Plastic pollution is one of the human-created severe threats on marine and coastal systems. Phthalates (PAEs) are a class of chemical compounds widely used in the manufacturing and processing of plastics (plasticizers) which are employed in a wide variety of industrial and consumer products (i.e., personal care products and food). As PAEs do not form a covalent bond with polymers, they are easily released into the environment from such commercial products. For these reason, PAEs can either be absorbed by suspended particles that can sink to the bottom of aquatic ecosystems and build up in the sediments, or they can become readily available to marine organisms. Marine sediments can also act as an uptake source by benthic microorganisms in these ecosystems. Among PAEs, di(2-ethylhexyl)phthalate (DEHP) is the most widely produced and used, as well as the most persistent phthalate found in seawaters and many studies have recently reported its negative effects on acquatic species. This study examines the potential impact of DEHP on Gromiids, unicellular heterotrophic protozoa which are a common component of benthic marine communities. These organisms are characterize by the accumulation of a significant volume of stercomata (waste pellets), together with mineral grains and other extraneous particles, within the cell. In fact, they play a key role in benthic food webs by feeding on detritus and recycling nitrogen and carbon. A chronic toxicity assay was carried out to assess the impact of this pollutant in the gromiids physiology and behavior. Contaminated colture were exposed and monitored for up 4 weeks, and at the end of the experiment all the live individuals were analysed by steomicroscopy and μ-FTIR (Fourier Transform Infrared) spectromicroscopy. Under the microscope, some individual showed a discernible decrease in cellular turgor, which was most likely caused by sediment loss and cell membrane breakdown. Meanwhile, FTIR results revealed the presence of synthetic material inside the cell. FTIR data allowed to answer the question whether there are any noticeable biochemical differences in the proteinaceous shells and the cytoplasm depending on the exposure of the cell organism to this bio-accessible plasticizers. As observed in other unicellular organisms related to gromiids, such as foraminifera, DEHP can induce similarly oxidative stress and protein aggregation. Additionally, this plasticizer can be assimilated into the gromiids cytoplasm, thereby entering biogeochemical cycles. In summary, gromiids could be a good proxy of on-going emerging pollutants, highlighting the possibility that plastic pollution could enter the marine sedimentary record providing a unique signal that is unequivocally attributable to human activities. It is essential to understand the mechanisms behind the interactions between plastic pollution and marine organisms, to develop effective mitigation strategies to safeguard marine biodiversity and ecosystem health.
Effect of plastics on marine ecosystem: preliminary findings of Phthalates (PAEs) on Gromiids
Buosi C.;De Giudici G.;Medas D.;
2024-01-01
Abstract
Plastic pollution is one of the human-created severe threats on marine and coastal systems. Phthalates (PAEs) are a class of chemical compounds widely used in the manufacturing and processing of plastics (plasticizers) which are employed in a wide variety of industrial and consumer products (i.e., personal care products and food). As PAEs do not form a covalent bond with polymers, they are easily released into the environment from such commercial products. For these reason, PAEs can either be absorbed by suspended particles that can sink to the bottom of aquatic ecosystems and build up in the sediments, or they can become readily available to marine organisms. Marine sediments can also act as an uptake source by benthic microorganisms in these ecosystems. Among PAEs, di(2-ethylhexyl)phthalate (DEHP) is the most widely produced and used, as well as the most persistent phthalate found in seawaters and many studies have recently reported its negative effects on acquatic species. This study examines the potential impact of DEHP on Gromiids, unicellular heterotrophic protozoa which are a common component of benthic marine communities. These organisms are characterize by the accumulation of a significant volume of stercomata (waste pellets), together with mineral grains and other extraneous particles, within the cell. In fact, they play a key role in benthic food webs by feeding on detritus and recycling nitrogen and carbon. A chronic toxicity assay was carried out to assess the impact of this pollutant in the gromiids physiology and behavior. Contaminated colture were exposed and monitored for up 4 weeks, and at the end of the experiment all the live individuals were analysed by steomicroscopy and μ-FTIR (Fourier Transform Infrared) spectromicroscopy. Under the microscope, some individual showed a discernible decrease in cellular turgor, which was most likely caused by sediment loss and cell membrane breakdown. Meanwhile, FTIR results revealed the presence of synthetic material inside the cell. FTIR data allowed to answer the question whether there are any noticeable biochemical differences in the proteinaceous shells and the cytoplasm depending on the exposure of the cell organism to this bio-accessible plasticizers. As observed in other unicellular organisms related to gromiids, such as foraminifera, DEHP can induce similarly oxidative stress and protein aggregation. Additionally, this plasticizer can be assimilated into the gromiids cytoplasm, thereby entering biogeochemical cycles. In summary, gromiids could be a good proxy of on-going emerging pollutants, highlighting the possibility that plastic pollution could enter the marine sedimentary record providing a unique signal that is unequivocally attributable to human activities. It is essential to understand the mechanisms behind the interactions between plastic pollution and marine organisms, to develop effective mitigation strategies to safeguard marine biodiversity and ecosystem health.
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