The Environmental Impact of Sunscreen
By Mia Lane, Zuzana Simackova, Raine Spentzos and Lily Weston, honourable mention: Leah Pettit
INTRODUCTION
Our project area is the environmental impact of sunscreen. We were drawn to this topic due to Hawaii recently banning sunscreens that harm coral reefs, and sunscreens with other chemicals that lead to environmental degradation. However, before we chose this we looked into potentially studying the environmental damage caused by next-day delivery or caused by pharmaceuticals. We decided to look into sunscreens as there was a clear experiment we could carry out and the topic was more specific, and therefore easier to research. Additionally, we could see clear areas that could be researched by each chemistry, biology, physics and ESS. Our research outcomes are to find which chemicals are worse for the environment and whether the sunscreens that contain these chemicals are more or less effective than the ‘environmentally-friendly’ ones.
areas of research
THE CHEMISTRY OF UV FILTRATONHow do the chemicals in sunscreen protect the skin?
|
How Sunscreen worksLooking into the physics behind sunscreen.
|
The impact of sunscreen on aquatic food chainsHow does sunscreen pollute water through contaminating the food chain?
|
The Impact of sunscreen on coral reefsExploring the toxic chemicals, octinoxate and oxybenzone, and how they are toxic to corals and cause them to be bleached and die.
|
How sunscreen works
- Radiation from the Sun is made up of electromagnetic waves ranging from infrared to ultraviolet rays
- The average distance between the Earth and the Sun over one Earth orbit is about 150,000,000,000 m, then it will take about 8 minutes for radiation from the Sun to get to Earth.
- Some electromagnetic radiation from the Sun is absorbed by the earth’s atmosphere and the rest reaches the Earth’s surface
- UV is absorbed by the ozone layer and re-emitted as heat, eventually heating up the stratosphere
- Some of this heat is re-radiated to outer space while some is sent to the Earth’s surface
- Sunscreens work by stopping UV radiation
- UV radiation:
- Shorter wavelengths than visible light
- Majority of energy emitted by the sun is in the form of UV however the ozone (layer of the planet’s atmosphere) filters out a majority of the UV radiation before it reaches the earth
- UV can cause permanent damage to skin and eyes even in its filtered form on the earth and if astronauts are exposed to UV in space their skin would burn in a matter of seconds
- The amount of UV a person is exposed to depends on several factors, including proximity to the equator, altitude, time of day and cloudiness
- UV radiation is divided into categories based on its wavelength, UV-B radiation is to blame for sunburn and UV-As are responsible for long-term skin damage and sunscreen is able to protect from both
- Sunscreen is able to filter out the UV radiation before it is able to damage our skin
- Inorganic particles, such as titanium dioxide or zinc oxide, form a physical barrier, reflecting or scattering UV waves
- These are almost indistinguishable from white paint when sunscreens were first invented
- But nanotechnology allowed completely clear sunscreens to be created that are just as effective – they contain the same ingredients except the inorganic particle are very tiny and therefore become invisible
- Organic components meanwhile absorb UV rays and release their energy as heat.
The chemistry of UV filtration
The environmentally harmful chemical present in sunscreen, called Oxybenzone and Octinoxate, are largely responsible for UV-A and UV-B filtration.
