Availability of radium isotopes and heavy metals from scales and tailings of Polish hard coal mining

Radium and heavy metal contaminated tailings and scales resulting from Polish hard coal mining were investigated for their mobilisation potential by using leaching methods. The main focus is set on a three-step extraction procedure proposed by BCR (Bureau Communautaire de Référence, now Standards Measurements and Testing Programme) of the European Union, which was used for investigating the availability of radium isotopes. In addition, the results of a Polish extraction procedure for the heavy metals' water solubility are presented for rough comparison. After a special treatment, the BCR-reagents were measured by gamma-spectrometry to define their radium activity concentrations; the heavy metal content in the water soluble fractions was determined by ICP-AES. The samples were collected at two different sites influenced by the discharge of pit water from hard coal mining. The tailings were taken from a former tailing pond, which now is no longer in use, but the settled material is still present. At another abandoned and meanwhile flooded tailing pond, the scales were scraped from the inside of a discharge tube. The results obtained show that there is different leaching behaviour between the radium isotopes. The tailings being characterised by surface adsorbed radium provide up to 25% of the initial (226)Ra content, (228)Ra is altogether leached up to 15%. The scales comprise stable radiobaryte (Ba[Ra]SO(4)) and can be considered as being unable to provide radium isotopes, since no trace of radium dissolution was observed. The leaching behaviour of heavy metals is similar to that of radium. Mn, Ni and Zn are dissolved by water from the tailings; the scales do not provide any.     

Estimation of radon concentrations in coal mines using a hybrid technique calibration curve

The results of epidemiological studies in various countries show that radon and its progeny cause carcinogenic effects on mine workers. Therefore, it becomes of paramount importance to monitor radon concentrations and consequently determine the radon dose rates in coal mines for the protection of coal miners. A new calibration curve was obtained for radon concentration estimation using hybrid techniques. A calibration curve was generated using 226Ra activity concentration measured by a HPGe detector-based gamma-ray spectrometer versus alpha-track-density rate due to radon and its progeny on CR-39 track detector. Using the slope of the experimentally determined curve in the units of Becqueral per kilogram (Bq kg-1) per unit alpha-track-density per hour (cm-2 h-1), radon concentrations (Bq m-3) were estimated using coal samples from various coal mines in two provinces of Pakistan, Punjab and Balochistan. Consequently, radon dose rates were computed in the simulated environment of the coal mines. Results of these computations may be considered with a caveat that the method developed in this paper provides only a screening method to indicate the radon dose in coal mines. It has been shown that the actual measurements of radon concentrations in the coal mines are in agreement with the estimated radon concentrations using the hybrid-technique calibration curve.     

Assessment of groundwater quality impacts due to use of coal combustion byproducts to control subsidence from underground mines

Coal combustion byproducts are to be placed in an underground coal mine to control subsidence. The materials were characterized to determine potential groundwater impacts. No problems were found with respect to heavy or toxic metals. Coal combustion byproduct leachates are high in dissolved solids and sulfates. Chloride and boron from fly ash may also leach in initially high concentrations. Because the demonstration site is located beneath deep tight brine-bearing aquifers, no problems are anticipated at the demonstration site.     

Nutrient export by rivers to the coastal waters of China: management strategies and future trends

We analyzed past and future trends in river export of dissolved nitrogen (N) and phosphorus (P) to the coastal waters of China, for a selection of rivers, as calculated by the Global NEWS models (Nutrient Export from WaterSheds). Over the period 1970–2000, river export of dissolved nutrients increased considerably, especially of dissolved inorganic N and P. Anthropogenic sources of N and P in rivers have become increasingly important, in particular N and P losses from agriculture. We tested the sensitivity of calculated nutrient export by rivers to changes in selected controlling factors. The calculated export of dissolved N and P is sensitive to changes in hydrology, synthetic fertilizer use and manure excretion in river basins. Changes in sewage inputs have large effects on dissolved inorganic P export. We analyzed future trends up to 2050 for several scenarios to illustrate the combined effects of selected management options. In the Base Scenario, the N and P export by the selected rivers increases considerably between 2000 and 2030. The increase continues from 2030 to 2050 except for DIP. Strategies to reduce N and P export by rivers include changes in agriculture, sewage and energy use. Changes in agriculture have the largest impact on future dissolved N and P river export to the coastal waters of China. The effectiveness of reduction strategies differs between nutrient forms and basins.     

