Relationships between radionuclides, metals, and sediment properties in sediment of a bay exposed to anthropogenic pressure and mixed sediment sources (Kastela Bay, Adriatic Sea, Croatia).

Natural and anthropogenic radionuclides, metals, organic matter, sediment grain size, mineral composition, and sediment sources were studied in marine sediment of Kastela Bay up to a depth of 0.5 m. Deposition of man-modified material into the sea was evidenced in sediment mineral composition. Presence of pyrite and hematite in this sediment may pose an environmental concern. Metals, radionuclides, and organic matter were grouped in three groups: (i) variables under no anthropogenic influence and preferentially associated with carbonates (Ca, Sr); (ii) variables under no or weak anthropogenic influence and preferentially associated with aluminosilicates (Al, K, Ti, V, Cr, Mn, Fe, Co, Ni, Ga, Rb, Y, 40K, 232Th); (iii) variables under notable anthropogenic influence and/or natural processes of separation (Cu, Zn, Pb, As, 226Ra, 238U, 137Cs, organic matter). Predominant influencing parameters change with sediment depth for some variables. Anthropogenic influence was the most emphasised for Cu, Zn, and Pb, followed by 137Cs.

Radiological risks from 40 K, 226Ra and 232Th in urbanised and industrialised karstic coastal area (Kastela Bay, Croatia).

Radiological risks associated with 40 K, 226Ra and 232Th massic activities in limestones, marls, stream sediments and soils of the Kastela Bay (Croatia) coastal area were assessed by calculating outdoor absorbed dose rates in air (D), annual outdoor effective dose rates (Def), radium equivalent activities (Raeq) and external hazard indices (Hex). Radionuclides relative contributions to D and Hex were determined for all four types of samples as well as their total contribution to Hex in all samples. D, Def, Raeq and Hex were the lowest in limestones and the highest in soils. Maximum Raeq and Hex in soil were below the recommended values of 370 Bq/kg and 1.0. No adverse radiological effects were determined in the researched area. The most important contribution to D and Hex in limestones was almost exclusively from 226Ra, in marls from 40 K, in stream sediments from 226Ra and in soils from 232Th. The most significant total contribution to Hex in all samples came from 226Ra and 232Th, and the lowest came from 40 K. 226Ra showed the largest variability of its total contribution to Hex, with tendency to higher values. Special attention should be given to 226Ra when studying radiological risks in typical karstic areas, irrespectively of other possible influences of geological background.

40K, 226Ra, 232Th, 238U and 137Cs relationships and behaviour in sedimentary rocks and sediments of a karstic coastal area (Kastela Bay, Croatia) and related rocks and sediments' differentiation.

Natural (40K, 226Ra, 232Th, 238U) and anthropogenic (137Cs) radionuclides in consolidated sedimentary rocks (limestones s.l. and marls) and unconsolidated sediments (stream sediments and soils) of the Kastela Bay (Adriatic Sea, Croatia) coastal area were studied. Kastela Bay is a typical karstic environment and it is under strong anthropogenic influence due to industrialisation and urbanisation. Relationships between radionuclides, their behaviour in different types of samples and possible influencing factors were studied. Radionuclides were also studied in relation to selected metals (Al, K, Ca, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Pb and As) and distribution in limestones s.l., marls, stream sediments and soils. Radionuclides' massic activities were determined by gamma-spectrometry and metal mass fractions were measured by EDXRF technique. Relationships were studied using statistical tools (principal component analysis, factor analysis). It was found that stream sediments were more similar to source rocks (limestones s.l. and marl) than to soils in terms of natural radionuclides' activities. 40K and 232Th in consolidated rocks were preferentially bound to alumosilicates and associated with the majority of studied metals. However, this was not the case with 226Ra and 238U, which did not show any preferences regarding binding to mineral components or associating with metals. On the other hand, all four natural radionuclides presented the same behaviour in unconsolidated sediments, i.e. they were all preferentially bound to alumosilicates and associated with the majority of metals. 137Cs did not associate with any of the metals or other radionuclides in sediments. The statistical approach applied in this study revealed differences in radionuclides' relationships and behaviour in a karstic environment and implied possible influencing processes or factors. This approach can be applied in other types of environments as well to study preferential radionuclides' binding to certain mineral components that influences radionuclides' mobility and transport to other environmental compartments.

Barbary sheep tissues as bioindicators of radionuclide and stabile element contamination in Croatia: exposure assessment for consumers.

