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Organochlorine pesticides in sediments of Laizhou Bay and its adjacent rivers, North China
2011
Zhong, Guangcai | Tang, Jianhui | Zhao, Zhen | Pan, Xiaohui | Chen, Yingjun | Li, Jun | Zhang, Gan
Organochlorine pesticides (HCHs, DDTs and HCB) have been investigated in sediments of Laizhou Bay and its adjacent rivers. The average concentrations of HCHs, DDTs and HCBs are 0.09ng/gdw, 0.59 and 0.05 for marine sediments and 0.55, 8.6 and 1.1 for riverine sediments, respectively. Laizhou Bay is less contaminated by HCHs and DDTs in comparison with other coastal regions around the world, including the other two biggest bays in Bohai Sea. Fresh input of lindane and dicofol-type DDT were found in several riverine sites. Relatively strong TOC-dependence of HCB distribution in the entire studied area suggested no point source existed and/or water–sediment equilibrium achieved. No significant difference of α/γ-HCH ratios have been observed between marine and riverine sediments. However, o,p′-DDT/p,p′-DDT ratios varied largely between the two regions.
Afficher plus [+] Moins [-]Pore water transport of enterococci out of beach sediments
2011
Phillips, Matthew C. | Solo-Gabriele, Helena M. | Reniers, A.J.H.M. | Wang, John D. | Kiger, Russell T. | Abdel-Mottaleb, Noha
Enterococci are used to evaluate the safety of beach waters and studies have identified beach sands as a source of these bacteria. In order to study and quantify the release of microbes from beach sediments, flow column systems were built to evaluate flow of pore water out of beach sediments. Results show a peak in enterococci (average of 10% of the total microbes in core) released from the sand core within one pore water volume followed by a marked decline to below detection. These results indicate that few enterococci are easily removed and that factors other than simple pore water flow control the release of the majority of enterococci within beach sediments. A significantly larger quantity and release of enterococci were observed in cores collected after a significant rain event suggesting the influx of fresh water can alter the release pattern as compared to cores with no antecedent rainfall.
Afficher plus [+] Moins [-]DDT in endangered Galapagos sea lions (Zalophus wollebaeki)
2011
Alava, Juan José | Ross, Peter S. | Ikonomou, Michael G. | Cruz, Marilyn | Jimenez-Uzcátegui, Gustavo | Dubetz, Cory | Salazar, Sandie | Costa, Daniel P. | Villegas-Amtmann, Stella | Howorth, Peter | Gobas, Frank A.P.C.
We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525μg/kg lipid and were 1.9 times higher than that (281μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p′-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.
Afficher plus [+] Moins [-]Mussel farming as a nutrient reduction measure in the Baltic Sea: Consideration of nutrient biogeochemical cycles
2011
Stadmark, J. | Conley, D.J.
Nutrient loads from the land to the sea must be reduced to combat coastal eutrophication. It has been suggested that further mitigation efforts are needed in the brackish Baltic Sea to decrease nutrients, especially in eutrophic coastal areas. Mussel farming is a potential measure to remove nutrients directly from the sea. Mussels consume phytoplankton containing nitrogen (N) and phosphorus (P); when the mussels are harvested these nutrients are removed from the aquatic system. However, sedimentation of organic material in faeces and pseudo-faeces below a mussel farm consumes oxygen and can lead to hypoxic or even anoxic sediments causing an increased sediment release of ammonium and phosphate. Moreover, N losses from denitrification can be reduced due to low oxygen and reduced numbers of bioturbating organisms. To reveal if mussel farming is a cost-effective mitigation measure in the Baltic Sea the potential for enhanced sediment nutrient release must be assessed.
Afficher plus [+] Moins [-]Evaluations of heavy metal pollution in sediment and Mullus barbatus from the Izmir Bay (Eastern Aegean) during 1997–2009
2011
Kucuksezgin, Filiz | Kontas, Aynur | Uluturhan, Esin
Izmir Bay is one of the great natural bays of the Mediterranean. The surface sediment and fish samples were collected during 1997–2009. The sediment concentrations of inner bay showed significant enrichments during sampling periods. Outer and middle bays exhibited low levels of metal enrichments except the estuary of Gediz River. The concentrations were generally higher than the background levels from the Mediterranean and Aegean except Cd and Pb levels gradually decreased. Metal EF is used as an index to evaluate anthropogenic influences of metals in sediments. Maximum metal enrichment was found for Hg in the outer bay, while Pb indicated maximum enrichment in the middle-inner bays. Metal levels were evaluated in sediments in accordance with the numerical SQG of the USEPA. The levels of fish tissues were lower than the results reported from polluted areas of the Mediterranean. The highest BAFs were detected for Hg and Cd in fish.
