Distribution and sources of (129)I in rivers of the Baltic region

The concentration of (129)I was measured in 54 river waters discharging into the Baltic Sea from Sweden, Finland, Estonia, Latvia, Lithuania, Poland and Germany. Sample collection was performed during a well-bracketed time interval (June-July 1999), thus allowing comparison of the rivers over a wide latitude range without the effect of long temporal spread. Although there is no direct input of anthropogenic (129)I in the watersheds, the concentration of the isotope is about two to three orders of magnitude higher than the expected pre-nuclear era natural values in the rivers of Finland and northern Sweden, and in the rivers of southern Sweden, Lithuania, Estonia, Latvia, Poland and Germany; the (129)I concentration may reach five orders of magnitude higher. Furthermore, there are significant correlations between the (129)I concentration and latitude and/or distance from the North Sea and between (129)I and Cl. These findings suggest seawater as a main source of (129)I to the rivers through atmospheric transport. Of the many chemical parameters investigated, the pH may account for some of the variability in (129)I concentrations of the rivers. The contribution from nuclear weapon tests and the Chernobyl accident to the riverine (129)I is insignificant compared to the releases from the nuclear fuel reprocessing facilities. The total flux of (129)I by rivers to the Baltic Sea and related basins represents minor amounts of the isotope pool in these marine waters. External radioactivity hazards from (129)I are considered to be negligible in the Baltic region. However, as the main (129)I intake to the human body is likely through water, due to the large amount of daily water consumption, more concern should be given to internal radioactivity hazard that may be associated with the isotope's localized elevated concentration in the human organs.     

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.     

Trends in the spatial and temporal distribution of 129I and 99Tc in coastal waters surrounding Ireland using Fucus vesiculosus as a bio-indicator

Spatial and temporal trends in (129)I and (99)Tc concentrations around the Irish coastline have been evaluated using Fucus vesiculosus as a bio-indicator. (129)I concentrations in a recent set of seawater samples have also been recorded and reveal an identical spatial pattern. Concentrations of (129)I in Fucus from the northeast coast of Ireland proved to be at least two orders of magnitude higher than concentrations in Fucus from the west coast. The (129)I content of Fucus increased significantly between 1985 and 2003, in line with increases in discharges of (129)I from the Sellafield nuclear reprocessing plant. Similar trends were observed in the case of (99)Tc. (129)I/(99)Tc ratios in Irish seawater were deduced from the Fucus data, and compared to ratios in discharges from Sellafield and from the French reprocessing plant at Cap de la Hague. Levels of (129)I and (99)Tc in Fucus from the west coast were found to be enhanced with respect to levels in seaweeds from other regions in the Northern Hemisphere unaffected by discharges from nuclear installations such as those referred to.     

Wet and dry deposition of 129I in Seville (Spain) measured by accelerator mass spectrometry.

Iodine-129 (T1/2 = 1.57 x 10(7) yr) concentrations have been determined by accelerator mass spectrometry in rainwater samples taken at Seville (southwestern Spain) in 1996 and 1997. This technique allows a reduction in the detection limits for this radionuclide in comparison to radiometric counting and other mass spectrometric methods such as ICP-MS. Typical 129I concentrations range from 4.7 x 10(7) 129I atoms/l (19.2%) to 4.97 x 10(9) 129I atoms/l (5.9%), while 129I depositions are normally in the order of 10(8)-10(10) atoms/m2d. These values agree well with other results obtained for recent rainwater samples collected in Europe. Apart from these, the relationship between 129I deposition and some atmospheric factors has been analyzed, showing the importance of the precipitation rate and the concentration of suspended matter in it.     

Tracing anthropogenic nuclear activity with (129)I in lake sediment

This study reports the first data of (129)I fallout in Scandinavia, covering the last 80 years. The investigation is based on sediment sections from a lake in central Sweden. In addition to analysis of (129)I, a combination of several radionuclides ((210)Pb, (137)Cs and (14)C) was used to establish an accurate chronology of the sediment profile. The concentration of (129)I exhibits an increasing trend ( approximately 10(7) to approximately 10(9)atoms/g) during the last 40 years, suggesting a significant atmospheric input from the nuclear reprocessing facilities in Sellafield (UK) and La Hague (France). A peak corresponding to fallout from the Chernobyl accident (1986) is clearly distinguishable, whereas the impact of fallout from the nuclear weapons' tests since the early 1950s is not distinguished.     