Input of heavy metals to the forest floor as a result of Cracow urban pollution

The influence of Cracow's urban pollution on small forest ecosystems was studied during 1998-2000. Seven sites located at different distances from the Cracow conurbation and from busy road were selected. Two sites were situated 26 and 31 km from Cracow town along an eastern transect, the other five-3, 8, 14, 26 and 35 km respectively, from Cracow-along a southern transect. At the beginning of September, five litter traps were set at each site. The quantity of litter fall, along with percentage composition of each species, were estimated for an area of 1 m(2). The concentration of Cd, Pb, Cu, Zn and Fe in the litter fall and the input of these metals to the forest floor were determined. The input of cadmium ranged from 84 microg m(-2) at Kornatka in 1998 to 382 microg m(-2) at Bonarka in 2000. The input of lead was about 10 times higher than cadmium and varied from 406 microg m(-2) at Weglówka in 1998 to 3717 microg m(-2) at Bonarka in 2000. Input of Cu, Zn and Fe to the forest floor showed the similar tendency. During 1998-2000, the highest heavy metal concentrations in the litter fall and their impact on the forest floor were always found at sites close to the Cracow conurbation and, in the eastern transect, close to a steel works. Input of metals to the forest floor tended to decrease with increasing distance from the centre of Cracow.     

Ground water input to coastal salt ponds of southern Rhode Island estimated using 226Ra as a tracer

The naturally occurring radionuclide 226Ra (t1/2 = 1600 years) was used as a tracer to determine ground water input to Point Judith, Potter, Green Hill and Ninigret ponds in southern Rhode Island. Measurements of 226Ra activity were made in samples collected from salt ponds, pore waters, sediments, and local ground water wells during June-August, 1997. These results were combined with a simple box model to derive ground water input fluxes of 0.1-0.3 cm3 cm-2 d-1 (2-5 x 10(7) L d-1), which are comparable to previous estimates of ground water input to these ponds.     

Sorption and transport of radionuclides by tumbleweeds from two plastic-lined radioactive waste ponds

Previous research has examined the uptake of radionuclides by tumbleweeds growing in contaminated soils, but none has heretofore examined the sorption of radionuclides to tumbleweeds blowing into radioactively contaminated water. Three tumbleweed species; Russian thistle (Salsola kali), Jim Hill mustard (Sisymbrium altissimum) and summer cypress (Kochia scoparia) blow in, and out of, two plastic-lined radioactive wastewater ponds, constructed in 1993 on the US Department of Energy's Idaho National Engineering and Environmental Laboratory in southeast Idaho. This research quantified radionuclide sorption to tumbleweeds, tumbleweed movement from the ponds, and determined radionuclide transport from the ponds. Average plant/water concentration factors associated with tumbleweeds taken from the ponds ranged from 5 for 152Eu to over 9000 for 54Mn. Based on changes in tumbleweed numbers and average concentrations associated with them, 66.2 MBq were estimated to have been transported from the ponds via tumbleweeds between 18 October 1994 and 8 November 1996. This amounts to about 0.01% of the non-tritium and 0.0002% of the tritium activity released to the ponds through 8 November 1996. A power function best described the radionuclide buildup curve for tumbleweeds submerged in the ponds. Visually marked tumbleweeds traveled from the ponds in the predominant wind direction a maximum of 737 m. Management practices which may reduce the number of tumbleweeds blowing both into and out of contaminated ponds are discussed.     

Coupled radon, methane and nitrate sensors for large-scale assessment of groundwater discharge and non-point source pollution to coastal waters

We constructed a survey system of radon/methane/nitrate/salinity to find sites of submarine groundwater discharge (SGD) and groundwater nitrate input. We deployed the system in Waquoit Bay and Boston Harbor, MA where we derived SGD rates using a mass balance of radon with methane serving as a fine resolution qualitative indicator of groundwater. In Waquoit Bay we identified several locations of enhanced groundwater discharge, out of which two (Childs and Quashnet Rivers) were studied in more detail. The Childs River was characterized by high nitrate input via groundwater discharge, while the Quashnet River SGD was notable but not a significant source of nitrate. Our radon survey of Boston Harbor revealed several sites with significant SGD, out of these Inner Harbor and parts of Dorchester Bay and Quincy Bay had groundwater fluxes accompanied by significant water column nitrogen concentrations. The survey system has proven effective in revealing areas of SGD and non-point source pollution.     

