Marine debris is a global environmental issue. The chemistry of water and sediments, thus environmental quality and eventually the trophic chain, are affected by the dispersal of chemicals. Various studies have provided evidence that smoked cigarette butts (CBs) represent an important part of marine litter from the Mediterranean coasts to South America and Australia. CBs are the predominant human coastal litter item that can be bioaccumulated in marine organisms. CBs present a vector for transporting and introducing toxicants, including nicotine, harmful metals, total particulate matter and known carcinogens to aquatic habitats. The health risks associated with smoking cigarettes have been addressed for decades while the fate of CBs after the disposal has only more recently received some attention. In particular, the European regulation classified CBs as hazardous waste for their acute toxicity (H6) mainly due to the nicotine content. It is a matter of fact that distribution and diffusion of CBs and their associated toxicants in the aquatic environment can be a threat to various prokaryotic and eukaryotic species inhabiting these aquatic habitats, including Foraminifera. In this study, the viability and ultrastructural analysis involved three foraminiferal species from three different biomineralization pathways: the calcareous perforate Rosalina globularis, the calcareous imperforate Quinqueloculina spp. and the agglutinated Textularia agglutinans. The toxicological effects of CBs and synthetic nicotine were evaluated in terms of survival rate, cellular stress, and decalcification. FTIR (Fourier-transform infrared) spectroscopy analysis allowed us to investigate the response of key macromolecules and calcium carbonate to this pollutant. To further enrich our knowledge on bioavailability of nicotine in the medium culture, High Performance Liquid Chromatography analysis (HPLC) was carried out. Different acute tests were conducted at different times; all confirmed that CBs and synthetic nicotine are acutely toxic at lethal and sublethal concentrations for all three cultured foraminiferal taxa. Each species showed a species-specific response related to the type of shell biomineralization. FTIR analyses showed that synthetic nicotine promotes shell decalcification and also alters the composition of cytoplasmic macromolecules, such as lipids and proteins. At lethal concentration the lipid content increased maybe due to vesicles formation. Proteins signal evidenced overall cellular dyshomeostasis associated to beta sheets and aggregate structures. Finally, the HPLC analyses confirmed that foraminifera can absorb until the 85% of the synthetic nicotine to which they have been exposed. It is clear that CBs and nicotine contained in them affects the viability, the shell-building mechanism, and the macromolecular composition of the foraminifera themselves. The integration among acute toxicity assay, synchrotron and chemical HPLC analyses provided a valuable approach for the assessment of nicotine as biomarker of exposure to the toxicants associated with smoking and the impact of this emerging and hazardous material on calcifying marine species.
Toxicological effects of CBs and nicotine as emerging pollutant for benthic foraminifera
Medas D.;Buosi C.;
2023-01-01
Abstract
Marine debris is a global environmental issue. The chemistry of water and sediments, thus environmental quality and eventually the trophic chain, are affected by the dispersal of chemicals. Various studies have provided evidence that smoked cigarette butts (CBs) represent an important part of marine litter from the Mediterranean coasts to South America and Australia. CBs are the predominant human coastal litter item that can be bioaccumulated in marine organisms. CBs present a vector for transporting and introducing toxicants, including nicotine, harmful metals, total particulate matter and known carcinogens to aquatic habitats. The health risks associated with smoking cigarettes have been addressed for decades while the fate of CBs after the disposal has only more recently received some attention. In particular, the European regulation classified CBs as hazardous waste for their acute toxicity (H6) mainly due to the nicotine content. It is a matter of fact that distribution and diffusion of CBs and their associated toxicants in the aquatic environment can be a threat to various prokaryotic and eukaryotic species inhabiting these aquatic habitats, including Foraminifera. In this study, the viability and ultrastructural analysis involved three foraminiferal species from three different biomineralization pathways: the calcareous perforate Rosalina globularis, the calcareous imperforate Quinqueloculina spp. and the agglutinated Textularia agglutinans. The toxicological effects of CBs and synthetic nicotine were evaluated in terms of survival rate, cellular stress, and decalcification. FTIR (Fourier-transform infrared) spectroscopy analysis allowed us to investigate the response of key macromolecules and calcium carbonate to this pollutant. To further enrich our knowledge on bioavailability of nicotine in the medium culture, High Performance Liquid Chromatography analysis (HPLC) was carried out. Different acute tests were conducted at different times; all confirmed that CBs and synthetic nicotine are acutely toxic at lethal and sublethal concentrations for all three cultured foraminiferal taxa. Each species showed a species-specific response related to the type of shell biomineralization. FTIR analyses showed that synthetic nicotine promotes shell decalcification and also alters the composition of cytoplasmic macromolecules, such as lipids and proteins. At lethal concentration the lipid content increased maybe due to vesicles formation. Proteins signal evidenced overall cellular dyshomeostasis associated to beta sheets and aggregate structures. Finally, the HPLC analyses confirmed that foraminifera can absorb until the 85% of the synthetic nicotine to which they have been exposed. It is clear that CBs and nicotine contained in them affects the viability, the shell-building mechanism, and the macromolecular composition of the foraminifera themselves. The integration among acute toxicity assay, synchrotron and chemical HPLC analyses provided a valuable approach for the assessment of nicotine as biomarker of exposure to the toxicants associated with smoking and the impact of this emerging and hazardous material on calcifying marine species.
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