Separating microplastics from marine and freshwater sediments is challenging, but necessary to determine their distribution, mass, and ecological impacts in benthic environments. Density separation is commonly used to extract microplastics from sediments by using heavy salt solutions, such as zinc chloride and sodium iodide. However, current devices/apparatus used for density separation, including glass beakers, funnels, upside-down funnel-shaped separators with a shut-off valve, etc., possess various shortcomings in terms of recovery rate, time consumption, and/or usability. In evaluating existing microplastic extraction methods using density separation, we identified the need for a device that allows rapid, simple, and efficient extraction of microplastics from a range of sediment types. We have developed a small glass separator, without a valve, taking a hint from an Utermöhl chamber. This new device is easy to clean and portable, yet enables rapid separation of microplastics from sediments. With this simple device, we recovered 94–98% of <1,000 µm microplastics (polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polystyrene). Overall, the device is efficient for various sizes, polymer types, and sediment types. Also, microplastics collected with this glass-made device remain chemically uncontaminated, and can, therefore, be used for further analysis of adsorbing contaminants and additives on/to microplastics.
Pollution and Marine Debris
Marine litter is widely dispersed throughout coastal environments. Assessing the distribution and accumulation of such contaminants is crucial to understand their environmental impacts. This study presents a baseline for the monitoring of litter and microplastics in intertidal sediments along the Atlantic shores of southern Portugal and Morocco and identifies potential sources of contamination. Although variable, distribution and composition of both litter and microplastics did not follow a latitudinal pattern. Most of the litter had an undifferentiated source. Within the identifiable sources of litter, food packaging, fishing and tobacco were the most abundant, with variable contributions among sites. Over 97% of marine litter retrieved was plastic. Fragments and filaments were the most abundant categories of plastics at sites with the highest and lowest microplastic abundance respectively. Filaments were mainly made of Polypropylene (PP,50%) and Polyethylene terephthalate (PET,29%) while the predominant polymers for fragments were Polyethene (PE, 75%) and PP (25%).
In this work, samples were collected from the Argentinean continental shelf –including a Marine Protected Area (MPA) - to assess the occurrence and distribution of synthetic microfibers (MFs), a widespread type of microplastic. MFs were present at 100% of the samples showing an average concentration of 182.85 ± 115.14 particles per Kg of dry sediment and 0.14 ± 0.08 items per m3 of marine water. MFs less than 1 mm were the most abundant (56.4% and 63%, for sediment and surface seawater respectively), followed by 1–2 mm and then 2–3 mm. In regards to the colour, both sediments and water had the major percentage of black MFs (25.6% and 28%, respectively) and the lowest one of green MFs (2.5% and 3%, respectively). Finally, MFs content in sediments was inversely correlated with depth (r = -0.93, p < 0.05). These findings provide the first evidence of microplastic contamination at the Argentinean continental shelf.
Human activities lead to several impacts on marine ecosystems, among which a massive input of plastic entering the marine environment. This scenario has the potential to threaten ecosystem health and integrity, also reducing the ability of marine ecosystems to provide good and services on which human well-being relies. In this study, the global scientific literature on marine microplastics was explored by combining social network analysis and bibliometrics. Network maps displayed the relationships among keywords, authors, countries, and journals dealing with the issue of microplastics in marine ecosystems. The citation analysis of journals showed that “Marine Pollution Bulletin” resulted the first among the scientific journals publishing articles on this subject. The results also highlighted that most research on the subject is focused on toxicology and environmental chemistry, while ecological studies focusing on the impact of microplastics at ecosystem level are still limited.
On the Colombian continental shelf, 12 km SW of the municipality of Galerazamba, Department of Bolívar, is the northern-most island of the Colombian Caribbean: Isla Arena. Despite being remote and uninhabited, this island is being affected by one of the most persistent problems in the marine environment: Marine Anthropogenic Litter (MAL). In this first Colombian insular MAL study, a total of 1436 MAL items were collected along Isla Arena, equivalent to an average abundance of 2.87 items/m2. MAL items belong to 54 categories that are grouped in nine material typologies. These typologies include plastic (36 categories), metal (6), glass (3), medical waste (3), machined wood (2), pottery (1), sanitary waste (1), rubber (1) and cloth (1). Isla Arena now is considered as an “Extremely dirty” site in terms of the Clean Coast Index. Hazardous litter items (sharp and toxic) occur in percentages as high as 10.2% (146 items, Avg: 0.29 items/m2). Along the island, current MAL amounts are so elevated that simple clean-up operations are an insufficient solution, and restoration measures are needed. MAL mainly comes from land-based sources, primarily generated by activities in the adjacent mainland river basins and coastal urban developments, particularly in the area of beaches. Marine anthropogenic litter found on Isla Arena reflects a strong influence from longshore-current transport. Management solutions need to begin at the same litter sources, and must include analytics, policy reforms and enforcement, and private and public investments.