Afficher plus [+] Moins [-]Sedimentation on the cold-water coral Lophelia pertusa: Cleaning efficiency from natural sediments and drill cuttings
2011
Larsson, Ann I. | Purser, Autun
Anthropogenic threats to cold-water coral reefs are trawling and hydrocarbon drilling, with both activities causing increased levels of suspended particles. The efficiency of Lophelia pertusa in rejecting local sediments and drill cuttings from the coral surface was evaluated and found not to differ between sediment types. Further results showed that the coral efficiently removed deposited material even after repeated exposures, indicating an efficient cleaning mechanism. In an experiment focusing on burial, fine-fraction drill cuttings were deposited on corals over time. Drill cutting covered coral area increased with repeated depositions, with accumulation mainly occurring on and adjacent to regions of the coral skeleton lacking tissue cover. Tissue was smothered and polyp mortality occurred where polyps became wholly covered by material. Burial of coral by drill cuttings to the current threshold level used in environmental risk assessment models by the offshore industry (6.3mm) may result in damage to L. pertusa colonies.
Afficher plus [+] Moins [-]Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27
2011
Nassef, Mohamed | Tawaratsumita, Takahiko | Oba, Yumi | Satone, Hina | Nakayama, Kei | Shimasaki, Yohei | Honjo, Tsuneo | Ōshima, Yūji
In this study, individual Japanese flounder were intraperitoneally injected with 2μg tributyltin-d27 (TBT-d27) fish⁻¹. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology.
Afficher plus [+] Moins [-]Identification of genes expressed in juvenile Haliotis rufescens in response to different copper concentrations in the north of Chile under controlled conditions
2011
Silva-Aciares, Fernando | Zapata, Manuel | Tournois, Jennifer | Moraga, Dario | Riquelme, Carlos
This study reports molecular markers potentially associated with resistance or sensitivity to the impact of copper in juvenile red abalone, Haliotis rufescens, in the north of Chile under experimental conditions. Genomic analysis was made applying subtractive hybridization libraries (SSH) to identify genes up-and down regulated during cooper exposure in abalone over periods of 12 and 168h exposed to 2.5 and 10μg/L of Cu⁺². Results obtained from the SSH library revealed 368 different sequences regulated by copper, that correspond to eight major physiological functions. The validation of these sequences obtained by SSH as well as their expression kinetics were made by PCR in real time on 14 potential genes regulated by metal stress. This study provides information for the characterization of potential genomic markers that may be used in future environmental monitoring and to investigate new mechanisms of stress to copper in this commercially important marine species.
Afficher plus [+] Moins [-]Hydrocarbon composition and distribution in a coastal region under influence of oil production in northeast Brazil
2011
Wagener, Angela de L.R. | Carreira, Renato S. | Hamacher, Claudia | Scofield, Arthur de L. | Farias, Cassia O. | Cordeiro, Lívia G.M.S. | Luz, Letícia G. | Baêta, Aída P. | Kalas, Francine A.
Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the presence and nature of polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons. The region receives treated produced waters through a submarine outfall system serving the industrial district. The total dispersed/dissolved concentrations in the water column ranged from 10–50ngL⁻¹ for ∑16PAH and 5–10μgL⁻¹ for total aliphatic hydrocarbons. In the sediments, hydrocarbon concentrations were low (0.5–10ngg⁻¹for ∑16PAH and 0.01–5.0μgg⁻¹ for total aliphatic hydrocarbons) and were consistent with the low organic carbon content of the local sandy sediments. These data indicate little and/or absence of anthropogenic influence on hydrocarbon distribution in water and sediment. Therefore, the measured values may be taken as background values for the region and can be used as future reference following new developments of the petroleum industry in the Potiguar Basin.
Afficher plus [+] Moins [-]Navy sonar, cetaceans and the US Supreme Court: A review of cetacean mitigation and litigation in the US
2011
Zirbel, K. | Balint, P. | Parsons, E.C.M.
One source of anthropogenic noise in the oceans which has attracted much concern is naval sonar. As a result of possible impacts of such sonar, several environmental NGOs have pursued legal cases in the United States criticizing environmental assessments conducted prior to exercises and proposed mitigation measures. Cases have been brought using the US National Environmental Protection Act, Marine Mammal Protection Act, Endangered Species Act, Coastal Zone Management Act and other statutes. This paper reviews the chronology and results of these various cases. During the G.W. Bush presidential administration, the legal battle went to the US Supreme Court in the case Winter vs. Natural Resources Defense Council. This case however, did not address the potential impacts of sonar on cetaceans or the effectiveness of mitigation measures. During the Obama administration, mitigation measures for naval exercises have been revised, and working groups planned, in an attempt to resolve conflict between parties.
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