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Research Article  |  Open Access  |  14 Jan 2024

Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada

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Water Emerg Contam Nanoplastics 2024;3:6.
10.20517/wecn.2023.66 |  © The Author(s) 2024.
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Abstract

Aim: To investigate the baseline abundance of microplastics on two sandy beaches along an exposed coastline in an understudied region of the Northwest Atlantic.

Methods: Sandy sediments were sampled from two beaches along the eastern shore of Nova Scotia, Canada from High, Mid, and Low intertidal positions. Density floatation using a sodium iodide (NaI) solution was used to separate particles from 100 g of sediments in each sample. Particles were characterized by size, shape, and colour, and Fourier transform infrared (FTIR) spectroscopy was conducted for polymer identification.

Results: At both beaches, the majority of particles found were small (< 1.4 mm), transparent microfibers. Microplastics were polymers of polyethylene terephthalate (PET), nylon, or alkyds (paints). The mean concentrations at both beaches were similar, at 5.08 ± 3.20 and 5.58 ± 4.52 microplastics per 100 g of sediment. Non-plastic (i.e., natural and semi-synthetic cellulosic) microfibers were up to 19 times more abundant than microplastics, with mean concentrations of 75.9 ± 60.1 and 97.7 ± 87.9 per 100 g sediment. Mean particle counts did not differ significantly across tidal ranges due to their high variability over small spatial scales (10 s of m).

Conclusion: Using new investigative tools yielded estimates of microplastic pollution 1-2 orders of magnitude lower than earlier research conducted at these sites, and was generally lower than values reported from other beaches globally. Sources of microfibers were potentially from high recreational use at these sites. Future monitoring could target these sites for time series analysis of microplastic change on exposed sandy beaches.

Keywords

Beach sand, density separation, microplastics, microfibers, cellulosic fibers, Northwest Atlantic, local sources, tourism, recreation

INTRODUCTION

Microplastics (MPs), synthetic polymers ≤ 5 mm in size[1], are ubiquitous marine pollutants found in all regions of the world ocean, from the surface[2] to the seafloor[3], and from the poles[4,5] to the tropics[6,7]. Primary MPs originate from the release of small particles into the environment during industrial manufacture, transportation, or use; secondary MPs, on the other hand, form when larger plastics undergo fragmentation due to chemical and/or mechanical abrasion as they disperse throughout the ocean[8]. The persistence of MP pollution on a global scale, combined with their small size, gives rise to concerns about their impacts on the marine environment and biota across all trophic levels[9], from microbes[10] and plankton[11] to marine mammals[12]. MPs have been shown to pose ingestion hazards to marine biota[13], increase exposure to toxic contaminants[14,15], and provide substrate to harmful microorganisms and/or invasive species[16]. Despite the increase in research on plastic pollution over the last decade[17], major gaps in understanding of baseline plastic concentrations remain, particularly in the Northwest (NW) Atlantic[18,19].

Beaches and intertidal environments are at a heightened risk of MP pollution, due to their proximity to plastic pollution sources and their role as (temporary) sinks for plastic pollution[20,21]. Thus, assessing baseline concentrations and patterns of deposition in intertidal areas is necessary for a better understanding of the fate of MPs along shorelines. To date, there have been numerous studies examining the abundance of MPs on beaches and shorelines around the world, reporting a range of particles typically in the 10 to 100s per kg of dry sediment, and a predominance of fibers over other types of particles[20,22-27]. Polyethylene and polyester are the most commonly reported MPs in marine sediments[28]. However, reporting anthropogenic (human-made) non-plastic particles derived from cellulose separately from synthetic, petroleum-based fibers[29-31] is becoming more common.

In contrast, very little research has focused on temperate areas of the NW Atlantic, particularly in Atlantic Canada[19,32]. The first study to investigate MP pollution in intertidal sediments (mud and sand) in Nova Scotia, Canada, documented notably high MP fiber abundances[33]. However, in 2012, Mathalon and Hill were unable to validate the identity of their sampled fibers using spectroscopic or other methods[33]. While these methods were not as prevalent in the literature at the time[34], it is now recognized that visual identification alone is insufficient to accurately determine MP concentrations[35,36]. In addition, Mathalon and Hill suspected laboratory contamination of samples, which is now a well-documented issue[33,37-39]. Given the uncertainty in these MP abundance estimates, yet their widespread use in the scientific literature (cited in 556 publications[40]), repetition of their study is clearly warranted.

The region of Atlantic Canada presents an intriguing opportunity for analysing the distribution of MPs, due to its low human population density but a long history of utilizing its coastal and marine environments, particularly for fishing, shipping, transportation, aquaculture, and tourism and recreation[41,42]. In this study, we investigate concentrations of MPs in beach sediments along an exposed coastline in Atlantic Canada, and compare our results to a previous study conducted in the same region[33] through new investigative tools. Our study contributes additional insight into the fate of a persistent environmental pollutant in an understudied region of the global ocean.

METHODS

Study sites and field sampling

Sediment samples were collected at Rainbow Haven beach (44° 38' 46.69" N, 63° 25' 10.131" W) on April 16, 2019 and at Martinique beach (44° 41' 27.86" N, 63° 08' 18.68" W) on April 17, 2019 in Nova Scotia [Figure 1]. Located along the Eastern Shore of Nova Scotia, Rainbow Haven (https://parks.novascotia.ca/park/rainbow-haven-beach) is a 3.2 km long, primarily sand and cobblestone beach, while Martinique (https://parks.novascotia.ca/park/martinique-beach) is a 5 km long crescent white sand beach that is also a protected area for shorebirds and a wildlife refuge for migratory waterfowl. Both beaches are popular swimming and day-use recreational areas and are located eastward along the coast from Halifax Harbour, a major shipping port and population center in the province. The mean tidal range at both beaches is approximately 1.5 m.

Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada

Figure 1. Locations of the two beaches (red stars) sampled in this study. Inset: Sample area (orange box) in relation to the Province of Nova Scotia, Canada.

On each beach at low tide, four cross-shore transects, approximately 50 m apart, were created, starting just below the wrack line and extending towards low water. On each transect, one sediment core was collected at High, Mid (at the midpoint between High and Low positions), and Low intertidal positions, following Mathalon and Hill[33]. This resulted in a total of 12 cores per beach. Beach sediment cores were collected using 15 cm tall, 750 mL pre-cleaned glass mason jars with metal lids. Immediately prior to collecting each sample, the jar was inverted (with the lid facing downwards), the lid was removed from the jar, and the jar was then driven into the sand until 2.5 cm of space remained within the jar. This covered an approximate depth of 12.5 cm of sediment. A metal trowel was placed underneath the opening of the jar to prevent the contents from falling out as the jar was removed. The jar was turned upright and the lid was quickly secured and the sample was kept in a cooler with ice packs. After returning from the field, the jars were frozen (at -20 °C) until processed.

Laboratory processing

Prior to processing, jars were thawed at 4 °C for a minimum of 72 h. Once thawed, the sediment representing > 5 cm depth was removed from the jar; the remaining sediment in the jar, representing the 0-5 cm depth, was covered with aluminum foil and placed in an oven at 60 °C until dry (~72 h to 1 week). Once dry, the sediment was transferred to a glass beaker and was homogenized by manually mixing the sediment for 1 min in a laminar flow hood. After mixing, a 100.0 g subsample was removed with a metal spoon, and placed in a 500 mL glass beaker for density flotation.

A maximum density sodium iodide (NaI, Sigma Aldrich) solution (mean density of 1.8 ± 0.04 g·cm-3) was prepared, using ultrapure water (Milli-Q®; Millipore Sigma) at 25 °C, to separate plastics from the sediment via floatation[43]. NaI was chosen over other solutions, such as sodium chloride (NaCl), as it can more efficiently extract higher-density MPs, such as polyvinylchloride (PVC, 1.3-1.7 g·cm-3) and polyethylene terephthalate (PET, 1.4-1.6 g·cm-3)[34]. In a fume hood, the NaI solution (210 mL) was added to the 500 mL glass beaker containing 100.0 g (~70.0 mL volume) of sediment to attain a 3:1 NaI to sediment volume ratio. The solution was manually stirred for 2 min with a glass stirring rod. After stirring, the rod was rinsed with a small amount of ultrapure water into the solution, and the solution was covered with aluminum foil and allowed to stand for 30 min. The supernatant was decanted and vacuum filtered onto a 47 mm, 20 µm polycarbonate membrane filter (PCTE, Sterlitech). The 500 mL beaker (with the remaining sediment) was rinsed three times with ultrapure water to capture any remaining particles on the sides of the beaker, and the remaining small amount of supernatant was pipetted into the vacuum funnel. The sides of the vacuum funnels were also rinsed three times with ultrapure water to ensure all particles were transferred onto the filter. Filters were carefully removed and transferred to Petri slides (Millipore Sigma) and then dried (covered) in a desiccator overnight. Once dried, the Petri slides were stored at room temperature.

Particle characterization

Filters were examined under a dissecting microscope at 40-100× magnification. Suspected MPs were removed by hand using ultra fine-tipped jeweler’s forceps and placed on double-sided tape in Petri slides. Suspected particles were photographed using a microscope-mounted digital camera (Nikon SMZ-25 fitted with a Di-3 digital camera, Nikon Instruments, Inc.). All suspected particles were classified according to morphology, colour, and transparency, following specific criteria[44-46]. Particle size, measured as the longest dimension, was determined from the microscope photographs using image analysis software (NIS-Elements D, Nikon Instruments, Inc.). We counted all transparent fibers, but only measured the length of a subset of these particles due to their high abundance.

Polymer composition for select particles was identified by Fourier transform infrared (FTIR) spectroscopy at Surface Science Western, University of Western Ontario, London, Ontario, Canada. Selected particles were randomly chosen from each major colour and morphology combination (i.e., transparent fibers, blue fragments, black films, etc.), totalling 200 particles or 7% of the dataset. Selected particles were transferred to a diamond compression cell and analyzed by FTIR in transmission mode under the Hyperion 2000 microscope attached to a Bruker Tensor II spectrometer. Particle spectra were matched to a known polymer through manual comparison of individual spectral components using spectral libraries, references, and the knowledge of multiple IR experts; thus, particle matches are considered to be highly certain. For microfibers that had FTIR spectra consistent with a cellulosic material, the method of Cai et al. was applied to distinguish between dyed cellulosic textiles (e.g., cottons) and semi-synthetic cellulosic (e.g., regenerated) materials[47]. Each spectrum in question was visually examined for a peak, shoulder, or no peak at ~1,105 cm-1. Particles with spectra that contained a peak at this wavelength were classed as cellulosic fibers; particles with no peak or a shoulder at this wavelength were classed as semi-synthetic fibers. Thus, we report a MP count that includes plastics and alkyds (paints and surface coatings), as well as a separate anthropogenic cellulosic fiber count (following Huntington et al.[48]), which includes both cellulosic fibers (i.e., textile fibers made from processed and dyed plant fibers, such as cotton or linen but have been manipulated for human purposes), and semi-synthetic fibers (i.e., particles comprised of rayon or viscose).

