Should we measure plutonium concentrations in marine sediments near Fukushima?

Pu contamination originating from Fukushima accident has not been detected in marine sediment samples collected outside a 30 km circle around the plant. It is shown, by means of numerical modelling, that if any impact from the accident has occurred, this would remain in a very close area to Fukushima because of the low Pu mobility in the marine environment. Since the situation inside the 30 km zone remains unknown, further studies on the determination of Pu isotopes in sediments within this area are required.     

Transuranics transfer in a Spanish marine ecosystem

Due to an accidental release of transuranics at Palomares, Almeria (Spain), an area of 2.3 km² was contaminated (1,2,3). With the objective of studying the possible transfer of the transuranic from land to sea (4), a sampling network for marine sediments and sea water was established between Cape Palos and Cape Gata. Concentrations of plutonium, americium and radiocesium were determined in sediment cores taken from the sea shelf surrounding Palomares. The depositional history of sediments was elucidated using the unsupported²¹⁰Pb method. An increase in transuranic concentrations was observed off the southern coast of Palomares, the sources of which are discussed in this paper.     

Optimisation of sample pre-treatment method for the determination of triclosan in marine sediments by high-performance liquid chromatography and marine benthic quality assessment in the southern Baltic Sea

This study comprises optimisation of sample preparation and HPLC analytical procedure for the determination of a personal care product ingredient, triclosan (TCS), in marine sediments. The testing of several varying pre-treatment parameters confirmed that ultrasonic extraction is an effective method for the isolation of TCS from marine sediments, and that the choice of extraction solvent appeared to be of major importance. The selection of the mobile-phase composition and the absorption wavelength was made for the high-performance liquid chromatography analysis step. Based on the validated method, a preliminary assessment of the benthic ecosystem quality with regards to TCS contamination has been demonstrated in the southern Baltic Sea – a semi-enclosed sea, characterised by poor water exchange, thus particularly susceptible to anthropopression. TCS has been identified and quantified in situ in marine bottom sediments, sediment dwelling isopod – Saduria entomon L. and estimated in silico in pore waters based on the equilibrium partition theory in order to assess the potential exposure and uptake from the aqueous phase. TCS concentrations identified in the bottom sediments of the Gdansk Basin, as the natural habitat for studied S.entomon L., appear to be threatening to the benthic environment. Particularly when considering S. entomon L. as a major nutrition source for cod (Gadus morhua) undergoing the feminisation process, since the recent studies prove TCS to have a potential to induce critical alterations in the endocrine system of marine ichthyofauna.     

Size fractionation of marine sediments by pinched inlet gravitational split-flow thin fractionation and the study of size dependent PCDD/Fs concentrations from different bay areas

Pinched inlet gravitational split-flow thin fractionation (PI-GSF) has been applied to the continuous size fractionation of marine sediments in order to study the difference in sediment size distribution and the concentration of PCDD/Fs contained in different particle sizes. A PI-GSF channel, known to improve the separation efficiency by reducing the sample inlet thickness, was utilized to fractionate sediments collected from three different bay areas (Geoje, Ulsan, and Pohang) in Korea into 5 different sub-populations (<2.0, 2.0-5.0, 5.0-10, 10-20, 20-63 microm in diameter). The sorted sediment fractions from PI-GSF were examined using electron microscopy to obtain size distribution and the results showed a variation in particle size distribution between bay areas. When the collected particle fractions were examined for size dependent levels of PCDD/Fs, the concentrations of total PCDD/Fs were shown to be much greater for samples collected close to heavy industry complexes than sediments from bay areas without major industry.     

Identification of sources of oil spills in soils and sediments by gas chromatography/mass spectrometry

Gas chromatography/mass spectrometry has been applied to the study of the residual oil contamination of the sediments in the area of an emergency mazut spill in an industrial enterprise. The contamination level appeared to be very high in nearly all samples collected within a rather wide area; however, the oil in the studied samples have undergone significant weathering; therefore, we have concluded that they had got into the sediments long before the spill under consideration or had been accumulating in them systematically for many years. The methodology of the identification of oil in soils taking into account their transfer and weathering is considered; it employs characteristics of the hydrocarbon type composition along with the individual marker compounds.     

