Copper and manganese in loggerhead turtles (Caretta caretta) tissues in the Mediterranean

The natural radionuclides 238U ,234Th, 40K and the main man-made 137Cs, have been studied inMytilus galloprovincialis (Lamarck, 1819) sampled in the Thermaikos gulf – North Aegean Sea, considered as a bioindicator for radiological assessment in the Mediterranean. The ratio 234U/238U has also been determined. In terms of 137Cs, the activity concentrations in seawater from the studied area have been measured as well, and the concentration factors of 137Cs in Mytilus galloprovincialis are given as a parameter of the organism response to radioactive pollution

Lead accumulation and metallothionein induction in different tissues of mussels (M. galloprovincialis) and clams (C. chione) exposed to various Pb concentrations

Heavy metal pollution of coastal areas due to anthropogenic activity has become a global problem with serious environmental consequences. Various marine organisms have been employed as bioindicators for pollution, and expanding the scientific arsenal with such organisms is a continuing research objective. In this study, the effects of Pb pollution in seawater on two bivalves of different habitats were investigated. Mytilus galloprovincialis (a nearshore and intertidal rocky substrate inhabitant mussel) and Callista chione, (a sand-buried smooth clam), were exposed to a wide range of Pb concentrations in seawater for 20 days, followed by a 10-day depuration period, in a laboratory experiment. Gills, mantles and the remaining bodies of the two species were separated and the accumulated Pb was determined. The synthesis of Pb-induced proteins (metallothioneins and/or other proteins) was also investigated in the tissues of the two species by Ellman assays, Coomasie-stained and fluorimetric SDS-PAGE experiments. Our results show that both species exhibit a relatively high tolerance to even very high Pb pollution levels and they accumulate considerable amounts of Pb in their tissues. Zinc levels in the examined tissues are affected in most of the tested conditions. The 10 days depuration period of our experiments was not enough for the complete removal of Pb from the organisms. Biochemical analysis showed that low molecular weight, sulfhydryl-containing proteins (metallothioneins), as well as proteins with molecular weight of about 50 kDa are synthesized in a species-dependent and tissue dependent way, due to Pb accumulation

The removal of trace metals at the wastewater treatment plant of Psyttalia

The present study investigates the levels of trace metals in the input and output of the Psyttalia wastewater treatment plant, as well as the removal of the various trace metal forms (dissolved, particulate) during primary sedimentation. The trace metals determined were: Pb, Cd, Cu, Zn, Cr, and Ni. The experimental procedure included the collection and analysis of inflow and outflow samples. Dissolved and particulate forms were separated by filtration through 0.45 and 8 Μm Millipore filters and trace metals were determined using atomic absorption spectrometry. The results indicate that particulate matter consists mainly of large particles (> 8 µ m ) and the sedimentation process is more effective in their removal in contrast to smaller particles. The removal of trace metals during primary sedimentation follows the decreasing sequence: Particulate metal in large particles > Particulate metal in small particles > Dissolved metal. Concerning the various metals the removal follows the sequence: Pb ~= Cu>Zn ~= Cr>Cd>Ni. The quantities of trace metals that are discharged to the sea through the outflow pipes of the Psyttalia treatment plant follow the decreasing sequence: Zn >> Cr > Cu > Ni > Pb > Cd

Chromium and Nickel distribution in sediments of a coastal area impacted from metallurgical activities: the case of the Larymna Bay

In the present study, the distribution of Cr and Ni was investigated in the surface sediments from the Larymna Bay (Northern Evoikos Gulf) and in metallurgical slag samples discharged in the marine environment. The results were compared to concentrations of Cr and Ni in parent rocks that outcrop extensively in the catchment area of N. Evoikos in order to distinguish natural and anthropogenic sources of these two elements. Elevated concentrations of Cr and Ni as well as high values of magnetic susceptibility were determined in all samples. Low leachability was determined for Cr since chromite is the major crystalline phase of Cr in the samples analyzed whereas higher leachability was observed for Ni

Sea bottom sediments of Elefsis Gulf: A potential secondary source of metals under simulated ocean acidification conditions

Hypoxic coastal areas are considered as high-priority systems for Ocean Acidification (OA) research, because the co-occurrence and interaction of low oxygen with other environmental stressors, such as elevated pCO2, warming and eutrophication, may put them at greater risk. In this work, an anoxic coastal phenomenon exhibiting relatively reduced pH at the near bottom water layer was studied. In-situ and microcosm experiment measurements, simulating OA conditions, were conducted in order to assess the fate of dissolved trace metals that could either sink towards the sediment or be released towards the water column. OA conditions seem to induce the release of Al, Ni, Cd, Fe, Mn and As from the sediment while, in combination with anoxia, a restriction in this dissolution mechanism was found. Cr, Zn and Pb seem to follow a sink type mechanism under more acidified conditions while, in addition to anoxia, a source type mechanism is revealed. Hg seems to follow a source type mechanism under OA in any case. Regarding Fe species, it becomes evident that Fe (II) is the dominant species, indicating an increased stability as a result of acidified conditions

Dissolved organic matter cycling in eastern Mediterranean rivers experiencing multiple pressures. The case of the trans-boundary Evros River