Long-term study of 99Tc in the marine environment on the Swedish west coast

The activity concentration of (99)Tc in brown seaweed (Fucus vesiculosus and Fucus serratus) and seawater were analysed in samples collected in 1991, 1995 and 2001 at several stations along the Swedish west coast. In addition to these locations, a well-defined site (S?rdal, 56.76 degrees N, 12.63 degrees E) was included with (99)Tc activity concentration data in seaweed from 1967 to 2000. Over the years, the major source of (99)Tc in the coastal waters of western Sweden has been the radioactive liquid discharge from the nuclear fuel reprocessing plant in Sellafield (UK) transported via ocean currents in the North Sea. The (99)Tc activity concentration in seaweed at the S?rdal site increased from approximately 30 Bq kg(-1) up to 230 Bq kg(-1) (dry weight) between 1997 and 2000 due to the Sellafield EARP (Enhanced Actinide Removal Plant) discharges in 1995-1996, yielding an approximate transport time of 4-5 years between the Irish Sea and the Kattegat. Due to the very sharp gradient in (99)Tc concentration between the Baltic Sea and the North Sea, (99)Tc is presently one of the best transit tracers for the recent ventilation events in the Baltic Sea.     

Discharge of 137Cs and 90Sr by Finnish rivers to the Baltic Sea in 1986-1996

The total amounts of 137Cs and 90Sr transported from Finland by rivers into the Gulf of Finland, Gulf of Bothnia and Archipelago Sea since 1986 were estimated. The estimates were based on long-term monitoring of 137Cs and 90Sr in river and other surface waters and on the statistics of water discharges from Finnish rivers to the above sub-areas of the Baltic Sea. The total amounts of 137Cs and 90Sr removed from Finland into the Baltic Sea during 1986-1996 were estimated to be 65 and 10 TBq, respectively. The results show that, although the deposition of 137Cs was much higher than that of 90Sr after the Chernobyl accident, the amount of 137Cs removed from Finland is only six times as high as that of 90Sr. This emphasizes the importance of 90Sr while considering radiation doses from surface waters and 137Cs while estimating doses via pathways from catchment soil, lake sediments and biota after a fallout situation.     

Bis(4-chlorophenyl) sulfone (BCPS) in Swedish marine and fresh water wildlife-a screening study

Bis(4-chlorophenyl) sulfone (BCPS) is a high production volume chemical (HPVC) applied in thermostable polymers. BCPS has been detected as an environmental contaminant both in Europe and in North America but it is still not a commonly studied pollutant. In this study, three Baltic Sea fish species; herring (Clupea harengus), salmon (Salmo salar) and perch (Perca fluviatilis) from the Swedish coast, and one inland fish species, arctic char (Salvelinus alpinus), were analysed to screen for the occurrence and distribution of BCPS. Salmon and arctic char, were sampled in the early 1970s as well as the late 1990s. Fish eating grey seal (Halichoerus gryphus) and guillemot (Uria aalge) from the Baltic Sea were included to screen for whether BCPS biomagnify or not. The representativeness of the analysed samples for studying bioaccumulation of environmental pollutants was compared through analysis of two well known persistent and bioaccumulating compounds, 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), and 4,4'-DDE. Pooled muscle and blubber samples based on 4-10 individuals were used for analysis, as well as individual samples of grey seal blubber. 2,4,4'-Trichlorodiphenyl sulfone, was synthesised and applied as an internal standard. BCPS was detected in all marine samples but in only one of the fresh water fish samples. The highest BCPS concentrations detected, 1600 and 1900 ng/g lipid weighet (l.w.), were found in muscle from Baltic guillemot. The results indicate that BCPS is bioaccumulated in both grey seal and guillemot, and that the guillemot has higher concentrations of BCPS than the grey seal (50-500 ng/g l.w.). The concentrations found in different species of fish from the Baltic Sea ranged between 15-37 ng/g l.w. and lower concentrations were found in freshwater species (n.d.-1.8 ng/g l.w.). The present study shows that BCPS is found in all investigated species of wildlife but, in most species, still at low concentrations. However, the guillemot has levels in the low ppm range indicating a considerable biomagnification of BCPS in this species.     

