خيارات البحث
النتائج 1921 - 1930 من 4,935
Microplastics do not affect standard ecotoxicological endpoints in marine unicellular organisms النص الكامل
2019
Gambardella, Chiara | Piazza, Veronica | Albentosa, Marina | Bebianno, Maria João | Cardoso, Cátia | Faimali, Marco | Garaventa, Francesca | Garrido, Soledad | González, Sergio | Pérez, Sara Isabel | Sendra, Marta | Beiras, Ricardo
Microplastics do not affect standard ecotoxicological endpoints in marine unicellular organisms النص الكامل
2019
Gambardella, Chiara | Piazza, Veronica | Albentosa, Marina | Bebianno, Maria João | Cardoso, Cátia | Faimali, Marco | Garaventa, Francesca | Garrido, Soledad | González, Sergio | Pérez, Sara Isabel | Sendra, Marta | Beiras, Ricardo
In this study, the acute toxicity of microplastics (MPs) on unicellular organisms as marine decomposers and microalgae was assessed, by evaluating standards endpoints included in International Standard Organization (ISO) protocols. The bacteria Vibrio fischeri and the diatom Phaeodactylum tricornutum were exposed to different sizes (1–500 μm) of polyethylene MPs in order to evaluate bioluminescence inhibition and microalgal growth. No acute toxicity was found on bacteria or microalgae in an order of magnitude above environmentally relevant concentrations, suggesting that tested MPs did not affect the investigated biological processes. In conclusion, standard ecotoxicological endpoints are not sufficiently sensitive to assess the potential effects of MPs on decomposers and primary producers, conversely to nanoplastics. These findings highlight that the current approach for MP risk assessment in unicellular species should be revised, by providing alternative endpoints to be included in standardized protocols, able to monitor the fate and biological effects of MPs.
اظهر المزيد [+] اقل [-]Microplastics do not affect standard ecotoxicological endpoints in marine unicellular organisms النص الكامل
2019
Gambardella, C. | Piazza, V. | Albentosa, Marina | Bebianno, María Joao | Cardoso, C. | Faimali, M. | Garaventa, F. | Garrido, Soledad | González-Gil, Sonsoles | Pérez, S. | Sendra, Marta | Beiras, Ricardo
In this study, the acute toxicity of microplastics (MPs) on unicellular organisms as marine decomposers and microalgae was assessed, by evaluating standards endpoints included in International Standard Organization (ISO) protocols. The bacteria Vibrio fischeri and the diatom Phaeodactylum tricornutum were exposed to different sizes (1–500 μm) of polyethylene MPs in order to evaluate bioluminescence inhibition and microalgal growth. No acute toxicity was found on bacteria or microalgae in an order of magnitude above environmentally relevant concentrations, suggesting that tested MPs did not affect the investigated biological processes. In conclusion, standard ecotoxicological endpoints are not sufficiently sensitive to assess the potential effects of MPs on decomposers and primary producers, conversely to nanoplastics. These findings highlight that the current approach for MP risk assessment in unicellular species should be revised, by providing alternative endpoints to be included in standardized protocols, able to monitor the fate and biological effects of MPs. | Sí
اظهر المزيد [+] اقل [-]Microplastics do not affect standard ecotoxicological endpoints in marine unicellular organisms النص الكامل
2019
Gambardella, Chiara | Piazza, Veronica | Albentosa, Marina | Bebianno, Maria João | Cardoso, Cátia | Faimali, Marco | Garaventa, Francesca | Garrido, Soledad | González, Sergio | Pérez, Sara | Sendra, Marta | Beiras, Ricardo
In this study, the acute toxicity of microplastics (MPs) on unicellular organisms as marine decomposers and microalgae was assessed, by evaluating standards endpoints included in International Standard Organization (ISO) protocols. The bacteria Vibrio fischeri and the diatom Phaeodactylum tricornutum were exposed to different sizes (1-500 μm) of polyethylene MPs in order to evaluate bioluminescence inhibition and microalgal growth. No acute toxicity was found on bacteria or microalgae in an order of magnitude above environmentally relevant concentrations, suggesting that tested MPs did not affect the investigated biological processes. In conclusion, standard ecotoxicological endpoints are not sufficiently sensitive to assess the potential effects of MPs on decomposers and primary producers, conversely to nanoplastics. These findings highlight that the current approach for MP risk assessment in unicellular species should be revised, by providing alternative endpoints to be included in standardized protocols, able to monitor the fate and biological effects of MPs. | PCIN-2015-187-C03-01 | info:eu-repo/semantics/publishedVersion
اظهر المزيد [+] اقل [-]Contaminants bioaccumulation and pathological assessment in Mytilus galloprovincialis in coastal waters facing the brownfield site of Bagnoli, Italy النص الكامل
2019
We studied the bioaccumulation of metals and PAHs, the pathological conditions, regressive phenomena and pathogens in wild Mytilus galloprovincialis taken along the North Pier facing the former second Italian largest steelworks of Bagnoli. There was no Cd and Pb bioaccumulation with respect to the EU role 221/2002. Metal shell index decreased as follows: Pb > Ni > Zn > Cu and correlates with the pollution state. The level of BaP was up to thirtysixfold higher the EU rule 835/2011. The sum of 4 hydrocarbons, PAH4, were up to seventeen-fold the rule. PAH levels increased toward the coast. Prevalence values of tissue necrosis and inflammatory lesions were between 50 and 100%. In May animals showed lesion like granulocytomas and inflammatory capsules. Signs of atresia, necrotic oocytes and diffused cases of hermaphroditism were detected. An appropriate localization of farming to avoid contamination from sediment turbulence and risks for consumer health is needed.