Muscle, liver and kidney of 21 Barbary sheep (Ammotragus lervia) from Mosor Mountain, Croatia, were sampled to quantify the activity of caesium and potassium radionuclides and five toxic and ten essential stabile elements in order to establish reference values for this species and to evaluate the potential of Barbary sheep tissues to reflect environmental pollution. We also assessed seasonal diet (botanical composition and dry matter content) of Barbary sheep based on analyses of a rumen content of culled animals. None of the 19 plant species (mostly grasses) identified as part of the Barbary sheep diet is known as a stabile element or radionuclide hyperaccumulator. Measured levels reflected low environmental pollution with arsenic, cadmium, mercury and lead, with levels generally less than those reported for wild herbivorous ungulates. Methodological differences (detection limit of elements in muscle) were shown to hamper interpretation and comparison of the Toxic Contamination Index (TCI) values with those published for other species. There was no homeostasis disturbance of trace elements in Barbary sheep, either due to inadequate intake via food or as an adverse effect due to a high toxic metal(loid) burden. Consumption of the muscle and liver of wild Barbary sheep can be considered safe for the health of adult consumers regarding toxic metal(loid)s and radioactive caesium, though the liver should be avoided as a food item in vulnerable population groups due to the possible adverse effects of cadmium and lead. Otherwise, muscle and liver are a rich source of copper, iron, selenium and zinc for consumers and, as such, can benefit the overall dietary intake of essential elements.

137Cs in mushrooms from Croatia sampled 15-30 years after Chernobyl.

The aim of this study was to select species with higher potential to accumulate 137Cs among the available mushroom species, by determining the activity concentrations of 137Cs in mushrooms collected along north and north-western part of Croatia. A total of 55 samples of 14 different species were analyzed and the potential of mycorrhizal and saprotrophic species to accumulate 137Cs was compared. A wide range of the dry weight activity concentrations of 137Cs was detected, ranging from 0.95 to 1210 Bq/kg (154 Bq/kg mean value; 52.3 Bq/kg geometric mean) in mycorrhizal and 1.05-36.8 Bq/kg (8.90 Bq/kg mean value; 5.49 Bq/kg geometric mean) in saprotrophic species. Statistical analyses showed that mycorrhizal species accumulate significantly higher concentrations of 137Cs and thus could perform better as long-term bioindicators of environmental pollution by radiocaesium then saprotrophic species. The comparison of Boletus sp. and Hydnum repandum (both mycorrhizal species commonly found in Croatia) showed, in general order of magnitude, higher accumulation in Hydnum repandum. Clearly, mushrooms, especially mycorrhizal species, can be used as significant indicators even decades after the occurrence of any serious 137Cs contamination event. However, as a wide range of values indicates that various parameters may influence the total uptake of the 137Cs into the mushroom fruit bodies, it is necessary to emphasize that 137Cs activity detected in a single mushroom sample is very site-specific.

Dietary items as possible sources of (137)Cs in large carnivores in the Gorski Kotar forest ecosystem, Western Croatia.

The mountain forest ecosystem of Gorski Kotar is distant from any significant sources of environmental pollution, though recent findings have revealed that this region is among the most intense (137)Cs contaminated area in Croatia. Therefore, the aim of this study was to investigate (137)Cs and (40)K load in three large predator species in the mountain forest ecosystem. Radionuclides mass activities were determined by the gamma-spectrometric method in the muscle tissue of brown bear (47), wolf (7), lynx (1) and golden jackal (2). The highest (137)Cs mass activity was found in lynx (153 Bq kg(-1)), followed by brown bear (132 Bq kg(-1)), wolf (22.2 Bq kg(-1)), and golden jackal (2.48 Bq kg(-1)). Analysis of 63 samples of dietary items suggests that they are not all potentially dominant sources of (137)Cs for wildlife. The most important source of radionuclides for the higher parts of the food-chain from the study area were found to be the mushroom species wood hedgehog (Hydnum repandum), with a transfer factor TF of 5.166, and blueberry (Vaccinium myrtillus) as a plant species (TF=2.096). Food items of animal origin indicated higher mass activity of radionuclides and therefore are possible moderate bioindicators of environmental pollution. The results also revealed that possible unknown wild animal food sources are a caesium source in the study region, and further study is required to illuminate this issue.

Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement.

Radiological characterization of tap waters in Croatia and the age dependent dose assessment.