Bacterial antibiotic resistance levels in Danish farmland as a result of treatment with pig manure slurry

Resistance to tetracycline, macrolides and streptomycin was measured for a period of 8 months in soil bacteria obtained from farmland treated with pig manure slurry. This was done by spread plating bacteria on selective media (Luria Bertani (LB) medium supplemented with antibiotics). To account for seasonal variations in numbers of soil bacteria, ratios of resistant bacteria divided by total count on nonselective plates were calculated. Soil samples were collected from four different farms and from a control soil on a fifth farm. The control soil was not amended with animal manure. The occurrence of tetracycline-resistant bacteria was elevated after spread of pig manure slurry but declined throughout the sampling period to a level corresponding to the control soil. Higher load of pig manure slurry yielded higher occurrence of tetracycline resistance after spreading; however, the tetracycline resistance declined to normal occurrence defined by the tetracycline resistance occurrence in the control soil. Concentrations of tetracycline in soil and in pig manure slurry were measured using HPLC. No tetracycline exceeding the detection limit was found in soil samples. Manure slurry concentrations of tetracycline for three of the farms were 42, 81 and 698 microg/l, respectively. For streptomycin and macrolides, only minor variations in resistance levels were detected. Results obtained in this study thus indicate that tetracycline resistance levels in soil are temporarily influenced by the addition of pig manure slurry. The results indicate also that increased amount of pig manure slurry amendment may result in increased levels of tetracycline resistance in the soil.     

Simultaneous biological removal of endosulfan (alpha+beta) and nitrates from drinking waters using wheat straw as substrate

Nitrate and endosulfan (alpha+beta) removal was studied in an upflow biological denitrification reactor packed with wheat straw as carbon source and support particles for microorganisms. While almost complete nitrate elimination and between 65% and 70% endosulfan (alpha+beta) elimination occurred when the temperature was higher than 20 degrees C; below that value, nitrate removal efficiency decreased to about 10%. Nitrate, dissolved organic carbon (DOC), and endosulfan (alpha+beta) removal efficiencies decreased considerably at 1500 microg/l endosulfan concentration in the batch experiments. Although a high removal efficiency was observed for endosulfan (alpha+beta) and nitrate in the biological denitrification continuous reactor, the effluent water could not be used for drinking purpose because of the unacceptable levels of endosulfan (alpha+beta), colour and dissolved organic content. During the continuous study, 23.4% of the initial weight of wheat straw was lost and 24 g was consumed per gram of nitrogen removed. The results of the continuous study showed that 21.3% of the endosulfan removal was achieved by adsorption onto the wheat straw and 68.2% of the endosulfan removal occurred by biological activity and the remaining portion was detected in the effluent water.     

Long-term flux of Chernobyl-derived 137Cs from soil to French rivers: a study on sediment and biological indicators

Sediment and aquatic plants were collected annually since the early 1990s in the main French rivers, upstream of nuclear power plants. These time series were used in order to assess the parameters of a compartmental model describing the Chernobyl-derived (137)Cs flux from soil to rivers. In order to reduce the dispersal of (137)Cs measured activities in sediment samples due to the granulometric heterogeneity, a correction method was set up using sediment test-fractions artificially enriched with specific diameter particles. The method was based on (137)Cs affinity for fine particles, especially clays, and thus clay and fine silt contents of each sample was analysed. Corrected sediment data showed (1) that the method efficiently reduced the variability; and (2) that (137)Cs activities in French rivers decreased with a half-life of 4 to 6 years since 1987 (after correction by radioactive decay). A similar half-life value was obtained for aquatic plants pointing out that this half-life is related to the gradual decay of the flux from soil to rivers, not to the indicator itself. Comparing our results with similar ones published by other authors, it appeared possible that this kinetic varies with the time period over which the study is conducted, the longer the period the lower is the kinetic.     

On the occurrence of radioactive fallout over Norway as a result of the Windscale accident, October 1957

A fire at the Windscale plant at Cumbria in the UK between the 10th and the 11th of October 1957 resulted in the first publicised release of radioactivity to the wider environment. The cloud of contamination passed to the southeast of England before travelling northwards on the 14th of October as a result of weather fronts in Europe. Monitoring of radioactive fallout in Norway was at the time conducted by the Norwegian Defence Research Establishment (FFI) using a network of air and precipitation monitoring stations. This article presents results from these monitoring activities which were originally contained in laboratory journals and a series of internal reports produced by FFI. Although mainly classified during the 1950s and 1960s, recent years have seen the incremental declassification of these reports and as the 50th anniversary of the accident approaches, a distillation and reanalysis of this information has been conducted. Results indicate that radioactivity from Windscale was first detected at Bergen and Sola in the south west of Norway and a little later at Vaernes, significant amounts of radioactivity being deposited at these locations during the second and third weeks of that month. Results relating to concentrations of activity in air and precipitation and fallout levels are presented for the relevant period and discussed in relation to fallout levels in Norway during the period 1957-1960.     

