137Cs determination and mutagenicity tests in wild Mus musculus domesticus before and after the Chernobyl accident

Wild rodents were collected alive in a suburban area to the north of Rome before, during, 6 months and 1 year after the Chernobyl accident. Radionuclide determinations to assess their content of (137)Cs and mutagenicity tests (bone-marrow micronucleus test and sperm abnormalities assay) were performed on the captured animals. The results obtained for the species Mus musculus domesticus (which was the rodent captured in highest numbers), compared with the results obtained before the fallout, showed an increase of both micronucleated polychromatic erythrocytes (MPCEs/1000 PCEs) and (137)Cs content during and after the fallout.     

Research on the impact of forest stand structure on atmospheric deposition

Dry and wet deposition onto thirty forest stands in relation to stand structure is studied by sampling throughfall and bulk precipitation. Nine measurement sites are situated in Pseudotsuga menziesii stands, ten in Pinus sylvestris and eleven in Quercus robur stands. All stands are situated within a radius of 1.2 km to assure a more or less equal air pollution load. In each stand, detailed forest structure inventories are made to determine aerodynamic roughness, collecting efficiency and surface area parameters. Measurements to data cover a four month period (April-July 1990). First results show relatively high throughfall deposition in Pseudotsuga menziesii stands. Lowest throughfall fluxes are recorded for Quercus robur and intermediate values for Pinus sylvestris stands. There are indications of a relatively strong canopy exchange in Quercus robur stands during the measurement period. Many results from forest stand structure inventories are not available yet. However, a strong relation is observed between throughfall deposition in Pseudotsuga menziesii stands and total crown volume.     

A numerical study on the vertical dispersion of passive contaminants from a continuous source in the atmospheric surface layer

A numerical solution of the diffusion equation is obtained for the vertical diffusion from a continuous source. The wind speed profile and the eddy diffusivity in this equation are expressed in terms of the surface-layer similarity relations obtained in the well-known Kansas experiments. A comparison is made with vertical concentration measurements obtained during the Prairie Grass and Porton experiments. The numerical results are in agreement with these experimental data.     

Estimation of anthropogenic and natural heavy metals in the northwestern Mediterranean rainwater and total atmospheric deposition

As already done for aerosols, natural and anthropogenic Pb, Cd, Cu, and Zn concentrations in rainwater have been separated by a statistical numerical method. The natural part is found to strongly decrease from aerosol to rainwater: from 10–20% to 1% for Pb, Cu and Zn, and from 0.9% to 0.6% for Cd. The mean natural and anthropogenic levels in total atmospheric deposition is estimated.     

Laboratory investigations of the impact of dry deposition of SO2 and wet deposition of acidic species on the atmospheric corrosion of galvanized steel

A series of short-term laboratory experiments were conducted in which galvanized steel samples were exposed to sub-ppm levels of SO₂. Dew was produced periodically on the test panels, and, at the end of some experiments, panels were sprayed with solutions of various pH levels. Both dew and rain rinse samples were analyzed for SO₃²⁻, SO₄²⁻ and Zn.The laboratory results suggest that as a first approximation the damage to galvanized steel induced by the dry deposition of SO₂ can be calculated by equating the dry SO₂ flux to the Zn corrosion flux. SO₂ will deposit onto a fresh dry surface until an amount similar to that of a monolayer has formed. Under wet conditions, the dry deposition flux is controlled by the gas-phase resistance of the atmosphere. Wet deposition of ammonium bisulphate induces corrosion which depends not only on the pH of the incident rain, but also on the exposure history of the samples.     

Effective dose estimation and lifetime cancer mortality risk assessment from exposure to Chernobyl <Superscript>137</Superscript>Cs on the territory of Belgrade City and the region of Vojvodina,Serbia

Purpose  

The purpose of this paper is to determine the activity concentrations of radionuclide ¹³⁷Cs in soil samples on the territory of Belgrade and the province of Vojvodina. Also, the lifetime cancer mortality risk from external exposure during 1 year is assessed, and the effective dose is estimated.     