Activity concentrations of (234)U, (238)U, (226)Ra, (228)Ra, (210)Po and (210)Pb in tap waters, originating from various geological regions of Croatia, were determined. Activity concentrations of measured radionuclides are in general decreasing in this order: (238)U≈(234)U>(228)Ra≈(210)Pb>(226)Ra≈(210)Po. Based on the radionuclide activity concentrations average total annual internal doses for infants, children and adults, as well as contribution of each particular radionuclide to total dose, were assessed and discussed. The highest doses were calculated for infants, which makes them the most critical group of population. All values for each population group were well below the recommended reference dose level (RDL) of 0.1mSv from one year's consumption of drinking water according to European Commission recommendations from 1998. Contribution of each particular radionuclide to total doses varied among different age groups but for each group the lowest contribution was found for (226)Ra and the highest for (228)Ra.

Seasonal and spatial variations of 210Po and 210Pb activity concentrations in Mytilus galloprovincialis from Croatian coast of the Adriatic Sea.

Results of 2 years monitoring of (210)Po and (210)Pb activity concentrations in soft tissue of the species Mytilus galloprovincialis from Croatian part of the Adriatic coast are presented. The samples were collected at thirteen coastal stations (some of which are also a part of the Mediterranean Mussel Watch Project) in spring and autumn of 2010 and 2011. The collected mussels were ranging between 4 cm and 6 cm in shell length. After sample pre-treatment lead and polonium were radiochemically separated on Sr resin. (210)Po was determined by alpha-particle spectrometry and (210)Pb was determined, via (210)Bi, by a low-level gas proportional counter. The results of (210)Po activity concentrations were found to vary between (104±11) and (1421±81) Bq kg(-1) dry weight while (210)Pb activity concentrations were much lower and in range (8.2±5.3)-(94.1±29.8) Bq kg(-1) dry weight. Higher (210)Po and (210)Pb activity concentrations were determined in spring period. The inter-site differences seen in their activity concentrations can be due to natural background levels of sites. The (210)Po/(210)Pb activity concentration ratios in all cases exceeded unity for all mussel samples and ranged between 4.0 and 47.9.

(210)Po and (210)Pb activity concentrations in Mytilus galloprovincialis from Croatian Adriatic coast with the related dose assessment to the coastal population.

Activity concentrations of (210)Po and (210)Pb in the species Mytilus galloprovincialis from Croatian Adriatic coast were determined. The samples were collected in thirteen sampling places which are also a part of Croatian Mediterranean mussel watch project. The results of (210)Po and (210)Pb activity concentrations were found to vary between (22.1±2.5)-(207±21) Bq kg(-1) fresh weight and (2.8±1.4)-(9.3±0.7) Bq kg(-1) fresh weight, respectively. (210)Po/(210)Pb ratio ranged between 6.2 and 30.7. The highest measured activities were found in the enclosed basins of the Neretva channel, where the majority of Croatian mussel cultivation is taking place. The estimated consequent average total annual effective ingestion dose due to (210)Po and (210)Pb from mussel consumption in Croatian coastal region is 202±99 µSv with 96% contribution of (210)Po to the total effective dose.

A recent history of metal accumulation in the sediments of Rijeka harbor, Adriatic Sea, Croatia.

We studied metal pollution in the sediments of Rijeka harbor, including anthropogenic influence during recent decades and at the present time. Sediment profiles were collected at ten sampling points. The concentrations of 63 elements in bulk sediment were obtained using ICP-MS, and the concentrations of selected elements were evaluated by statistical factor analyses. We also calculated metal-enrichment factors and geoaccumulation indices and constructed spatial-distribution maps. Mercury (Hg) was the heaviest pollutant, with concentrations exceeding 4 mg/kg. Silver (Ag) was the second most important pollutant, with constantly increasing values. The average concentrations of the most toxic elements were comparable to those found in sediments of other ports throughout the world, and their toxicity ranged from threshold values [chromium (Cr), arsenic (As)] and midrange-effect values [cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), nickel (Ni)] to extreme-effect values (Hg). Metal pollution has decreased during recent decades, except for Ag and barium (Ba).

Origin and transport of (238)U and (226)Ra in riverine, estuarine and marine sediments of the Krka River, Croatia.

Spatial distribution of (238)U and (226)Ra activities in sediment columns along the Krka River and estuary, were studied using gamma spectrometry. Markedly different (238)U and (226)Ra activities between riverine, estuarine and marine sediments were observed. Distribution of these radionuclides, as well as their anthropogenic and natural origin, was evaluated by activity measurements, taking into account sedimentation rates estimated by (137)Cs distribution in sediment columns. Naturally present (238)U and (226)Ra activities were highest in riverine and lowest in marine sediments. (238)U and (226)Ra activities in historic riverine sediments revealed anthropogenic influence from town of Knin, which diminished for 15-20% in 1990s due to warfare that caused stop of industrial, agricultural and transport activities. Drainage of the flysch material naturally elevates (238)U and (226)Ra activities in the vicinity of its inflow in the upper part of estuary. (238)U and (226)Ra from the phosphate ore discharge in the port of Sibenik did not spread further in estuary, which was also confirmed by (238)U and (226)Ra activities detected in Mytilus sp. mussels' tissue.

