Affiner votre recherche
Résultats 1501-1510 de 5,149
Sedimentary mercury (Hg) in the marginal seas adjacent to Chinese high-Hg emissions: Source-to-sink, mass inventory, and accumulation history Texte intégral
2018
Kim, Jihun | Lim, Dhongil | Jung, Dohyun | Kang, Jeongwon | Jung, Hoisoo | Woo, Hanjun | Jeong, Kapsik | Xu, Zhaokai
We comprehensively investigated sedimentary Hg in Yellow and East China Seas (YECSs), which constitute potentially important depocenters for large anthropogenic Hg emissions from mainland China. A large dataset of Al-TOC-Hg concentrations led to an in-depth understanding of sedimentary Hg in the entire YECSs, including distribution and its determinants, source-to-sink, background levels, inventory in flux and budget, and accumulation history. Especially, the net atmospheric Hg flux to the sediments was estimated to be 1.3 × 10−5 g/m2/yr, which corresponded reasonably well to that calculated using a box model. About 21.2 tons of atmospheric Hg (approximately 4% of the total anthropogenic atmospheric Hg emissions from China) were buried annually in the YECS basin. This result implies that most of atmospheric Hg from China is transferred to the surface of the Pacific (including the East/Japan Sea and South China Sea) by the westerlies and, consequently, can play a critical role in open-sea aquatic ecosystems.
Afficher plus [+] Moins [-]The need for a formalised system of Quality Control for environmental policy-science Texte intégral
2018
Research science used to inform public policy decisions, herein defined as “Policy-Science”, is rarely subjected to rigorous checking, testing and replication. Studies of biomedical and other sciences indicate that a considerable fraction of published peer-reviewed scientific literature, perhaps half, has significant flaws. To demonstrate the potential failings of the present approaches to scientific Quality Control (QC), we describe examples of science associated with perceived threats to the Great Barrier Reef (GBR), Australia. There appears a serious risk of efforts to improve the health of the GBR being directed inefficiently and/or away from the more serious threats. We suggest the need for a new organisation to undertake quality reviews and audits of important scientific results that underpin government spending decisions on the environment. Logically, such a body could also examine policy science in other key areas where governments rely heavily upon scientific results, such as education, health and criminology.
Afficher plus [+] Moins [-]Source identification and risk assessment based on fractionation of heavy metals in surface sediments of Jiaozhou Bay, China Texte intégral
2018
Liang, Xianmeng | Song, Jinming | Duan, Liqin | Yuan, Huamao | Li, Xuegang | Li, Ning | Qu, Baoxiao | Wang, Qidong | Xing, Jianwei
To identify sources and evaluate ecological risks of heavy metals in sediments of Jiaozhou Bay, contents and chemical fractions of Cd, Cr, Cu, Pb, Zn, Ni, Sb and Sn were studied. Results suggested that higher metal contents appeared at inner bay and near marine dumping area. Labile fractions of heavy metals accounted for 0.5–77% (~36%) of total contents indicating their significant anthropogenic sources. The enrichment levels of Cd and Sb were relatively higher. Cu, Ni, Cd and Zn were at low to medium risks. Cr, Pb, Sn and Sb were at no or low risks. Total contents of heavy metals were mainly controlled by natural sources, while anthropogenic inputs were important sources of labile fractions of heavy metals in sediments of Jiaozhou Bay with industrial and domestic activities as main contributors for Cu, Pb, Zn, Cr, Ni and Sn, and agricultural activities for Cd and regional coal combustion for Sb.
Afficher plus [+] Moins [-]Environmental status assessment using biological traits analyses and functional diversity indices of benthic ciliate communities Texte intégral
2018
Xu, Yuan | Stoeck, Thorsten | Forster, Dominik | Ma, Zuhang | Zhang, Liquan | Fan, Xinpeng
In this study, we tested the hypothesis that the functional diversity of benthic ciliates has high potential to monitor marine ecological status. Therefore, we investigated the spatial and temporal variation of functional diversity of benthic ciliates in the Yangtze Estuary during one year using biological traits analyses and functional diversity indices. Traits and community compositions showed clear spatial and temporal variations. Among a variety of biological traits, feeding type and body size emerged as strongest predictable variables. Functional divergence (FDiv) had an advantage over two other functional diversity indices, as well as over classical diversity measures (i.e. richness, evenness, Shannon-Wiener) to infer environmental status. Significant correlations between biological traits, FDiv and environmental variables (i.e. nutrients, temperature, salinity) suggested that functional diversity of benthic ciliates might be used as a bio-indicator in environmental status assessments. Further mandatory researches need to implement functional diversity of ciliates in routine monitoring programs were discussed.
Afficher plus [+] Moins [-]Effective and easy to use extraction method shows low numbers of microplastics in offshore planktivorous fish from the northern Baltic Sea Texte intégral
2018
Budimir, Stjepan | Setälä, Outi | Lehtiniemi, Maiju
Although the presence of microplastics in marine biota has been widely recorded, extraction methods, method validation and approaches to monitoring are not standardized. In this study a method for microplastic extraction from fish guts based on a chemical alkaline digestion is presented. The average particle retrieval rate from spiked fish guts, used for method validation, was 84%. The weight and shape of the test particles (PET, PC, HD-PE) were also analysed with no noticeable changes in any particle shapes and only minor weight change in PET (2.63%). Microplastics were found in 1.8% of herrings (n=164) and in 0.9% of sprat (n=154). None of the three-spined sticklebacks (n=355) contained microplastic particles.
