While plastic items like bottles, bags, and balloons are highly visible litter and well-known as ugly eyesores and hazards to wildlife, there is another form of plastic that is generally not visible but is far more numerous and may be equally or more hazardous in the environment. This is microplastic, small pieces ranging from 5 mm in size down to microscopic. Microplastics are categorized as primary microplastic – that which was always tiny, and secondary microplastic-which results from the fragmentation of larger pieces. As with larger pieces, microplastics represent a variety of different polymers, such as polyethylene, polystyrene, etc. They are found in a variety of shapes, including spheres, fragments, films, and fibers. In the past decade there has been a great amount of study on microplastics – where they come from, where they are found, how organisms interact with them, and what effects they may have on the organisms and the ecosystem. Most of these studies have focused on the marine environment since that is where they were initially detected, but they have subsequently been found to be abundant in freshwater and terrestrial environments as well. This review examines the research, emphasizing aquatic environments, and suggests avenues for improving future research.
Pollution and Marine Debris
Marine microplastic particles (MPs,<5 mm) exhibit wide ranges of densities,sizes, and shapes, so that the entire MPs“ensemble”at every time instant can be character-ized by continuous distributions of these parameters. Accordingly, this community ofparticles demonstrates distributions of dynamical properties, such as sinking or risingvelocity, critical shear stress, and the re-suspension threshold. Moreover, all the MPs’properties vary significantly with the time spent in marine environment and withparticular conditions experienced by the particle on its journey. A brief review of thepresent-day numerical efforts towards prediction of MPs transport shows the prevalenceof the Lagrangian particle tracking approach, especially for floating litter. In a broadercontext, the present practice of MPs transport modelling follows the“selective”strategy(e.g., only a certain sub-class of MPs, or specific processes, are considered, sometimes in onlyone- or two-dimensional setting). The heterogeneous nature of MPs, their enormous longevityand movability in marine environment, and the wide spectrum of the involved environ-mental processes suggest further integration (or coupling) of different models in future, aswell as application of other types of models (ensemble modeling, chaos theory approaches,machine learning, etc.) to the problems of MPs transport and fate in the marine environment.Key words:microplastics, transport, modelling.
Studies related to the evaluation of plastics in freshwaters have been increasing in recent years because approximately 80% of plastic items found in the sea are from inland waters. Despite the ecological relevance of these surveys, no information has been available until now about the hazard related to plastic mixtures in freshwaters. To fill this knowledge gap, we carried out a study aimed to assess the environmental risk associated with the “cocktail” of plastics and environmental pollutants adsorbed on their surface in one of the larger European freshwater basins. Plastic debris was collected by a manta trawl along one transect each in four of the Italian subalpine great lakes (Lake Maggiore, Como, Iseo and Garda) and administered to zebra mussels (Dreissena polymorpha), a useful freshwater biological model present in all these lakes. We estimated a plastic density from 4908 MPs/km2 (Lake Iseo) to 272,261 MPs/km2 (Lake Maggiore), while the most common polymers found were polyethylene and polypropylene, with percentages varying between 73% and 100%. A biomarkers suite consisting of 10 different endpoints was performed after 7 days of exposure to investigate the molecular and cellular effects of plastics and related adsorbed pollutants. The main results highlighted a diffuse but different toxicity due to plastics for each lake, and there were significant changes in the antioxidant and detoxifying enzyme activities in Lake Maggiore, Iseo and Garda, an increase in protein carbonylation in L. Como, and a cellular viability decrease of approximately 30% for zebra mussels from L. Iseo and Garda. Despite this variability in the endpoints' responses, the application of the biomarker response index showed a similar environmental hazard due to plastics for all the sampled lakes.
We present the results of devising new techniques and technical means for utilizing small-sized unmanned aerial vehicles (UAVs) in ecological monitoring of marine water basins in compliance with the MARPOL 73/78 international convention. The development of a hardware-software complex is described for the system of recognizing oil spills using elements of artificial intelligence. The laboratory experiments on identifying oil spills by laser induced fluorescence (LIF) methods are presented, as well as the methods of recording the spectrum of upward solar radiation.
With the increasing focus on marine plastic pollution, quantification of the environmental losses of plastics in the world, with differentiation into geographic regions, polymers and loss occurrences along the plastics value chains, is required. In this study, we make a global estimation of the losses of plastics to the environment across the entire plastic value chain, using existing literature and databases coupled with improved and additional methodological modelling of the losses. The resulting loss estimates are unprecedented in their detailed differentiations between polymers (23), plastic applications (13), geographical regions (11), and plastic value chain stages. Comprehensive sensitivity and uncertainty analyses were also conducted to identify key drivers in terms of plastic losses. We overall found that approximately 6.2 Mt (95% confidence interval, CI: 2.0–20.4 Mt) of macroplastics and 3.0 Mt (CI: 1.5–5.2 Mt) of microplastics were lost to the environment in 2015. The major macroplastic loss source was identified as the mismanaged municipal solid waste (MSW) management in low-income and lower-middle income countries (4.1 Mt). For microplastics, the major sources were abrasion of tyre rubbers, abrasion of road markings and plastics contributing to city dust generation. To curb marine plastic pollution, such quantified mapping as ours are needed to evaluate the magnitude of the plastics losses to environment from different sources and locations, and enable a further assessment of their environmental damage. Through our uncertainty and sensitivity analyses, we highlight plastics sources that should be prioritized in further research works to obtain a more comprehensive and accurate representation of global plastics losses.
