خيارات البحث
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A simple technique for counting marine debris at sea reveals steep litter gradients between the Straits of Malacca and the Bay of Bengal النص الكامل
2013
Ryan, Peter G.
A size and distance-based technique was used to assess the distribution, abundance and composition of floating marine debris in the northeast Indian Ocean. Densities of floating litter (>1cm) were greater and more variable in the Straits of Malacca (578±219itemskm−2) than in oceanic waters of the Bay of Bengal (8.8±1.4itemskm−2). The density of debris in the Straits was correlated with terrestrial vegetation, and peaked close to urban centres, indicating the predominance of land-based sources. In the Bay of Bengal, debris density increased north of 17°N mainly due to small fragments probably carried in run-off from the Ganges Delta. The low densities in the Bay of Bengal relative to model predictions may result from biofouling-induced sinking and wind-driven export of debris items. Standardised data collection protocols are needed for counts of floating debris, particularly as regards the size classes used, to facilitate comparisons among studies.
اظهر المزيد [+] اقل [-]Monitoring micropollutants in marine waters, can quality standards be met? النص الكامل
2013
Ghekiere, An | Verdonck, Frederik | Claessens, Michiel | Monteyne, Els | Roose, Patrick | Wille, Klaas | Goffin, Annelies | Rappé, Karen | Janssen, Colin R.
The environmental risks of 33 micropollutants occurring in Belgian coastal zone were assessed as single-substances and as mixtures. Water and sediment samples were taken in harbors, coastal waters and the Scheldt estuary during 2007–2009. Measured environmental concentrations were compared to quality standards such as Predicted No Effect Concentrations (PNECs), Environmental Quality Standards (EQSs), and Ecotoxicological Assessment Criteria (EAC). Out of a total of 2547 samples analyzed, 232 and 126 samples exceeded the EQS and EAC, respectively. Highest risks were observed for TBT, PBDEs, PCBs and the PAHs anthracene, indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene, benzo(k)fluoranthene, and benzo(b)fluoranthene in the water compartment and for TBT and PCBs in the sediment compartment. Samples taken at all stations during the April 2008 campaign indicate a potential risk of the contaminant mixtures to the aquatic environment (except W06 station). This study argues the need to revise quality standards when appropriate and hence the overall regulatory implication of these standards.
اظهر المزيد [+] اقل [-]Recent mercury contamination from artisanal gold mining on Buru Island, Indonesia – Potential future risks to environmental health and food safety النص الكامل
2013
Male, Yusthinus Thobias | Reichelt-Brushett, Amanda Jean | Pocock, Matt | Nanlohy, Albert
In November 2011 gold was found at Mount Botak, Buru Island, Mollucas Province, Indonesia. Since 2012 mercury has been used to extract the gold requiring large volumes of water and resulting in deposition of mercury into Wamsait River and Kayeli Bay. Total mercury in waste ponds was over 680mg/kg. In sediments at the mouth of the local river and a small feeder creek >3.00mg/kg and >7.66mg/kg respectively. River and bay sediments were proportionately higher in available mercury than elemental mercury and more strongly bound mercuric sulfide compared to that in trommel waste. This preliminary investigation raises concerns about the long term distribution and speciation of mercury. The floodplain is an important agricultural resource, and Mollucas Province is recognised nationally as the centre for Indonesian fish stocks. Challenges for management include communicating the potential future risks to the community and leaders and identifying mechanisms to reduce mercury waste.
اظهر المزيد [+] اقل [-]A baseline study of metals in cod (Gadus morhua) from the North Sea and coastal Norwegian waters, with focus on mercury, arsenic, cadmium and lead النص الكامل
2013
Julshamn, Kaare | Duinker, Arne | Nilsen, Bente M. | Nedreaas, Kjell | Maage, Amund
This study is one of several baseline studies that will provide basic and reliable information about the content of undesirable substances in important species of fish caught in Norwegian waters. Concentrations of metals in the muscle and livers of 516 cod caught at 22 positions in the North Sea were analysed. An additional 687 cod were caught from 13 fjords and coastal areas along the coast of Norway. Three out of 1203 samples of muscle exceeded the maximum limit of 0.5mgHgkg−1 wet weight set by the EU for foodstuffs. The mercury concentration in cod muscle was higher and the cadmium concentration in the liver was lower in the North Sea and coastal areas in the southern part of Norway than in the Barents Sea and coastal areas in the northern part of Norway. These differences are perhaps caused by differences in the cod diet.
