POIZON - Microplastics and Persistent Pollutants: A Double Threat to Life in the Oceans
once it casts its spell, it holds us in a net of astonishment forever"
Jacques Yves Cousteau
The Poizon project was conceived in 2008 and developed between 2010 and 2013. It was a pioneering project in Portugal focused on research on microplastics in the oceans, in line with research that was being started in other institutions, particularly in Europe (PTDC/MAR/102677/2008).
Microplastics represent a growing global problem and a direct threat to the marine environment, becoming a hugely popular topic after the discovery and dissemination of the large “garbage patch” existing in the North Pacific Gyre, by Captain Charles Moore.
Microplastics (<5mm particles) result from larger fragments due to photo‑chemical degradation and abrasion, they are persistent, they are found either floating on the surface, suspended in the water column, or deposited on the bottom. Easily confused with food, microplastics are potential vectors in the transfer and exposure of marine organisms to highly toxic persistent organic pollutants (POP), such as PCBs, DDT, and PAH, hydrophobic compounds that easily adsorb to plastic particles. Ingestion of microplastics poses a long-term threat to marine organisms, not only because of the possible mechanical obstruction of the digestive tract but also because of the toxic effects of POPs.
In the project proposal we identified 3 lines of investigation, to answer 3 groups of questions:
1. Monitoring of microplastics on the Portuguese coast. What types and quantities are present? Identification and quantification of polymers by infrared spectroscopy (FT-IR), quantification of POPs (PCB, DDT and PAH) using GC-MS. The result will be the establishment of a reference line for microplastics and associated contamination on the Portuguese coast.
2. Degradation of plastics. How long do polymers (granules or films) take to degrade in conditions similar to those of the ocean and beaches? Photochemical degradation in an accelerated aging chamber simulating oceanic conditions, followed by abrasion. The result will be to know the degradation rate and the time it takes for the granules or films to produce particles <1mm, improving the prediction of the amount of microplastics resulting from the polymers that reach the oceans.
3. Transfer of POP to marine invertebrates from the ingestion of microplastics. Are there physical/mechanical damages associated with ingestion? Are there changes in feeding rates or histopathological effects of ingested POPs? At this point, ecotoxicological tests of ingestion of particles contaminated with a polycyclic aromatic hydrocarbon will be carried out.
What is a polymer?
Polymers are chemical compounds of high molecular mass, made up of the repetition of structural units (monomers), which are small molecules with the ability to link together through long chemical chains. The repeat of the monomers can be linear or it can be branched. As for their classification, polymers can be natural or synthetic.
These macromolecules are formed by polymerization reaction, the two main mechanisms being the chain growth reaction (or addition polymerization) and the gradual growth reaction (or condensation polymerization). Addition polymerization is used to manufacture polymers such as polyethylene, polypropylene and polyvinyl chloride (PVC). Examples of polymers formed by this type of reaction are polystyrene, polyurethanes and polyethers.
What is plastic?
Plastic is a synthetic material, produced from organic polymers that can be easily molded under certain conditions of temperature and pressure. Plastics have been produced since the 20th century and their intensive use is currently considered an environmental problem due to the amount of waste it generates annually.
The materials used in the production of plastics are as diverse as cellulose, coal, natural gas, salt and crude oil (crude oil). There are different types of plastics, which can be grouped into two main families of polymers, thermoplastics and thermosetting. Thermoplastics are those whose structure changes with temperature, such as polyolefins and polyurethanes. Thermosetting, also called thermosetting or thermosetting, are those whose rigidity does not change with temperature, such as polyesters.
What are microplastics?
Microplastics (particles < 5mm) are the result of larger particles due to photo-chemical degradation and abrasion, they are persistent, they are found either floating on the surface, suspended in the water column or deposited on the bottom. All plastics (natural or crude) are biodegradable, which means they have the ability to be degraded by environmental (ultraviolet radiation, sea salinity) and biological (microorganisms) conditions. Some plastics have very slow degradation rates which make them persistent in the environment. These rates depend on polymer stability, temperature and available oxygen. Currently, about 90% of marine debris floating in the oceans is synthetic plastics of anthropogenic origin.