Survey of gross beta radioactivity in surface waters of the Midland,Michigan area (lake Huron and the Chippewa,Pine, and Tittabawassee rivers)

Measurements of Lake Huron water as supplied to the Midland location of the Dow Chemical Company over the period 1970–1981 show that a mean concentration of ≈ 3 pCi/L gross beta activity held relatively constant with a range of yearly mean values from 2 to 4 pCi/L and a range of individual values from 1 to 7 pCi/L. This is comparable to observed values for other Great Lakes' waterways reported in the litarature. There was no apparent seasonal fluctuation. Midland area river water for 1967–1981 show median values of 3 to 4 pCi/L and a range of 2 to 11 pCi/L, comparable to those reported in the literature from througout the United States. The observed activity concentrations in the water are well below the limits of the EPA drinking water standards.     

Reconnaissance of submarine groundwater discharge at Ubatuba coast,Brazil, using 222Rn as a natural tracer

Submarine groundwater discharge (SGD), which includes fresh groundwater and recycled seawater, has been recognized as a widespread phenomenon that can provide important chemical elements to the ocean. Several studies have demonstrated that SGD may approach or even exceed freshwater sources in supplying nutrients to coastal zones. This work reports preliminary results of a study carried out in a series of small embayments of Ubatuba, S?o Paulo State, Brazil, covering latitudes between 23 degrees 26'S and 23 degrees 46'S and longitudes between 45 degrees 02'W and 45 degrees 11'W. The main aims of this research were to set up an analytical method to assess 222Rn and 226Ra activities in seawater samples and to apply the excess 222Rn inventories obtained to estimate SGD. Measurements made during the summer of 2001 included 222Rn and 226Ra in seawater, 226Ra in sediment, seawater and sediment physical properties, nutrients and seepage rates. A continuous 222Rn monitor was also used to determine in situ collection of data to study short-term changes at one location. All methods indicated significant inflow of subsurface fluids at rates in excess of several cm per day.     

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.     

Use of 129I and 137Cs in soils for the estimation of 131I deposition in Belarus as a result of the Chernobyl accident

Using radioactivity measurements for 131I and 137Cs and nuclear activation analysis (NAA) or accelerator mass spectrometry (AMS) for 129I, ratios of 131I/137Cs and 129I/137Cs have been determined in soils from Belarus. We find that the pre-Chernobyl ratio of 129I/137Cs in Belarus is significantly larger than expected from nuclear weapons fallout. For the Chernobyl accident, our results support the hypothesis that there was relatively little fractionation of iodine and caesium during migration and deposition of the radioactive cloud. For sites having 137Cs > 300 Bq/kg, 129I can potentially give more reliable retroactive estimates of Chernobyl 131I deposition. However, our results suggest that 137Cs can also give reasonably good (+/-50%) estimates for 131I in Belarus.     

Characterization of natural organic matter from eight Norwegian surface waters: Proton and copper binding

As a part of the International NOM-Typing Project, proton and copper binding studies were conducted on ultrafiltered (>1000 dal.) and dialysed (>100 dal.) natural organic matter (NOM) samples from eight Norwegian Lakes. The NOM samples were similar with respect to proton and copper binding, although minor differences were observed among the samples of different origin. Slight variations occurred for seasonal changes and lime additions. The proton binding pK_a values grouped in three distinct classes: pK_a1 = 4.20–4.28; pK_a2 = 6.61–6.87; and pK_a3 = 9.27–9.8. The average total proton binding site concentration of the NOM samples was: 12.7 meq/g total organic carbon (TOC). Two binding sites were established for copper with average log K1 = 4.84 and log K2 = 7.17. The average site concentration for samples isolated by reverse osmosis (RO) was 0.56 μmol/mg C. Copper binding characteristics appear to be influenced by the method of sample isolation. For NOM isolated by low pressure evaporation (evap), binding site concentrations are smaller, conditional stability constants are higher, variability of the copper complexation capacity is smaller, and correlation with elemental composition (C, N, H) is better than in the case of NOM isolated by RO.     

Pre-concentration of naturally occurring radionuclides and the determination of (212)Pb from fresh waters

A novel technique has been developed for determining the ²¹²Pb activity of fresh waters. This is of interest to environmental monitoring programmes that utilise gross α-activity methods to screen for anthropogenic radionuclides. The contribution from ²¹²Pb varies, and is difficult to experimentally measure due to its relatively short half-life (t_½ = 10.6 h) and low environmental activity (<0.1 Bq l⁻¹). The use of a three-stage technique that encompasses a unique form of pre-concentration, separation and analysis by liquid scintillation counting allows a lower detection limit of 0.006 Bq l⁻¹ with a chemical yield of 92.5 ± 5.6%. The measurement can be obtained within 7 h of sample collection, and is calculated using the radioactive decay of ²¹²Bi. Other naturally occurring radionuclides may also be extracted using the pre-concentration stage of the technique, with efficiencies above 90% at a range of pH values.