Chemical Vapour Generation for Tin Determination in High-content Calcium Matrix by Inductively Coupled Plasma Atomic Emission Spectrometry

Chemical vapour generation by reduction with sodium tetraborohydride and coupled to induc¬¬tively coupled plasma spectrometry (HG-ICP-AES) was examined for tin analysis in high-content calcium matrix samples. Comparison of calibration curves in aqueous and matrix-matched solution showed good linearity (R2 = 0.9951 – 0.9999) in the observed range of concentration. The effects of added calcium were established as attenuation of emission intensity for 3 % at 224.605 nm and 235.484 nm and only 1 % at 283.999 nm and 189.991 nm of tin lines. The best limit of detection, i.e. 1.9 mg L–1 in aqueous and 2.1 mg L–1 in matrix-matched solution were obtained at 189.991 nm. Method of standard addition was applied for the analysis of laboratory samples of high purity calcite and aragonite shell structures and it gave 0.11 µg g–1 and 0.17 µg g–1 of tin, respectively. The accuracy of method was tested by certified reference material (NRCC, MESS-3) and good recoveries (100.08 %) were obtained in both calibration modes. Tin content was determined by HG-ICP-AES method using matrix-matched calibration in shell samples of Mytilus galloprovinciallis. The obtained values of tin content showed relatively flat distribution in shells along the coast (0.511 – 0.718 µg g–1). Higher concentrations were measured on several hotspots, especially fishing ports and harbours. (doi: 10.5562/cca2259

Biomineralization in the Sea Hare Aplysia punctata Initiated by Nano-Dolomite

X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), environmental scanning electron microscopy (ESEM) and energy dispersive X-ray analysis (EDS) were used in study of starting biomineralization processes in embryos of the sea hare species Aplysia punctata. 10 days old embryos appeared amorphous according to XRD patterns. TEM of the same sample showed that first grains of nanocrystalline dolomite began to form in the amorphous area. The identification of dolomite was confirmed according to TEM dark field images and SAED, as well as by HRTEM. In further development stages of the embryos very faint aragonite rings became visible by SAED. It was shown that the biomineralization process in A. punctata started by formation of the dolomite nanograins which served as centres of crystallization for further aragonite deposition in the larval shell. The creation of unusual intermediate crystalline phase of nano-dolomite in A. punctata embryos is of equal interest for biologist and ecologist as an evolutionary ancestral trait of molluskan biomineralization, as well as for materials scientists, as a promising template in potential bioengineering application and design of appropriate biomimetic routes that could lead to the development of new implantable biomaterials. The discussion of the present results is based on recent knowledge on general biomineralization in mollusks

Procjena dotoka slatke vode uzduž istočne obale Jadrana kao mogućeg izvora stresa za morske organizme

Seawater salinity changes and thermal stress have been considered to be among the most important determinants of rocky intertidal zone organism distribution. The aim of present study was to determine the freshwater influx and evaluate the mussel Mytilus galloprovincialis shells as indicators of natural environmental conditions by comparing δ13C of shell carbonate layers with seawater salinity and tem- perature values measured over the 1998-2007 period. Our results show that the salinity was relatively constant in the open sea, with typical values of the northern and southern Adriatic being 37.65 ± 0.40 and 38.37 ± 0.19 respectively. It varied in intertidal zones, estuaries, locations close to under-sea freshwa- ter springs and during rainy days in closed lagoons on different locations along eastern Adriatic coast. Sa- linity and temperature variations at investigated sites showed freshwater influx which was also reflected in lower δ13C values of mussel M. galloprovincialis shell carbonates. Based on the measured parameters, three groups of locations in the investigated area (25 locations) can be defined: locations with strong to medium freshwater influence (9), with minor freshwater influence (6) and marine environment locations (10). Our results confirm that mussel M. galloprovincialis responds sensitively to subtle changes in the environmental conditions. Results of the isotopic analyses presented in this study support the hypothesis that the δ13C in mussel’s shell might be used as an indicator of environmental salinity conditions and hypo-osmotic stress. Therefore such investigations might represent an additional tool for waste water management and environmental protection.Promjena saliniteta i temperature morske vode u stjenovitom obalnom području ograničava i utječe na raspodjela morskih organizama. U području otvorenog mora salinitet je relativno stalan, a u istraživanom razdoblju (1998.-2007.) se kretao od 37,65 ± 0,40 za sjeverni i do 38,37 ± 0,19 za južni Jadran. Salinitet značajno koleba u zoni plime i oseke, na području ušća rijeka i podmorskim izvorima slatke vode te tijekom kišnih dana u zatvorenim lagunama. Zbog dotoka slatke vode temperatura mora na istraživanim postajama pokazuje unutar sezonske razlike, uz jaka sezonska kolebanja. Kolebanje vrijednosti saliniteta i temperature morske vode na području od Limskog kanala do Dubrovnika (sjeverni - južni Jadran) pod utjecajem dotoka slatke vode izravno su se odrazili i na vrijednosti δ13C u ljušturama dagnje Mytilus galloprovincialis. Vrijednosti δ13C iz 1998. godine su rangirane i korelirane s prosječnim vrijednostima temperature i saliniteta morske vode tijekom devetogodišnjeg istraživanog razdoblja (1998.-2007.). Na temelju sadržaja d13C u ljušturama, temperature i saliniteta morske vode istraživano područje (25 postaja) je grupirano u tri skupine: srednje do jak utjecaj slatke vode (9), manji utjecaj slatke vode (6) i lokacije morskog okoliša (10). Utvrđeno je da su ljušture školjkaša, odnosno vrijednosti δ13C, dobri pokazatelji kolebanja prirodnih čimbenika, naročito saliniteta, posredstvom dotoka slatkih voda. Dagnja M. galloprovincialis se može koristiti kao indikator kolebanja ekoloških čimbenika i možebitnih onečišćenja. Stoga navedena istraživanja predstavljaju dodatni koristan alat u biomonitoring programima, primjerice ispitivanju kvalitete okoliša, upravljanju otpadnim vodama i zaštiti okoliša

Isotopic characteristics of shells Mytilus galloprovincialis from eastern coastal area of Adriatic Sea

Samples of Mytilus galloprovincialis were collected from entire Eastern Adriatic coast to determine δ18O and δ13C performed on calcite and aragonite shell layers. The aim of this work was to check whether shells of M. galloprovincialis are good environmental indicators (water temperature, salinity). Based on measured isotopic composition of oxygen in shell layers and assumed isotopic composition in water temperatures of calcite and aragonite of shell layers were calculated. The calculated temperatures for M. galloprovincialis shell growth of calcite and aragonite shell layer are in good agreement with measured temperatures of sea water. According to our results of δ18O and δ13C in shell layers we canseparate the locations of the investigated area into three groups: those with more influence of fresh water, those with less influence of fresh water and those of marine environments

Biomineralix (COST action TD0903), 2009-2014: an overview.

20 pagesInternational audienc