Contamination reduction protocols

Following Dimitrijevic et al., many steps were taken to minimize MP contamination during sample collection and processing[49]. In the field, researchers wore clothing made from natural materials (i.e., not fleece) or non-shedding clothing, wore nitrile gloves, and minimized the amount of time samples were exposed to air during the collection process. Mason jars were pre-cleaned in the laboratory and transported to and from the field sites in pre-cleaned totes, and researchers rinsed their gloves with ultrapure water between taking each sample. In the laboratory, researchers wore yellow coveralls (Tyvek 2000, Dupont) or 100% cotton lab coats, a muslin headscarf, and nitrile gloves, which were all cleaned with a lint roller prior to sample processing. Prior to sample processing, all work surfaces, including the laminar flow hood, fume hood, and microscope work area, were cleaned three times using a distinctly-coloured sponge (yellow or pink) dampened with ultrapure water. The microscope work area was covered with plastic sheeting to limit the amount of airborne contamination[37]. Prior to use in density floatation, the NaI solution was vacuum filtered through a 2.7 µm, 90 mm grade D Whatman glass filter and stored in glass jugs. As much field and laboratory equipment as possible was either made of metal or glass and all were rinsed with ultrapure water three times prior to use.

Background and procedural blanks were collected during the laboratory processing of all samples. Individual background blanks for each sample were created by placing a 47 mm, 3 µm PCTE filter, dampened with ultrapure water, in a Petri slide. The background blank was opened whenever its respective sediment sample was exposed to air during sample processing. A procedural blank was conducted each day of sample processing, corresponding to approximately every three samples processed. Each blank was prepared following the same floatation procedure as the sediment samples, but 70 mL of ultrapure water instead of sediment was used. Background and procedural blank filters were examined under 40X magnification and the morphology and colour of any observed particles were recorded.

Statistical analysis

All calculations and statistical analyses were conducted using the R software environment (version 4.2.1, R Core Team[50]) in RStudio (version 2023.06.0, Posit Software).

Particles found in background and procedural blanks were used to correct the final particle counts by establishing a Limit of Detection (LOD) following Dawson et al.[51]. The LOD was calculated as the mean + 3* standard deviation (SD) for each particle colour and morphology combination. Corrective action (subtraction of the LOD across all blanks from the number tallied in the sample) was only taken if an item of the same colour and morphology was found in both the blanks and the samples. If the corrected values were less than zero (i.e., subtraction resulted in a negative number), the value was set to zero. Following the blank correction of samples, particle counts per sample were further adjusted to account for the amount of visual identification errors. Using the results of FTIR spectroscopy, the number of particles in each colour-morphology combination was multiplied by a correction factor to account for the amount of visual identification error[46,52]. Final counts were rounded up to the nearest whole integer (to maintain the nature of count data). See Supplementary Materials for original particle counts, LOD values, correction factors, and corrected data.

We tested the difference in particle counts between Beaches (Rainbow Haven, Martinique) and among Intertidal Positions (High, Mid, and Low tide) using generalized linear models (GLMs). We used a negative binomial error distribution to provide a better fit for our over-dispersed count data (number of particles per standard 100 g samples). GLMs for anthropogenic cellulosic fiber counts and MP counts were conducted separately, using the glm.nb function in the MASS package[53]; Tukey post-hoc testing was conducted using the emmeans function in the emmeans package[54]. Model assumptions were assessed from plots of residuals and normal quantiles using the DHARMa package[55].

RESULTS

Background blanks that accounted for airborne laboratory contamination contained a mean of 4.2 ± 5.7 SD particles per sample. Particles found on background blanks were primarily transparent, blue, brown, and black fibers. Procedural blanks that accounted for particle contamination during sample processing contained a mean of 3.6 ± 3.4 SD particles per sample. Particles found on procedural blanks were primarily transparent, red, and blue fibers [Supplementary Materials].

MPs were found in 23 of 24 samples from High to Low intertidal positions, with counts ranging from 0-14 particles per 100 g of sediment. The overall mean concentration was 5.08 ± 3.20 SD and 5.58 ± 4.52 SD MPs per 100 g of sediment at Rainbow Haven and Martinique beaches, respectively. The mean counts of MPs per 100 g of sediment were generally greater at Mid than at High or Low intertidal positions, and High intertidal positions had greater mean counts than Low intertidal positions [Figure 2A]. However, there was no statistically significant difference in mean MP counts per 100 g of sediment detected between Beaches (GLM Likelihood ratio Χ2 = 0.25, df = 1, P = 0.62), nor a significant interaction between Beach and Intertidal Position (GLM Likelihood ratio Χ2 = 0.97, df = 2, P = 0.61), but there was a significant difference detected in Intertidal Position (GLM Likelihood ratio Χ2 = 6.22, df = 2, P = 0.045). Across both beaches, mean MP counts were significantly greater at Mid than Low intertidal position (P = 0.047), although there was no significant difference between High and Low (P = 0.73) nor High and Mid (P = 0.23) intertidal positions [Figure 2A].

Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada

Figure 2. Mean (± SE) (A) MPs and (B) anthropogenic fiber counts (no. particles 100 g-1 sediment) by intertidal position sampled at Martinique (blue line) and Rainbow Haven (grey line) beaches. Note the difference in vertical axis scales between panels. MPs: Microplastics.

At both beaches, anthropogenic cellulosic fibers were up to 19 times more abundant than MP particles, ranging from 1-270 particles per 100 g sediment. The overall mean concentration was 75.9 ± 60.1 SD and 97.7 ± 87.9 SD anthropogenic fibers per 100 g sediment at Rainbow Haven and Martinique beaches, respectively. Mean counts of anthropogenic fibers per 100 g of sediment at Martinique Beach followed the same general pattern across the intertidal zone as for MPs [Figure 2B]. In contrast, at Rainbow Haven, mean anthropogenic cellulosic fiber counts were greatest at the Mid intertidal position, followed by Low and then High intertidal position, respectively [Figure 2B]. Overall, these differences between Beaches (GLM Likelihood ratio Χ2 = 0.94, df = 1, P = 0.33), among Intertidal Position (GLM Likelihood ratio Χ2 = 3.89, df = 2,P = 0.14), and their interaction (GLM Likelihood ratio Χ2 = 1.38, df = 2, P = 0.50), were not statistically significant.