Radioactive isotopes in atmospheric aerosols over Russia and the Sea of Japan following nuclear accident at Fukushima Nr. 1 Daiichi Nuclear Power Station in March 2011

Artificial radionuclides, such as iodine-131 (¹³¹I), cesium-134 (¹³⁴Cs), and cesium-137 (¹³⁷Cs), as well as natural isotopes of beryllium-7 (⁷Be) and potassium-40 (⁴⁰K) have been registered in atmospheric aerosols over Vladivostok selected from 11 March to 17 June 2011. Additionally, ¹³⁴Cs and ¹³⁷Cs were detected in atmospheric aerosols over Tomsk selected from 16 March to 17 June 2011. Artificial radionuclides were also discovered in atmospheric wet depositions sampled in Vladivostok from 3 to 17 May 2011. Moreover, these radionuclides have been registered in atmospheric aerosols over the sea surface of the Sea of Japan selected from 3 to 31 May 2011 during an expedition of the “Nadezhda” sailing ship. From 18 March to 15 April, an increase in concentrations of atmospheric aerosols over Vladivostok from 108.8 to 321.5 μg/m³ has been registered. It was accompanied by increased activity concentrations of ¹³⁴Cs, ¹³⁷Cs, and the ¹³¹I. During the period from 18 March to 15 April, activity concentrations of ¹³⁷Cs and ¹³⁴Cs in atmospheric aerosols increased 100 times compared with the minimum detectable concentration (MDC) level and peaked in the weekly sample gathered from 8 to 15 April (145.0 and 105.3 μBq/m³, respectively). Variability of concentrations of natural isotopes of ⁷Be and ⁴⁰K was not greater than 1 order of magnitude throughout the sampling period. Maximal values of ¹³⁷Cs and ¹³⁴Cs concentrations (1,281.5?±?141 and 384.4?±?42.3 μBq/m³, respectively) in Tomsk were reached in samples taken from 1 to 2 April. For the atmospheric aerosol samples from the Sea of Japan, the largest concentration of ¹³¹I (392.3?±?215.7 μBq/m³) was detected from 13 to 19 May, while all other samples had much lower concentration values. Synoptic analysis of back trajectories movement of air masses showed that the radioactive cloud came to Vladivostok from the regions of Siberia and northeastern part of China. Synoptic analysis for Tomsk showed that during the period of maximal activity concentrations (1–9 April), air masses were arriving from the European part of Russia and north of Kazakhstan.     

Constraints on the use of 137Cs as a time-marker to support CRS and SIT chronologies

CRS and SIT are two (210)Pb-based models widely used in the radiometric dating of recent sediments. (210)Pb chronologies should be validated using at least one independent tracer, such as (137)Cs. This paper demonstrates that simple methods based on the identification of (137)Cs fallout peaks cannot provide a definitive support for CRS and SIT chronologies. Two main arguments will support this assertion: Firstly, the (137)Cs time-marks cannot support a CRS or SIT chronology if the derived sedimentation rates cannot explain the whole (137)Cs activity profile without postulating mixing. Secondly, the support by the (137)Cs time-marks for a given CRS or SIT chronology cannot be considered as definitive if other dating models can equally explain the whole set of data, thereby producing a different chronology. Several case studies selected from the literature are used to support the present discussion.     

Precision of atmospheric dry deposition data from the Clean Air Status and Trends Network