اظهر المزيد [+] اقل [-]Deepwater Horizon Oil could have naturally reached Texas beaches النص الكامل
2019
Thyng, Kristen M.
Following the Deepwater Horizon (DWH) spill, oil residues were found in all five Gulf states of the United States (Texas, Louisiana, Mississippi, Alabama and Florida). However, only a small amount was found in Texas, leading to speculation that it may have arrived there via ship through bilge water instead of naturally via currents. We report on a numerical modeling effort to simulate surface drifters during and after the DWH spill to demonstrate that surface water parcels – and therefore oil carried by those parcels – could reasonably have reached Texas waters at the appropriate time and location from known oiled locations without human interference. We additionally give context for the conditions in 2010 through a study of summer connectivity with the Galveston Bay coastline, which shows that in some years oil from the DWH pipe likely would not have reached Texas.
اظهر المزيد [+] اقل [-]Seawater acidification and temperature modulate anti-predator defenses in two co-existing Mytilus species النص الكامل
2019
Kong, Hui | Clements, Jeff C. | duPont, Sam | Wang, Ting | Huang, Xizhi | Shang, Yueyong | Huang, Wei | Chen, Jianfang | Hu, Menghong | Wang, Youji
The effects of short-term (7 days) experimental ocean acidification (−0.4 pH units) and warming (+5 °C) on anti-predator defenses of two sympatric Mytilus species from China, M. coruscus and M. edulis, in the presence and absence of predator cues were investigated. Results suggested species-specific independent negative effects of acidification and warming on the number and weight of byssal threads, the force of thread attachment, and total thread plaque area. Similar negative effects were observed for clustering behaviour, with acidification and warming independently increasing the number of solitary individuals and decreasing the percentage of mussels in clusters. Acidification effects on byssus were strongly exacerbated when predators were present. Ultimately, this study suggests that short-term exposure to experimental warming and acidification can negatively impact anti-predator defense strategies in mussels with potential ramifications for predator-prey interactions and ecological functioning in systems where mussel beds play a key ecological role.
اظهر المزيد [+] اقل [-]Particle characteristics of microplastics contaminating the mussel Mytilus edulis and their surrounding environments النص الكامل
2019
Scott, Nicholas | Porter, Adam | Santillo, David | Simpson, Holly | Lloyd-Williams, Sophie | Lewis, Ceri
We investigated the environmental partitioning and particle characteristics of macro-, meso- and microplastics and their uptake into the mussel, Mytilus edulis. Sediment samples, overlying seawater and mussels from 9 intertidal locations in the South West of England were analysed for abundance and type of microplastic. Micro- and mesoplastic-like particles were found in 88.5% of the 269 mussels sampled, ranging from 1.43 to 7.64 items per mussel. Of these plastic particles, 70.9% were identified as semi-synthetic (mainly modified-cellulose). Mussel microplastic abundance, but not polymer type, was correlated with that of their surrounding sediment, but not with sea-surface microplastic concentration or mussel size for our study sites. We found significant differences in the relative abundance of polymer types and particle sizes between seawater, sediment, and mussels, with mussels over-representing modified-cellulose fibre abundance but under-representing polyvinyl. Mussels contained significantly smaller plastic fragments than their surrounding sediment and shorter fibres than their overlying seawater.