اظهر المزيد [+] اقل [-]A baseline study of benthic community associated with Amphioxus Sand in subtropical Hong Kong النص الكامل
2013
Chen, Y. | Cheung, S.G. | Shin, P.K.S.
An annual investigation on the seasonal changes of benthic community structure associated with Amphioxus Sand was conducted at two sites in the eastern waters of subtropical Hong Kong, where three species of amphioxus, Branchiostoma belcheri, B. japonicum and B. malayanum coexist. A total of 84 species and 4169 individuals were recorded at Tai Long Wan, whereas a total of 87 species and 3915 individuals were recorded at Pak Lap Wan. Benthic polychaetes were dominant, including high abundance of Onuphis eremita and Prionospio malmgreni. Results of cluster analysis showed significant community structures between the two areas because of difference in sediment granulometry. However, temporal changes within these Amphioxus Sand communities were minimal. In general, the Amphioxus Sand communities in Hong Kong showed higher species richness of Polychaeta as compared with similar studies elsewhere, possibly implying an increased level of organic pollution in Hong Kong waters.
اظهر المزيد [+] اقل [-]Contaminants in magnificent frigatebird eggs from Barbuda, West Indies النص الكامل
2013
Trefry, Sarah A. | Diamond, Antony W. | Spencer, Nora C. | Mallory, Mark L.
We examined persistent organic pollutant and trace element concentrations in eggs of magnificent frigatebirds (Fregata magnificens), a species of conservation concern breeding in the West Indies. Despite that frigatebirds feed at high positions in tropical marine food chains, we detected low levels of most contaminants, suggesting limited contamination of their prey.
اظهر المزيد [+] اقل [-]Effectiveness of emetics to study plastic ingestion by Leach’s Storm-petrels (Oceanodroma leucorhoa) النص الكامل
2013
Bond, Alexander L. | Lavers, Jennifer L.
Most plastic ingestion studies rely on dissection of dead birds, which are found opportunistically, and may be biased. We used Leach’s Storm-petrels (Oceanodroma leucorhoa) in Newfoundland to study the effect of dose volume, and the efficacy of emesis using syrup of ipecac as an emetic. Ipecac is a safe method of non-lethally sampling stomach contents, and recovered all ingested plastic. Almost half the storm-petrels sampled had ingested plastic, ranging from 0 to 17 pieces, and weighing 0.2–16.9mg. Using the Ecological Quality Objective for Northern Fulmars, adjusted for storm-petrels smaller size, 43% exceeded the threshold of 0.0077g of plastic. Many adult seabirds offload plastic to their offspring, so storm-petrel chicks likely experience a higher plastic burden than their parents. The ability to study plastic ingestion non-lethally allows researchers to move from opportunistic and haphazard sampling to hypothesis-driven studies on a wider range of taxa and age classes.
اظهر المزيد [+] اقل [-]Impacts of long-line aquaculture of Pacific oysters (Crassostrea gigas) on sulfate reduction and diffusive nutrient flux in the coastal sediments of Jinhae–Tongyeong, Korea النص الكامل
2013
Hyun, Jung-Ho | Kim, Sŭng-han | Mok, Jin-Sook | Lee, Jae-seong | An, Sung-Uk | Lee, Won-Chan | Jung, Rae-Hong
We investigated the environmental impacts of long-line aquaculture of Pacific oysters (Crassostrea gigas) on sediment geochemistry and carbon oxidation by sulfate reduction and diffusive benthic nutrient flux in a coastal ecosystem in Korea. Inventories of the NH4+ and HPO42- at the farm site were 7.7–11.5 and 1.8–8.0 times higher, respectively, than those at a reference site. Sulfate reduction rates (SRRs) at the oyster farm were 2.4–5.2 times higher than SRRs at the reference site. The SRRs at the farm site were responsible for 48–99% (average 70%) of the total C oxidation in the sediment. The diffusive benthic fluxes of NH4+ and HPO42- at the oyster farm were comparable to 30–164% and 19–58%, respectively, of the N and P demands for primary production, and were responsible for the enhanced benthic microalgal biomass on the surface sediment.
