Assessment of pollution level using Mytilus galloprovincialis as a bioindicator species: The case of the Gulf of Trieste.

A multidisciplinary approach was used to estimate the pollution level of the marine environment in the North Eastern Adriatic by measurement of the isotopic composition of carbon and nitrogen (δ(13)C, δ(15)N), metal/metalloids analyses (Fe, Cu, Zn, As, Se, Cd and Pb, including As speciation) in the Mytilus galloprovincialis, as well by using metallothioneins (MT) concentrations, micronuclei (MN) in gill cells and biological parameters (condition index and gonadosomatic index). Concentrations of MT were in the range from 44 to 175 µg g(-1) wet matter tissue and were higher at the end of the winter season. The frequency of MN did not indicate an elevated level. Sewage sludge pollution was not confirmed. Elevated As concentrations in mussel are related to salinity and low nutrients concentrations and not to pollution. Elevated concentrations of Cu, Zn and Pb were found in the Bay of Koper in comparison with the Bays of Strunjan and Piran.

Influence of releases of I-129 from reprocessing plants on the marine environment of the North Adriatic Sea.

Compared to the pre-nuclear era, large amounts of (129)I have been released to the marine environment, especially as liquid and gaseous discharges from two European reprocessing plants located at Sellafield and La Hague. Their liquid discharges influence Northern Europe and most research was conducted in the area of the North Atlantic Ocean and the Baltic Sea. In this article data on (129)I content and (129)I/(127)I ratios observed in the North Adriatic Sea, which is a rather enclosed basin of the Mediterranean Sea, are presented. To the best of our knowledge no data on (129)I in the Mediterranean Sea have previously been reported. As this area is isolated from direct liquid discharges, the main transport pathway is probably gaseous releases from reprocessing plants. Surface sea water, the marine alga Fucus virsoides, an iodine accumulator, and the Mediterranean mussel Mytilus galloprovincialis collected in 2009 and 2010, and marine sediment collected in 2005 and 2009 were analysed. The (129)I/(127)I isotopic ratios observed were in the range from 0.8 to 3.0×10(-08) for seawater, from 0.06 to 0.35×10(-08) for marine sediment, from 0.05 to 0.10×10(-08) for F. virsoides and from 0.3 to 0.9×10(-08) for M. galloprovincialis.

Saccharomyces cerevisiae: the effect of different forms and concentrations of iodine on uptake and yeast growth.

The essentiality of iodine for humans, especially in the early stages of life, is well recognized. The chemical forms of iodine in food supplements, infant formulae and iodated salt are either iodide (KI) or iodate (KIO(3)). Because there are no or rare data about iodine uptake by yeasts, we investigated the influence of different sources of iodine, as KI, KIO(3) and periodate (KIO(4)), on its uptake in and growth of the model yeast Saccharomyces cerevisiae. KIO(3) inhibited the growth of the yeast the most and already at a 400 microM initial concentration in the growth medium; the OD was reduced by 23% in comparison with the control, where no KIO(3) was added. The uptake of different iodine sources by the yeast S. cerevisiae was minimal, in total <1%. Tracer experiments with radioactive (131)I added as KI showed that the yeast S. cerevisiae does not have the ability to transform KI into volatile species. We investigated the specificity of iodine uptake added as KIO(3) in the presence of Na(2)SeO(4) or ZnCl(2) or K(2)CrO(4) in the growth medium, and it was found that chromate had the most influence on reduction of KIO(3) uptake.

127I and 129I/127I isotopic ratio in marine alga Fucus virsoides from the North Adriatic Sea.

The only stable iodine isotope is 127I and the natural 129I/127I ratio in the biosphere has increased from 10(-15)-10(-14) to 10(-10)-10(-9), mainly due to emissions from nuclear fuel reprocessing plants. In Europe they are located at La Hague (France) and Sellafield (England), where the ratio of 129I/127I is up to 10(-4). The marine environment, i.e. the oceans, is the major source of iodine with average concentrations of around 60 mirogL(-1) iodine in seawater. Brown algae accumulate iodine at high levels of up to 1.0% of dry weight, and therefore they are an ideal bioindicator for studying the levels of 127I and 129I in the marine environment. A radiochemical neutron activation analysis (RNAA) method, developed at our laboratory, was used for 129I determination in the brown alga Fucus virsoides (Donati) J. Agardh, and the same technique of RNAA was used for total 127I determination. The samples were collected along the coast of the Gulf of Trieste and the West coast of Istria in the North Adriatic Sea in the period from 2005 to 2006. Values of the 129I/127I ratio up to 10(-9) were found, which is in agreement with the present average global distribution of 129I. The levels of stable iodine found were in the range from 235 to 506 microg g(-1) and the levels of 129I from 1.7 to 7.3 x 10(-3)Bq kg(-1) (2.6-10.9 x 10(-7) microg g(-1)), on a dry matter basis.