Heavy metals in marine sediments from the Mar Piccolo of Taranto (Ionian Sea, southern Italy)

Heavy metals concentrations (Cd, Cu, Hg, Pb, Sn and Zn) have been determined monthly in surface sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy. a semi-enclosed marine basin very important from a mussel-culture point of view. In sediments, sulphides, percentage of organic carbon and redox potential were also determined to show possible correlations between metals levels and redox characteristics of marine sediments. Analytical results, elaborated by multivariate statistical techniques, confirm that sediments collected in the first inlet of Mar Piccolo, where shipbuilding activities are present, have a contamination level greater than those collected in the second inlet. For each metal, the geoaccumulation index (Igeo) has been calculated as criterion to evaluate both pollution levels and metals enrichment in examined sediments: Igeo values confirm that the first inlet is an moderately polluted area from Hg and Pb. In any case, high sulphide concentrations and negative values of redox potentials bring to a conclusion that metals are present in sediments, mainly as insoluble sulphides and then as not bioavailable compounds for filter feeders organisms such as mussels.     

Distribution of trace elements in the marine sediments along the South China Sea,Malaysia

In order to complete having data base of elemental assessment of the east coast of Peninsular Malaysia marine sediments along the South China Sea coasts, trace elements are analyzed and their distribution in marine sediments is undertaken. The present study is done parallel with pervious study on elemental assessment of heavy metals, rare earth elements and actinides in the marine sediments of the east coast of Peninsular Malaysia. Thirty surface sediment samples were collected in this area, including regions of Kelantan, Terengganu, Pahang, Rompin and Johor Baharu. Multielemental analysis was carried out by instrumental neutron activation analysis and inductively coupled plasma atomic emission spectroscopy. In both cases methodology validation was performed by certified reference material analyses. For the surface elemental distributions the enrichment factor values, average I _geo and mC _d values indicate that the trace elements of the surface sediments are uncontaminated in all sampling stations that are consistent with previous studies results of heavy metals, rare earth elements and actinides.     

The origin of arsenobetaine in marine animals

Trimethyl(carboxymethyl)arsonium zwitterion (arsenobetaine) is virtually ubiquitous in marine animals consumed by man. Experimental work on the transformation of arsenate to arsenobetaine in the marine environment is reviewed. Current evidence favors the conversion of arsenate to dimethyl(ribosyl)arsine oxides by algae, and the microbially mediated transformation of dimethyl(ribosyl)arsine oxides to arsenobetaine or to its immediate precursors in the sediments. Information about the transfer of arsenobetaine from the sediments to marine animals is lacking.     

Magnetic normalization of particle size effects in a heavy metal pollution study of intertidal sediments from the Yangzte Estuary

Magnetic, granulometric and geochemical analyses were conducted on an intertidal sediment core from the Yangtze Estuary to evaluate the possibility of normalizing samples for particle size effects in a heavy metal pollution study by means of magnetic proxies. It has been found that the magnetic parameter XARM, indicating fine grained ferrimagnetic minerals, correlates well with the clay content and organic matter concentration of the sediments. XARM also shows significant relationship with heavy metals. Therefore XARM is proposed as a proxy for clay content in the sediments, and can be used to compensate for the particle size effect in sedimentary heavy metal records, where magnetic minerals are not subject to significant post-depositional alteration.     

Post-Chernobyl accident radioactivity measurements in the Comunidad Autonoma de Valencia, Spain.

Increased atmospheric radioactivity after the accident in Chernobyl was first detected on air filters. Measurements were begun in Valencia on May 2, 1986, with the maximum activity being observed around May 3-4, 1986. As a consequence of this accident, annual campaigns of measurements on migrating birds (several species of aquatic birds and song-thrushes) were started. The data corresponding to the campaign immediately after the accident (1986/87) show a generalized contamination (approximately 50% of the measured specimens). Significant levels of 134Cs, 137Cs and 110Agm were found. It is important to note that 110Agm is only present in Aythya ferina. In the successive campaigns in 1988/89 and 1989/91 few samples were found to be contaminated and only 137Cs was identified. Strontium-90 was measured and identified in some specimens, mainly in their bones.     

