Elsevier

Marine Pollution Bulletin

Volume 136, November 2018, Pages 464-471
Marine Pollution Bulletin

Microplastic and charred microplastic in the Faafu Atoll, Maldives

https://doi.org/10.1016/j.marpolbul.2018.09.023Get rights and content

Highlights

  • Microplastic abundance was surveyed in the Faafu Atoll (Maldives).

  • Microplastic particles and charred microparticles were found in sediments and seawater.

  • Contamination was higher in the inner reef area.

  • Chemicals associated to the microparticles were highlighted.

Abstract

Microplastics are recognized as a growing threat for the marine environment that may even affect areas generally considered pristine. In this work we surveyed the microplastic contamination in the Faafu Atoll (Maldives, Indian Ocean) across twelve sampling station, located either inside or outside the reef rim. Sediments and seawater samples were collected. Despite the remoteness of the atoll, the scarce local population and low touristic annual afflux, the detected average abundance were 0.32 ± 0.15 particles/m3 in the surface water and 22.8 ± 10.5 particles/m2 in the beach sediments. Polymers identified through Fourier-Transform Infrared spectroscopy were mostly polyethylene, polypropylene, polystyrene, polyvinylchloride, polyethyleneterephtalate, and polyamide. Elastomeric residues and charred microparticles were also found. In particular, the charred microparticles were prevalently located nearby the inhabited island and they might be considered a peculiarity of the area, related to local practice of burning plastic waste at the shoreline.

Introduction

Plastic has undoubtedly extraordinary properties: is easy to process, durable, lightweight and it has low production costs. These properties are the reasons of its capillary use across the world and of its exponential production. It has been estimated that the cumulative value of worldwide plastic production has already exceed the 5 billion tons and it is expected to increase to 33 billion tons by 2050 (Plastics Europe, 2016).

A side effect of this mass production is that an enormous quantity of plastic waste ends up into the ocean due to improper disposal (from 4.8 to 12.7 million metric tons each year) and accordingly to anticipated trends, the number will continue to grow (Jambeck et al., 2015). Plastic is just now so abundant that it has been proposed as a new stratigraphic indicator of Anthropocene (Zalasiewicz et al., 2016).

Once introduced into the environment, plastic may persist for decades due to its chemical properties (Barnes et al., 2009; Ivar do Sul and Costa, 2014), and undergo over time to disintegration into smaller fragments under the combined effect mechanical breakdown caused by waves, UV induced photolysis, and biological degradation (Browne et al., 2007; Barnes et al., 2009; Ceccarini et al., 2018).

This process lead to the formation of very tiny particles – called microplastics (smaller than 5 mm) that represent the new challenge of the plastic contamination problem (Eriksen et al., 2013; Lusher et al., 2015): over 92% of all plastic items currently found at sea are microplastic (Moore, 2008). Open ocean water bodies (Cole et al., 2011; Desforges et al., 2014; Hidalgo-Ruz et al., 2012; Lusher et al., 2014), beaches and coastlines (Claessens et al., 2011; Hengstmann et al., 2018; Moore et al., 2002; Zhang et al., 2018), subtropical oceanic gyres (Brach et al., 2018; Ory et al., 2017), polar areas (Lusher et al., 2015; Obbard, 2018), deep ocean sediments (Van Cauwenberghe et al., 2015), and freshwater systems (Eriksen et al., 2013; Vaughan et al., 2017; Wagner and Lambert, 2018) have been already documented to accumulate microplastics.

Microplastic may severely affect marine wildlife. Main problems arise due to ingestion (Gall and Thompson, 2015): microplastic particles are mistaken by food because their size, shape and colour (Schuyler et al., 2014) by the marine fauna as zooplankton and larval fish (Desforges et al., 2015; Sun et al., 2017; Steer et al., 2017), sessile invertebrates (Wright et al., 2013) sea turtles (Camedda et al., 2014) marine birds (Van Franeker et al., 2011) and fish species (Boerger et al., 2010). In addition to direct mechanical effects, i.e. particles may entangle block or abrade feeding appendages and internal organs (Wright et al., 2013), a variety of indirect effects is also observed: harmful substances present as ingredient in the microplastic particles may leach into the digestive tract reducing survival, feeding, immunity or antioxidant capacity (Browne et al., 2007), organic and metal contaminants may be accumulated from surrounding water and found an easy enter inside the organism (Koelmans et al., 2016); a wide range of rafting alien species and microbial communities may found in microplastic a vector to colonize ecosystems (Barnes, 2002; Kirstein et al., 2016).

Although worldwide attention to the marine plastic litter has been grown in the last decades, together with the number of scientific publications devoted to the microplastic topic, knowledge about the abundance, composition and size distribution of plastic debris in areas remote to human civilization is still considered scarce (Thompson et al., 2004; Bergmann et al., 2015; van Sebille et al., 2015). This information is fundamental to support the management of the problem (GESAMP, 2015).

Maldivian coral reef is the seventh largest coral reef system on the globe, with a total surface of 8920 km2, accounting for 3.13% of the world's reef area (Spalding et al., 2001) and probably accounting for the highest coral cover values in the western Indian Ocean (Goreau et al., 2000). Unfortunately, several threats are contributing to its environmental decline. Some are natural such as coral bleaching, algal overgrowth, invertebrate outbreaks and coral diseases (Montano et al., 2012; Saponari et al., 2018), other are human-related, such as coral mining, pollution, fishing, tourism and land reclamation (Jaleel, 2013).

The microplastic contamination in the Maldivian area and the possible impact on the coral reef ecosystem has been still scarcely investigated (Barnes, 2004, Browne et al., 2011; van Sebille et al., 2015; Imhof et al., 2017). Considering that the Republic of Maldives is constituted by a human population of about 300 thousands located in an archipelago of about 1200 islands, and it is now facing a rapid economic growth, scientific investigation is needed in order to plan sustainable development policies and efficient waste management practice.