Partition of iodine (¹²⁹I and ¹²⁷I) isotopes in soils and marine sediments

Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope ¹²⁹I is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter.Due to its long half-life (15.7 million years), ¹²⁹I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of ¹²⁹I and ¹²⁷I chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify ¹²⁹I in humic and fulvic acid and humin. The results show that 30-56% of the total ¹²⁷I and 42-60% of the total ¹²⁹I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, ¹²⁷I and ¹²⁹I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 ¹²⁹I was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions.     

234U and 238U isotopes in water and sediments of the southern Baltic

The aim of this work was to determine the concentration of 234U and 238U and calculate the values of the 234U/238U activity ratio in waters and sediments from the various regions of the southern Baltic Sea: Gdańsk Deep, S?upsk Narrow and Bornholm Deep. The concentration of uranium in analysed sediments from southern Baltic increase with core depth to what probably is connected with diffusion from sediments to water through interstitial water, where uranium concentration is much higher than in bottom water. The highest concentrations of uranium were observed in sediments of S?upsk Narrow (0.66-7.11 mg kg(-1) d.w.) and S?upsk Bank (0.61-6.93 mg kg(-1) d.w.), the lowest in sediments from Bornholm Deep (0.54-3.77 mg kg(-1) d.w.). The 234U/238U activity ratio results indicated that the sedimentation of terrigenic material and Vistula River transport are the general sources of uranium in the southern Baltic sediments. The value of 234U/238U activity ratio in sediments from reduction areas from southern Baltic (Gdańsk Deep and Bornholm Deep) indicated that reduction process of U(VI) to U(IV) and removing of anthropogenic uranium from seawater to sediments constitutes a small part only in Gdańsk Deep.     

129I/127I, 129I/137Cs and 129I/99Tc in the Norwegian coastal current from 1980 to 1998

Discharges of the nuclides 129I, 137Cs and 99Tc from the nuclear reprocessing facilities at Sellafield (UK) and La Hague (France) are very useful as oceanic tracers. On the basis of 129I/127I, 137Cs and 99Tc measurements in archived seaweeds, the ratios of 129I/127I, 129I/137Cs and 129I/99Tc have been estimated in seawater at two locations (Utsira and Kiberg) in the Norwegian Coastal Current from 1980 to 1998. These ratios, which vary up to two orders of magnitude over this period, are potentially very interesting for determining "transit times" in the Arctic and North Atlantic oceans. While the long-term trends in these ratios are quite clear, measurements in monthly and bimonthly samples show considerable structure. Further studies are required to determine the exact origin of this structure, which may be a limiting factor in the time resolution that can be obtained with these parameters.     

129I in the environment of the La Hague nuclear fuel reprocessing plant--from sea to land

In recent years, particular attention was paid to the long-lived radionuclides discharged with authorized low-level radioactive liquid and gaseous effluents by the nuclear spent fuel reprocessing plants of La Hague and Sellafield. The knowledge of (129)I (half-life=15.7 x 10(6) a) distribution in the environment is required to assess the radiological impact to the environment and population living in the area under the direct influence of La Hague NRP discharges. Measurement difficulties of (129)I in environmental matrices, where it is usually present at trace level, limited data published on (129)I activity levels in the European and more particularly in the French territory. Studies conducted to qualify a new alternative measurement method, direct gamma-X spectrometry with experimental self-absorption correction, led to test samples collected in the La Hague marine and terrestrial environment : seaweeds, lichens, grass, bovine thyroids, etc. All these results, often already published separately for analytical purposes and treated for intercomparison exercises, are presented here together in a radioecological manner. The levels of (129)I activity and (129)I/(127)I ratios in these samples show the spatial and temporal influence of the La Hague NRP in its local near-field environment as well as at the regional scale along the French Channel coast.     