Developing a methodology for carbon isotope analysis of lacustrine diatoms

Stable isotope analysis of sedimentary carbon in lakes can help reveal changes in terrestrial and aquatic carbon cycles. A method based on a single, photosynthetic organism, where host effects are minimised, should offer more precision than carbon isotope studies of bulk lake sediments. Here we report the development of a systematic method for use on fossil lacustrine diatom frustules, adapted from previous studies in marine environments. A step-wise cleaning experiment on diatomaceous lake sediments from Lake Challa, near Mount Kilimanjaro, was made to demonstrate the necessary treatment stages to remove external sedimentary carbon. Changes in soluble carbon compounds during these cleaning experiments were measured using gas chromatography/mass spectrometry (GC/MS). The mass spectrometry methods were refined to measure the small percentage of carbon in these samples and details of these methods are presented. Samples of cleaned diatoms containing <1% carbon yielded robust results. Carbon isotope analyses of diatom samples containing different species mixtures were performed and suggested that differences existed, although the effects lay within current experimental error and require further work. Unlike what was found in work on oxygen and silicon isotopes from diatom frustules, mineral contamination had no discernible impact on the diatom carbon isotope ratios from these sediments. The range of values found in the lakes investigated thus far can be interpreted with reference to the supply and nature of carbon from the catchment as well as to the demand generated from lake primary productivity.     

Relationship between particle size and radiocesium in fluvial suspended sediment related to the Fukushima Daiichi Nuclear Power Plant accident

We collected fluvial suspended sediments in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and analyzed the ¹³⁷Cs concentration in bulk and size-fractioned samples to investigate the particle-size-dependent distribution of radiocesium. The ¹³⁷Cs concentration in bulk suspended sediments decreased from August to December 2011, possibly reflecting a decrease of radiocesium concentration in its source materials. Smaller particles had higher radiocesium concentrations, reflecting larger specific surface areas. Silt- and sand-size fractions occupied more than 95 % of the total ¹³⁷Cs in the suspended sediments. The contribution of clay-size fractions, which had the highest ¹³⁷Cs concentration, was quite small because of their low frequency. A line of the data showed that the particle size distribution of radiocesium was essential to evaluate the migration and distribution of radiocesium in river systems where radiocesium is mainly present as particulate form after the FDNPP accident.     

Improved ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons in sediments

The aim of this work was to optimize an ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons (PAHs) in sediments and to compare it with the reflux procedure using methanolic potassium hydroxide. Sample extracts were purified with a miniaturized silica gel chromatographic column and analyzed by gas chromatography-mass spectrometry (GC-MS). Ultrasonication using n-hexane-acetone (1:1, v/v) solvent mixture on dried homogenized marine sediment gave better precision (smaller relative standard deviation (RSD) values) and comparable quantities of individual PAH's compared to the reflux procedure. Ultrasonication with the n-hexane-acetone (1:1, v/v) mixture, utilizing four 15 min extraction cycles, was found to be sufficient for extracting PAHs from wet sediments. The optimized ultrasonic extraction procedure extracted aliphatic and aromatic hydrocarbons from the National Institute of Standards and Technology SRM 1941a with recoveries greater than 90%. The major advantages of ultrasonication compared to the reflux method are the lower extraction times, simplicity of the apparatus and extraction procedure. The optimized ultrasonication procedure has been used in our laboratory to extract hydrocarbons from naturally wet sediments from rivers, and coastal and marine areas.     

Radioecological Research on the Marine Environment Facing the Italian Base in Antarctica (1989–91)

Abstract

The results of the analysis of both natural (Th-232, U-238 and K-40) and artificial (Cs-137) radioactivity contained in samples collected during the 1989–90 and 1990–91 PNRA Scientific Campaigns in the Terra Nova Bay (Ross Sea) marine ecosystem, are presented in this paper. The data refers to samples of sea water, pack water, sediments and organisms belonging to demersal ichthyofauna (Pagothenia bernacchii, Chionodraco hamatus) and soft bottom macrofauna (Adamussium colbecki) collected in different coastal and off shore stations of the area investigated. Some sea water samples collected on the way to subAntarctic areas were also considered. The radiocontamination detected in sediments was correlated to the quantities of organic matter, organic carbon and nitrogen contained in the samples. Additionally, Cs-137 concentration factors were calculated for the different biological specimens and their anatomical components. Data values, with special consideration for anthropogenic Cs-137, are compared to results obtained from similar matrixes collected in the Northern Hemisphere in temperate waters before and after the accident at the Chernobyl nuclear plant.     