Easily confused with food, microplastics are potential vectors in the transfer and exposure of marine organisms to highly toxic persistent organic pollutants (POP), such as polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH) and Dichloro-Diphenyl-Trichloroethane (DDT) ) and derivatives. These hydrophobic compounds are preferred to adsorb to plastic particles. This adsorption process occurs during the exposure time to which microplastics are subjected in oceans and coastal areas. The effects of these pollutants vary according to the families they belong to, and may eventually have harmful effects on public health.
Ingestion of microplastics poses a long-term threat to marine organisms, not only because of the possible mechanical obstruction of the digestive tract but also because of the toxic effects of POPs. As they are less than 5 mm in size, they are in the food particle size range of all major groups of marine animals, from birds to bivalves. Regarding the organisms that confuse plastics with food and ingest them, they end up being more subject to problems of bioaccumulation of pollutants.
MICROPLASTICS ON THE PORTUGUESE COAST
* (2018) Antunes, J, Frias, J, & Sobral, P. Microplastics on the Portuguese coast. Marine Pollution Bulletin, 131, 294-302. https://doi.org/10.1016/j.marpolbul.2018.04.025
* (2013) Antunes, JC, Frias, JPGL, Micaelo, AC, Sobral, P., Resin pellets from beaches of the Portuguese coast and adsorbed persistent organic pollutants. Estuarine, Coastal and Shelf Science – in press. doi: http://dx.doi.org/10.1016/j.ecss.2013.06.016
* (2013) Frias, JPGL, Antunes, JC, Sobral, P., Local marine litter survey – A case study in Alcobaça municipality, Portugal. Journal of Integrated Coastal Zone Management 13(2), 169-179. It hurts: 10.5894/rgci395
* (2013) Mizukawa,K., Takada,H., Ito,M., Bee Geok,Y., Hosoda,J., Yamashita,R., Saha,M., Suzuki,S., Miguez,C., Frias , J., Antunes, JC, Sobral, P., Santos, I., Micaelo, C., Ferreira, AM Monitoring of a wide range of organic micropollutants on the Portuguese coast using plastic resin pellets. Marine Pollution Bulletin (70), 296-302. doi: http://dx.doi.org/10.1016/j.marpolbul.2013.02.008
* (2011) Martins, J., Sobral, P. Plastic marine debris on the Portuguese coastline: A matter of size? Marine Pollution Bulletin (62), 2649-2653. doi:10.1016/j.marpolbul.2011.09.028.
* (2010) Frias, JPGL, Sobral, P., Ferreira, AM Organic pollutants in microplastics from two beaches of the Portuguese Coast. Marine Pollution Bulletin (60), 1988-1992. doi:10.1016/j.marpolbul.2010.07030.
* Lecture on Marine Waste at the Externato Cooperativo da Benedita within the scope of the POIZON project and the national project COSTWATCH – 2012.
* Lecture in the Autonomous Region of Madeira
* Lecture at the Faculty of Sciences
* Lecture in Brazil
* VIDEO POIZON publicity video
Sampling campaigns in collaboration with the Coastwatch project in the municipality of Alcobaça – January and February 2012.
Prof. Paula Sobral
Department of Environmental Science and Engineering
Faculty of Science and Technology - NOVA University of Lisbon
Paula Sobral (coordinator)
Marine ecology and pollution - marine litter, microplastics and persistent pollutants
Environmental Engineering, Ecological Engineering Branch. Ingestion of plastic microparticles in marine bivalves.
Environmental Engineering, Sanitary Engineering Branch. Distribution and accumulation of plastic on the Portuguese coast.
IPMA - Institute of the Sea and Atmosphere
Doctor in Marine Sciences, specializing in Marine Chemistry. Analysis of persistent pollutants adsorbed to plastics.
Chemical engineering. Analysis of persistent pollutants adsorbed to plastics.
Applied Chemistry, Master in Biotechnology. Analysis of persistent pollutants adsorbed to plastics.
PIEP Pole of Innovation in Polymer Engineering (IDEM)
Doctor in Engineering and Materials Science. Polymer Degradation Study.
Master in Materials Processing and Characterization. Polymer Degradation Study.