اظهر المزيد [+] اقل [-]Spatial attribution of sulfate and dust aerosol sources in an urban area using receptor modeling coupled with Lagrangian trajectories النص الكامل
2013
Chalbot, Marie–Cecile | Lianou, Maria | Vei, Ino–Christina | Kotronarou, Anastasia | Kavouras, Ilias G.
PM10 and PM2.5 (particles with diameter less than 10 μm and 2.5 μm, respectively) aerosol samples were collected from 2002 to 2004 in Athens, Greece and analyzed for elements ranging from Na to Pb using X–ray fluorescence. Positive matrix factorization (PMF) was applied to identify and quantify the types of PM10 and PM2.5 sources. The agreement between calculated and measured particle mass concentrations was very good for both aerosol fractions. Mineral soil, road dust and sea salt particles were the most significant types of coarse particles (PM10–2.5) while their contributions to PM2.5 fraction were minimal. Secondary sulfate, diesel particles from shipping and other oil combustion activities and primary traffic exhausts were determined as the most important types of PM2.5 sources. The analysis of normalized average air mass residence times showed weak seasonal patterns on the pathways of air masses prior to their arrival in Athens. Using trajectory regression analysis, the four adjacent regions (less than 500 km) accounted for the largest fraction of fine sulfate and diesel particles. On the contrary, shipping emissions and neutralization by sea salt may explain the high contributions of the regions covering the Mediterranean Sea and Dardanelle straights. The four adjacent regions and central Europe accounted for most of road and mineral dust particles. The transport from northern Africa over Mediterranean Sea also appeared to influence the mineral dust particles.
اظهر المزيد [+] اقل [-]Effects of anthropogenic metallic contamination on cholinesterases of Gambusia holbrooki النص الكامل
2013
Brandão, Fátima | Correia, Alberto Teodorico | Gonçalves, Fernando | Nunes, Bruno
Effects of anthropogenic metallic contamination on cholinesterases of Gambusia holbrooki النص الكامل
2013
Brandão, Fátima | Correia, Alberto Teodorico | Gonçalves, Fernando | Nunes, Bruno
Metal contamination causes multiple biological dysfunctions, including impairment of key physiological functions by targeting enzymes. This feature is a matter of concern, since it may imply significant disturbances in energy allocation, behaviour, reproduction, and survival. Inhibition of the cholinesterase (ChE) activity of aquatic organisms by metals has been described, and systematically used in biomonitoring studies as effect criterion of environmental exposure to these compounds. The present paper addresses the feasibility of using ChE inhibition to quantify the adverse acute and chronic effects of metals (copper, zinc, lead, and cadmium) on nervous tissue of Gambusia holbrooki. With the exception of acute exposure to copper, ChE activity was not significantly impaired. The meanings of the reported findings are further discussed, aiming at a more comprehensive use of this biomarker in environmental assessment. Based on the obtained results, the role of ChE inhibition in environmental metal contamination scenarios should be questioned or even discarded.
اظهر المزيد [+] اقل [-]Effects of anthropogenic metallic contamination on cholinesterases of Gambusia holbrooki النص الكامل
2013
Brandão, Fátima | Correia, Alberto Teodorico | Gonçalves, Fernando | Nunes, Bruno
Metal contamination causes multiple biological dysfunctions, including impairment of key physiological functions by targeting enzymes. This feature is a matter of concern, since it may imply significant disturbances in energy allocation, behaviour, reproduction, and survival. Inhibition of the cholinesterase (ChE) activity of aquatic organisms by metals has been described, and systematically used in biomonitoring studies as effect criterion of environmental exposure to these compounds. The present paper addresses the feasibility of using ChE inhibition to quantify the adverse acute and chronic effects of metals (copper, zinc, lead, and cadmium) on nervous tissue of Gambusia holbrooki. With the exception of acute exposure to copper, ChE activity was not significantly impaired. The meanings of the reported findings are further discussed, aiming at a more comprehensive use of this biomarker in environmental assessment. Based on the obtained results, the role of ChE inhibition in environmental metal contamination scenarios should be questioned or even discarded. | The present work was funded by Fundação para a Ciência e a Tecnologia: project “BiOtoMetal” (PTDC/AMB/70431/2006). We would like to acknowledge the contribution of Jonathan Wilson, for his decisive contribution to the final format of this article. | published
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