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Long-term investigation of 137Cs and 134Cs in drinking water in the city of Zagreb, Croatia

Franić Zdenko, Branica Gina, Petrinec Branko, Marović Gordana

Nukleonika

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2020

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Vol. 65, No. 3

193--198

EN

This paper presents the results of long-term investigations of 137Cs and 134Cs activity concentrations in drinking water in the city of Zagreb for the period 1987–2018. The highest activity concentrations of both radionuclides were measured in 1987, decreasing exponentially ever since, while 134Cs in several subsequent years fell under the detection limit. After the Fukushima Daiichi accident in 2011, the presence of 134Cs in drinking water was detected again. The environmental residence time for 137Cs was estimated to be 8.1 years in drinking water and 5.7 years in fallout. The correlation between 137Cs in fallout and in drinking water is very good, and this indicates that fallout is the main source of water contamination. The observed 134Cs/137Cs activity ratio in drinking water for the post-Chernobyl period was similar to the ratio found in other environmental samples. The estimation of annual effective doses received by the adult members of the Croatian population due to the intake of radiocaesium in drinking water showed quite small doses of 0.28 µSv in 1987 decreasing to 2.5 nSv in 2018, which indicated that drinking water was not a critical pathway for the transfer of radiocaesium to humans.

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(137)Cs activity distribution in the Lithuanian coastal waters of the Baltic Sea

Davuliene L., Tarasiuk N., Spirkauskaite N., Trinkunas G., Valkunas L.

Oceanologia

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2007

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No. 49 (1)

71-90

EN

The main (137)Cs accumulation zone in the study area was found to be located at depths below the 50-metre isobath, i.e. below the layer of hydrodynamic activity. In coastal waters not influenced by the fresh water discharge from the Curonian Lagoon, (137)Cs occurs mostly in soluble form. The particulate 137Cs activity concentration in the marine area affected by Curonian Lagoon water can make up 10% of the total (137)Cs activity concentration. The circulation model was developed to assess the distribution of artificial radionuclides in Lithuanian territorial waters. The model was validated on the basis of data acquired during the measurement campaign in the Lithuanian part of the Baltic Sea and the Curonian Lagoon in the years 1999-2001. The model enables the (137)Cs activity concentration to be simulated as a passive admixture (error within c. 15%).

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Influence of time, temperature, pH and inhibitors on bioaccumulation of radiocaesium - 137Cs by lichen Hypogymnia physodes

Pipíška M., Horník M., Kočiová M., Augustín J., Lesný J.

Nukleonika

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2005

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Vol. 50,suppl.1

39-44

EN

Caesium bioaccumulation experiments were carried out at 4 to 60°C using natural samples of the lichen Hypogymnia physodes. Thalli were incubated in 2.5 mi mol.l 1 CsCl solutions labelled with 137CsCl for up to 24 h at pH values from 2 to 10. Bioaccumulation of Cs+ ions in the first phase of the lichen-CsCl solution interaction is rapid, neither pH, nor temperature dependent within the range 4 to 60°C and observed also with the lichen biomass thermally inactivated at 60°C or chemically by formaldehyde. The second phase of 137Cs bioaccumulation is time, temperature and pH dependent and is inhibited by formaldehyde and thermal inactivation. The process at the initial concentration C0 = 2.5 ěmol.l 1 CsCl and 20°C reached equilibrium within 12 hours. It can be described by the first order reaction kinetics equation: log [Ct] = 1.89 - 0.00153 t, R = 0.950. Maximal values of Cs-bioaccumulation were observed at 20°C with minimum at 4°C and 40°C and at pH 4 5 with minimum at pH 2 and pH 6. Low caesium efflux values from lichen thalli by water and 0.1 mol.l 1 neutral salts at 20°C and 24 h equilibrium were observed. Efflux characterized by distribution coefficients D = [Cs]solution/[Cs]biomass at biomass/solution ratio 1:25 (w/v, wet wt.), decreases in the order: Li+- 78 × 10 3 >NH4 + = K+ 15 × 10 3 > Cs+ = Na+ 11 × 10 3. Low extractability of caesium from lichen by water and salt solutions can explain long persistent times of radiocaesium contamination sorbed by lichens, observed by many authors in caesiumcontaminated forest and mountain regions. Hypothesis of the role of the lichen secondary metabolites as caesium binders is discussed.