Across all samples combined (n = 2,220 particles), 99.2% of all particles extracted from beach sediments were fibers, with the remaining fraction composed of films (0.36%), fragments (0.27%), and foams (0.18%), respectively. Of the subset of particles identified by FTIR spectroscopy (n = 200), 93.5% were of anthropogenic cellulosic origin (88% natural, 5.5% semi-synthetic), 5% were plastics [3% were PET, 1% nylon (polyamide), and 1% alkyds], and the remaining 1.5% were either natural particles (i.e., plants) or unable to be identified (i.e., no match in spectral library).

The characteristics of particles (both anthropogenic and plastic) were markedly similar between beaches [Supplementary Figure 1], and thus were compared among intertidal positions for the beaches combined. Particle morphology did not vary among intertidal positions, with fibers dominating at all three tidal heights [Figure 3A]. Transparent particles dominated at all intertidal positions, but yellow, red, blue, and black particle colours were also observed, with the occasional brown, green, and grey coloured-particles [Figure 3B]. Yellow particles at Low intertidal positions, and red particles at High intertidal positions, were slightly more abundant than elsewhere. However, we suspect a few of the yellow fibers were actually transparent cellulosic fibers stained from the NaI salts used in the extraction process, suggesting our counts of yellow-coloured fibers may be slightly overestimated.

Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada

Figure 3. Characteristics of MPs and anthropogenic particles by intertidal position, collected from Martinique and Rainbow Haven beaches combined. (A) Particle shape and (B) colour, as a percentage of all particles found (n = 2,220); (C) polymer composition as a percentage of all particles identified using FTIR spectroscopy (n = 200); and (D) size, measured as the longest dimension (in mm). See Materials and Methods for further details. PET: Polyethylene terephthalate; MPs: microplastics; FTIR: Fourier transform infrared.

Of the particles analyzed using FTIR spectroscopy, cellulosic particles were the most common at all tidal heights, followed by semi-synthetic celluloses and PET [Figure 3C]. Alkyds (as paints or surface coatings) were found only at Mid and Low intertidal positions, while nylon (polyamide) fibers were found only at Mid intertidal positions [Figure 3C]. Sodium benzoate was a common secondary contaminant found on 24 (or ~14%) of the anthropogenic cellulosic fibers as identified from FTIR spectroscopy.

While particle sizes ranged from 65-9,176 µm, most anthropogenic and plastic particles were small, being ≤ 1.4 mm (1,400 µm) in longest dimension [Figure 3D]. At Low intertidal positions, there were slightly fewer particles < 1.4 mm and slightly more particles between 1.8-3 mm; otherwise, the distribution of particle lengths was very similar among intertidal positions.

DISCUSSION

In this study, we demonstrate a high abundance of anthropogenic microfiber pollution in the intertidal sediments of two exposed sandy beaches along the Eastern Shore of Nova Scotia. Transparent anthropogenic cellulosic fibers ≤ 1.4 mm in size were the most commonly encountered particle type across the intertidal, being up to 19 times more abundant than MP pollution. Globally, fibers are the dominant MP morphology found on beaches, accounting for 90% of all particles[20,28]. However, in recent years, more attention has been given to documenting human-made, non-plastic microfibers (e.g., anthropogenic celluloses) in addition to synthetic and semi-synthetic textile fibers[29-31]. Similar to our findings, small (≤ 1 mm) non-plastic, cellulosic microfibers have been previously documented to comprise a large portion of sediment samples collected from beaches worldwide, ranging from 19%-93.8% of extracted particle types[20,25,26,56]. Such fibers have also been reported to occur in other marine habitats[31,57], as well as ingested by marine species[58-60], suggesting their distribution is as widespread as other types of plastic pollution. Although the relative rate of degradation is faster for anthropogenic cellulosic fibers than for plastics in marine environments[61] - potentially reducing their persistence in the environment compared to plastics - many anthropogenic celluloses are treated with a range of colourants (dyes, pigments) and finishes (flame retardants, antimicrobial agents, stabilizers, softeners) that may leach into the environment[62,63]. As anthropogenic cellulosic fibers may have similar toxicological impacts as plastics to marine biota once ingested[64], additional research is needed to determine the ecotoxicological risk of anthropogenic microfiber pollution to intertidal fauna in Atlantic Canada and elsewhere.

MP contamination at Rainbow Haven and Martinique beaches was towards the lower end of the range of particles reported by studies in other areas of the globe [Table 1], suggesting low MP pollution at our sites. We identified plastic polymers of nylon, alkyds, PET, and non-plastic semi-synthetic celluloses (e.g., viscose, rayon). Once deposited on the beach, the higher density of these polymers compared to seawater (e.g., nylon = 1.13-1.15 g·cm-3; PET = 1.29-1.40 g·cm-3; viscose/rayon = 1.53 g·cm-3, cellulose = 1.5 g·cm-3; alkyds = 1.2-1.7 g·cm-3; seawater = 1.027 g·cm-3) may make them more likely to be retained within the sediments along this wave-exposed coastline. Further, turbulent mixing of beach sediments during high wave action may bury MPs within the sand, and protect them from washing back into the water column[21]. PET is frequently used in the construction of food packaging, beverage bottles, and clothing, while nylon is widely used in textiles, nets and ropes, and sportswear[49,70]. Fragments of alkyd plastics, frequently used in paints and other surface coatings, suggest an urban or marine source for these particles, possibly from fishing or recreational boats[7,25,46]. However, in combination with the high abundance of anthropogenic celluloses in our samples, some of which were contaminated with sodium benzoate (a widely used antifungal and antimicrobial agent in foods and cosmetics, including sunscreens), it suggests that certain MP sources might be local rather than arriving from distant locations (i.e., from wear and tear of textiles, such as swimsuits, beach towels, blankets, clothing, etc., and fragmentation of plastic containers discarded on the beach). Tourism has been implicated as a large contributor of MPs at beaches worldwide[24,25,27,71,72]. Due to their proximity to urban centers, Rainbow Haven and Martinique beaches are popular recreational sites throughout the year[73], lending further support to local tourism as the source of some microfiber pollution in this area.

