Historical microplastic records in marine sediments: Current progress and methodological evaluation
Graphical abstract
Introduction
The Anthropocene is proposed as the current geological epoch, characterized by remarkable changes in the biological, physical, and chemical processes in the Earth’s systems (Waters et al., 2016). These changes are expected to exhibit a stratigraphic signature different from that of the Holocene epoch. However, this definition is yet to be formalized and officially accepted as such (Finney and Edwards, 2016). The massive infrastructures, substantial agriculture, and distribution systems, along with industrialized societies, are the defining characteristics of the Anthropocene (Donges et al., 2017). The technosphere is defined by Haff (2014) as the interlinked set of communication, transportation, and other systems that act to metabolize fossil fuels and other energy resources. The geologically preservable synthetic man-made artifacts are known as technofossils. These technofossils are stratigraphic markers of the Anthropocene (Zalasiewicz et al., 2014). The incorporation of such materials into the rock record has been observed in recent studies. For instance, Fernandino et al. (2020) reported anthropogenic materials, such as bottle caps, nails, and plastic fragments, cemented in recently formed sedimentary rocks in Brazil. Given the current massive production and mismanagement of plastic items, many are expected to end up buried and become part of the stratigraphic record (De-la-Torre et al., 2021a).
The massification of plastic production dates back to the 1950s (Geyer et al., 2017) and has increased continuously since. In 2019, global plastic production reached 368 million tons, 2.5% more than the previous year (PlasticsEurope, 2020). Moreover, the COVID-19 pandemic has driven greater plastic pollution from personal protective equipment, such as face masks, face shields, and gloves (Aragaw, 2020, De-la-Torre et al., 2021b), and packaging materials (Adyel, 2020). Incorrect disposal or mismanagement of plastic wastes, along with their pronounced durability, turns them into persistent pollutants in the environment (Andrady, 2011). Marine litter interacts and poses a threat to apex predators, such as marine birds, mammals, and reptiles, through ingestion and entanglement (Battisti et al., 2019a, Battisti et al., 2019b, Poeta et al., 2017b, Staffieri et al., 2019).
MPs are plastic particles smaller than 5 mm originated from the breakdown of larger plastics under environmental conditions (secondary MPs) or are manufactured micro-sized plastics (primary MPs) (Cole et al., 2011). Owed to their very small sizes and wide distribution, MPs are found in all environmental compartments, such as sediments, soils, atmosphere, and hydrosphere (De-la-Torre et al., 2020, Dioses-Salinas et al., 2020, Dris et al., 2016, Eriksen et al., 2018), and ingested by a wide range of organisms (Garcés-Ordóñez et al., 2020, Ory et al., 2017, Santillán et al., 2020, Thiel et al., 2018). Upon entering the environment, MPs interact with the physical and chemical medium, potentially serving as a vector of toxic contaminants (Torres et al., 2021), and translocate from prey to predator along the trophic chain (De-la-Torre, 2020). Moreover, plastic items, like expanded polystyrene, interact with different plant assemblages and are seemingly used as opportunistic substrates (Battisti et al., 2020, Poeta et al., 2017a). Hence, the interaction, transport, and fate of MPs can be recognized as a biogeochemical cycle (Bank and Hansson, 2019). The study by Woodall et al. (2014) indicates that the deep-sea sediments are major marine MP sinks. In land, atmospheric movement and deposition are important drivers of MP pollution in freshwater bodies and soils (Constant et al., 2020, Dioses-Salinas et al., 2020). Due to their seemingly ubiquitous presence in sediments and terrestrial deposits, MPs could become suitable stratigraphic indicators of the Anthropocene (Zalasiewicz et al., 2016).