Oxybenzone and Octinoxate are two of the 17 active ingredients approved by the Food and Drug Administration for use in sunscreens. They absorb radiation and enter into excited states. Upon their return to their ground states, they emit the absorbed energy as radiation of a longer wavelength that is no longer harmful. They dissipate this energy by an alternate pathway. The different molecules in the 17 active ingredients absorb photons of different wavelengths, e.g. oxybenzone captures photons in the 290-320 nm range. Consequently, commercial sunscreens contain a range of active ingredients to ensure that a broader spectrum of wavelengths is captured. Oxybenzone absorbs UV-B and UV-A II radiation and Octinoxate absorbs UV-B radiation. When Octinoxate absorbs UV radiation in this range, it is degraded into photoproducts; upon exposure it gets converted to into a less UV-absorbent form. This conversion can however be at least partly prevented by other UV blockers. Sources: https://pubchem.ncbi.nlm.nih.gov/compound/oxybenzone https://inchemistry.acs.org/content/inchemistry/en/atomic-news/suncreen-science.html https://www.science.gov/topicpages/u/uv-filter+octyl-methoxycinnamate+omc http://www.smartskincare.com/skinprotection/sunblocks/sunblock_octinoxate.html In detail Atomic spectra produce absorption lines. Molecules are made up of several atoms that can vibrate and rotate. Each vibration or rotation is equal to a different energy state. Hence, there are many more energy transitions possible, which are closely spaced. Therefore, instead of absorbing energies of specific frequencies like atoms, molecules absorb group of frequencies, forming absorption bands. |
Each molecule has a unique absorption range, so using several different molecules leads to better UV protection
|
THe impact of sunscreen on aquatic food chains
In a study, Spanish scientists looked at the environmental impact of sunscreen. Most sunscreen contains titanium dioxide and zinc oxide, which react with UV light. They form compounds such as hydrogen peroxide when in water, and high amounts of this chemical.High amounts of hydrogen peroxide could harm phytoplankton. If this happens, larger animals which feed on the plankton could be affected
This is because if plankton are killed, the impact could be huge, because they are the main food source for larger marine animals. Additionally, bio-magnification means that chemicals such as oxybenzone are increasingly concentrated inthe tissues of tolerant organisms at successively higher levels in a food chain.
A large number of ultraviolet (UV)-absorbing compounds, usually present in personal-care products, textiles exposed to UV radiation and plastics materials, elicit hormonal activity in vitro and in vivo. Induction of vitellogenin, alterations in gonads, decrease in fertility and reproduction, and feminisation in sex characteristics of male fish have been associated with frequently-used UV filters, including benzophenones and camphor-related substances.*
*(Díaz-Cruz, M. and Barceló, D. (2009). Chemical analysis and ecotoxicological effects of organic UV-absorbing compounds in aquatic ecosystems. TrAC Trends in Analytical Chemistry, 28(6), pp.708-717.)
This is because if plankton are killed, the impact could be huge, because they are the main food source for larger marine animals. Additionally, bio-magnification means that chemicals such as oxybenzone are increasingly concentrated inthe tissues of tolerant organisms at successively higher levels in a food chain.
A large number of ultraviolet (UV)-absorbing compounds, usually present in personal-care products, textiles exposed to UV radiation and plastics materials, elicit hormonal activity in vitro and in vivo. Induction of vitellogenin, alterations in gonads, decrease in fertility and reproduction, and feminisation in sex characteristics of male fish have been associated with frequently-used UV filters, including benzophenones and camphor-related substances.*
*(Díaz-Cruz, M. and Barceló, D. (2009). Chemical analysis and ecotoxicological effects of organic UV-absorbing compounds in aquatic ecosystems. TrAC Trends in Analytical Chemistry, 28(6), pp.708-717.)
The impact of sunscreen on coral reefs
· Oxybenzone and octinoxate (both chemicals that have been previously found in sun cream) are toxic to corals and cause them to bleach and die. Coral bleaching happens when corals ‘expel the energy supplying algae that live within them’. In fact, half of our coral reefs have been lost due to climate change, a crisis worsened by this chemical contamination
· However, there is a debate between scientists over whether the impact of sun cream on coral reefs is significant enough to warrant the implementation of policies banning these chemicals
· ‘Hawaii last year became the first state to ban sales of sunscreens with oxybenzone and octinoxate, chemicals that are found in as much as three-quarters of sunscreens on the U.S. market. Key West, Fla., followed suit last month, making it the first city to ban sales of such sunscreens. Florida and California are considering similar bans.
Source: https://www.washingtonpost.com/national/health-science/sunscreen-bans-aimed-at-protecting-coral-reefs-spark-debate--among-scientists/2019/03/15/b35d4030-4512-11e9-8aab-95b8d80a1e4f_story.html?noredirect=on&utm_term=.4d78892938af
– this shows that environmentalists and law makers are tackling the issue, suggesting that it is a serious problem
· Furthermore, some dermatologists think these bans could have adverse effects on public health. ‘Meanwhile, some dermatologists and sunscreen makers oppose the bans, saying they will lead to fewer people protecting themselves from sun exposure and increase the risk of skin cancer.’