Table 1

Comparison of MP abundance in sandy sediments reported from other published studies around the globe

LocationMP abundance (no. kg-1 d.w. sediment)Source
Atlantic coast, Canada50.8 ± 32.0 to 55.8 ± 45.2aOur current study
Atlantic coast, Canada2,000-8,000a,bMathalon and Hill[33]
Bay of Fundy, Canada268 ± 208.7cForsythe[65]
Atlantic coast, USA63.8 ± 19.1 to 126.3 ± 43.2Whitemire and Van Bloem[66]
Pacific coast, USA38.8 ± 7.2 to 140.0 ± 24.8Whitemire and Van Bloem[66]
Pacific coast, Mexico179 ± 50Piñon-Colin et al.[27]
Pacific coast, Gulf of California76 ± 12Piñon-Colin et al.[27]
Baja California, Mexico135 ± 92Piñon-Colin et al.[27]
Pacific Islands, USA98.8 ± 27.7 to 187.5 ± 22.4Whitemire and Van Bloem[66]
Alaska, USA21.3 ± 4.3 to 128.8 ± 36.1Whitemire and Van Bloem[66]
Bohai Sea, China102.9 ± 39.9 to 163.3 ± 37.7Yu et al.[25]
India45 ± 12 to 220 ± 50Tiwari et al.[67]
Arabian Gulf13.5 (range 6-38)Abayomi et al.[56]
Europe, Mediterranean coast291 ± 62Lots et al.[26]
Slovenia coast133.3 (median)Laglbauer et al.[68]
Baltic coast14-532bStolte et al.[24]
Baltic coast88.10 (median)Hengstmann et al.[69]
Europe, Baltic coast270 ± 90Lots et al.[26]
Belgian coast92.8 ± 37.2Claessens et al.[23]
Europe, Atlantic coast190 ± 35Lots et al.[26]

Combining the results of two previous regional studies[33,65] with our current findings on MP pollution in intertidal zones can shed light on the distribution of this pervasive environmental pollutant on Atlantic Canadian coastlines. Compared to our 0-1.4 MPs per 10 g sediment, Mathalon and Hill documented 20-80 MP fibers per 10 g sediment at Rainbow Haven beach[33]. Given that our sample processing methods differed (Mathalon and Hill used a chemical digestion and short density floatation with NaCl compared to our longer NaI floatation only[33]), it is difficult to directly compare absolute values of MP concentrations between studies. However, at the time, Mathalon and Hill could not validate the identity of their sampled fibers using spectroscopic or other methods, and laboratory contamination of samples was also suspected, suggesting their MP fiber estimates were overestimated by 1-2 orders of magnitude[33]. More recently, Forsythe[65] examined MPs (validated using FTIR) in the intertidal zone at various locations in the Bay of Fundy, an area known for its dynamic tidal range[74], documenting a mean concentration of 268 ± 208.7 MPs per 1 kg sediment, of which 89% were fibers. As in our study, Mathalon and Hill[33] and Forsythe[65] did not find any significant differences in MP quantities across tidal ranges. Collectively, these results suggest MPs and anthropogenic microfibers are evenly distributed along intertidal gradients in the sandy sediments around Nova Scotia. However, the high variability within beaches among samples and transects taken over small spatial scales (10 s of meters) documented in our and these studies also stresses the need for caution when extrapolating to identify broader spatial patterns of pollution in the intertidal zones of Atlantic Canada. More research is clearly needed before the fate of MP pollution is fully understood in these wave- and tidal-dominated systems.

Blue, black, and other brightly coloured MPs are the most frequently detected particles in sediments worldwide[24,28], due to the high global production of plastics with these colours, and/or the ease of visually distinguishing particles of these colours from sediment during sampling[75]. The distribution of colours we report herein may be an indicator of the residence time of these microfibers on Nova Scotia beaches, as the high load of transparent microfibers suggests significant exposure of these particles to UV solar radiation[76]. As we sampled in April before the height of the recreational and tourism season, it is possible that the majority of microfibers were deposited the previous year and lost their colour over the fall and winter through environmental exposure[7]. Future sampling to examine the seasonal deposition of microfibers along the coastline of Nova Scotia would provide additional insight into the sources and residence time of anthropogenic pollution to Atlantic Canadian coastlines. For example, targeted sampling before, during, and after summer could test not only for seasonal changes in plastic loading, but also whether the sources of contamination and MP types change with seasonal recreational use.

Our study documented MP and anthropogenic (non-plastic) microfiber pollution along exposed beaches in Atlantic Canada, and added new investigative tools (e.g., FTIR, contamination control protocols) to refine previous estimates in this understudied region. While our sampling design replicated that of Mathalon and Hill[33] in order to enable a regional comparison, the design shares similarities to those recommended by other monitoring programs for beach litter assessments[77,78]. However, since our results suggest MPs (and anthropogenic microfibers) are patchily distributed over small spatial scales (10 s of m) in this region, many more replicates would be needed to detect differences in the spatial patterns of MP distribution and attribute potential differences to environmental or anthropogenic factors. With additional sampling effort comes increased costs and time, making monitoring potentially less feasible to conduct. Fisner et al. suggest that time series assessments may be more realistic than aiming for estimates of absolute particle density[79]. We suggest future work in this region could target Rainbow Haven beach as a focal point for time series analysis of MP change on exposed sandy beaches.

DECLARATIONS

Acknowledgments

The authors wish to acknowledge Harvey C and Zimmerman R for assistance in the field, and Marteinson S and Breeze H for providing financial support for Fourier transform infrared analysis. In addition, we thank our colleagues Gurney-Smith H and Law B, as well as four anonymous reviewers, whose constructive comments helped improve this manuscript.

