Abstract
Plastic contamination in the ocean has recently received a lot of attention. Plastic production has been growing and its use spread to many sectors. More than 80% of plastic enters the ocean from land-based sources, with the remaining having ocean-based sources. Once in the ocean, plastic undergoes fragmentation and degradation that lead to the formation of microplastics (MPs) and nanoplastics (NPs), and their dimensions are becoming an environmental concern. Thus, this chapter provides an overview of the effects of MPs and NPs on marine organisms, from bacteria to fish. Plastic affects marine organisms from molecular to population levels but some knowledge gaps exist regarding the biogeochemical cycle of plastic, how it behaves and is distributed in the aquatic-sediment compartment and in deep-sea. Moreover, more attention is necessary concerning NPs ecotoxicological effects already detected and because not all polymer types and size effects have been investigated. In addition, risk assessment of plastic particles is needed to characterize their risks and for data to be comparable.
TopIntroduction
Plastic pollution in the ocean was first reported in the 1970s, yet in recent years, it has drawn tremendous attention from scientists and different parts of society (Law, 2017). In the middle of the 19th century, the first synthetic plastic, known as ‘Bakelite’, was invented and its countless properties have ever since led to different types of plastics shaping the world (PlasticsEurope, 2020). The increasing use of plastics in day-to-day life had world plastic production reaching 368 million tonnes in 2019 (Figure 1) (PlasticsEurope, 2020). In Europe, plastic production decreased between 2018 and 2019 by 3.9 million tonnes, representing 16% of the world’s plastic production, whilst China alone is responsible for producing 31% of this amount (PlasticsEurope, 2020). Today, 60% of plastic products have a lifetime between 1 and 50 years, sometimes even more; however, a gap of information remains between the amount of plastic waste collected, and the quantity of plastic produced and/or consumed (PlasticsEurope, 2020).
Figure 1. Amount of global plastic production
The Plastics Europe Fact sheet (2020) states that the leading plastic polymers manufactured are polypropylene (PP; 19.4%), low-density polyethylene (LDPE; 17.4%), high-density polyethylene (HDPE; 12.4%), polyvinyl chloride (PVC; 10%), polyurethane (PUR; 7.9%), polyethylene terephthalate (PET; 7.9%), and polystyrene (PS; 6.2%). All these polymers have high demand in many industries, such as electronics, personal health care, food packaging, housing insulation, as well as in medical equipment and devices (PlasticsEurope, 2020).
The increasing use of plastics has incremented their release into the marine environment, where around 80% of plastic debris originates from land-based sources; illegal dumping and inadequate waste mismanagement, wastewater treatment plants inefficiency in filtering smaller particles, coastal littering, tourism, and industrial activity (Sebille et al., 2016). The remaining originates from ocean-based sources; fishing equipment, shipping, offshore oil and gas platforms, and undersea exploration (Sebille et al., 2016). Therefore, plastics are found in the atmosphere, ocean, lakes and rivers, soils, sediments, and animal biomass all around the world, being a ubiquitous problem (Lau et al., 2020). Despite expanded attempts in recent years to estimate the quantity of plastic pollution entering rivers and oceans (Tramoy et al. 2019), critical data gaps remain. Moreover, plastic particles can be detected in different compartments of freshwater environments, estuaries, and in the marine environment such as coastal beaches, water columns, and deep sediments (Ricciardi et al., 2021).
Key Terms in this Chapter
Nanoplastics: Particles with a colloidal characteristic, formed unintentionally (i.e. from the deterioration and production of plastic objects) and ranging in size from 1 to 100 nm.
Biomagnification: Or biological magnification is the process by which a a concentration of a pollutant (such as plastic particles) in organisms in a food chain increases towards the top of that chain.
Biological Effects: Processes that occur in the body and cells of an organism.
Microplastics: Plastic particles, with size < 5 mm normally formed from the deterioration/degradation of plastic objects/products.
Ecotoxicology: The branch of toxicology concerned with the effects of toxic chemicals on biological organisms, especially at the population, community, and ecosystem level.
Leachate: A solution resulting from leaching as a soluble constituent from a solid passing phase, or suspended solids, or any other component of the material.
Marine Pollution: Refers to diret or indirect introduction by humans of substances or energy into the marine environment (including estuaries) resulting in harm to living resources, hazards to human health, hundrances to marine actividies including fisheries, impairment of the quality of sea water and reduction of amenities.