Afficher plus [+] Moins [-]Environmental genotoxicity and cytotoxicity levels in herring (Clupea harengus), flounder (Platichthys flesus) and cod (Gadus morhua) inhabiting the Gdansk Basin of the Baltic Sea Texte intégral
2018
Valskienė, Roberta | Baršienė, Janina | Butrimavičienė, Laura | Grygiel, Wlodzimierz | Stunžėnas, Virmantas | Jokšas, Kęstutis | Stankevičiūtė, Milda
Frequencies of eight nuclear abnormalities (NAs) reflecting environmental genotoxicity and cytotoxicity, were examined in 739 specimens of herring (Clupea harengus), flounder (Platichthys flesus) and cod (Gadus morhua) collected between 2009 and 2017 at 50 study stations located in the Gulf of Gdansk and the southern part of the Gdansk Deep (the Baltic Sea). The highest levels of geno-cytotoxicity were recorded in fish caught at stations located in close proximity to chemical and conventional munitions dumping sites or in zones polluted by Chemical Warfare Agents (CWAs). The values of NAs were significantly higher (up to 51-fold compared with the reference level) in herring caught at seven stations and in cod from one station located close to the munitions dumping sites. Exceptionally high total genotoxicity (∑Gtox) risk was found for flounder collected from 18 (72.0%) stations, herring caught at 12 (38.7%) stations and cod caught at four (17.4%) studied stations.
Afficher plus [+] Moins [-]Boat noise in an estuarine soundscape – A potential risk on the acoustic communication and reproduction of soniferous fish in the May River, South Carolina Texte intégral
2018
Smott, Somers | Monczak, Agnieszka | Miller, Michaela E. | Montie, Eric W.
The impact of boat related noise on marine life is a subject of concern, particularly for fish species that utilize acoustic communication for spawning purposes. The goal of this study was to quantify and examine the risk of boat noise on fish acoustic communication by performing acoustic monitoring of the May River, South Carolina (USA) from February to November 2013 using DSG-Ocean recorders. The number of boats detected increased from the source to the mouth with the highest detections near the Intracoastal Waterway (ICW). Boat noise frequency ranges overlapped with courtship sounds of silver perch (Bairdiella chrysoura), black drum (Pogonias cromis), oyster toadfish (Opsanus tau), spotted seatrout (Cynoscion nebulosus), and red drum (Sciaenops ocellatus). In the May River estuary, red drum may experience the greatest risk of auditory masking because of late afternoon choruses (21% time overlap with boat noise) and only one spawning location near the noisy ICW.
Afficher plus [+] Moins [-]Six decades of change in pollution and benthic invertebrate biodiversity in a southern New England estuary Texte intégral
2018
Hale, Stephen S. | Buffum, Henry W. | Hughes, Melissa M.
Pollution has led to a decline of benthic invertebrate biodiversity of Narragansett Bay, raising questions about effects on ecosystem functions and services including shellfish production, energy flow to fishes, and biogeochemical cycles. Changes in community composition and taxonomic distinctness (biodiversity) were calculated from the 1950s—when quantitative benthic invertebrate data first became available—to 2015. Change in community composition of the bay was correlated with changes in dissolved inorganic nitrogen, dissolved oxygen, and sediment contaminants. A mid-bay reference site showed moderate changes in community composition but no change in biodiversity. In contrast, a more impacted site in the upper bay showed substantial differences in community composition over time and a decline in taxonomic distinctness. Bay-wide, as inputs of some stressors such as nutrients and sediment contaminants have declined, there are signs of recovery of benthic biodiversity but other stressors such as temperature and watershed development are increasing.
Afficher plus [+] Moins [-]Contamination and ecological risk assessment of heavy metals and metalloids in surface sediments of the Tajan River, Iran Texte intégral
2018
Alahabadi, Ahmad | Malvandi, Hassan
This study's objectives were to evaluate the elements degree of contamination in the Tajan River and the status of contamination in this river for future ecotoxicology studies. Based on geo-accumulation index (Igₑₒ) and contamination factor (CF) indices, Cr, Mn, Fe, Ci, Ni and Zn showed low contamination levels at all stations, while Se showed a very high degree of contamination. Potential ecological risk factor (Eᵣⁱ) and risk index (RI) indices values showed low ecological risk for the river, and this was confirmed by the pollution load index (PLI) results as well as a comparison of the concentrations of these elements with the mean values of the earth's crust and sediments worldwide. Overall, the results showed that the river cannot be regarded as a contaminated river with respect to the elements studied (with the exception of selenium and arsenic) for ecotoxicology studies, but can be considered a reference river.
Afficher plus [+] Moins [-]Baseline activity concentration of 210Po and 210Pb and dose assessment in bivalve molluscs at the Andalusian coast Texte intégral
2018
Hurtado-Bermúdez, Santiago | Jurado-González, José Antonio | Santos, Juan Luis | Díaz-Amigo, Carlos Francisco | Aparicio, Irene | Mas, José Luis | Alonso, Esteban
In this study, the activity concentrations of ²¹⁰Po and ²¹⁰Pb were determined in different types of bivalve molluscs sampled during the period of May 2014–June 2015 along the Andalusian littoral. Radioactivity concentrations of ²¹⁰Po were determined through alpha-particle spectrometry using ²⁰⁹Po as an internal tracer. Radioactivity concentrations of ²¹⁰Pb were determined through low-level gamma-ray spectrometry. The activity concentrations of ²¹⁰Po and ²¹⁰Pb varied between 40 ± 2 and 515 ± 9 Bq kg⁻¹ dry weight (d.w.), and ND (lower than limit of detection) and 73 ± 10 Bq kg⁻¹ d.w., respectively. The committed effective dose to humans was calculated to range from 39 to 477 μSv year⁻¹. Radioactivity and dose levels were compared with previous studies from other countries.
Afficher plus [+] Moins [-]