Plastics are non-biodegradable, and increasing accumulation of plastic debris in the ocean is a major cause for concern. The World Economic Forum, Ellen MacArthur Foundation, and McKinsey & Company claimed in 2016 that technological innovations can solve the plastic problem. Such a claim raises an as yet unanswered question: how much technological innovation is needed and is it economically feasible? We offer answers to this question via a system dynamics model that we developed to simulate different scenarios aimed at controlling plastic debris entering the global ocean. Our results show that ocean cleanup technologies could achieve a 25% reduction in the level of plastic debris in the ocean below 2010 levels in 2030. However, this would require removing 15% of the stock of plastic debris from the ocean every year over the period 2020–2030, which equates to 135 million tons of plastic in total (metric tons). The implementation cost of such an ocean cleanup effort would amount to €492 billion-€708 billion, which represents 0.7%–1.0% of the world GDP in 2017 – this calculation is based on unit costs in €/kg estimated in The Ocean Cleanup project feasibility study. The Ocean Cleanup project alone is designed to collect 70,320 tons of plastic debris over a 10 year period. Removing 135 million tons of plastic debris would require investing in 1924 similar cleanup projects. These results help to assess the economic feasibility of removing such large volume of plastics. Moreover, our results provide quantitative confirmation that technological solutions alone are not sufficient to solve plastic pollution issues. A portfolio of diverse solutions – not only technological ones – is likely to have greater technical, political and economic feasibility. Our model shows that such a combined portfolio implemented over the period 2020–2030 could reduce the ocean plastic stock to 2013 levels (94 million tons) by 2030.
Pollution and Marine Debris
Analyses of thermotolerant coliform and heterotrophic bacteria as well as Escherichia coli and Vibrio species were carried out on plastic samples and in the surrounding waters of Guanabara Bay to evaluate plastic debris as vehicles of bacterial dispersal. Chemical characterizations of plastics were performed using Fourier transform infrared spectroscopy (FTIR). Plastic debris with high coliform contents were found, while their respective water samples had only low titers. No correlations were observed, however, between the amounts of bacteria and the chemical compositions of the plastic debris. Forty-four bacterial strains were PCR-confirmed as E. colipathotypes, and 59 strains of Vibrio spp. (with 12 being identified as Vibrio cholerae , Vibrio vulnificus , and Vibrio mimicus ). These findings suggest these plastics can function as a substrate for bacterial biofilms(including pathogens). These debris, in turn, can be dispersed in aquatic environments not otherwise showing recent fecal bacterial contamination.
In situ studies of plastic deterioration can help us understand the longevity of macroplastic as well as the generation of microplastics in the environment. Photo-oxidation contributing to the generation of microplastics in the marine environment was explored using four types of plastic (polyethene, polystyrene, poly(ethylene terephthalate) and Biothene® exposed in light and in shade, in both air and sea water. Metrics for deterioration were tensile extensibility and oxidation rate. Measurements were conducted at intervals between 7 and 600 days' exposure. Deterioration was faster in air than in sea water and was further accelerated in direct light compared to shade. Extensibility and oxidation were significantly inversely correlated in samples exposed in air. Samples in sea water lost extensibility at a slower rate. Polystyrene, which enters the waste stream rapidly due to its wide application in packaging, deteriorated fastest and is, therefore, likely to form microplastics more rapidly than other materials, especially when exposed to high levels of irradiation, for example when stranded on the shore.
The strandline is one of the first deposition habitats of microplastics before they are integrated to the beach as a standing stock or finally removed. Beaches, entirely or partially protected by beachrocks, have different sediment dynamics and therefore may present variation in microplastic deposition. The aim of this work was to test if protected and unprotected (i.e., exposed to waves) areas of a sandy beach present different microplastic accumulation on the strandline – a habitat greatly influenced by both water and sediment dynamics. Microplastic (MP) amounts were significantly higher at the protected area (Mprotected = 642.6 ± 514.8 MP m−2, Mexposed = 130.6 ± 126.8 MP m−2, Mann-Whitney U test, U = 14.5, p = 0.0009), showing that beachrocks influence microplastic accumulation on the beach face. Therefore, hard structures parallel to the beach may also affect microplastics deposition on beach sediments, being important to consider these structures on microplastic surveys.
The presence of plastic marine debris in our oceans has emerged rapidly in the last few years as an environmental impact urgently in need of attention, and plastic will be a pollutant of concern for the foreseeable future. Concerns have been raised about possible adverse health impacts as a result of microplastic ingestion by marine wildlife as well as human seafood consumers, yet there is very little data to inform appropriate management actions and consumer advice. Now is the time to consider the best strategic choices for the research, management and outreach needed to address priority issues around microplastics. It is essential to treat marine plastic pollution not only as an area in need of comprehensive research and waste management solutions, but also as a permanent pollutant in order to formulate management responses similar to those for other pollutants. First, it is essential to consider developing monitoring protocols to gather important baseline information about microplastics to inform management responses. Second, targeted research is needed to identify differences in microplastic accumulation among selected species and fisheries. Third, research is needed to explore potential threshold levels of microplastics in seafood that could trigger management actions or consumer advisories. Finally, a range of model management practices to address microplastics should be considered, such as regulating inputs from wastewater, assessing what consumer advisories are needed, and taking into account localized inputs from gear used in seafood harvesting and cultivation.
