Refine search
Results 641-650 of 3,189
Sources and ecological risk assessment of PAHs in surface sediments from Bohai Sea and northern part of the Yellow Sea, China
2015
Li, Jiafu | Dong, Han | Zhang, Dahai | Han, Bin | Zhu, Chenjian | Liu, Shaopeng | Liu, Xiangmin | Ma, Qianyao | Li, Xianguo
Sources and ecological risk of sixteen priority PAHs in surface sediments from Bohai Sea (BS) and northern part of the Yellow Sea (NPYS) were investigated. The total concentrations of PAHs varied in ranges 149.24–1211.81 and 148.28–907.47ng/g for BS and NPYS, respectively. Principal component analysis-multiple linear regression (PCA–MLR) suggested that coal combustion, vehicular emission and coke oven could be the primary PAH contributors, accounting for 56.6%, 29.2% and 14.2% of PAH concentrations, respectively. Analysis with sediment quality guidelines (SQGs) indicated that acenaphthylene, fluorene, phenanthrene, fluoranthene, pyrene and dibenzo(a,h)anthracene may occasionally cause adverse biological effects in some stations. Organic carbon (OC)-normalized analysis and mean effects range-median quotient (M-ERM-Q) suggested that the combined ecological risk of PAHs was generally low. The toxic equivalent concentrations of carcinogenic PAHs were 12.87–64.6ng/g-BaPeq and 5.95–68.80ng/g-BaPeq in BS and NPYS, respectively, suggesting low carcinogenic risk for both BS and NPYS.
Show more [+] Less [-]Environmental assessment of coastal surface sediments at Tarut Island, Arabian Gulf (Saudi Arabia)
2015
Youssef, Mohamed | El-Sorogy, Abdelbaset | Al Kahtany, Khaled | Al Otiaby, Naif
Thirty eight surface sediments samples have been collected in the area around Tarut Island, Saudi Arabian Gulf to determine the spatial distribution of metals, and to assess the magnitude of pollution. Total concentrations of Fe, Mn, As, B, Cd, Co, Cr, Cu, Hg, Mo, Pb, Se, and Zn in the sediments were measured using ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). Nature of sediments and heavy metals distribution reflect marked changes in lithology, biological activities in Tarut bay. Very high arsenic concentrations were reported in all studied locations from Tarut Island. The concentrations of Mercury are generally high comparing to the reported values from the Gulf of Oman, Red Sea. The concentrations of As and Hg exceeded the wet threshold safety values (MEC, PEC) indicating possible As and Hg contamination. Dredging and land filling, sewage, and oil pollution are the most important sources of pollution in the study area.
Show more [+] Less [-]Hydrodynamic evaluation of long term impacts of climate change and coastal effluents in the Arabian Gulf
2015
Elhakeem, Abubaker | Elshorbagy, Walid
A comprehensive basin wide hydrodynamic evaluation has been carried out to assess the long term impacts of climate change and coastal effluents on the salinity and seawater temperature of the Arabian Gulf (AG) using Delft3D-Flow model. The long term impacts of climate change scenarios A2 and B1 of the IPCC-AR4 on the AG hydrodynamics were evaluated. Using the current capacity and production rates of coastal desalination, power, and refinery plants, two projection scenarios until the year 2080 with 30year intervals were developed namely the realistic and the optimistic discharge scenarios. Simulations of the individual climate change scenarios ascertained overall increase of the AG salinity and temperature and decrease of precipitation. The changes varied spatially with different scenarios as per the depth, proximity to exchange with ocean water, flushing, vertical mixing, and flow restriction. The individual tested scenarios of coastal projected discharges showed significant effects but within 10–20km from the outfalls.
Show more [+] Less [-]Polycyclic aromatic hydrocarbons alter the structure of oceanic and oligotrophic microbial food webs
2015
Cerezo, Maria Isabel | Agusti, Susana
One way organic pollutants reach remote oceanic regions is by atmospheric transport. During the Malaspina-2010 expedition, across the Atlantic, Indian, and Pacific Oceans, we analyzed the polycyclic aromatic hydrocarbon (PAH) effects on oceanic microbial food webs. We performed perturbation experiments adding PAHs to classic dilution experiments. The phytoplankton growth rates were reduced by more than 5 times, being Prochlorococcus spp. the most affected. 62% of the experiments showed a reduction in the grazing rates due to the presence of PAHs. For the remaining experiments, grazing usually increased likely due to cascading effects. We identified changes in the slope of the relation between the growth rate and the dilution fraction induced by the pollutants, moving from no grazing to V-shape, or to negative slope, indicative of grazing increase by cascade effects and alterations of the grazers' activity structure. Our perturbation experiments indicate that PAHs could influence the structure oceanic food-webs structure.
Show more [+] Less [-]Baseline monitoring of organic sunscreen compounds along South Carolina's coastal marine environment
2015
Bratkovics, Stephanie | Wirth, Edward | Sapozhnikova, Yelena | Pennington, Paul | Sanger, Denise
Organic ultraviolet filters (UV-F) are increasingly being used in personal care products to protect skin and other products from the damaging effects of UV radiation. In this study, marine water was collected monthly for approximately one year from six coastal South Carolina, USA sites and analyzed for the occurrence of seven organic chemicals used as UV filters (avobenzone, dioxybenzone, octocrylene, octinoxate, oxybenzone, padimate-o and sulisobenzone). The results were used to examine the relationship between beach use and the distribution of UV-F compounds along coastal South Carolina, USA. Five of the seven target analytes were detected in seawater along coastal South Carolina during this study. Dioxybenzone and sulisobenzone were not detected. The highest concentrations measured were >3700ng octocrylene/L and ~2200ng oxybenzone/L and beach use was greatest at this site; a local beach front park. Patterns in concentrations were assessed based on season and a measure of beach use.
