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1.
The North-East Atlantic porbeagle (Lamna nasus) population has declined dramatically over the last few decades and is currently classified as ‘Critically Endangered’. As long-lived, apex predators, they may be vulnerable to bioaccumulation of contaminants. In this study organohalogen compounds and trace elements were analysed in 12 specimens caught as incidental bycatch in commercial gillnet fisheries in the Celtic Sea in 2011. Levels of organohalogen contaminants were low or undetectable (summed CB and BDE concentrations 0.04–0.85 mg kg−1 wet weight). A notably high Cd concentration (7.2 mg kg−1 wet weight) was observed in one mature male, whereas the range observed in the other samples was much lower (0.04–0.26 mg kg−1 wet weight). Hg and Pb concentrations were detected only in single animals, at 0.34 and 0.08 mg kg−1 wet weight, respectively. These contaminant levels were low in comparison to other published studies for shark species.  相似文献   
2.
The aim of this study was to assess the level of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination and enrichment in the surface sediments of the Seyhan River, which is the receiving water body of both treated and untreated municipal and industrial effluents as well as agricultural drainage waters generated within Adana, Turkey. Sediment and water samples were taken from six previously determined stations covering the downstream of the Seyhan dam during both wet and dry seasons and the samples were then analyzed for the heavy metals of concern. When both dry and wet seasons were considered, metal concentrations varied significantly within a broad range with Al, 7210–33 967 mg kg?1 dw; Cr, 46–122 mg kg?1 dw; Cu, 6–57 mg kg?1 dw; Fe, 10 294–26 556 mg kg?1 dw; Mn, 144–638 mg kg?1 dw; Ni, 82–215 mg kg?1 dw; Pb, 11–75 mg kg?1 dw; Zn, 34–146 mg kg?1 dw in the sediments while Cd was at non‐detectable levels for all stations. For both seasons combined, the enrichment factor (EF) and the geo‐accumulation index (Igeo) for the sediments in terms of the specified metals ranged from 0.56 to 10.36 and ?2.92 to 1.56, respectively, throughout the lower Seyhan River. The sediment quality guidelines (SQG) of US‐EPA suggested the sediments of the Seyhan River demonstrated “unpolluted to moderate pollution” of Cu, Pb, and Zn, “moderate to very strong pollution” of Cr and Ni. The water quality data, on the other hand, indicated very low levels of these metals suggesting that the metal content in the surface sediments were most probably originating from fine sediments transported along the river route instead of water/wastewater discharges with high metal content.  相似文献   
3.
The statistical properties of long-crested nonlinear wave time series measured in an offshore basin have been analyzed in different aspects such as the distributions of surface elevation, wave crest, wave trough, and wave period. Comparison with linear, second-order and third-order theoretical models indicates that although bound wave effects also contribute to the deviation from a Gaussian process, it is the modulational instability that primarily determines the discrepancy in the evolution process in the presence of strong nonlinearity. Interestingly enough, wave crest is more sensitive to the quasi-resonant four-wave interaction effect than wave trough and the scaled maximal wave crest presents a linear regression model with the coefficient of kurtosis. Meanwhile, the estimation of the observed statistical properties is reconstructed on the basis of an ensemble of 100 wave series simulated by the NLS-type equations and compared favourably with the experimental results in most cases. Moreover, with the increased third-order nonlinear effect the difference between NLS and Dysthe simulations is enlarged and mainly reflected on the distribution of wave crest.  相似文献   
4.
The Zheyaoshan deposit is the largest within the Baiyinchang (BYC) volcanic-hosted massive sulfide (VHMS) district, located in the northern Qilian orogenic belt of North China. The deposit is hosted by quartz keratophyre tuffs, with wall-rock alteration mainly comprising chlorite, sericite, quartz, pyrite and epidote. Mineral assemblages within the altered host rocks can be divided into a sericite-quartz-dominant assemblage (sericite-silicified zone), a chlorite-dominant assemblage (chlorite-dominant zone) and a pyrite-dominant assemblage (mineralized zone) based on geochemical analysis and alteration characteristics. We have conducted detailed processing and critical analysis of the geochemical data of both the altered and least-altered host rocks in order to investigate the problem of closure in the geochemical dataset to eliminate the influence that each component has on the other in terms of mass change, and have applied the standardized method of the mass change calculation to analyze this data. The results show that: (1) the sericite-silicified zone formed along fissures due to the ingress of hydrothermal fluids, with MnO2, Na2O and CaO being mobilized into the hydrothermal fluids leached and MgO, Fe2O3, SiO2, K2O, BaO deposited. Additionally, Ag, Cu and chalcophile elements (Ag, As and Bi) were enriched while Pb, Zn and large ion lithophile elements (LILEs) (Cs, Sr, Eu, Be) were mobilized into hydrothermal fluids; (2) the physiochemical conditions and pH levels of the hydrothermal fluids changed during sericitization, with MgO, Fe2O3, BaO being further enriched and MnO, Na2O, CaO further depleted, leading to formation of chlorite and the initial precipitation of metallogenic the (Cu, Zn, Pb) and chalcophile elements (Ag, As, Bi); (3) the negative Eu anomaly was mainly due to its strong activity when Eu is mobilized into the hydrothermal fluids during since plagioclase break-down during the sericite-silicification process; (4) AI and CCPI values gradually increase towards the orebody. The chlorite-dominant assemblage and sericite-quartz-dominant assemblage on the periphery of the chlorite-dominant zone can all be used as vectors towards the volcanic massive sulfide orebody and for regional-scale mineral exploration. Either leached elements or enriched elements can be considered as significant indicator elements and as prospective indicators for geochemical exploration within the BYC district. The Eu anomaly may be especially useful as an indicator for distinguishing the least-altered rocks which has great significance for exploration on the regional scale.  相似文献   
5.