(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme.

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.

Environmental contamination assessment of the surroundings of the ex-ferrochromium smelter Dugi Rat, Croatia.

The objective of this study was to chemically characterize the soil samples affected by the dust emission and slag dumping from ferrochromium smelter, as well as uptake of metals by vegetation growing on that soil. There were 38 samples collected altogether, including unpolluted background soil samples, polluted soil samples taken in the vicinity of the factory, slag material, bottom and fly ash. Grass material was also taken from both polluted and unpolluted soil. All samples were analyzed with energy dispersive X-ray fluorescence (EDXRF). The results showed (especially for chromium and manganese) metal concentrations in soil samples taken in the vicinity of the factory increased up to 56 times in relation to normal background soil concentrations. Slag material, fly and bottom ash were highly enriched with chromium, manganese and nickel. There was a significant chromium uptake by vegetation growing on the contaminated soil.

Chemical and radiological profile of the coal ash landfill in Kastel Gomilica.

The objective of this study was to determine the chemical, radiological and leaching properties of slag and ash produced by a thermoelectric unit of a former factory Adriavinil and deposited in the area of Kasktel Gomilica near Split, Croatia. A total of 33 samples were analysed. The bioavailable fraction of the slag and ash was estimated using different leaching tests. The waste material was characterized by a high activity of naturally occurring radionuclides 238U, 235U and 226Ra and by elevated concentrations of heavy metals. The concentrations of most heavy metals were three to four times as high as in the common soil. Uranium slag and ash concentration was almost 40 times higher than in control soil. More than 37% of the total U could be removed from the slag and ash with the sea water.

Uranium in sediments, mussels (Mytilus sp.) and seawater of the Krka river estuary.

The response of an aquatic environment to the decrease of phosphate discharges from a technologically improved transhipment terminal, situated at the Croatian Adriatic coast in the port of Sibenik, has been assessed based on uranium activity and concentration in sediment, seawater and mussels Mytilus sp. The highest 238U activities (485+/-16Bqkg(-1) dry weight) were found in the sediment sample collected from the sampling site closest to the terminal. The maximum concentrations in the sediment samples are above the natural ranges and clearly indicate the harbour activities' influence. The 238U/226Ra activity ratios in sediment samples demonstrate the decreasing trend of phosphate ore input. Mussel samples showed levels of 238U activities in the range from 12.1+/-2.9 to 19.4+/-7.2 Bqkg(-1) dry weight, thus being slightly higher than in normally consumed mussels. Only the seawater, taken just above the bottom sediment at the sampling site closest to the terminal, shows a slightly higher uranium concentration (3.1+/-0.2 microgL(-1)) when compared to the samples taken in upper seawater layers (2.1+/-0.2 microgL(-1)) but is in the range of the concentration level of uranium in natural seawater. Since the transhipment terminal in the port of Sibenik was modernised in 1988, discharge of phosphate ore into the seawater was drastically reduced and, consequently, uranium concentration levels in seawater have decreased. However, enhanced uranium activity levels are still found in deeper sediment layer samples and in mussel.

Environmental contamination assessment of the surroundings of the ex-Sibenik's ferro-manganese smelter, Croatia.

The objective of this study was chemical and radiological characterization of soil samples affected by the dust emission and slag dumping from ferro-manganese smelter as well as uptake of metals by vegetation growing on that soil. Iron was the main component of metallurgical slag deposited near the smelter. Slag material was highly enriched in Zn, Cr, Cu, Co, and Pb. V and Cr were enriched in the soil taken near the smelter approximately by a factor of two, Pb and Cu were increased fivefold whereas the mean content of Mn was about 130 times higher than the levels in background soil samples. Activities of agricultural soil samples were typical for the soil developed on late Cretaceous carbonate surface. 40K, 232Th, and 137Cs showed somewhat lower activities in background soil compared to the soil taken near the smelter while the opposite was found for 226Ra and 238U. Plot of factor 1 against factor 2, obtained by Principal component analysis, showed perfect separation of the samples taken in the vicinity of the smelter, slag material, and normal background agricultural soil. Perfect correlation (Canonical R =0.992) was obtained between chemical composition of soil and vegetation samples taken from the same spots. The content of Mn was approximately 36 times higher in vegetation taken from the vicinity of the smelter compared to the background values.