The PAH composition in limpets (Patella vulgate L.) from the coasts of Sicily (Italy)

This article examines the presence, distribution, nature and sources of 19 Polycyclic Aromatic Hydrocarbons (PAH), in Patellae (patella vulgate L.) and seaweed (vulva) sampled in different stations of Sicilian coastal environments and analyzed for their polycyclic aromatic hydrocarbon (PAH) content. Analysis was performed by gas chromatography/mass spectrometry (GC/MS) with selected ion monitoring (SIM), after saponification of the sample and clean up of the extract. In the limpets the total concentration of polycyclic aromatic hydrocarbons ranged from 34 to 750 μg/Kg of dry matrix. The relative standard deviation (RSD) of the replicas on the concentrations of individual compounds ranged from 4 to 20%. The accuracy of method was estimated by analyzing "blank" samples spiked with known quantities of analytes and the recover percentage was 82 ± 12%. The detection limit (LOD) of analytical procedure was less than 0.2 μg/Kg d.w. for all analytes. The quantification limit (LOQ) of analytical procedure was less 0.7 μg/Kg d.w. The resulting distributions and weight ratios of specific compounds are discussed in terms of sampling location and origin. The results obtained show that levels of contamination vary from one sampling station to the next, while relative distributions of PAH is homogeneous in most stations. Lipidic content and total PAH concentrations were found not to be correlated and the compounds present in limpets were shown to be mainly of petrogenic origin. There is no evidence of coal-tar contamination. Copyright © 2006 Taylor & Francis Group, LLC

Polycyclic Aromatic Hydrocarbons (PAH) in Volcano island (Aeolian archipelago) mud utilized for therapeutic purpose

This paper examines the possible presence, distribution, nature and sources of 18 Polycyclic Aromatic Hydrocarbons (PAHs) as constituent of the muds pool collected in Vulcano Aeolian Island. PAHs are important from environmental and toxicological point of view. Analysis was performed by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM). The total concentration of Polycyclic Aromatic Hydrocarbons ranged from 112 to 154 g/Kg of dry matrix. The volcanic muds, used for therapeutic purposes, are moderately contaminated

The single salt approximation for the major components of seawater: association and acid–base properties

In this note we propose the use of the single salt approximation for the composition of seawater. This approximation has been applied to a synthetic seawater. Association and acid-base properties h..

Occurrence and concentration of PAHs in clams and sediments of the marine coastal lagoon of Ganzirri (Italy). Extraction, GC-MS analysis, distribution and sources

The distribution of selected Polycyclic Aromatic Hydrocarbons (PAHs) in surface sediments and clams of marine coastal lagoons, called Ganzirri, located at the Sicilian coast of the, Messina's strait, has been investigated by GC/MS analysis with Selected Ion Monitoring (SIM) mode. The lagoon is characterized by abundant organic detritus, deriving from aquagenic and anthropogenic inputs. Anoxic/reduced conditions of sediments make them a preferential site for uptake and preservation of PAHs. From an eco-toxicological point of view, the aquatic ecosystem investigated appears to be moderately polluted. The investigations have been performed on the 16 PAHs recommended by US-EPA as priority pollutants to be monitored in the framework of environmental quality control. The sediment PAH concentrations ranged from 135 to 1650 mu g/kg dry matrix. The total concentrations of PAHs in clams ranged from 60 to 1427 mu g/kg d.w. The relative standard deviation (RSD) for all samples of the concentration replicates of individual compounds ranged from 10% to 25%. The resulting distributions and ratios of specific compounds have been discussed in terms of sampling location and origin of contaminants. The results obtained show that levels of contamination are not homogeneous throughout the stations. In the Ganzirri Lagoon, the bioavailability of hydrophobic organic compounds, such as PAHs, seems to be mainly governed by chemical characteristics of the contaminants. Pyrolytic compounds (penta- and hexa-aromatics) are not readily available. In contrast, petroleum hydrocarbons (some tetra-aromatics) are accumulated by clams to a great extent

Chemical speciation of organic matter in natural waters. Interaction of nucleotide 5' mono-, di- and triphosphates with major components of seawater

AbstractThe interactions of nucleotide 5' mono-, di- and triphosphates in a multicomponent ionic medium simulating the macro-composition of seawater (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, Synthetic Sea Water, SSW) have been investigated at different ionic strengths and at T= 25°C. A chemical speciation model, according to which all the internal interactions between the components of the ionic medium are taken into account, was applied to determine the effective formation constants of species in the nucleotide-seawater system. The results were compared to protonation parameters calculated from single electrolyte systems. A simpler model (SSW considered as a single salt BA, with Bz+ and Az-), representative of the cation (Na+, K+, Ca2+, Mg2+) and anion (Cl-, SO42-) macro-components of seawater respectively, was also used to calculate the overall complexing ability of the seawater salt towards all the systems here investigated

Trophic Transfer of Trace Elements in an Isotopically Constructed Food Chain From a Semi-enclosed Marine Coastal Area (Stagnone di Marsala, Sicily, Mediterranean)