Authors’ contributions

Made substantial contributions to the conception and design of the study and performed data analysis and interpretation: Kelly NE, Gavel H

Performed data acquisition, as well as providing administrative, technical, and material support: Kelly NE, Trela O, Vander Kuylen A

Wrote paper: Kelly NE

Provided comments and review: Gavel H, Trela O, Vander Kuylen A

Availability of data and materials

The dataset for this research is included in the Supplementary Materials attached to this publication.

Financial support and sponsorship

Funding for this work was provided by Fisheries and Oceans Canada to Kelly NE.

Conflicts of interest

All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Copyright

© The Author(s) 2024.

Supplementary Materials

REFERENCES

1. Frias JPGL, Nash R. Microplastics: finding a consensus on the definition. Mar Pollut Bull 2019;138:145-7.

2. Isobe A, Azuma T, Cordova MR, et al. A multilevel dataset of microplastic abundance in the world’s upper ocean and the Laurentian Great Lakes. Micropl Nanopl 2021;1:16.

3. Harris PT, Maes T, Raubenheimer K, Walsh JP. A marine plastic cloud - Global mass balance assessment of oceanic plastic pollution. Cont Shelf Res 2023;255:104947.

4. Isobe A, Uchiyama-Matsumoto K, Uchida K, Tokai T. Microplastics in the Southern Ocean. Mar Pollut Bull 2017;114:623-6.

5. Lusher AL, Tirelli V, O’Connor I, Officer R. Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples. Sci Rep 2015;5:14947.

6. Baztan J, Carrasco A, Chouinard O, et al. Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current. Mar Pollut Bull 2014;80:302-11.

7. Ivar do Sul JA, Costa MF, Fillmann G. Microplastics in the pelagic environment around oceanic islands of the Western Tropical Atlantic Ocean. Water Air Soil Pollut 2014;225:2004.

8. Andrady AL. The plastic in microplastics: a review. Mar Pollut Bull 2017;119:12-22.

9. Ivar do Sul JA, Costa MF. The present and future of microplastic pollution in the marine environment. Environ Pollut 2014;185:352-64.

10. Zettler ER, Mincer TJ, Amaral-Zettler LA. Life in the “plastisphere”: microbial communities on plastic marine debris. Environ Sci Technol 2013;47:7137-46.

11. Prata JC, da Costa JP, Lopes I, Duarte AC, Rocha-Santos T. Effects of microplastics on microalgae populations: a critical review. Sci Total Environ 2019;665:400-5.

12. Kühn S, van Franeker JA. Quantitative overview of marine debris ingested by marine megafauna. Mar Pollut Bull 2020;151:110858.

13. Baechler BR, Stienbarger CD, Horn DA, et al. Microplastic occurrence and effects in commercially harvested North American finfish and shellfish: current knowledge and future directions. Limnol Oceanogr Lett 2020;5:113-36.

14. Hermabessiere L, Dehaut A, Paul-Pont I, et al. Occurrence and effects of plastic additives on marine environments and organisms: a review. Chemospher 2017;182:781-93.

15. Avio CG, Gorbi S, Milan M, et al. Pollutants bioavailability and toxicological risk from microplastics to marine mussels. Environ Pollut 2015;198:211-22.

16. Kirstein IV, Kirmizi S, Wichels A, et al. Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles. Mar Environ Res 2016;120:1-8.

17. Schmid C, Cozzarini L, Zambello E. Microplastic’s story. Mar Pollut Bull 2021;162:111820.

18. Haarr ML, Falk-Andersson J, Fabres J. Global marine litter research 2015-2020: geographical and methodological trends. Sci Total Environ 2022;820:153162.

19. Melvin J, Bury M, Ammendolia J, Mather C, Liboiron M. Critical gaps in shoreline plastics pollution research. Front Mar Sci 2021;8:689108.

20. Harris PT. The fate of microplastic in marine sedimentary environments: a review and synthesis. Mar Pollut Bull 2020;158:111398.

21. Zhang H. Transport of microplastics in coastal seas. Estuar Coast Shelf Sci 2017;199:74-86.

22. Browne MA, Crump P, Niven SJ, et al. Accumulation of microplastic on shorelines woldwide: sources and sinks. Environ Sci Technol 2011;45:9175-9.

23. Claessens M, De Meester S, Van Landuyt L, De Clerck K, Janssen CR. Occurrence and distribution of microplastics in marine sediments along the Belgian coast. Mar Pollut Bull 2011;62:2199-204.

24. Stolte A, Forster S, Gerdts G, Schubert H. Microplastic concentrations in beach sediments along the German Baltic coast. Mar Pollut Bull 2015;99:216-29.

25. Yu X, Peng J, Wang J, Wang K, Bao S. Occurrence of microplastics in the beach sand of the Chinese inner sea: the Bohai Sea. Environ Pollut 2016;214:722-30.

26. Lots FAE, Behrens P, Vijver MG, Horton AA, Bosker T. A large-scale investigation of microplastic contamination: abundance and characteristics of microplastics in European beach sediment. Mar Pollut Bull 2017;123:219-26.

27. de Jesus Piñon-Colin TJ, Rodriguez-Jimenez R, Pastrana-Corral MA, Rogel-Hernandez E, Wakida FT. Microplastics on sandy beaches of the Baja California Peninsula, Mexico. Mar Pollut Bull 2018;131:63-71.

28. Gago J, Carretero O, Filgueiras AV, Viñas L. Synthetic microfibers in the marine environment: a review on their occurrence in seawater and sediments. Mar Pollut Bull 2018;127:365-76.

29. Henry B, Laitala K, Klepp IG. Microfibres from apparel and home textiles: prospects for including microplastics in environmental sustainability assessment. Sci Total Environ 2019;652:483-94.

30. Barrows APW, Cathey SE, Petersen CW. Marine environment microfiber contamination: global patterns and the diversity of microparticle origins. Environ Pollut 2018;237:275-84.