Marine plastic debris, including microplastics (<5 mm in size), comprises a suite of chemical ingredients and sorbed chemical contaminants. Thus, microplastics are a potential, and debated, source of anthropogenic chemicals for bioaccumulation and biomagnification. Several studies have investigated the role of microplastics as a vector of contaminants to marine organisms via modeling exercises, laboratory experiments, and field studies. Here, we examined relationships among chemical contaminants and microplastics in lanternfish (family Myctophidae), an important link in marine food webs, from the North Pacific Ocean as a case study from the field. We compared the body burden of several chemical groups (bisphenol A [BPA], nonylphenol [4-NP], octylphenol [4n-OP], alkylphenol ethoxylates [APEs], pesticides, polychlorinated biphenyls [PCBs], and polybrominated diphenyl ethers [PBDEs]) in fish caught within and outside the North Pacific Subtropical Gyre where plastic is known to accumulate. We also tested whether there was a relationship between chemical concentrations in fish and plastic density at each sampling location. Mean concentrations of common plastic constituents (BPA, 4-NP, 4n-OP, APEs, and total PBDEs) were comparable between myctophids collected within and outside the North Pacific Gyre. Pesticides were higher in lanternfish caught outside the gyre and were associated with lower plastic density. Total PCBs were also higher in fish outside the gyre. In contrast, lower chlorinated PCB congeners were higher in fish residing in the accumulation zone and were correlated with higher plastic density. This finding is consistent with other studies demonstrating an association between lower chlorinated PCBs and plastics in biota and suggests that microplastic may be a transport mechanism for some chemicals in nature.
Microplastics are emergent contaminants in the marine environment. They enter the ocean in a variety of sizes and shapes, with plastic microfiber being the prevalent form in seawater and in the guts of biota. Most of the laboratory experiments on microplastics has been performed with spheres, so knowledge on the interactions of microfibers and marine organisms is limited. In this study we examined the ingestion of microfibers by the sea anemone Aiptasia pallida using three different types of polymers: nylon, polyester and polypropylene. The polymers were offered to both symbiotic (with algal symbionts) and bleached (without algal symbionts) anemones. The polymers were introduced either alone or mixed with brine shrimp homogenate. We observed a higher percentage of nylon ingestion compared to the other polymers when plastic was offered in the absence of shrimp. In contrast, we observed over 80% of the anemones taking up all types of polymers when the plastics were offered in the presence of shrimp. Retention time differed significantly between symbiotic and bleached anemones with faster egestion in symbiotic anemones. Our results suggest that ingestion of microfibers by sea anemones is dependent both on the type of polymers and on the presence of chemical cues of prey in seawater. The decreased ability of bleached anemones to reject plastic microfiber indicates that the susceptibility of anthozoans to plastic pollution is exacerbated by previous exposure to other stressors. This is particularly concerning given that coral reef ecosystems are facing increases in the frequency and intensity of bleaching events due to global change stressors such as ocean warming and acidification.
Procellariiformes are the most threatened bird group globally, and the group with the highest frequency of marine debris ingestion. Marine debris ingestion is a globally recognized threat to marine biodiversity, yet the relationship between how much debris a bird ingests and mortality remains poorly understood. Using cause of death data from 1733 seabirds of 51 species, we demonstrate a signifcant relationship between ingested debris and a debris-ingestion cause of death (dose-response). There is a 20.4% chance of lifetime mortality from ingesting a single debris item, rising to 100% after consuming 93 items. Obstruction of the gastro-intestinal tract is the leading cause of death. Overall, balloons are the highest-risk debris item; 32 times more likely to result in death than ingesting hard plastic. These fndings have signifcant implications for quantifying seabird mortality due to debris ingestion, and provide identifable policy targets aimed to reduce mortality for threatened species worldwide.
There are no doubts that plastics problem in the ocean environment has become an increasingly worldwide focus in past several decades. A number of experts regard the plastic wastes as one of the hardest anthropogenic threats. The degraded items of large individual plastics lead to millions of microplstics (MPs) ultimately. As a result, the new pollution has appeared in the ocean. The ever-growing MPs have been detected in subtotal sea products, such as sea food and table salts. The MPs can bring potential health risk to people by enrichment in sea products. Furthermore, the economic development of offshore fishery and the marine tourism have been inhibited badly. This article will make a brief review on present studies about MPs in the ocean.
Oil spills are serious environmental issues that potentially can cause adverse effects on marine ecosystems. In some marine areas, like the Baltic Sea, there is a large number of wrecks from the first half of the 20th century, and recent monitoring and field work have revealed release of oil from some of these wrecks. The risk posed by a wreck is governed by its condition, hazardous substances contained in the wreck and the state of the surrounding environment. Therefore, there is a need for a common standard method for estimating the risks associated with different wrecks. In this work a state-of-the-art model is presented for spatial and stochastic risk assessment of oil spills from wrecks, enabling a structured approach to include the complex factors affecting the risk values. A unique feature of this model is its specific focus on uncertainty, facilitating probabilistic calculation of the total risk as the integral expected sum of many possible consequences. A case study is performed in Kattegat at the entrance region to the Baltic Sea to map the risk from a wreck near Sweden. The developed model can be used for oil spill risk assessment in the marine environment all over the world.