Organometallics in the nearshore marine environment of Australia

This review draws together published information on the occurrence and biogeochemical cycling of selenium, arsenic and tin in the nearshore marine environment of Australia. The selenium content of marine organisms is well documented but little information is available on the selenium content of waters and sediments. The speciation of selenium in organisms, water and sediments is unknown although it appears that selenium is associated with proteins. The occurrence and speciation of arsenic in marine organisms has been extensively studied, with arsonobetaine being isolated as the probable end-product of arsenic metabolism in marine food chains. However, organisms can produce other organoarsenic compounds, e.g. trimethylarsine oxide, which may be metabolized to toxic end-products. Little is known about the occurrence and speciation of arsenic in waters and sediments. Arsenic(V) is dominant in oxygenated waters, with appreciable quantities of arsenic(III) in some deoxygenated waters. There are few data for tin in water, sediments or organisms and no data on naturally occurring tin species. Tributyltin has been measured in water, sediment and organisms from areas affected by boating activity.     

Concept of seasonality in the light of the Chernobyl accident.

Seasonality could have a strong influence on the radiological impact of environmental radioactive contamination. Short-lived radionuclides (e.g., 131l) and those that mainly enter the food chain by direct contamination (e.g., 137Cs) are especially important in this context. In particular, the contamination of cereals is influenced by seasonality. For temperate latitudes it is generally true that radioactive contamination during winter, when the fields lie fallow and the domestic animals are stabled, will result in a significantly lower radiological impact than if a similar contamination were to take place in the summer shortly before harvesting. The impact of the Chernobyl accident on the radioactive contamination of human diet was strongly influenced by seasonality.     

Magnetic normalization of particle size effects in a heavy metal pollution study of intertidal sediments from the Yangzte Estuary

Magnetic, granulometric and geochemical analyses were conducted on an intertidal sediment core from the Yangtze Estuary to evaluate the possibility of normalizing samples for particle size effects in a heavy metal pollution study by means of magnetic proxies. It has been found that the magnetic parameter_ϰARM, indicating fine grained ferrimagnetic minerals, correlates well with the clay content and organic matter concentration of the sediments._ϰARM also shows significant relationship with heavy metals. Therefore_ϰARM is proposed as a proxy for clay content in the sediments, and can be used to compensate for the particle size effect in sedimentary heavy metal records, where magnetic minerals are not subject to significant post-depositional alteration.

     

A Study on the Engineering Geological Properties of Fine-grained Marine Sediments

Through studies on the engineering geological properties of fine marine sediments, this article fully verified that the sedimentary environment is an important factor which determines the engineering geological properties of fine marine sediments. Meanwhile, these properties are controlled and affected by factors such as composition, physico-chemical nature, micro-textures, etc. of fine soils.     

Speciation of heavy metals in sediments of the lagoon of Venice collected in the industrial area

In this study a procedure of sequential extraction of metals from sediments was applied to samples from the lagoon of Venice. Compared to the measurement of total concentrations, the knowledge of metal partitioning among sediment phases can help in estimating the risk posed by metal polluted sediments and give information on contamination sources and on the factors that influence metal enrichment in sediments. The results permitted to estimate for each metal the percentage of the total content that could be potentially remobilized from sediments, owing to changes in environmental conditions. The immediately available fraction represented in general a low proportion of the total content. An important proportion of most metals (except for Zn, Cd and Cu) was associated to residual phases and therefore was not expected to be released under the normal environmental conditions. The large amounts of metals bound to Fe-Mn oxides/hydroxides confirmed the strong scavenging efficiency of this phase. The carbonate phase was the preferential associative form for Pb, Cd and Zn, whereas Cu was bound in prevalence to the organic matter/sulphide phase.     

Dispersion model of cesium-137 in surface oceanic waters

The¹³⁷Cs radionuclide dispersion in the marine environment through the compartmental model is reported. The model simulates the surface water contamination caused by routine or accidental radionuclide releases. For the simulation the OCEAN program was applied in the North Sea, near to Sellafield and adjacent areas, based on published transfer coefficient data. The results are in good agreement with the literature and the model developed can be applied to the brazilian coastal regions.