The oil spill accidents may drastically impact the environment and ecosystem at intertidal zones. The spilled oil will penetrate the sediments and accumulate to cause lethal or sublethal effects on the benthic invertebrates. An M-BACI experiment was manipulated in situ to assess the ecological responses of benthic macrofauna to different degrees of diesel oil spill. Both biotic and abiotic parameters were studied for 126 days, subjected to both “pulse” and “press” oil contaminations. The content of aliphatic hydrocarbons (displayed as ratios of n-C17/Pr and n-C18/Ph) slightly dropped then continuously existed in the sediment during the experiment time. The macrofaunal assemblage structures were dramatically altered in species number, abundance and biomass. In general, it takes longer time for the macrofauna assemblages to recover under high concentration oil spill than that under low concentration. Our results highlight the diversified strategies for survival and recolonization among dominant species, which distinguish themselves between: i) tolerant species, ii) opportunistic species, and iii) equilibrium species.
In this study, we assessed plastic accumulation in marine sediments due to finfish aquaculture using floating net-pens. We studied plastic concentrations around three fish farms located at the Mediterranean coastline of Spain. The macroplastic categories and abundances were determined by video monitoring, detecting the majority of elements (78%), including ropes, nets and fibres, a basket trap and a cable tie, close to the facilities, which were not exclusively linked to fish farming but also to fishing activities. Concentrations of microplastics (<5 mm) ranged from 0 to 213 particles/kg dry weight sediment with higher values in sites directly under the influence of the fish farms. Most particles (27.8%) were within the size fraction from 1.1 to 2.0 mm and fibre was the most common shape with 62.2%. The Infrared spectroscopy analysis showed that PE and PP were the predominant types of polymers analysed. In addition, changes in the enthalpy of melting (ΔHm (J/g)) and the degree of crystallinity indicate degradation of the microplastics analysed. This study shows that, in the studied fish farms, levels of microplastic pollution can be one order of magnitude lower compared to other areas suffering other anthropogenic pressures from the same or similar regions. Nevertheless, more research effort is needed to get concluding results.
Rivers transport land-based plastic waste into the ocean. Current efforts to quantify riverine plastic emission come with uncertainty as field observations are scarce. One of the challenging aspects is the lack of consistent measurement methods that allow for comparing rivers over space and time. Recent studies have shown that simple visual observations provide a robust first-order characterization of floating and superficially suspended plastic transport, both in quantity, spatiotemporal distribution and composition. For this study, we applied this method to the river Seine, France, to provide new insights in the spatiotemporal variation in riverine plastic transport. First, we studied the response of plastic flow to increased river discharge by comparing measurements taken during low flow and high flow periods. Second, we investigated the variation of riverine plastic transport over the river length to improve our understanding of the origin and fate of riverine plastics. We demonstrate that during a period with higher river discharge, plastic transport increased up to a factor ten at the observation point closest to the river mouth. This suggests that the plastic emission into the ocean from the Seine may also be considerably higher during increased discharge. Upstream of Paris plastic transport increased only with a factor 1.5, suggesting that most plastics originate from Paris or areas further downstream. With this paper we aim to shed additional light on the seasonal variation in riverine plastic transport and its distribution along the river length, which may benefit future long-term monitoring efforts and plastic pollution mitigation strategies.
Marine litter is a worldwide problem. It impacts negatively marine environment, organisms, human health and coastal communities. In this research, abundance, composition and sources of marine litter (macro-debris > 2.5 cm) and beach cleanliness were assessed for three beaches in the central Croatian Adriatic Sea. Mean abundance for the studied region was 3.35 items/m2 and the highest recorded CCI value was 150. Most of the collected litter was made of artificial polymer material (93.86%), and main sources of litter were shoreline activities representing (31.68% of the total sample) and fishing and aquaculture representing (12.66% of the total sample). Land-based and sea-based sources accounted for 32.76% and 15.16%, respectively. Results from the present study provide another evidence of marine litter problem and high presence of plastic items in the marine environment of the Adriatic Sea. Presence of litter from different countries shows the internationality of marine litter problem which can only be solved by international collaborations and partnerships as well as by taking individual responsibility of all. Presence of the short-life single-use plastic items and the problems associated with them have been recognized in this study as most of the items collected were single-use items. High abundance of these items indicates not only their large use in everyday life, but also the lack of awareness of the general public about the environmental problem they cause. Moreover, the results obtained in this research imply the need for better waste management systems.
Designing effective policy interventions to motivate mitigation actions requires more realistic assumptions about human decision-making based on empirical evidence from the behavioural sciences. We therefore need to consider behavioural rather than only economic costs and benefits in policy intervention designs.