MONITORING OF MESO AND MICROPLASTIC DEBRIS IN PLAYA GRANDE BEACH(TENERIFE, CANARY ISLANDS, SPAIN) DURING A MOON CYCLE

María González-Hernández1, Cintia Hernández-Sánchez2,3, Javier González-Sálamo1,3,

Jessica López-Darias1, and Javier Hernández-Borges1,3,*

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.2Departamento 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.3Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias, Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, s/nº. 38206 San Cristóbal de La Laguna, Spain.

INTRODUCTION

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSIONS

Microplastics abundance in the coastal zones varies not only over space but also over time. As a result, the sampling period and the spatial distribution are of special concern. Concerning the periodicity of the sampling, many studies

frequently develop a single sampling while others develop a long-term evaluation, in many cases once a month. In order to accomplish this, it is important to know how the abundance of microplastics varies on small temporal scales, which

can also differ from one place to another, as a result of the local variation in hydrological processes; of particular interest is also the monitoring during a moon cycle, in order to study the possible influence of the tides on microplastics arrival.

To the best of our knowledge, microplastics monitoring during a complete moon cycle has only been developed in two occasions1,2, in the first case in different parts of an estuary and, in the second, in different parts of a sandy beach (water

sampling).

In this work, the occurrence and composition of meso- (5-25 mm) and microplastics (1-5 mm) in Playa Grande beach (Tenerife, Canary Islands, Spain) was monitored during a complete moon cycle on the different moon phases between 17th

June and 16th July 2019. A total of 10 points were sampled each day finding an average content of mesoplastics of 18 g/m2 (0.36 g/L) and of microplastics of 78 g/m2 (1277 items/m2 or 1.6 g/L). Polypropylene (PP) and polyethylene (PE) were

the most abundant types of plastics. Among the analysed particles, fragments accounted for 83 % of the total. The obtained results revealed that microplastics presence could not be related in this case with the tides but with the orientation

and strength of the wind.

REFERENCES ACKNOWLEDGEMENTS1 A. R. A. Lima, M. Barletta, M. F. Costa, J. A. A. Ramos, D. V Dantas, P. A. M. C. Melo, A. K. S. Justino and G. V. B. Ferreira, J. Fish Biol., 2016, 89, 619–640.

2 J. A. A. Ramos and W. V. N. Pessoa, Mar. Pollut. Bull., 2019, 142, 428–432.

3 C. B. Crawford and B. Quinn, Microplastics, standarisation and spatial distribution, Microplastic Pollution, 2017, 101–130.

4 M. González-Hernández, C. Hernández-Sánchez, J. González-Sálamo, J. López-Darias and J. Hernández-Borges, Mar. Pollut. Bull., 2020, 150,110757

J.G.S. would like to thank “Cabildo de Tenerife” for the Agustín de Betancourt contract at the Universidad de La Laguna. Authors thank the Research Support General Service (SEGAI) of the Universidad de La Laguna for the IR analysis. The support of the Fundación CajaCanarias (project 2016TUR07) is also granted.

➢The analysis of the variation of meso and microplastic debris in Playa Grande beach (Tenerife, Canary Islands, Spain) during a moon cycle (sampling was develop on full moon, third quarter moon, new moon, first quarter moon and fullmoon again) revealed important variations in the amounts of plastics that arrive to the beach.

➢Up to 16,000 particles were found during the whole study being the distribution of morphology and plastic types very similar to those of found in previous studies of the Canary Islands.

➢No apparent relation was found between the moon phase and the presence of meso and microplastics. Indeed, an important effect of the wind direction and speed and, therefore, on the wave heights, was found (see ref. 4 for moreinformation).

MICROPLASTICS ANALYSIS

ATR-FTIR analysis

❑ Instrument: Bruker IFS 66/S

❑ Source: High-intensity

❑ Beamsplitter: KBr

❑ Detector: Deuterium triglycine sulphate

❑ Operational mode: Double sided, forward-backward, 10 kHz

❑ Wavenumber range: 4000-550 cm-1

❑ Resolution: 8 cm-1

❑ Rate: 16 scans per sample

Microplastics separation

❑ Flotation with NaCl saturated solution (≈ 1.2 kg/L)

Vacuum assisted filtration

Classification by shape(visualization in stereomicroscope)

Sample collection

❑ Beach zone: High tide line

❑ Sampling points number: 10

❑ Sampling points distribution: 10 m from each other

❑ Sampling area: 50 cm x 50 cm

❑ Sampling depth: 5 cm

❑ In situ sieving: 1 mm and 5 mm

SAMPLED BEACHES

Beach name Playa Grande

Municipality Arico

Sampling date06/17/19 (full Moon); 06/26/19 (third quarter); 07/01/19 (new Moon);

07/09/19 (first quarter); 07/16/19 (full Moon)

Coordinates N 28o 9’ 9.068’’ O 16o 25’ 54.443’’

Total length 120 m

Touristic impact Low/medium

Orientation Northeast

Sand type Fine (black)

Cleaning Sporadic days (developed by volunteers)

Number of sampling points 10

Table 1. Data of the sampled beach and sampling days.

Fig. 1. Location of the Canary Islands and of the beach studied in this work (Playa Grande), as well as the satellite view of the beach showing the location of the sampling points.

Mesoplastics

Total content Maximum Minimum Average

Total weight of microplastics (g)* 226.9141 157.1329 5.8460 45.38282

g/m2 - 63 2.3 18

g/L - 1.3 0.047 0.36

Table 2. Amount of mesoplastics (5-25 mm) found in Playa Grande during a Moon cycle (5 sampling days).

*Mesoplastics were weighted using a precision balance.

Table 3. Amount of microplastics (1-5 mm) found in Playa Grande during a Moon cycle (5 sampling days).

*Microplastics were weighted using a precision balance.

MicroplasticsTotal content Maximum Minimum Average

Number of particles detected 15958 6427 472 3192Total weight of microplastics (g)* 164.5479 92.0869 2.2961 32.9096Items/m2 6383 2571 189 1277g/m2 - 327 0.92 78g/L - 6.5 0.018 1.6

Fig. 2. Microplastic amount and number of microplastic particlesfound in Playa Grande during a moon cycle (June–July 2019).

Fig. 3. Percentage of microplastics and tar collected in Playa Grandeafter flotation separation in a NaCl saturated solution.

Fig. 4. Results obtained after the visual classification of the microplasticscollected at Playa Grande following the classification of Crawford et al3.

Fig. 5. Results obtained after the chemical classification of the particles collected atPlaya Grande and submitted to flotation in a saturated NaCl solution. PP:polypropylene; PE: polyethylene; PS: polystyrene.