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Long-term decreases in persistent organic pollutants in South African coastal waters detected from beached polyethylene pellets
2012
Ryan, Peter G. | Bouwman, Hindrik | Moloney, Coleen L. | Yuyama, Masaki | Takada, Hideshige
Polyethylene pellets provide a convenient means to monitor Persistent Organic Pollutants (POPs) in marine systems. Pellets collected between 1984 and 2008 at three South African beaches were analysed for PCB, HCH and DDT. Concentrations of all three POPs decreased over the last two decades, although this signal was less clear for PCBs, and further monitoring is needed to assess trends in this family of compounds. DDT concentrations at two sites were higher than previous records for southern Africa, but there is no evidence of a link to the ongoing use of DDT for malaria control. HCHs concentrations were lower than in pellets from the east coast of southern Africa, suggesting that this pesticide was mainly used in the eastern part of the region. Our study demonstrates the potential for International Pellet Watch to track temporal as well as geographical patterns in the abundance of POPs in marine environments.
Afficher plus [+] Moins [-]On the biological connectivity of oil and gas platforms in the North Sea
2012
Thorpe, S.A.
Tests are made of the conjecture that the platforms in the North Sea are biologically connected, with organisms originating from some platforms reaching and substantially augmenting those at others so that, together, the platforms effectively form a sort of artificial reef. The M₂ tide results in a relatively rapid transfer of organisms between neighbouring platforms. Some 60% of platforms in the southern UK Sector are directly connected by tidal flows. Such connection in the northern Sector is relatively rare, about 23% of platforms being connected. Mean flows connect platforms in ‘strings’ sharing a common streamline spread by turbulent dispersion. Metrics are devised to indicate how well a particular platform is connected to others. Strings are broken when contributions to the concentration of organisms from platforms fall below detection limits. Many platforms are likely to be connected in strings in the southern UK Sector, but relatively few in the northern Sector.
Afficher plus [+] Moins [-]Tolerance and accumulation of copper in the salt-marsh shrub Halimione portulacoides
2012
Cambrollé, J. | Mancilla-Leytón, J.M. | Muñoz-Vallés, S. | Luque, T. | Figueroa, M.E.
The present study evaluated the tolerance and accumulation potential in the salt-marsh shrub Halimione portulacoides under moderate and high external Cu levels. A greenhouse experiment was conducted in order to investigate the effects of a range of external Cu concentrations (0 to 60mmoll⁻¹) on growth and photosynthetic performance by measuring gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments. We also determined total copper, nitrogen, phosphorus and sulfur concentrations in the plant tissues. H. portulacoides survived with external Cu concentrations of up to 35mmolCul⁻¹, although the excess of metal resulted in a biomass reduction of 48%. The effects of Cu on growth were linked to a drastic reduction in net photosynthesis. However, H. portulacoides tolerated Cu levels of up to 15mmolCul⁻¹ without suffering adverse physiological effects. Our results indicate that this species could play an important role in the restoration of Cu-contaminated soils.
Afficher plus [+] Moins [-]Reducing dissolved inorganic nitrogen in surface runoff water from sugarcane production systems
2012
Webster, A.J. | Bartley, R. | Armour, J.D. | Brodie, J.E. | Thorburn, P.J.
Nitrogen (N) lost from farms, especially as the highly bioavailable dissolved inorganic form, may be damaging Australia’s Great Barrier Reef (GBR). As sugarcane is the dominant cropping system in GBR catchments, its N management practises are coming under increasing scrutiny. This study measured dissolved inorganic N lost in surface runoff water and sugarcane productivity over 3years. The experiment compared the conventional fertiliser N application rate to sugarcane (average 180kgN/ha/year) and a rate based on replacing N exported in the previous crop (average 94kgN/ha/year). Dissolved inorganic N losses in surface water were 72%, 48% and 66% lower in the three monitored years in the reduced N fertiliser treatment. There was no significant difference in sugarcane yield between the two fertiliser N treatments, nor any treatment difference in soil mineral N – both of these results are indicators of the sustainability of the lower fertiliser N applications.
Afficher plus [+] Moins [-]Petroleum hydrocarbon contamination in Nelson Lagoon, Alaska, sampling three different matrices
2012
Lance, Ellen W. | Matz, Angela C. | Reeves, Mari K. | Verbrugge, Lori A.
Polycyclic aromatic hydrocarbon (PAH) levels were measured in sediments, bivalves and semi-permeable membrane devices (SPMDs) in the relatively pristine marine environment of Nelson Lagoon, Alaska. Most PAH levels in Nelson Lagoon were low, and similar to global background concentrations. Sampling media type can significantly influence conclusions of PAH contamination in the environment. Concentration of a broad size range of PAHs was observed in the tissues of blue mussels (Mytilus edulis). SPMDs collected some two- to three-ring PAHs from the dissolved water phase, while sediments collected five- to six-ring PAHs that were likely adsorbed onto particulate matter. Benzo(a)pyrene, a potent carcinogen, was found in mussels at levels similar to more industrialized harbors in Alaska.
