Microplastic Debris in Six Beaches of Tenerife (Canary Islands, Spain)
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MICROPLASTIC DEBRIS IN SIX BEACHES OF TENERIFE (CANARY ISLANDS, SPAIN) Clara Álvarez-Hernández1, Carlos Cairós1, Jessica López-Darias1,2, Elisa Mazzetti1, Cintia Hernández-Sánchez3,4, Javier González-Sálamo1,4, and Javier Hernández-Borges1,4,* 1Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL). Avda. Astrofísico Fco. Sánchez, s/nº. 38206 San Cristóbal de La Laguna, Spain. 2Servicio General de Apoyo a la Investigación (SEGAI), Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n◦, 38206 La Laguna, (Tenerife), Spain. 3Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Forense y Legal y Parasitología, Área de Medicina Preventiva y Salud Pública, Escuela Politécnica Superior de Ingeniería, Sección de Náutica, Máquinas y Radioelectrónica Naval, Universidad de La Laguna (ULL). Vía Auxiliar Paso Alto, nº 2, 38001 Santa Cruz de Tenerife, Spain. 4Instituto Universitario de Enfermedades Tropicales y Salud Pública, Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, s/nº. 38206 San Cristóbal de La Laguna, Spain. INTRODUCTION Relative recent evidence has shown that the southward flowing Canary Current is leaving on the Canary Islands important amounts of marine debris, especially plastic, from the open North Atlantic Ocean, mainly on North and Northeast exposed beaches1–3. However, up to the development of this study by the end of 2018, no works had focused on the study of the presence of microplastics in beaches of the occidental islands (Tenerife, La Palma, La Gomera and El Hierro), which is highly necessary in order to fully evaluate their content, distribution and also the possible detection of “hot spots” or “black points” with an extremely high content of microplastics. In this work, the occurrence and composition of microplastics (1-5 mm) was evaluated in six beaches of the island of Tenerife for the first time4. Two of them were located at the North coast (El Socorro and San Marcos) and the rest in the South littoral (Leocadio Machado, El Porís, Los Abriguitos and Playa Grande). Sampling was developed during the months of October, November and December 2018 (depending on the beach). Isolated microplastics were identified by attenuated total reflection Fourier transform infrared spectroscopy. All beaches showed a relatively low content of microplastics, except Playa Grande, which showed an average content of 98.97 g/m2. The major polymers found were polyethylene (PE), polypropylene (PP) and polystyrene (PS), accounting for 69 %, 18 % and 4 %, respectively. EXPERIMENTAL SAMPLED BEACHES MICROPLASTICS ANALYSIS Table 1. Characteristics of the six sampled beaches of Tenerife (Canary Islands, Spain). El Socorro San Marcos Los Abriguitos Leocadio Machado El Porís Playa Grande Municipality Los Realejos Icod de los Vinos Arico Granadilla de Abona Arico Arico Microplastics separation X:342.950,02 X:331.108,97 X:358.740,03 X:348.563,88 X:359.434,32 X:359.438,20 Vacuum assisted filtration Location (UTM) Y:3.141.891,82 Y:3.140.303,61 Y:3.113.886,72 Y:3.102.922,52 Y:3.116.222,21 Y:3.114.911,95 ❑ Flotation with NaCl saturated Total longitude (m) 210 131 99 69 77 77 solution (≈ 1.2 kg/L) Orientation NW NW S SE SE NE Sampling date 5/10/18 4/10/18 1/12/18 1/12/18 29/11/18 10/10/18 Sampling points 11 4 6 5 6 8 Intertidal zone (m) 8 14 8 41 13 5 Cleaning of the Daily Daily Alternating days Daily Alternating days Never beach Classification by shape (visualization in stereomicroscope) ATR-FTIR analysis ❑ Instrument: Bruker IFS 66/S Sample collection ❑ Source: High-intensity ❑ Beach zone: Above high tide line ❑ Beamsplitter: KBr ❑ Sampling points number: Depending on the beach length ❑ Detector: Deuterium triglycine sulphate ❑ Sampling points distribution: 10 m from each other ❑ Operational mode: Double sided, forward- backward, 10 kHz Fig. 1. Location of the Canary Islands and of the beaches of Tenerife studied in this work as ❑ Sampling area: 50 cm x 50 cm ❑ Wavenumber range: 4000-550 cm-1 well as the satellite view of the six beaches showing the sample points. A) El Socorro (Los ❑ Sampling depth: 5 cm ❑ Resolution: 8 cm-1 Realejos); B) San Marcos (Icod de los Vinos); C) Los Abriguitos (Arico); D) Leocadio Machado ❑ In situ sieving: 1 mm, 2 mm and 5 mm (Granadilla de Abona); E) El Porís (Arico); F) Playa Grande (Arico). ❑ Rate: 16 scans per sample RESULTS AND DISCUSSION Table 2. Characteristics of the sampled beaches and amount of microplastics found in each of them. Beach El Socorro San Marcos Los Abriguitos Leocadio Machado El Porís Playa Grande Length (m) 165 131 99 33 77 74 Number of sampling points 11 4 6 5 6 8 Number of particles detected 36 2 24 144 118 5943 Total weight of microplastics (g) 0.4309 0.0011 0.3475 3.0053 5.1753 197.9481 Items/m2 13.1 2.0 16.0 115.5 78.7 2971.5 g/m2 0.16 0.0011 0.23 2.4 3.5 99 g/L 0.0031 0.0000 0.0046 0.048 0.069 2.0 Fig. 2. Detail of the microplastic recovered from Playa Grande (Tenerife, Canary Islands, Spain) sorted by particle size. Fig. 3. Particle size distribution of microplastics found in Playa Grande (Tenerife, Canary Fig. 4. Results obtained after the visual and chemical classification of the fragments recovered from the six beaches. PP: polypropylene; PE: polyethylene; PS: Polystyrene; U: unknown. Islands, Spain). CONCLUSIONS ➢ The sampling of 6 beaches of the island of Tenerife revealed a low microplastic content (below 115.5 items/m2, 3.5 g/m2 and 0.069 g/L) above the high tide line, except for Playa Grande beach, located on the South of the islands and with a NE orientation, which is not periodically cleaned, and which suffers from strong microplastic debris episodes as a result of the Canary Current. ➢ Microplastic content of Playa Grande (2971.5 items/m2, 99 g/m2 and 2.0 g/L) is comparable, or even higher, to those previously found in some beaches of the oriental islands of the archipelago and clearly suggests the need of developing periodical monitoring programs for further studies. ➢ Most microplastics obtained were fragments of PP, PS and PE (ATR-IR was used for microplastic characterization) which is also in accordance with global plastic production. REFERENCES ACKNOWLEDGEMENTS 1 A. Herrera, M. Asensio, I. Martínez, A. Santana, T. Packard and M. Gómez, Mar. Pollut. Bull., 2018, 129, 494–502. J.L.D. and J.G.S. would like to thank “Cabildo de Tenerife” for the Agustín de Betancourt contract at the Universidad de La Laguna (ULL). C.C. would like to thank the Canary Agency of Economy, Industry, Trade and Knowledge (ACIISI) of the Canary Islands Government for the contract to support research 2 C. Edo, M. Tamayo-Belda, S. Martínez-Campos, K. Martín-Betancor, M. González-Pleiter, G. Pulido-Reyes, C. García-Ruiz, F. Zapata, F. Leganés, F. activities of the International Research Campus (CEI) of the Universidad de La Laguna (ULL). Authors thank the Research Support General Service (SEGAI) of Fernández-Piñas and R. Rosal, Mar. Pollut. Bull., 2019, 143, 220–227. the Universidad de La Laguna (ULL) for the laboratory facilities and IR analysis. The support of the Fundación CajaCanarias (project 2016TUR07) is also 3 J. Baztan, A. Carrasco, O. Chouinard, M. Cleaud, J. E. Gabaldon, T. Huck, L. Jaffrès, B. Jorgensen, A. Miguelez, C. Paillard and J.-P. 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