اظهر المزيد [+] اقل [-]Microbeads—a Case Study in How Public Outrage Fueled the Emergence of New Regulations النص الكامل
2019
Several country–wide bans have recently been implemented for microbeads, which are a form of microplastics that are found in our oceans. The effect of the ban on reducing the overall quantity of microplastics in our oceans, however, may not be significant. This paper explores the scientific data related to microbeads to evaluate whether an underlying risk or combination of risks led to the ban, what impact public perception and activism had on this issue, and how this case study may be extrapolated to other emerging issues, such as per- and polyfluoroalkyl substances (PFAS). In some cases, the strategy for communicating with the public and managing the outrage can be equally as important as the regulatory and technical strategies.
اظهر المزيد [+] اقل [-]Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes النص الكامل
2019
Dredging poses a potential threat to coral reefs, yet quantifying impacts is often difficult due to the large spatial footprint of potential effects and co-occurrence of other disturbances. Here we analyzed in situ monitoring data and remotely-sensed sediment plumes to assess impacts of the 2013–2015 Port of Miami dredging on corals and reef habitat. To control for contemporaneous bleaching and disease, we analyzed the spatial distribution of impacts in relation to the dredged channel. Areas closer to dredging experienced higher sediment trap accumulation, benthic sediment cover, coral burial, and coral mortality, and our spatial analyses indicate that >560,000 corals were killed within 0.5 km, with impacts likely extending over 5–10 km. The occurrence of sediment plumes explained ~60% of spatial variability in measured impacts, suggesting that remotely-sensed plumes, when properly calibrated against in situ monitoring data, can reliably estimate the magnitude and extent of dredging impacts.
اظهر المزيد [+] اقل [-]Trace element contamination in marine sediments along the southeast Indian shelf following Cyclone Gaja النص الكامل
2019
In this study, twenty seven surface sediments were collected off Pushpavanam, Nagapattinam coast, southeast coast of India for understanding the sedimentological and geochemical behaviour after the Cyclone Gaja. The sediment samples were analysed for texture, organic matter (OM), carbonates, and trace metals such as Cr, Cu, Zn, Ni, Co including Fe and Mn. The Geoaccumulation index, contamination factor, enrichment factor and pollution load index revealed that Cu, Zn, Ni and Co is highly contaminated in the study area. Fe and Cr are moderately to considerably contaminated, while Mn shows uncontaminated.The principal component analysis also confirms the concentration of Cu, Zn, Ni and Co were mainly derived from the anthropogenic sources and related activities. Since Cyclones like Gaja often causes frequent ecological disturbance to the coastal environments and it distributes pollutants such as trace elements from localized area of contamination to offshore.
اظهر المزيد [+] اقل [-]Preliminary study and first evidence of presence of microplastics and colorants in green mussel, Perna viridis (Linnaeus, 1758), from southeast coast of India النص الكامل
2019
S.A., Naidu
Pollution by microplastics (MPs) is currently a global problem in the coastal and marine environment. Transfer of MPs from land to sea and their inclusion in the food web has a significant adverse effect on the marine life and human health. The present study was carried out at the fishing harbour of Chennai, southeast coast of India. The possible MPs were isolated from the soft tissues of the commercially important bivalve Perna viridis and examined by microscopic and DXR Raman spectroscopic methods. The MPs were identified as to be polystyrene polymers in the soft tissues. This investigation revealed that size and color are the major factors affecting the bioavailability of MPs to bivalves in the study area. The presence of colorants in organisms revealed an anthropogenic origin through the use of a wide array of applications. Hence, coastal zones are a hotspot for pollution by MPs, and filter feeding bivalves are at the highest risk. Therefore, further studies are required to understand the accumulation rates and residence time of MPs across the food webs.
اظهر المزيد [+] اقل [-]Biomagnification and risk assessment of polychlorinated biphenyls in food web components from Zhoushan fishing ground, China النص الكامل
2019
Zhou, Shanshan | Zhu, Hongbin | Huang, Shaorong | Zhou, Jiayi | Zhang, Shenwei | Wang, Chanzong
Trophodynamics and risks of polychlorinated biphenyls (PCBs) in organisms from the Zhoushan fishing ground (ZFG), China were studied. Σ₂₂PCBs varied from 1.36 to 36.75 ng/g wet weight, which were far below the maximum residue levels allowed in fishery products. However, estimated daily intake and hazard ratio calculations present possible adverse effects due to PCB pollution. Significantly positive correlations appeared between wet-weighted concentrations of target chemicals and trophic levels (TLs) of the organisms, with trophic magnification factors (TMFs) from 1.15 to 9.72. The TMF values first increased with an increase of compound's KOW values, and then decreased, with log KOW around 7.0 as an inflection point. TL is suggested as the key factor controlling contaminant burden among the species for only PCBs 105, 138, 153, and 171. For the remaining PCBs, lipid content of the organism or metabolite capacity of the compound may be more important influence on their bioaccumulation.
اظهر المزيد [+] اقل [-]