Recent studies determined the temporal record of MPs in stratified sediment cores aiming to evaluate the historical change of MP concentrations across decades (Dahl et al., 2021, Lin et al., 2020, Martin et al., 2020). Along with dating techniques, these methods allow a better understanding of historical trends in MP pollution and, thus, their suitability as indicators of the Anthropocene. Uddin et al. (2021) presented a review of the MPs in sediment profiles and the methods for their chronological reconstruction. Their concluding remarks suggest that 210Pb radioisotope activity is preferred for sediment dating, and MP data should be reported in terms of burial rates (MP m−2 year−1 and g m−2 year−1 if possible). However, the influence of several factors, such as laboratory conditions, standards, and protocols for sampling, MP extraction, polymer identification, and contamination control in sedimentary record studies was not assessed. Laboratory procedures used to investigate MPs require thorough measures to avoid cross-contamination and chemical–analytical techniques to avoid false positives/negatives. Following such procedures are mandatory to assure the quality and veracity of the reported data. Although previous articles have analyzed the methodological steps of MP assessment (Dehaut et al., 2019, Dioses-Salinas et al., 2020), investigating MPs in sediment cores, along with their historical trends, require unique procedural and technical considerations that require standardization. The aim of this paper is to present an up-to-date review of the studies evaluating the concentration of MPs in sedimentary records and analyze the procedural steps carried out. First, the current progress regarding multidecadal MP records was reviewed. Then, we critically analyzed the methodologies involved in MP assessment, with a special focus on those related to MP extraction from the sediment column. We aim to contribute to the procedural protocols in this line of research by presenting the best practices during core sampling, radioisotope dating, and MP analysis.
Section snippets
Literature search
A literature search was conducted in February 2021 to retrieve academic documents evaluating the concentration of MPs in sedimentary records. The Scopus and ScienceDirect databases were consulted with the keywords “microplastics” in conjunction with “core” or “dating” or “210Pb” or “sediment core” or “historical” or “trend”. The references of the retrieved articles were also checked. A total of 19 records were obtained and summarized. The reported MP concentration (MP kg−1) was extracted from
MP abundance across decades
All of the studies consulted agreed that the concentration of MPs has increased over time. For instance, Dahl et al. (2021) investigated the accumulation of MPs in 210Pb-dated cores from Posidonia oceanica meadows along the Spanish Mediterranean coast. MP pollution was negligible until the 1970s, when intensified horticulture started in one of the sampling sites, and then increased dramatically, surpassing previous decades by many orders of magnitude. Evidently, the surface layers were the most
Sampling and dating
For decades, sedimentary cores have been used as tools to reconstruct the chronological trends in contamination of coastal and marine environments, the influence of environmental legislation on the emission of pollutants, and the rate of deposition of contaminants (Muir and Rose, 2007, Valette-Silver, 1993). According to Zou et al. (2019), there are four conditions that must be met to properly assess historical trends in sedimentary cores: (1) Cores must be inert and the perturbation from
Conclusions
MPs are widespread across environmental compartments. One of the main sinks of MPs is the deep-sea sediment, where they are expected to become buried and remain intact over time. Due to their fate and persistence, researchers suggest MPs as convenient stratigraphic markers of the Anthropocene, a proposed epoch characterized by the influence of human actions on the environment. However, whether the Anthropocene epoch should be formally considered as such remains under debate. In recent years, MP
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
The authors would like to thank the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru (VRI-PUCP) for financial support and to the Editor and anonymous reviewers for their constructive comments, which helped us to improve the manuscript.
References (114)
Microplastics in the marine environment
Mar. Pollut. Bull.
(2011)The plastic in microplastics: A review
Mar. Pollut. Bull.
(2017)Surgical face masks as a potential source for microplastic pollution in the COVID-19 scenario
Mar. Pollut. Bull.
(2020)- et al.
Identification of microplastics using Raman spectroscopy: Latest developments and future prospects
Water Res.
(2018) - et al.
Interactions between anthropogenic litter and birds: A global review with a ‘black-list’ of species
Mar. Pollut. Bull.
(2019) - et al.
Identification and quantification of microplastics using Fourier-transform infrared spectroscopy: Current status and future prospects
Curr. Opin. Environ. Sci. Heal.
(2020) - et al.
Microplastics in the Black Sea sediments
Sci. Total Environ.
(2021) - et al.
Occurrence and distribution of microplastics in marine sediments along the Belgian coast
Mar. Pollut. Bull.
(2011) - et al.
Curli production enhances clay-E. coli aggregation and sedimentation
Colloids Surf. B
(2019) - et al.
Microplastics as contaminants in the marine environment: A review
Mar. Pollut. Bull.
(2011)
A temporal record of microplastic pollution in Mediterranean seagrass soils
Environ. Pollut.
Abundance and distribution of microplastics on sandy beaches of Lima, Peru
Mar. Pollut. Bull.
New plastic formations in the Anthropocene
Sci. Total Environ.
Occurrence of personal protective equipment (PPE) associated with the COVID-19 pandemic along the coast of Lima, Peru
Sci. Total Environ.