31. Sanchez-Vidal A, Thompson RC, Canals M, de Haan WP. The imprint of microfibres in southern European deep seas. PLoS One 2018;13:e0207033.

32. Anderson JC, Park BJ, Palace VP. Microplastics in aquatic environments: implications for Canadian ecosystems. Environ Pollut 2016;218:269-80.

33. Mathalon A, Hill P. Microplastic fibers in the intertidal ecosystem surrounding Halifax Harbor, Nova Scotia. Mar Pollut Bull 2014;81:69-79.

34. Hanvey JS, Lewis PJ, Lavers JL, Crosbie ND, Pozo K, Clarke BO. A review of analytical techniques for quantifying microplastics in sediments. Anal Methods 2017;9:1369-83.

35. Lenz R, Enders K, Stedmon CA, Mackenzie DMA, Nielsen TG. A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement. Mar Pollut Bull 2015;100:82-91.

36. Song YK, Hong SH, Jang M, et al. A comparison of microscopic and spectroscopic identification methods for analysis of microplastics in environmental samples. Mar Pollut Bull 2015;93:202-9.

37. Woodall LC, Gwinnett C, Packer M, Thompson RC, Robinson LF, Paterson GLJ. Using a forensic science approach to minimize environmental contamination and to identify microfibres in marine sediments. Mar Pollut Bull 2015;95:40-6.

38. Wesch C, Elert AM, Wörner M, Braun U, Klein R, Paulus M. Assuring quality in microplastic monitoring: about the value of clean-air devices as essentials for verified data. Sci Rep 2017;7:5424.

39. Prata JC, Reis V, da Costa JP, Mouneyrac C, Duarte AC, Rocha-Santos T. Contamination issues as a challenge in quality control and quality assurance in microplastics analytics. J Hazard Mater 2021;403:123660.

40. Web of Science. Citations of Microplastic fibers in the intertidal ecosystem surrounding Halifax Harbour, Nova Scotia 2023. Available from: https://www.webofscience.com/wos/woscc/citation-report/557a62ad-a1dd-4fe6-b153-2235df983f90-aeb88243. [Last accessed on 10 Jan 2024]

41. Lotze HK, Milewski I. Two centuries of multiple human impacts and successive changes in a North Atlantic food web. Ecol Appl 2004;14:1428-47.

42. MacLean M, Breeze H, Walmsley J, Corkum J. State of the scotian shelf report. Can Tech Rep Fish Aquat Sci 3074. Available from: https://publications.gc.ca/collections/collection_2014/mpo-dfo/Fs97-6-3074-eng.pdf. [Last accessed on 10 Jan 2024]

43. Kedzierski M, Le Tilly V, César G, Sire O, Bruzaud S. Efficient microplastics extraction from sand. A cost effective methodology based on sodium iodide recycling. Mar Pollut Bull 2017;115:120-9.

44. Hartmann NB, Hüffer T, Thompson RC, et al. Are we speaking the same language? Recommendations for a definition and categorization framework for plastic debris. Environ Sci Technol 2019;53:1039-47.

45. Karlsson TM, Kärrman A, Rotander A, Hassellöv M. Comparison between manta trawl and in situ pump filtration methods, and guidance for visual identification of microplastics in surface waters. Environ Sci Pollut Res Int 2020;27:5559-71.

46. Kelly NE, Feyrer L, Gavel H, et al. Long term trends in floating plastic pollution within a marine protected area identifies threats for endangered northern bottlenose whales. Environ Res 2023;227:115686.

47. Cai H, Du F, Li L, Li B, Li J, Shi H. A practical approach based on FT-IR spectroscopy for identification of semi-synthetic and natural celluloses in microplastic investigation. Sci Total Environ 2019;669:692-701.

48. Huntington A, Corcoran PL, Jantunen L, et al. A first assessment of microplastics and other anthropogenic particles in Hudson Bay and the surrounding eastern Canadian Arctic waters of Nunavut. FACETS 2020;5:432-54.

49. Dimitrijevic J, Kelly NE, Moore AM, Breeze H, Ross PS. Best practices for the extraction and enumeration of microplastics in various marine environmental matrices. Can Tech Rep Fish Aquat Sci 3334. Available from https://publications.gc.ca/collections/collection_2019/mpo-dfo/Fs97-6-3334-eng.pdf. [Last accessed on 10 Jan 2024]

50. R Core Team. R: a language and environment for statistical computing. R Foundation for Statistical Computing. Vienna, Austria. 2022. Available from: https://www.R-project.org/. [Last accessed on 10 Jan 2024].

51. Dawson AL, Santana MFM, Nelis JLD, Motti CA. Taking control of microplastics data: a comparison of control and blank data correction methods. J Hazard Mater 2023;443:130218.

52. Covernton GA, Collicutt B, Gurney-smith HJ, et al. Microplastics in bivalves and their habitat in relation to shellfish aquaculture proximity in coastal British Columbia, Canada. Aquacult Environ Interact 2019;11:357-74.

53. Venables WN, Ripley BD. Modern applied statistics with S. 4th Edition. New York: Springer; 2002.

54. Lenth RV. emmeans: Estimated marginal means, aka least-squares means. R package version 1.9.0. Available from: https://CRAN.R-project.org/package=emmeans. [Last accessed on 10 Jan 2024].

55. Hartig F. DHARMa: residual diagnostics for hierarchical (multi-level/mixed) regression models. R package version 0.4.6. Available from: https://CRAN.R-project.org/package=DHARMa. [Last accessed on 10 Jan 2024].

56. Abayomi OA, Range P, Al-Ghouti MA, Obbard JP, Almeer SH, Ben-Hamadou R. Microplastics in coastal environments of the Arabian Gulf. Mar Pollut Bull 2017;124:181-8.

57. Suaria G, Achtypi A, Perold V, et al. Microfibers in oceanic surface waters: a global characterization. Sci Adv 2020;6:eaay8493.