Ingestion of microplastics (MPs) has been documented in several marine organisms, but their occurrence in deep-sea species remains almost unknown. In this study, MPs were investigated in two economically and ecologically key crustaceans of the Mediterranean Sea, the Norwegian lobster Nephrops norvegicus and the shrimp Aristeus antennatus. Both the species were collected from 14 sites around Sardinia Island, at depths comprised between 270 and 660 m. A total of 89 and 63 stomachs were analysed for N. norvegicus and A. antennatus respectively, and more than 2,000 MPs-like particles were extracted and sorted for identification and characterization by μFT-IR. In N. norvegicus, 83% of the specimens contained MPs, with an average abundance of 5.5 ± 0.8 MPs individual−1, while A. antennatus showed a lower frequency of ingestion (67%) and a lower mean number of MPs (1.66 ± 0.1 MPs individual−1). Composition and size of particles differed significantly between the two species. The non-selective feeding strategy of N. norvegicus could explain the 3–5 folds higher numbers of MPs in its stomach, which were mostly composed of films and fragments derived by polyethylene and polypropylene single-use plastic items. Contrarily, most MPs in the stomachs of A. antennatus were polyester filaments. The MPs abundance observed in N. norvegicus is among the highest detected in Mediterranean species considering both fish and invertebrates species, and provides novel insights on MPs bioavailability in deep-sea habitats. The overall results suggest that both N. norvegicus and A. antennatus, easily available in common fishery markets, could be valuable bioindicators and flagship species for plastic contamination in the deep-sea.
Microplastic fibers represent a significant share of the global marine micrcroplastic pollution, particularly in coastal areas. In controlled laboratory experiments, we offered fluorescent microplastic fibers (40–4400 μm lengths, median 150 μm) and spherical microplastic beads (9.9 μm Ø) together with commercial fish food to the Atlantic ditch shrimp Palaemonetes varians. The shrimps ingested fibers and beads along with the food. Upon ingestion, the beads and the shortest fibers (up to 100 μm) passed from the stomach into the gut and were egested within the fecal strings. The longer fibers first remained in the stomach but were regurgitated, i.e. extruded through the esophagus, within 12–14 h. Regurgitation is an evolutionary adaptation of particular crustacean species and other invertebrates to remove large and indigestible food particles from the stomach. Accordingly, the process of regurgitation attained a new task nowadays, i.e. the elimination of anthropogenic filamentous microplastic debris from the stomach to avoid harm. This behavioral feature may represent a selective advantage in view of the continuously increasing environmental plastic pollution.
Plastic pollution has become a major concern in Indonesian coast and marine environment today. It occurs because 14% of the solid waste (SW) components in this country is plastic, and the SW management (SWM) infrastructure and services are still limited. The objectives of this article are to discuss the improper SWM and its impact to plastic pollution in Indonesia. Ten plastic pollution studies concerning macroplastics (MaP) and microplastics (MP) were described. These studies covered 5 regions, namely Java, East Nusa Tenggara, East Kalimantan, South Sulawesi, North and Southwest Sumatera. The highest MP abundance of 37,440–38,790 particles/kg dry weight (DW) sediment was found in Jakarta Bay, followed by Wonorejo Coast in Surabaya City (414–590 MP particles/kg DW sediment). The MP has entered the food chain through bivalves and fish. Therefore, the plastic pollution which is related to population density, and inadequacy of SWM, needs urgent solution.
Marine plastics pollution (MPP) is an alarming problem affecting many countries, particularly in the Asia-Pacific region, and generated mostly from land-based sources. Five Asian countries (i.e. China, Indonesia, the Philippines, Vietnam and Sri Lanka) have been identified as the largest sources of MPP globally. This article presents two cases studies focused on the two largest polluters: China and Indonesia. Both countries face similar challenges in dealing with plastic pollution. They have weak legal and institutional frameworks in place to deal with MPP. The two case studies also show that there have been more creative and effective measures taken at the domestic level by local governments and non-state actors, many of which involve partnerships among different stakeholders. This article argues that governance efforts to address MPP require an ‘all hands-on deck’ approach, involving multi-level and multi-actor strategies and targeted regulatory and non-regulatory measures. However, our findings also suggest that most efforts should be directed at the subnational level, from which the problem mainly originates. This article proposes a number of legal and policy recommendations, based on the lessons learned from the case studies, which can be instrumental in reducing the global MPP crisis.
Plastics and microplastics (MPs) are emerging pollutants which have become a global environmental issue. They are abundant in oceanic and terrestrial environments, undergoing bioaccumulation and trophic transfer and potentially harming the entirety of mankind. Microplastics in the environment may be transferred to humans via different pathways, such as dietary intake and inhalation. This chapter summarizes the occurrences of MPs in seawaters, sediments, freshwaters, bivalves, and atmospheric fallouts. Generally, the spatial distribution of plastics and MPs in seawaters suggested that higher levels were found in areas which are closer to lands. Similarly, high levels of MPs in freshwaters, sediments, and aquatic organisms were associated with intensified human activities. The occurrences of MPs in bivalves from around the globe suggested a potential human exposure via dietary intake. Moreover, trophic transfer of MPs under controlled conditions suggested that MPs can be transferred to organisms at higher trophic levels. Plastics and MPs were found in atmospheric fallouts from urban, suburban, and remote mountain sites, suggesting the potential for long-range atmospheric transport of MPs. This chapter provides the reader with a snapshot of the plastic and MP pollution in the global oceans and planetary boundaries. Future studies are desirable for examining the exposure pathways, mechanisms of toxicity, and possible health effects.