This study aimed to expand knowledge on the sources and potential impacts of eight UV filters using water samples from beaches and waste-water plants on Gran Canaria island, Spain. The researchers report that high visitor numbers and sheltered conditions raised pollution levels at beaches, and that seawater concentrations sometimes presented a high level of environmental risk.
Ultraviolet (UV) filters are chemicals that disperse UV light and are increasingly used in personal care products – especially sunscreens and lotions – as well as in industry to extend the lifetime of plastics and other materials. They are considered to be emerging pollutants, with research to date indicating certain damaging environmental effects and, in some cases, a tendency to bioaccumulate (build up within the bodies of living things). In July 2022, the EU added three UV filters to the Surface Water Watch List1, i.e. butyl methoxydibenzoylmethane, also known as avobenzone; octocrylene; and benzophenone-3, also known as oxybenzone.
Understanding the dynamics of UV-filter pollution and the potential impact at concentrations found in the environment is at an early stage of development. This study builds on this knowledge by measuring concentrations of UV filters in samples from beaches and waste-water treatment plants in Gran Canaria island, Spain, and comparing them with existing data on environmentally harmful effects.
The researchers took monthly samples between May and October 2019 and measured the concentration of eight different chemicals. They took sea-water samples at around midday from three beaches with different patterns of use by local and international tourists and sampled wastewater at the inlet and outlet of three waste-water treatment plants to assess the removal rate for the different substances. They also identified seven published studies on the effects of three of the chemicals at known concentrations on specific organisms, including microalgae, invertebrates and fish, to determine the levels at which these substances are potentially harmful.
The researchers report that octocrylene (OC)was found in every sample of seawater, with the most common, benzophenone-3 (BP3), found in 83% of seawater samples. On the island’s Las Canteras beach, overall levels of BP3 peaked dramatically in August according to the researchers. They suggest that this may be because the beach is primarily used seasonally by locals and is enclosed by a natural barrier, resulting in a low water-replacement rate. Arinaga beach, also frequented mainly by locals, showed a similar seasonal pattern, they say, but with much lower concentrations, possibly because it is exposed to much higher water replacement. On Playa del Inglés, however, they say that, in addition to August’s BP3 peak, there was a spike in October, possibly because it is visited all year round by international tourists, with intermediate concentrations coinciding with moderate levels of water replacement.
The researchers say they also found UV filters in every sample of waste-water treatment plant influent and effluent. They report varying levels of removal by treatment plants, with removal rates varying from above 50% for four of the substances (OC, BP3, 4-methylbenzylidene camphor (4MBC), and butyl methoxydibenzoylmethane (BMDBM)), but dropping as low as 17% for one substance (methylene bis-benzotriazolyltetramethylbutylphenol (MBP)).
The researchers say that OC, whenever present, was found at levels posing a high risk for all species previously studied, while 4MBC was found at medium- or high-risk levels in every sample. They report varying results for BP3, including high-risk levels in several cases, particularly from July onwards, for the microalgae and mussel species previously studied.
Levels of UV filters in seawater at beaches are largely determined by direct input from personal-care products used by beach visitors, argue the researchers, with sea-water concentrations heavily influenced by water-replacement rates at individual beaches. They suggest that although such chemicals are often present in waste-water emissions they are mostly released in open water and quickly become highly diluted.
The researchers posit that the presence and toxicity of chemicals in the environment is related to their tendency to dissolve in water or organic solvents, with more water-soluble compounds (such as BP3) more likely to be detected in water samples, and highly fat-soluble compounds (such as OC) more likely to accumulate in living organisms. With some chemicals found in seawater at levels presenting a high environmental risk, they say that issues such as bioaccumulation, products of degradation and chemical-combination effects also need to be taken into consideration.
Cadena-Aizaga, M. I., Montesdeoca-Esponda, S., Sosa-Ferrera, Z. and Santana-Rodríguez, J. J. (2022) Occurrence and environmental hazard of organic UV filters in seawater and wastewater from Gran Canaria Island (Canary Islands, Spain). Environmental Pollution 300: 118843.
To cite this article/service:
“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.
Notes on content:
The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.
- 9 november 2022
- Generaldirektoratet för miljö