Plutonium concentrations in waters from the southern Baltic Sea and their distribution in cod (Gadus morhua) skin and gills

The concentrations of (238)Pu and (239+240)Pu in water samples and suspended particulate fractions, as well as in colloidal fraction from the southern Baltic Sea are presented. The (239+240)Pu concentration in surface seawater samples fall within range from 5.2 mBq.m(-3) for Gdańsk Bay to 150 mBq.m(-3) for Pomeranian Bay, most of which (from 52 to 96%) constituted filterable forms (相似文献   

PCDD/Fs and DL-PCBs intake from fish caught in Polish fishing grounds in the Baltic Sea — Characterizing the risk for consumers

Fish and fishery products are among the primary sources of dietary exposure to dioxins. It is known that some fish species caught in the Baltic Sea contain elevated level of those compounds. Levels of dioxins and DL-PCBs in 236 Baltic fish samples (including 65 salmon, 14 sea trout, 63 sprat, 63 herring, 31 cod), and 20 cod liver samples from the Polish fishing grounds (the ICES zones 24–27), collected in the time frame of 2006–2011 as part of Polish monitoring survey have been used for risk assessment. To characterize potential health risk associated with dioxins intake, doses ingested in a single portion of fish and cod liver by adults (200 g for fish, 125 g for cod liver), and children (100 g for fish, 25 g for cod liver) were expressed as percent of Tolerable Weekly Intake (TWI) and Provisional Tolerable Monthly Intake (PTMI).Average dioxins intake estimated for fatty fish species was about 250% TWI for children, and about 170% TWI for adults, with maximum values of 436.3 and 288.0% TWI, respectively. Maximum exposure expressed as percent of PTMI was below 90% for children and below 60% in adults. For sprat and herring, mean dioxins intakes were lower, but still not at “safe” level: 100–150% TWI for children and about 70–100% for adults, with the maximum values of about 250 and 180%, respectively. Maximum exposure expressed as percent of PTMI was approximately 50% for children and 35% for adults.Intakes values calculated for practically “dioxin-free” cod are just theoretical because in calculating toxic equivalents (TEQs) an upperbound approach was applied, and vast majority of TEQs originates from the limit of quantification (LOQ) values of all non-quantified congeners.Frequent consumption of cod liver seems to be a health risk as, according to assumed scenario, dioxins intake of 100% PTMI for adults would be achieved by the 65th percentile, while for children by approximately 90th percentile of results.Serving sizes of salmonids, cod liver, and even sprat, and herring that lead to total dioxins intake equal to TWI, and PTMI were relatively small. Thus, one can easily exceed those toxicological reference values consuming above Baltic fish species available on the Polish market.Taking into account low fish consumption in Poland and, additionally, low share of Baltic fish in total consumption of marine fish, potential risk of high dioxins intake does not apply to general population. Occasionally elevated dioxins intake above TWI or PTMI is not necessarily related to health risk, because of uncertainty factors embedded in these toxicological reference values. However, some sub-populations in Poland that habitually consume fatty fish originating from the Baltic Sea or Baltic cod liver may be at an elevated health risk of potential consequences of chronic exposure to dioxins. Dietary recommendations based on risk-benefit analysis for consumers of such fish and fishery products from the Baltic Sea would be the most effective tool for risk management.     

Monitoring iodine-129 in air and milk samples collected near the Hanford Site: an investigation of historical iodine monitoring data

While other research has reported on the concentrations of (129)I in the environment surrounding active nuclear fuel reprocessing facilities, there is a shortage of information regarding how the concentrations change once facilities close. At the Hanford Site, the Plutonium-Uranium Extraction (PUREX) chemical separation plant was operating between 1983 and 1990, during which time (129)I concentrations in air and milk were measured. After the cessation of chemical processing, plant emissions decreased 2.5 orders of magnitude over an 8-year period. An evaluation of (129)I and (127)I concentration data in air and milk spanning the PUREX operation and post-closure period was conducted to compare the changes in environmental levels. Measured concentrations over the monitoring period were below the levels that could result in a potential annual human dose greater than 1 mSv. There was a measurable difference in the measured air concentrations of (129)I at different distances from the source, indicating a distinct Hanford fingerprint. Correlations between stack emissions of (129)I and concentrations in air and milk indicate that atmospheric emissions were the major source of (129)I measured in environmental samples. The measured concentrations during PUREX operations were similar to observations made around a fuel reprocessing plant in Germany. After the PUREX Plant stopped operating, (129)I concentration measurements made upwind of Hanford were similar to the results from Seville, Spain.     