58. Remy F, Collard F, Gilbert B, Compère P, Eppe G, Lepoint G. When microplastic is not plastic: the ingestion of artificial cellulose fibers by macrofauna living in seagrass macrophytodetritus. Environ Sci Technol 2015;49:11158-66.

59. Compa M, Ventero A, Iglesias M, Deudero S. Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast. Mar Pollut Bull 2018;128:89-96.

60. Savoca S, Capillo G, Mancuso M, et al. Detection of artificial cellulose microfibers in Boops boops from the northern coasts of Sicily (Central Mediterranean). Sci Total Environ 2019;691:455-65.

61. Zambrano MC, Pawlak JJ, Daystar J, Ankeny M, Cheng JJ, Venditti RA. Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation. Mar Pollut Bull 2019;142:394-407.

62. Sait STL, Sørensen L, Kubowicz S, et al. Microplastic fibres from synthetic textiles: environmental degradation and additive chemical content. Environ Pollut 2021;268:115745.

63. Sørensen L, Groven AS, Hovsbakken IA, et al. UV degradation of natural and synthetic microfibers causes fragmentation and release of polymer degradation products and chemical additives. Sci Total Environ 2021;755:143170.

64. Athey SN, Erdle LM. Are we underestimating anthropogenic microfiber pollution? A critical review of occurrence, methods, and reporting. Environ Toxicol Chem 2022;41:822-37.

65. Forsythe C. The quantification of microplastics in intertidal sediments in the Bay of Fundy, Canada. 2016. Available from: https://www.viurrspace.ca/server/api/core/bitstreams/46d54dbb-77ae-45d4-bdf8-3e38428545ce/content. [Last accessed on 10 Jan 2024].

66. Whitmire SL, Van Bloem SJ. Quantification of microplastics on National Park Beaches. NOAA Marine Debris Program. Available from: https://marinedebris.noaa.gov/microplastics/quantification-microplastics-national-park-beaches. [Last accessed on 10 Jan 2024].

67. Tiwari M, Rathod TD, Ajmal PY, Bhangare RC, Sahu SK. Distribution and characterization of microplastics in beach sand from three different Indian coastal environments. Mar Pollut Bull 2019;140:262-73.

68. Laglbauer BJL, Franco-Santos RM, Andreu-Cazenave M, et al. Macrodebris and microplastics from beaches in Slovenia. Mar Pollut Bull 2014;89:356-66.

69. Hengstmann E, Tamminga M, Vom Bruch C, Fischer EK. Microplastic in beach sediments of the Isle of Rügen (Baltic Sea) - Implementing a novel glass elutriation column. Mar Pollut Bull 2018;126:263-74.

70. United Nations Environment Programme. Chemicals in plastics - a technical report. Available from: https://www.unep.org/resources/report/chemicals-plastics-technical-report. [Last accessed on 10 Jan 2024].

71. Jayasiri HB, Purushothaman CS, Vennila A. Quantitative analysis of plastic debris on recreational beaches in Mumbai, India. Mar Pollut Bull 2013;77:107-12.

72. Gao F, Li J, Hu J, et al. The seasonal distribution characteristics of microplastics on bathing beaches along the coast of Qingdao, China. Sci Total Environ 2021;783:146969.

73. Tourism Nova Scotia. 2019 Nova Scotia visitor exit survey overall results. Available from: https://tourismns.ca/sites/default/files/2021-01/2019%20VES%20Full%20Year%20Report.pdf. [Last accessed on 10 Jan 2024].

74. Bundy A, Themelis D, Sperl J, den Heyer N. Inshore Scotian Shelf Ecosystem Overview Report: Status and Trends. 2014. Available from: https://publications.gc.ca/collections/collection_2014/mpo-dfo/Fs70-5-2014-065-eng.pdf. [Last accessed on 10 Jan 2024].

75. Lavers JL, Oppel S, Bond AL. Factors influencing the detection of beach plastic debris. Mar Environ Res 2016;119:245-51.

76. Pinlova B, Nowack B. Characterization of fiber fragments released from polyester textiles during UV weathering. Environ Pollut 2023;322:121012.

77. Cheshire A, Adler E, Barbière J. UNEP/IOC guidelines on survey and monitoring of marine litter. 2009. Available from: https://wedocs.unep.org/20.500.11822/13604. [Last accessed on 10 Jan 2024].

78. Lippiatt S, Opfer S, Arthur C. Marine debris monitoring and assessment: recommendations for monitoring debris trends in the marine environment. Available from: https://repository.library.noaa.gov/view/noaa/2681. [Last accessed on 10 Jan 2024].

79. Fisner M, Majer AP, Balthazar-Silva D, Gorman D, Turra A. Quantifying microplastic pollution on sandy beaches: the conundrum of large sample variability and spatial heterogeneity. Environ Sci Pollut Res Int 2017;24:13732-40.

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Kelly NE, Trela O, Gavel H, Vander Kuylen A. Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada. Water Emerg Contam Nanoplastics 2024;3:6. http://dx.doi.org/10.20517/wecn.2023.66

AMA Style

Kelly NE, Trela O, Gavel H, Vander Kuylen A. Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada. Water Emerging Contaminants & Nanoplastics. 2024; 3(1): 6. http://dx.doi.org/10.20517/wecn.2023.66

Chicago/Turabian Style

Kelly, Noreen E., Olga Trela, Heidi Gavel, Alyssa Vander Kuylen. 2024. "Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada" Water Emerging Contaminants & Nanoplastics. 3, no.1: 6. http://dx.doi.org/10.20517/wecn.2023.66

ACS Style

Kelly, NE.; Trela O.; Gavel H.; Vander Kuylen A. Plastic and anthropogenic microfiber pollution on exposed sandy beaches in Nova Scotia, Canada. Water. Emerg. Contam. Nanoplastics. 2024, 3, 6. http://dx.doi.org/10.20517/wecn.2023.66

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