Afficher plus [+] Moins [-]Radionuclides in resident and migratory fishes of a wedge bank region: Estimation of dose to human beings, South India
2012
Khan, M Feroz | Wesley, S Godwin
Baseline activity concentration of ¹³⁷Cs, ²¹⁰Po and ²¹⁰Pb was determined for 25 resident and 22 migratory fish species collected in a so-called wedge bank region in the extreme south of India. A nuclear power station is now under construction at Kudankulam near the target region and the data provide background information on the radionuclide activity concentration in the region. Three-way ANOVA revealed no significant variation in the concentrations of ¹³⁷Cs, ²¹⁰Po and ²¹⁰Pb between species based on feeding habit, habitat and migratory pattern except the effect of feeding habit on ²¹⁰Po concentration (p<0.05). The annual dose due to radionuclide ingestion through the fishes was calculated based on the survey results of fish consumption rates for the local population. The dose due to ¹³⁷Cs was negligibly small while those due to ²¹⁰Po and ²¹⁰Pb varied from 1.2 to 36.9 and 0.2 to 2.9μSvyr⁻¹, respectively.
Afficher plus [+] Moins [-]A comparative study on the effects of barite, ilmenite and bentonite on four suspension feeding bivalves
2012
F. Strachan, Maia | F. Kingston, Paul
The impact of drilling mud components on the filtration activity and survival of bivalve molluscs was investigated by exposing them to suspensions of ‘standard’ barite, finely milled barite, ilmenite and bentonite in sea water. Introduction of the components stimulated filtration activity in all four bivalves. In addition, the introduction of standard barite and ilmenite both had lethal effects, with none of the bivalves surviving the full duration of the experiments. In-vivo observations of the gill surfaces provided direct evidence of physical damage caused by the administration of barite and ilmenite. A marked difference between filtration activity and survival of animals dosed with ‘standard’ barite and ‘fine’ barite suggests that the observed effects were primarily caused by physical interference with gill function. The results also suggest that the use of fine barite in offshore drilling may provide a more favourable environmental impact profile than the use of ilmenite.
Afficher plus [+] Moins [-]Pilot study on effects of nanoparticle exposure on Crassostrea virginica hemocyte phagocytosis
2012
Abbott Chalew, Talia E. | Galloway, Justin F. | Graczyk, Thaddeus K.
Little is known about engineered nanoparticles (NPs) exposures on oysters. As sessile filter feeders, oysters are likely to be exposed to NPs suspended in the water column with unknown effects of NP exposure on oyster functioning. Our study indicates that waterborne NPs alter oyster hemocyte phagocytosis dynamics, an indication of sub-lethal effects of NP exposures. Silver NPs, titanium dioxide (TiO₂) NPs, and silver nitrate exposures reduced phagocytosis compared to the control. Increasing TiO₂ NPs and silver nitrate concentrations reduced phagocytosis. Silver NPs, up to 120ppb, increased phagocytosis, but higher concentrations reduced phagocytosis.
Afficher plus [+] Moins [-]Benthic foraminifera as proxies of pollution: The case of Guanabara Bay (Brazil)
2012
Donnici, Sandra | Serandrei-Barbero, Rossana | Bonardi, Maurizio | Sperle, Marcelo
Due to economic importance of Guanabara Bay, a multidisciplinary approach was adopted to investigate 88 surficial sediment samples in order to use the benthic foraminifera as indicators for the characterization of environmental variations. Grain-size analyses indicate that bottom sediments of the inner part of the bay are mainly muddy while those close to the entrance of the bay are sandy. Geochemical data show high concentration of heavy metals mainly in the northern region of the bay. Micropalaeontological analyses indicate the boundaries of the areas with the highest concentration of heavy metals. The dominant benthic foraminifera in the bay are Ammonia beccarii and Buliminella elegantissima, taxa capable of differentiating the presence of pollutants of different sources. B. elegantissima, in particular, has shown to be an indicator of anthropogenic pollution. The study highlights the worsening of environmental conditions since 2000 and those areas of the bay in need of a priority recovery.
Afficher plus [+] Moins [-]Hydrophobic modification of polyurethane foam for oil spill cleanup
2012
Li, Hua | Liu, Lifen | Yang, Fenglin
To improve the oleophilic/hydrophobic properties of polyurethane (PU) foams for oil spill cleanup, PU samples were modified by grafting with oleophilic monomer Lauryl methacrylate (LMA) in solvent and/or coating with LMA microspheres through heating and curing. Modified PU cubes were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). The water sorption of modified PU cubes was decreased by 24–50%, while the diesel or kerosene sorption of modified PU cubes was increased by 18–27%. In water–oil system, compared with blank PU cubes, the sorption capacity of PU cubes grafted with LMA was increased by 44% for diesel and 100% for kerosene. The sorption capacity of PU cubes coated with LMA microspheres was increased by 20% for diesel and 7% for kerosene. The solvent sorption of modified PU cubes could reach 50–69g/g. The modified PU cubes can be effectively used in oil/solvent spill cleanup.
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