The objective of our study was to provide a comprehensive evaluation on C, N, P cycling in medium sized Mediterranean rivers, such as the Evros, experiencing multiple pressures (intensive agriculture, industrial activities, population density). Our work aims also to contribute to the development of integrated management policies. Dissolved organic matter (DOM) cycling were investigated, during a one-year study. It was shown that the organic component of N and P was comparable to those of large Mediterranean rivers (Rhone, Po). In the lower parts of the river where all point and non-point inputs converge, the high inorganic N input favour elevated assimilation rates by phytoplankton and result in increased chl-a concentrations and autochthonous dissolved organic matter (DOM) production during the dry season with limited water flow. Moreover, carbohydrate distribution revealed that there is a constant background of soil derived mono-saccharides on top of which are superimposed impulses of poly-saccharides during blooms. During the dry season, inorganic nutrients and DOM are trapped in the lower parts of the river, whereas during high flow conditions DOM is flushed towards the sea and organic nitrogen forms can become an important TDN constituent (at least 40%) transported to shelf waters. The co-existence of terrigenous material with autochthonous and some anthropogenic is supported by the relatively low DOC:DON and DOC:DOP ratios, the positive correlation of DOC vs chl-a and the decoupling between DOC and DON. Overall, this study showed that in medium size Mediterranean rivers, such as the Evros, intensive agriculture and pollution sources in combination with water management practices and climatic variability are important factors determining C, N, P dynamics and export to coastal seas. Also, it highlights the importance of the organic fraction of N and P when considering management practices

Trace metals in a tidal Mediterranean embayment

The Euvoikos gulf, and the strait of Euripos therein, is a restricted embayment on the eastern coast of Greece having a significant, unusual tidal phenomenon and receiving some domestic, trade and industrial wastes from the town of Chalkis and several coastal industries. The purpose of the present work was to study the influence of the tidal current and the anthropogenic inputs on the distributions of several trace elements (namely, Pb, Cu, Zn, Cr, Fe, Mn and Ni) in the seawaters (as dissolved and particulate species) and the sea-bottom sediments. Thorough mixing, resuspension and transport of fine particles and direct discharges are the major mechanisms affecting the distribution patterns. © 1983

The chemical behaviour of trace metals in a small, enclosed and shallow bay on the coast of Attika, Greece

A lot of small and shallow bays that exist along the extended Greek coastline differ significantly from the open sea in the fluctuation of hydrological parameters, the degree of eutrophication and the concentration of pollutants. These characteristics can sometimes create environmental conditions that favour the development of specific ecosystems like the algae mats. The chemical behaviour of dissolved and particulate forms of the most interesting, from the environmental point of view, trace metals along with the variations of salinity and temperature as well as the eutrophication degree in a bay near Athens, Greece was studied in this paper for the period of 1 year (July 2000-June 2001). The results of this study showed that the waters inside the bay are of a higher eutrophication level than the neighbouring open Saronikos gulf. In most cases, the cove's water is enriched in both dissolved and particulate metals in comparison to the neighbouring coastal area and the various parts of Saronikos gulf. The low rate of water renewal, the increased particulate matter, the algal mat and certain human activities (mainly during the warm period of the year) are the main reasons. A good correlation between the fluctuations of the concentrations of some metals inside and outside the cove also occurs. It indicates the contact between the area's water masses and the need for environmental planning covering a wide area around the system. © 2007 Elsevier B.V. All rights reserved

Water quality in a Mediterranean marine protected area (North Sporades Islands, Greece)

Pollution in the marine protected area of North Sporades Islands was investigated in July 1997. Salinity, temperature, dissolved oxygen, dissolved inorganic nutrients, organic carbon, hydrocarbons as well as dissolved and particulate trace metals were determined at 15 offshore and coastal stations. Dissolved organic carbon and inorganic nutrient concentrations indicate the mesotrophic character of the investigated waters. The dissolved forms of nitrogen were slightly higher at coastal stations. Dissolved and particulate Cu, Zn and Ni, were higher in coastal stations, whereas concentrations of Pb were generally low and likely of atmospheric origin. Dissolved/Dispersed petroleum hydrocarbons (DDPH) were close to detection limits at all stations. Temperature and salinity vertical profiles, nutrient and trace metal concentrations revealed the presence of a slight influence of the Black Sea water coming from Dardanelles straits

TRACE-METALS IN SEDIMENTS OF A MEDITERRANEAN ESTUARY AFFECTED BY HUMAN ACTIVITIES (ACHELOOS RIVER ESTUARY, GREECE)

Trace metals were studied in the sediments of the ecologically, economically and scientifically important estuary of the Acheloos river, in western Greece. Human activities (dams, agriculture, traffic, etc.) influence the estuarine system of Acheloos and in combination with the hydrological, mineralogical and morphological characteristics of the estuary affect the chemical behaviour and the distribution patterns of trace metals in its sediments. The large scale disturbance of the system is imminent in the near future as it is planned to divert similar to 50% of the river water. A study of the distribution patterns of trace metals revealed that in the estuary there are zones with different metal levels. The concentrations of most metals (Al, Fe, Cu, Ni, Zn) are elevated in three of these zones (upstream, sill, seawards). A different behaviour was observed for Mn due to its association with carbonates that were observed in significant concentrations throughout the estuarine zone. A sequential extraction procedure, applied to the sediments, indicated low percentages of easily exchangeable metals, increased mobility of Cu and Zn and increased association of Ni, Cr and Fe with the aluminosilicate lattice. Although the river is not considered to be heavily polluted, some metals have shown an enrichment in the surface sediments as a result of general anthropogenic activities not derived from point sources