Show more [+] Less [-]Metal Pollution in Coastal Sediments
2015
Qian, Yu | Zhang, Weiguo | Yu, Lizhong | Feng, Huan
Coastal sediment is a vital habitat for aquatic and marine life in coastal ecosystem. However, urbanization and economic development in coastal areas have resulted in environmental problems globally. Due to coastal development such as new industrial facilities and commercial port expansion, anthropogenic metals are introduced to the adjacent areas. Therefore, metal pollution in coastal areas is one of the focused environmental concerns. Sediment quality in coastal zone reflects the long-term environmental status because it keeps a record of the development in the area. In this review paper, sediment metal concentrations in 52 selected sites worldwide are summarized for evaluation of the coastal environmental quality. The results from this study can be applied to science-based policy formulation and ecological restoration/rehabilitation practices in an integrated coastal zone environmental management.
Show more [+] Less [-]Fate of Deepwater Horizon oil in Alabama’s beach system: Understanding physical evolution processes based on observational data
2015
Hayworth, Joel S. | Prabakhar Clement, T. | John, Gerald F. | Yin, Fang
The impact of MC252 oil on northern Gulf of Mexico (GOM) beaches from the 2010 Deepwater Horizon (DWH) catastrophe was extensive along Alabama’s beaches. While considerable amount of cleanup has occurred along these beaches, as of August 2014, DWH oil spill residues continue to be found as surface residual balls (SRBs), and also occasionally as submerged oil mats (SOMs). Four years of field observations informing the fate and transport of DWH SRBs in Alabama’s beach system are presented here, along with a conceptual framework for describing their physical evolution processes. The observation data show that SRBs containing MC252 residues currently remain in Alabama’s beach system, although their relationship to SOMs is not fully known. Based on our field observations we conclude that small DWH SRBs are likely to persist for several years along the Alabama shoreline.
Show more [+] Less [-]Seasonal variation of bacterial communities in shellfish harvesting waters: Preliminary study before applying phage therapy
2015
Pereira, C. | Santos, L. | Silva, A.P. | Silva, Y.J. | Cunha, A. | Romalde, J.L. | Nunes, M.L. | Almeida, A.
The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro.During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/summer season is a critical period during which phage therapy should be applied.
Show more [+] Less [-]Prevalence and diversity of extended-spectrum-β-lactamase-producing Enterobacteriaceae from marine beach waters
2015
Maravić, Ana | Skočibušić, Mirjana | Cvjetan, Svjetlana | Šamanić, Ivica | Fredotović, Željana | Puizina, Jasna
A total of 1351 Enterobacteriaceae isolates from 144 seawater samples were collected over a four-year period from three public beaches in the eastern Adriatic Sea in Croatia. Approximately 35% of the strains were multidrug-resistant. BlaESBL genes were detected in 4.2% of the isolated Enterobacteriaceae, the main species of which were Escherichia coli, Enterobacter cloacae and Klebsiella pneumoniae. BlaTEM-1+SHV-12 was the most dominant genotype, followed by blaCTX-M-15.Raoultella terrigena and E. intermedius simultaneously harboured blaTEM-1,blaSHV-11/12 and blaCTX-M-15. Isolate fingerprinting revealed that marine E. coli isolates were clonally related to CTX-M-producing strains from a regional university hospital. These results indicate that marine beach waters are reservoirs of ESBL-producing Enterobacteriaceae and thus constitute a public health problem with further potential to act as mediators in gene flow between marine coastal areas and clinical settings.
Show more [+] Less [-]Metals in Mediterranean aquatic species
2015
Iamiceli, AnnaLaura | Ubaldi, Alessandro | Lucchetti, Dario | Brambilla, Gianfranco | Abate, Vittorio | De Felip, Elena | De Filippis, Stefania P. | Dellatte, Elena | De Luca, Silvia | Ferri, Fabiola | Fochi, Igor | Fulgenzi, AnnaRita | Iacovella, Nicola | Moret, Ivo | Piazza, Rossano | Roncarati, Alessandra | Melotti, Paolo | Fanelli, Roberto | Fattore, Elena | Di Domenico, Alessandro | Miniero, Roberto
Metals such as arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), vanadium (V), have been determined in species of Mediterranean marine organisms collected from areas supposed to be at background contamination levels. The Inductively Coupled Plasma Mass Spectrometry (ICP-MS) approach was adopted for the determination of all the metals. Arsenic, Cd and Pb determined in the 42 samples, do not exceed the pertinent maximum level except a sample of hake. In wild fish, the concentration range for Cr, Ni, V and Cu was, respectively: 0.07–0.09, 87.6–124, 0.022–0.075 and 0.79–1.74μg/g fresh weight (fw). The farmed fish samples show concentration levels below the wild fish ones, except for Cr which range at the same levels. Cadmium and Pb show a high sample number under the quantification limit. The elements do not bio-magnify among the species considered and appear to show low variations in relation to organisms’ position in the food chain and at sampling sites.
Show more [+] Less [-]