibiotic exposure on coral health and microbial symbiosis.

Pollutants of concern include: Heavy metals, persistent organic pollutants, nutrients and fertilizers, oil compounds and derivatives, pharmaceuticals and antibiotics, radioactive substances, biocides and pesticides, and microplastics. Missing from his list? UV filters. Land-based sources of pollutants include agricultural runoff via drainage canals, oil spills, treated and untreated wastewater, and anti-fouling paints. Dredging and sedimentation also contributes to the problem.

“Several different classes of antibiotics have been detected in seawater, sediments and coral tissues,” said Connelly. “[But) few studies have assessed impacts of environmental antibiotics exposure on coral health, despite corals’ important microbial symbioses.”

He noted that antibiotics significantly alter Pocillopora bacteria community composition and reduces diversity. Further, antibiotics treatment activates coral immunity, inflammation and molecular stress responses. Connelly showed evidence of a single microfragment in the antibiotic treatment exhibited “polyp bailout,” indicative of a toxic response. When corals are exposed to antibiotics, there is reduced bacteria diversity, lower abundance of beneficial microbes and an increase in potential pathogens.

National Academies’ Study

Earlier this year, the National Academies of Science, Engineering and Medicine released a study entitled, “Review of Fate, Exposure and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health.”

Charles Menzie, PhD, chair of the National Academies Committee on Sunscreens Environmental Impact, reviewed the study and its recommendations. He began by outlining the desirable sunscreen characteristics for humans and the environment. These characteristics include:

• Protection from UV radiation’s harmful effects;
• Safe for human use;
• Cosmetically acceptable;
• Low risk to ecosystem services;
• Low risk to aquatic environments; and
• Accessible and affordable.
• According to Menzie, researchers had two tasks:
• Review the fates and effects in aquatic environments for future application in ecological risk; and
• Ascertain the implication of potential changes in sunscreen usage on public health.

In his remarks, Menzie pointed out that only about a third of the US population regularly uses sunscreen, although use is higher during outdoor activities and at the beach (70-80%). But even when sunscreen is applied, dosage does not usually meet recommendations for optimal effectiveness. Similarly low are other strategies such as protective clothing, seeking shade and sun avoidance. Researchers noted that decreased use of sunscreen with no changes in other behaviors will likely lead to negative effects on health.

With that in mind, researchers made two recommendations:

• EPA should conduct an ecological risk assessment for all currently marketed UV filters and any new ones that become available.
• EPA, partner agencies (including NOAA, FDA, NIH, CDC, NSF and DOI), and sunscreen formulators and UV filter manufacturers should conduct, fund or support, and share research and data on sources, fate processes, environmental concentrations, bioaccumulation studies, modes of action, and ecological and toxicity testing for UV filters alone and as part of sunscreen formulations. Additionally, epidemiological risk modeling and behavioral studies related to sunscreen usage should be conducted to better understand human health outcomes from changing availability and usage.

Menzie noted that any policy and management actions taken will require consideration of their human and ecological outcomes and coordination across multiple agencies and organizations to develop creative solutions.

Environmental Risk of UV Filters

According to Carys Michelmore of the University of Maryland, UV filters are a diverse group of contaminants of emerging concern (CECs) contained in a number of consumer products, with differing physical and chemical characteristics that determine their occurrence, fate and effects in the aquatic environment.

But in her opening remarks, Michelmore admitted that climate change is the biggest threat to coral reefs. Still, she noted the ubiquitous presence of UV filters in seawater, sediment and organism tissue at varying concentrations. The material comes from wastewater, point exposure (sunbathers), and storm water/land run-off. Of course, detection does not mean harm. Channeling Paracelsus, she noted that concentration and exposure duration are critical in determining toxicity.

Michelmore reviewed a 2017 Hawaii Monitoring Project that she said was the first US study to look at coral tissue and sediment. Researchers looked at multiple sites, took multiple samples and investigated 13 UV filters. Regarding oxybenzone concentrations in surface seawater, Michelmore noted that the UV filter was ubiquitous—it was detected at all 19 sites. Levels correlated with the number of people and were higher in shallow water. But the study also raised questions, such as “if I measure UV filter levels at the surface, is that what the coral is exposed to?”

As a result, Michelmore recommended that monitoring studies get expanded with detailed spatial and temporal analyses. She suggested the investigation include partitioning and exposure pathways. After all, is seawater the only route of exposure to corals? Finally, Michelmore recommended laboratory FATE studies to measure persistence, degradation, bioavailability, bioaccumulation and metabolism.

“Scientists need to work together to conduct more studies to prioritize chemical pollutants of concern for coral reefs and to develop new testing methods for corals,” she concluded. “Management, regulation and marketing decisions need to be based on the current state of the science and considerations for both environmental and human health.”

Protect Reefs & People

The session’s final speaker, Nicole Crane PhD, Cabrillo College and co-lead, One People One Reef, warned that coral reefs are in steep decline worldwide due to multiple factors, including warming temperatures, ocean acidification, local and large-scale pollution, and overfishing.

She cited a 2016 study (Downs et al) that found up to 10,000 tons of sunscreen are thought to wash into the ocean each year. While data vary, some inorganic and organic UV filters have been shown to disrupt coral growth and reproduction and lead to bleaching.

Crane reviewed the growth rates of coralites, the stony cups built by each polyp. While growth rates can vary significantly, they are generally slow—between 1 and 20cm a year. During the growth cycle, crustose coralline algae (CCA) provide a landing pad for coral larvae to settle on the reef. These larvae need the right settlement conditions to attach and grow.

“Fish depend on coral and coral depend on fish,” noted Crane. “Fish diversity is important. If we can keep these ecosystems healthy, they may be able to defend themselves (from pollutants).”

Crane works in the Ulithi Atoll, studying the effects that coral degradation has on the local population. She noted that indigenous people are also connected to coral and reefs play a critical role in providing food and income.

“We work with the Ulithi people to understand what is happening to their reefs. It is a living system and is critical to the health of the people,” she explained.

But Crane delivered good news, too. If managed properly, the reefs can be resilient and people play an important role in that management. Every stressor that is reduced makes a difference, she insisted.

“We can’t solve all the problems at once. But if we identify the hot spots, we can see improvement,” she concluded. “It is incumbent on all of us to work together to solve daunting problems, especially those we have a chance of solving.”

But solving problems, as every cosmetic chemist understands, requires technology, science and collaboration.