Under this light, in this study we surveyed the level of microplastic contamination along the Faafu Atoll, a complex of 23 inhabited and uninhabited islands with a total of about 3000 locals, that is far about 140 km from the capital city Malè and 720.000 km from India, the closest country. For the best of our knowledge, this is the first on field investigation regarding its microplastic contamination.

Section snippets

Sampling location

The study was conducted during May 2018 in Faafu Atoll, Republic of Maldives (Fig. 1). This atoll is approximately 31 km long and 24 km wide and is subjected to two main oceanic stream/current: one toward southwest-northeast from May to November, and another in opposite direction from December to April (Montano et al., 2012). Twelve different sampling sites (Table 1), among those accessible in two side of the atoll, and showing heterogeneous characteristics in terms of reef morphology and

Abundance of plastic particles in the beach sediments

A total of 824 visible plastic particles were identified across the six surveyed beaches, with an average abundance of 22.7 ± 10.5 plastic particles/m2 (mean ± standard deviation, Fig. 2).

The highest concentration of particles was found at beach BD1 (38.5 ± 15.6 particles/m2) whereas the lowest concentration was found at beach FY (4.2 ± 2.0 particles/m2).

Since plastics larger than >25 mm represented a small percentage of the total plastic debris (as number of items), mesoplastic (5–25 mm) and

Conclusion

This study aimed to examine the microplastic contamination in the Faafu Atoll, a coral Maldivian atoll placed far about 140 km away from the capital city of Malè, and characterized by a low touristic pressure in comparison to the northern Maldivian atolls.

Despite the remoteness of the atoll and limited number of inhabitants, a considerable amount of plastic particles was found in the beach sediments and in the seawater samples collected inside the atoll rim. This result strengthens the

Acknowledgments

This works was financially supported by University of Milano-Bicocca – Mahre center. We warmly thank the Captain and the crew of Rhantari research vessel for the support during the sampling operation and our students Chiara D'Alconzo, Andrea Ghezzi and Erika Colombo for the help in performing the experiments.

References (67)

  • M.C. Fossi et al.

    Are baleen whales exposed to the threat of microplastics? A case study of the Mediterranean fin whale (Balaenoptera physalus)

    Mar. Pollut. Bull.

    (2012)
  • M.C Fossi et al.

    Large filter feeding marine organisms as indicators of microplastic in the pelagic environment: The case studies of the Mediterranean basking shark (Cetorhinus maximus) and fin whale (Balaenopteraphysalus)

    Mar. Env. Res.

    (2014)
  • S.C. Gall et al.

    The impacts of debris in marine life

    Mar. Pollut. Bull.

    (2015)
  • E. Hengstmann et al.

    Microplastic in beach sediments of the Isle of Rügen (Baltic Sea) - implementing a novel glass elutriation column

    Mar. Pollut. Bull.

    (2018)
  • H.K. Imhof et al.

    Mar. Pollut. Bull.

    (2017)
  • J.A. Ivar do Sul et al.

    The present and future of microplastic pollution in the marine environment

    Environ. Pollut.

    (2014)
  • A. Jaleel

    The status of coral reefs and the management approaches: the case of the Maldives

    Ocean Coast. Manag.

    (2013)
  • H.B. Jayasiri et al.

    Quantitative analysis of plastic debris on recreational beaches in Mumbai, India

    Mar. Pollut. Bull.

    (2013)
  • I.V. Kirstein et al.

    Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles

    Mar. Environ. Res.

    (2016)
  • A.L. Lusher et al.

    Microplastic pollution in the Northeast Atlantic Ocean: validated and opportunistic sampling

    Mar. Pollut. Bull.

    (2014)
  • K.J. McDermid et al.

    Quantitative analysis of small-plastic debris on beaches in the Hawaiian archipelago

    Mar. Pollut. Bull.

    (2004)
  • C.J. Moore

    Synthetic polymers in the marine environment: a rapidly increasing, long-term threat

    Environ. Res.

    (2008)
  • C.J. Moore et al.

    A comparison of neustonic plastic and zooplankton abundance in southern California's coastal waters

    Mar. Pollut. Bull.

    (2002)
  • R.W. Obbard

    Microplastics in polar regions: the role of long range transport

    Curr. Opin. Environ. Sci. Health

    (2018)
  • N.C. Ory et al.

    Amberstripe scad Decapterus muroadsi (Carangidae) fish ingest blue microplastics resembling their copepod prey along the coast of Rapa Nui (Easter Island) in the South Pacific subtropical gyre

    Sci. Total Environ.

    (2017)
  • M. Steer et al.

    Microplastic ingestion in fish larvae in the western English Channel

    Environ. Pollut.

    (2017)
  • X. Sun et al.

    Ingestion of microplastics by natural zooplankton groups in the northern South China Sea

    Mar. Pollut. Bull.

    (2017)
  • L. Van Cauwenberghe et al.

    Mar. Environ. Res.

    (2015)
  • J.A. Van Franeker et al.

    Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

    Environ. Pollut.

    (2011)
  • R. Vaughan et al.

    Microplastics in the sediments of a UK urban lake

    Environ. Pollut.

    (2017)
  • S.L. Wright et al.

    The physical impacts of microplastics on marine organisms: a review

    Environ. Pollut.

    (2013)
  • J. Zalasiewicz

    The geological cycle of plastics and their use as a stratigraphic indicator of the anthropocene

    Anthropocene

    (2016)
  • H. Zhang et al.

    Occurrences of organophosphorus esters and phthalates in the microplastics from the coastal beaches in north China

    Sci. Total Environ.

    (2018)
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