Trace element accumulation is particularly important in coastal and transitional environments, which act as contaminant buffers between the continental and marine systems. We compared trace element transfer to the biota in two locations with different open-sea exposures in a semi-enclosed marine coastal area (Stagnone di Marsala, Sicily, Italy) using isotopically reconstructed food chains. Samples of sediment, macroalgae, seagrasses, invertebrates, fish, and bird feathers were sampled in July 2006 and analysed for stable carbon and nitrogen isotopes (δ13C, δ15N) and trace elements (arsenic [As], cadmium [Cd], total mercury [THg], and lead [Pb]). Trophic magnification factors were calculated through the relationships between trace elements and δ15N in consumers. As and Pb were greater in organic matter sources (sediments and primary producers), whereas Cd and THg were greater in bird feathers. At the food chain level, an insignificant trophic transfer was found for all elements, suggesting biodilution rather than biomagnification. Sediments were more contaminated in the location with lower open-sea exposure. Macroalgae and seagrasses overall mirrored the spatial pattern highlighted in sediments, whereas differences between the two locations became further decreased moving toward higher trophic levels, indicating that trophic transfer of sediment and macrophyte-bound trace elements to the coastal lagoon food chain may be of relatively minor importance

Enhancement of Hydrolysis through the Formation of Mixed Heterometal Species: Al3+/CH3Sn3+ Mixtures

ABSTRACT: The hydrolysis of mixed-metal cations (Al3+/CH3Sn3+) was studied in aqueous solutions of NaNO3, at I = 1.00 ± 0.05 mol·dm−3 and T = 298.15 K, by potentiometric technique. Several hydrolytic mixed species are formed in this mixed system, namely, Alp(CH3Sn)q(OH)r with (p, q, r) = (1, 1, 4), (1, 1, 5), (1, 1, 6), (2, 1, 4), (1, 2, 5), (1, 4, 11), (1, 3, 8), and (7, 6, 32). The stability of these species, expressed by the equilibrium: pAl3+ + qCH3Sn3+ + rOH− = Alp(CH3Sn)q(OH)r 3(p+q)−r, βpqr OH, can be modeled by the empirical relationship: log βpqr OH = −3.34 + 2.67p + 9.23(q + r). By using the equilibrium constant Xpqr relative to the formation reaction: pAl(p+q)(OH)r + q(CH3Sn)(p+q)(OH)r = (p + q)Alp(CH3Sn)q(OH)r, it was found that the formation of heterometal mixed species is thermodynamically favored, and the extra stability can be expressed as a function of the difference in the stability of parent homometal species. This leads, in turn, to a significant enhancement of hydrolysis and solubility

sequestration of organometallic compounds by synthetic and naturally occurring polycarboxylate ligands binding of monomethylmercury ii by polyacrylic and alginic acids

AbstractThe sequestering capacity of synthetic and naturally occurring polycarboxylate ligands towards mono-methylmercury(II) was evaluated by stability quantitative data on the interaction of CH3Hg+ with different molecular weight synthetic polyacrylates (2 and 20kDa average M.wt) and alginate (70–100 kDa) extracted from brown algae Macrocystis pyrifera. The influence of ionic medium was evaluated by measurements on the CH3Hg+-polyacrylate systems in NaNO3 medium at different ionic strengths (0.10, 0.25, 0.50 and 0.75 mol L−1), and a Debye-HiJckel type equation was used for the dependence of complex formation constants on ionic strength. Measurements on the CH3Hg+ - alginate system were carried out at l = 0.10 mol L−1 in NaNO3 medium. By using the stability data, the sequestering capacity of both ligands towards monomethylmercury(II) was determined at different pH values. Results obtained show that the binding ability of polyacrylic ligands (PAA) is stronger than the alginate (AA), following the trend PA..

speciation of poly amino carboxylic compounds in seawater

AbstractIn this work quantitative data on the interaction of EDTA and EGTA with the major inorganic components of seawater are reported. Protonation constants and alkali and alkaline earth metal complex formation constants are reported at different ionic strengths (0< l/mol L−1≤1). These formation data were obtained from potentiometric measurements in several single and mixed electrolyte media (such as artificial seawater). Potentiometric measurements in artificial seawater (containing Na+, K+, Mg2+, Ca2+, Cl−and SO42−) were analysed by using the single salt approximation (the artificial seawater being considered as a single salt BA whose ions have fractional charge -zanion = zcation = 1.117). Several species BpHrL (L = EDTA or EGTA) are formed and their formation constants are reported at different salinities. Present results, together with similar data on the complexing capability of NTA, DTPA and TTHA towards inorganic components of natural fluids, allowed to find general conclusions on the important c..

speciation of chitosan with low and high molecular weight carboxylates in aqueous solution

Quantitative data on the speciation of chitosan (310kDa) with low and high molecular weight carboxylates in aqueous solution are reported. The following carboxylic ligands were considered: monocarboxylate (butyrate); dicarboxylates (malonate, succinate, azelate); tricarboxylate (1,2,3-propanetricarboxylate); tetracarboxylate (1,2,3,4-butanetetracarboxylate); polyacrylates (2.0 and 20kDa); polymethacrylate (5.4kDa). The investigation was performed by potentiometry at t ¼ 25 � C, at low ionic strength (without addition of supporting electrolyte) and at I ¼ 0:15mol L � 1 (NaCl). For all the systems the formation of (chitosan)LHi species was found (L ¼carboxylic ligand; i ¼1 to 4 depending on the carboxylic ligand considered). The stability of proton–chitosan–carboxylate species depends on the number of carboxylic groups involved in the complexation, and it was possible to calculate a rough free energy value per bond DGn ¼� 15 � 2kJ mol � 1 . By using the stability data, the quantitative sequestering capacity of chitosan towards the carboxylates here considered [expressed as the–log(total chitosan concentration) necessary to bind 50% of carboxylate, i.e., pL50] was calculated for different pH values, at low ionic strength and at I ¼ 0:15mol L � 1 . The pL50 values, ranging from 3 to 7, show that chitosan is quite a strong sequestering agent towards carboxylates. Evidences were also obtained for the different behaviour between low and high molecular weight carboxylates