Plastics and the Ocean. Группа авторов

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Название Plastics and the Ocean
Автор произведения Группа авторов
Жанр Химия
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Издательство Химия
Год выпуска 0
isbn 9781119768418



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while floating in San Diego Bay resulted in liver abnormalities in fish.

      An implication of the dictum that the dose makes the poison is that as the dose of a substance increases, so does its potential toxicity. There are certain substances in plastics that contradict this. I imagine a crowd unable to get through a door when an individual could. Binding to receptors can exhibit a U‐shaped curve where a very low dose given at the right time binds to a receptor and larger doses have less effect until the system is eventually overwhelmed at very high doses. Future ocean plastic research will examine such questions and others as they relate to population‐level effects.

      This volume concludes with two chapters on behavior change and legal remedies, which are certainly important in stemming the tide of vagrant plastics invading the ocean and the entire biosphere. However, the economic drivers of plastic pollution are in the ascendant, and until the worldwide growth of infinitely variable plastic products is redirected by a major paradigm shift, scientists will continue to work in a “different” plastic world.

       Anthony L. Andrady

       Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA

      We live in an era where human beings dominate and control most geochemical processes on Earth’s surface, including some aspects of the ocean system. It is impressive that Homo sapiens accounting for a mere 0.01% of the biomass on Earth, can exert such control; the mass of structures built on Earth by man now exceeds the total biomass on the planet (Elhacham et al. 2020). The present epoch of man deserves to be formalized a distinct period, the Anthropocene, within the geological time scale (Crutzen and Stoermer 2000). This era started in the post‐World War II (WWII) years (Steffen et al. 2015; Zalasiewicz et al. 2016) and is ongoing. Plastics, a unique identifier of the Anthropocene, survives as stratigraphic markers in the soil to guide future archeologists exploring our era. Historical origins of plastics, however, can be traced further back in history, perhaps to 1869, when Wesley Hyatt invented nitrocellulose as a potential substitute for elephant ivory that was used to make billiard balls at that time. Even though Wyeth’s celluloid billiard balls were a failure (as some of them exploded on impact), this unique product opened the floodgate for synthetic plastic products in to the consumer world. But, the commodity plastics we are familiar with today, came of age much later when the War effort spurned a rapid expansion of the materials industry in the US with public funding allowing new plastic resin plants to be built to produce vital plastics for the military supply chain.

      An estimated (Geyer et al. 2017) 7300 MMT of plastic resin and fiber was manufactured globally from just after WWII until the year 2015. By 2020, this figure rose to 8717 MMT. More than half of this was either PE (~36%) or PP (~21%). In addition, the thermoplastic polyester (e.g., poly(ethylene terephthalate) [PET]) used in beverage bottles, polystyrene (PS) in packaging, and poly(vinyl chloride) (PVC) as a building material, were also produced. Reflecting their high‐volume use, these same 4–5 classes of plastics typically dominate the plastic content in the municipal solid waste stream (MSW), in urban litter, as well as plastic debris in the marine environment. The current discussion is therefore focused on this limited set of plastic types: PE, PP, and PS foam that dominates floating plastic debris in surface waters of the ocean and nylons or polyamide (PA). PET, PS, and PVC, mostly found in the deep sediment. Deep‐sea sediment is the most important sink or repository of waste plastics that enter the ocean every year. While no systematic quantitative assessment is available, there is little doubt that plastics accumulate in the benthic sediment and a recent estimate places it conservatively at about 14 MMT (Barett et al. 2020).