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Effects of 137Cs low level exposure (internal and external) doses on plants

Marčiulioniene D., Kiponas D., Lukšiene B., Gaina V.

Nukleonika

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2005

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Vol. 50, nr 4

161-166

EN

Effects are described of internal exposure doses of ionizing radiation in above- and underground parts of test plants under natural conditions and in roots of Lepidium sativum L. from accumulated 137Cs under laboratory conditions. In the region most contaminated after the Chernobyl accident, in the tested 10 plant species for 137Cs ionizing radiation the internal exposure doses 3.5 times exceeded those in the Ignalina Nuclear Power Plant environment. Under laboratory conditions the effect of low internal (0.6-600 mSv) and external (40-5500 mSv) exposure doses from 137Cs on garden cress, Lepidium sativum L. roots was, practically, the same. Both internal and external exposure doses stimulated the plant root growth by 12 and 33%, respectively. Different effect of external and internal exposure on the developing plant cells was observed by analyzing the results of morphometric investigations of the primary root cap cells of Lepidium sativum L.

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137Cs content in mushrooms from localities in eastern Slovakia

Cipáková A.

Nukleonika

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2004

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Vol. 49,suppl.1

25-29

EN

The amount of radiocaesium in chosen species of mushrooms from localities in eastern Slovakia was studied. From the obtained results it was found that Macrolepiota procera and Armillariella mellea are defined by low ability to accumulate caesium. Higher values of 137Cs were measured in Russula aeruginea and Xerocomus subtomentosus and achieved 869.6 and 322.9 Bg kg 1 dry weight, respectively. Soaking and washing can be used to decrease radioactivity in mushrooms. Using water and solution of table salt in studied species of mushrooms decreased the amount of radiocaesium by 33 88%.

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Variation of Cs-137 deposition in soil and lakes in the north-east region of Poland

Zalewski M., Kapała J., Mnich Z., Zalewski P.

Nukleonika

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2002

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Vol. 47, nr 2

75-78

EN

The aim of this work is to assess the current deposits of Cs-137 in soil and in lakes in the Poland's north-eastern lake district (12-14 years after Chernobyl accident) a dozen or so years after the Chernobyl disaster. Caesium content in soil and sediment was determined by gamma spectrometry (in 79 soil samples and 136 sediment samples). The soil samples were collected in summer 1998-2000. The sediment from 29 lakes were sampled in May 2000. The highest surface activity was found in soil with the arithmetic mean (AM) 3.13 kBq m-2 and median (M) 2.37 kBq m-2. For lakes, the respective values were 1.89 kBq m-2 and 1.5 kBq m-2. In the case of the soil samples collected from forests, fields, lake shores and arable lands, the mean values of caesium deposition were: 4.37, 2.56, 3.42 and 1.52 kBq m-2, respectively. The mean surface activity of sedimentary samples (AM) from oligotrophic, mesotrophic and eutrophics lakes was found to have different values, viz. 1.48, 2.23 and 1.86 kBq m-2, respectively.

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Dissolved and suspended forms of caesium-137 in marine and riverine environments of the southern Baltic ecosystem

Knapińska-Skiba D., Bojanowski R., Piękoś R.

Nukleonika

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2002

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Vol. 47, nr 2

53-58

EN

Dissolved and particulate activities of caesium-137 are presented for the coastal and open southern Baltic Sea waters, fluvial waters (the Vistula and Swina rivers) and lagoon waters (the Vistula Lagoon) during 1996-1999 and compared to those collected before the Chernobyl accident. 137Cs was measured in the Baltic Sea waters at different depths as well as 0.2-0.3 m above the sea bed. In a layer of the Gdafsk Bay waters (the Gdafsk Deep location), extending from the surface down to 1-2 meters above the sea bed, the caesium-137 concentrations ranged between 57 and 66 Bq m-3 in 1999, whereas in the layer situated 0.2-0.3 m above the sea bed its concentration increased up to 87 Bq m-3. This phenomenon was also observed in 1994 and 1998. The concentrations of caesium-137 in riverine suspended particulate matter (r SPM) are lower than in the marine SMP (m SMP) and its activity attains respectively 36 and 222 Bq kg-1 based on dry weight. The proportion of caesium-137 in the suspended form in the Baltic Sea waters does not exceed 2 per cent, while in the fluvial suspended form it is as high as 55 per cent.