Petroleum drill cuttings are usually treated by techniques suitable for particular contaminant groups. The significance of this study consists in the development of a treatment technology that can simultaneously handle the hydrocarbon and metal constituents of drill cuttings. Bioaugmentation is combined with stabilisation/solidification (S/S), within S/S monoliths and in granulated S/S monoliths. Portland cement was used for S/S treatment at 30% binder dosage. Bioaugmentation treatment involved two bacterial densities of a mixed culture bio-preparation. The effects of inclusion of compost, fertiliser and activated carbon were also evaluated. After 28 days, the combined S/S and bioaugmentation treatments recorded up to 15% higher total petroleum hydrocarbon (TPH) loss than control S/S treatment without bioaugmentation. Embedding fertiliser, activated carbon and higher bacterial density within S/S monoliths resulted in the highest (99%) TPH reduction but higher concentrations of metals. The addition of compost and lower bacterial density to granulated S/S monoliths led to similar (98%) TPH degradation and lower amounts of metals. The results suggest that with better mixture optimisation, combining S/S and bioaugmentation could engender more sustainable treatment of drill cuttings.  相似文献   
6.
One of the major routes of human exposure to toxic metals is the consumption of vegetables grown on contaminated soils. Radishes were grown in three different soils (kitchen garden, agricultural and industrial soils), presenting various contamination levels. A sequential extraction procedure was compared with EDTA and HCl simple extractions methods in order to predict the metals phytoavailabilty to radish. The analysis of the results shows that the simple HCl and sequential chemical extractions bring complementary results, since HCl is correlated in the phytoavailability of Cd, Mn and Zn, whereas the sequential extraction is correlated in the phytoavailability of Cr, Fe, Mn, Ni. EDTA simple extraction brings here less interesting results than the two other tested extractions.  相似文献   
7.
The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO3, Cl, SO4 and NO3) and metals concentrations (27Al, 75As, 138Ba, 9Be, 111Cd, 59Co, 63Cu, 52Cr, 57Fe, 55Mn, 60Ni, 208Pb, 80Se, 66Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system.  相似文献   
8.
Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ~3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ~1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem.  相似文献   
9.
Plastic production pellets sampled from four beaches along a stretch of coastline (south Devon, SW England) and accompanying, loosely adhered and entrapped material removed ultrasonically have been analysed for major metals (Al, Fe, Mn) and trace metals (Cu, Zn, Pb, Ag, Cd, Co, Cr, Mo, Sb, Sn, U) following acid digestion. In most cases, metal concentrations in composite pellet samples from each site were less than but within an order of magnitude of corresponding concentrations in the pooled extraneous materials. However, normalisation of data with respect to Al revealed enrichment of Cd and Pb in plastic pellets at two sites. These observations are not wholly due to the association of pellets with fine material that is resistant to ultrasonication since new polyethylene pellets suspended in a harbour for 8 weeks accumulated metals from sea water through adsorption and precipitation. The environmental implications and potential applications of these findings are discussed.  相似文献   
10.
INTRODUCTIONTheattentiontothestudyofmetalsinthemarineaerosolparticulatesisincreasingduetotheirenvironmentalecologicaleffectsandcontributiontothebiogeochemicalcycle.Intheaspectofenvironmentalecologicaleffects,first,onthesideofclimate,aerosolswithmetalscanactascloudcondensationoricenuclei,absorbandscattersolarradiation,andaffecttheradiationbudgetontheearth.Therelativelyhighironcontent(5%)ofthedustcanabsorbtheshortwavelengthradiationefficiently.Second,onthesideofecologicaleffects,di~lvedAlse…  相似文献   
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