Reference conditions for rivers of the German Baltic Sea catchment: reconstructing nutrient regimes using the model MONERIS

We introduce an approach for establishing reference conditions (RC) for rivers of the German Baltic Sea catchment, based on predictive modelling. An extensive data set of statistics from the year 1880 was coupled with literature data, providing a comprehensive basis for the calculation of regional historical nutrient emissions into rivers, river nutrient concentrations, and nutrient loading into the sea. Four different scenarios were calculated: scenario 1 assumed RC following previously established criteria for lakes (Poikane et al. in Environ Manag 45(6):1286–1298, 2010), scenario 4 applied the nutrient emission conditions of 1880 (considering non-intensive land usage, the presence of tile drainage systems, sewer systems, and the human population from 1880), and scenarios 2 and 3 considered intermediate conditions. Our results showed that nutrient emissions from scenario 1 accounted for approximately one-tenth of the currently observed total nitrogen (TN) and total phosphorus (TP) emissions. The nutrient emissions calculated for 1880 (scenario 4) were found to be 47 % (TN) and 55 % (TP) higher than those calculated considering reference lake conditions (scenario 1). Our results suggest that RC nutrient concentrations in rivers in the German Baltic Sea catchment were clearly below 0.05 mg/l for TP and 1 mg/l for TN. This range is in accordance with historical and calculated pristine nutrient concentrations from other rivers in similar catchments.     

Iodine-129 in the environment of a nuclear fuel reprocessing plant: I. 127I and 127I contents of soils,food crops and animal products

Concentrations of ¹²⁹I and ¹²⁷I in soils, food crops and animal products collected in the environment of the small Karlsruhe nuclear fuel reprocessing plant (WAK) were determined by neutron activation analysis. ¹²⁹I levels in all samples were found to be elevated by several orders of magnitude above current average biospheric background values. Resultant thyroid doses from consumption of food produced at locations in the vicinity of the Karlsruhe reprocessing plant are, however, small relative to the natural background dose.     

Areal distribution of 129I in west cumbrian solis

¹²⁹I has been released during operations at the BNFL nuclear fuel reprocessing plant at Sellafield in west Cumbria over the past thirty years with about 95% being discharged into the sea and 5% into the atmosphere. Soil samples have been taken within a 40 km radius of Sellafield to determine the extent to which the ¹²⁹I is deposited in the immediate vicinity of the plant. The ¹²⁹I content has been determined by a sensitive neutron activation technique and levels in soil were found to be elevated above global levels in all samples. The areal distribution of ¹²⁹I was consistent with direct deposition following release to the atmosphere from Sellafield and the relationship between ¹²⁹I activity and the distance from Sellafield was of a form predicted by atmospheric dispersion models. The absence of any observable return of ¹²⁹I from the sea has implications for assessments of dose.     

Impact of trace metals and nutrients levels on phytoplankton from the Kuwait coast

The impact of marine pollution was estimated from seven stations of Kuwait coastal waters. The mean concentrations of all trace metals in seawater (0.07-7.04 microg/l) and in phytoplankton (14.90-52.01 microg/g) revealed less phytoplankton abundance in Stations IV VI during the four seasons. However, a relative surge in the phytoplankton abundance, with an increase in the mean concentrations of all trace metals in seawater (0.15-8.94 microg/l) and phytoplankton (22.82-61.25 microg/g), was observed in Station II. A low phytoplankton abundance was noted in Stations I, III, and VII despite low mean concentrations of all the trace metals in seawater (0.11-5.77 microg/l) and phytoplankton (1.40-20 microg/g) during the four seasons. Statistical tests revealed significant difference in Fe, Ni, and Pb between the four seasons in seawater and Fe and Co in phytoplankton. No significant difference in trace metals between locations was observed in seawater and in phytoplankton. The major nutrients in all the four seasons were found in the magnitude of SiO3 > NO3 > PO4 in all the stations, and thus, support the presence of rich diatoms and dinoflagellates than other phytoplankton groups. The seven stations also represented indicator species of oil and industrial waste pollution.     

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan

Using a sector-field ICP-MS the vertical distributions of the ⁹⁹Tc concentration and ⁹⁹Tc/¹³⁷Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The ⁹⁹Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m³, no greater than the estimated background level. Relatively high ⁹⁹Tc/¹³⁷Cs activity ratios (10-12 × 10⁻⁴) would be caused by the inflow of the high-⁹⁹Tc/¹³⁷Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The ⁹⁹Tc concentration and the ⁹⁹Tc/¹³⁷Cs activity ratio in water column showed gradual decreases with depth. Our results implied that ⁹⁹Tc behaves in a more conservative manner than ¹³⁷Cs in marine environments.