Current frontiers and recommendations for the study of microplastics in seafood
TrAC - Trends Anal. Chem.
Widespread distribution of microplastics in subsurface seawater in the NE Pacific Ocean
Mar. Pollut. Bull.
Abundant plankton-sized microplastic particles in shelf waters of the northern Gulf of Mexico
Environ. Pollut.
A methodological approach of the current literature on microplastic contamination in terrestrial environments: Current knowledge and baseline considerations
Sci. Total Environ.
Synthetic fibers in atmospheric fallout: A source of microplastics in the environment?
Mar. Pollut. Bull.
Microplastic sampling with the AVANI trawl compared to two neuston trawls in the Bay of Bengal and South Pacific
Environ. Pollut.
Distribution, sedimentary record, and persistence of microplastics in the Pearl River catchment, China
Environ. Pollut.
Anthropoquinas: First description of plastics and other man-made materials in recently formed coastal sedimentary rocks in the southern hemisphere
Mar. Pollut. Bull.
Microplastics distribution and characterization in epipsammic sediments of tropical Atlantic Ocean, Nigeria
Reg. Stud. Mar. Sci.
Prevalence of microplastic contamination in the digestive tract of fishes from mangrove ecosystem in Cispata, Colombian Caribbean
Mar. Pollut. Bull.
From radiometry to chronology of a marine sediment core: A 210Pb dating interlaboratory comparison exercise organised by the IAEA
Mar. Pollut. Bull.
Why it is important to analyze the chemical composition of microplastics in environmental samples
Mar. Pollut. Bull.
Microplastics in sub-surface waters of the Arctic Central Basin
Mar. Pollut. Bull.
A high-performance protocol for extraction of microplastics in fish
Sci. Total Environ.
Lead isotopes in environmental sciences: A review
Environ. Int.
Different surface charged plastic particles have different cotransport behaviors with kaolinite particles in porous media
Environ. Pollut.
Microplastics in sediment cores as indicators of temporal trends in microplastic pollution in Andong salt marsh, Hangzhou Bay, China
Reg. Stud. Mar. Sci.
A straightforward method for measuring the range of apparent density of microplastics
Sci. Total Environ.
Applications of polymer foams
Sediment radioisotope dating across a stratigraphic discontinuity in a mining-impacted lake
J. Environ. Radioact.
Microplastics identification by infrared spectroscopy – Evaluation of identification criteria and uncertainty by the Bootstrap method
Talanta
Low prevalence of microplastic contamination in planktivorous fish species from the southeast Pacific Ocean
Mar. Pollut. Bull.
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.
Pervasive plastisphere: First record of plastics in egagropiles (Posidonia spheroids)
Environ. Pollut.
Marine microplastics: Abundance, distribution, and composition
Microplastics in the environment: Challenges in analytical chemistry - A review
Anal. Chim. Acta
Occurrence and identification of microplastics in tap water from China
Chemosphere
Sorption of chemical contaminants on degradable and non-degradable microplastics: Recent progress and research trends
Sci. Total Environ.
Sediment sampling with a core sampler equipped with aluminum tubes and an onboard processing protocol to avoid plastic contamination
MethodsX
A review of microplastic distribution in sediment profiles
Mar. Pollut. Bull.
Microplastics in sediments: A review of techniques, occurrence and effects
Mar. Environ. Res.
Accumulation of plastic waste during COVID-19
Science
The plastic cycle: A novel and holistic paradigm for the anthropocene
Environ. Sci. Technol.
Polystyrene seedling trays used as substrate by native plants
Environ. Sci. Pollut. Res.
Fishing lines and fish hooks as neglected marine litter: first data on chemical composition, densities, and biological entrapment from a Mediterranean beach
Environ. Sci. Pollut. Res.
Sampling and quality assurance and quality control: A guide for scientists investigating the occurrence of microplastics across matrices
Appl. Spectrosc.
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2023, Science of the Total EnvironmentCitation Excerpt :Due to the light weight, corrosion resistance and low price, plastic products are widespread used in human life (Wang et al., 2019a; Xia et al., 2021; Sayed et al., 2021). According to statistics, the global plastic production had reached 368 million tons and increased 2.5 % over the previous year (Torres and De-la-Torre, 2021,). However, with the application of plastic products, more and more plastic wastes are discarded into the environment (Sayed et al., 2021).