· However, ‘Scientists agree that the major culprit in coral degradation is climate change. C. Mark Eakin, an oceanographer and the coordinator for NOAA’s Coral Reef Watch program, described sunscreen damage to corals as death by a thousand cuts. “Climate change,” he added, “has been like a nuclear blast.” “If we don’t deal with climate change,” he said by email, “it won’t matter what we do about sunscreens.”’. This would suggest that the sun cream issue is insignificant in comparison to climate change, and that we should instead be focusing our efforts elsewhere
· Additionally, ‘Some scientists say it is too early to know how damaging sunscreen is to corals because the studies are limited. About a half-dozen studies examine the effects of oxybenzone on corals, and some researchers have questioned the methods behind the studies.’ Because we do not know the exact impact of sun cream on coral reefs, we should perhaps also focus less on changing the chemical formulae of sun cream
· However, there is a debate between scientists over whether the impact of sun cream on coral reefs is significant enough to warrant the implementation of policies banning these chemicals
· ‘Hawaii last year became the first state to ban sales of sunscreens with oxybenzone and octinoxate, chemicals that are found in as much as three-quarters of sunscreens on the U.S. market. Key West, Fla., followed suit last month, making it the first city to ban sales of such sunscreens. Florida and California are considering similar bans.
Source: https://www.washingtonpost.com/national/health-science/sunscreen-bans-aimed-at-protecting-coral-reefs-spark-debate--among-scientists/2019/03/15/b35d4030-4512-11e9-8aab-95b8d80a1e4f_story.html?noredirect=on&utm_term=.4d78892938af
– this shows that environmentalists and law makers are tackling the issue, suggesting that it is a serious problem
· Furthermore, some dermatologists think these bans could have adverse effects on public health. ‘Meanwhile, some dermatologists and sunscreen makers oppose the bans, saying they will lead to fewer people protecting themselves from sun exposure and increase the risk of skin cancer.’
· However, ‘Scientists agree that the major culprit in coral degradation is climate change. C. Mark Eakin, an oceanographer and the coordinator for NOAA’s Coral Reef Watch program, described sunscreen damage to corals as death by a thousand cuts. “Climate change,” he added, “has been like a nuclear blast.” “If we don’t deal with climate change,” he said by email, “it won’t matter what we do about sunscreens.”’. This would suggest that the sun cream issue is insignificant in comparison to climate change, and that we should instead be focusing our efforts elsewhere
· Additionally, ‘Some scientists say it is too early to know how damaging sunscreen is to corals because the studies are limited. About a half-dozen studies examine the effects of oxybenzone on corals, and some researchers have questioned the methods behind the studies.’ Because we do not know the exact impact of sun cream on coral reefs, we should perhaps also focus less on changing the chemical formulae of sun cream
METHODOLOGY
|
|
RESULTS
Suncream brand |
LDR Resistance (x10^3 ohms) |
Garnier Clear+Protect |
103 |
Nivea |
105 |
Garnier UV Sport |
164 |
Aloha |
178 |
Piz Buin |
72.3 |
No suncream (control) |
577 |
CONCLUSION
We have found that the sunscreens that contain damaging chemicals such as titanium dioxide and octinoxate are the most effect, as shown in our data. Aloha and Garnier UV Sport lead to a reading of 164 Ohms and 178 Ohms respectively, this was significantly higher than the other brands. This high resistance means that the least light was let through, as LDRs decrease resistance with more light, and the brands were the most effective. These sunscreens are the most effective in keeping people safe from the sun, however they are also the most damaging for the environment which leads to difficult question of whether environmental or human health should be prioritised. We believe that scientists need to focus on developing sunscreen that is both effective and does not contain these harmful chemicals in order to create a sustainable way to protect people from the sun.