A collocated, dry deposition sampling program was begun in January 1987 by the US Environmental Protection Agency to provide ongoing estimates of the overall precision of dry deposition and supporting data entering the Clean Air Status and Trends Network (CASTNet) archive. Duplicate sets of dry deposition sampling instruments were installed adjacent to existing instruments and have been operated for various periods at 11 collocated field sites. All sampling and operations were performed using standard CASTNet procedures. The current study documents the bias-corrected precision of CASTNet data based on collocated measurements made at paired sampling sites representative of sites across the network. These precision estimates include the variability for all operations from sampling to data storage in the archive. Precision estimates are provided for hourly, instrumental ozone (O₃) concentration and meteorological measurements, hourly model estimates of deposition velocity (V_d) from collocated measurements of model inputs, hourly O₃ deposition estimates, weekly filter pack determinations of selected atmospheric chemical species, and weekly estimates of V_d and deposition for each monitored filter pack chemical species and O₃.Estimates of variability of weekly pollutant concentrations, expressed as coefficients of variation, depend on chemical species: NO₃⁻∼8.1%; HNO₃∼6.4%; SO₂∼4.3%; NH₄⁺∼3.7%; SO₄²⁻∼2.3%; and O₃∼1.3%. Precision of estimates of weekly V_d from collocated measurements of model inputs also depends on the chemical species: aerosols ∼2.8%; HNO₃∼2.6%; SO₂∼3.0%; and O₃∼2.0%. Corresponding precision of weekly deposition estimates are: NO₃⁻∼8.6%; HNO₃⁻∼5.2%; SO₂∼5.6%; NH₄⁺∼3.9%; SO₄²⁻∼3.5%; and O₃∼3.3%. Precision of weekly concentration, V_d estimates, and deposition estimates are comparable in magnitude and slightly smaller than the corresponding hourly values. Annual precision estimates, although uncertain due to their small sample size in the current study, are consistent with the corresponding weekly values.     

不同覆盖材料对沉积物P、N释放的抑制效果

以百花湖沉积物为实验对象,选取沸石、粘土、生物炭、褐铁矿和高岭土等5种覆盖材料开展模拟柱静态实验,研究上覆水中总氮(TN)、总磷(TP)和氨氮变化规律。在静态模拟柱90 d实验过程中,第45天时上覆水中TN、氨氮浓度最高,分别为8.79和6.10 mg/L。第45天时氨氮浓度最低的是生物炭组,为1.62 mg/L, 第45天时TN浓度最低的是粘土组,为1.92 mg/L。第45天后上覆水TN、氨氮浓度下降,实验结束时生物炭组TN和氨氮浓度均最低,其浓度分别为0.74和0.42 mg/L。实验过程中TP浓度不断上升,到实验结束时空白组TP浓度0.42 mg/L,高岭土组TP浓度最低为0.027 mg/L。百花湖水质主要超标指标为TP,而高岭土覆盖对沉积物中P释放的抑制优于其他4种材料,且在百花湖地区易获得、无污染,故建议以高岭土为百花湖原位覆盖材料。     

Influence of the surface microlayer on atmospheric deposition of aerosols and polycyclic aromatic hydrocarbons

Atmospheric dry deposition is an important process for the introduction of aerosols and pollutants to aquatic environments. The objective of this paper is to assess, for the first time, the influence that the aquatic surface microlayer plays as a modifying factor of the magnitude of dry aerosol deposition fluxes. The occurrence of a low surface tension (ST) or a hydrophobic surface microlayer has been generated by spiking milli-Q water or pre-filtered seawater with a surfactant or octanol, respectively. The results show that fine mode (<2.7 μm) aerosol phase PAHs deposit with fluxes 2–3 fold higher when there is a low ST aquatic surface due to enhanced sequestration of colliding particles at the surface. Conversely, for PAHs bound to coarse mode aerosols (>2.7 μm), even though there is an enhanced deposition due to the surface microlayer for some sampling periods, the effect is not observed consistently. This is due to the importance of gravitational settling for large aerosols, rendering a lower influence of the aquatic surface on dry deposition fluxes. ST (mN m⁻¹) is identified as one of the key factor driving the magnitude of PAH dry deposition fluxes (ng m⁻² d⁻¹) by its influence on PAH concentrations in deposited aerosols and deposition velocities (v_d, cm s⁻¹). Indeed, v_d values are a function of ST as obtained by least square fitting and given by Ln(v_d)=−1.77 Ln(ST)+5.74 (r²=0.95) under low wind speed (average 4 m s⁻¹) conditions.     

Effect of atmospheric N deposition on surface water chemistry and the implications for fisheries

In this paper the relative importance of NO3- and SO4(2-) as anions in oligotrophic surface waters and evidence that NO3 concentrations have been increasing in recent decades in reviewed. The relationship between NO3- and the concentrations of cations (H+ and Al3+) known to be harmful to aquatic biota is also discussed. It is generally concluded that although direct proof of an association is lacking, circumstantial evidence suggests that atmospheric input of nitrogen to soils on certain 'sensitive' geologies may be having consequences for surface waters and the biota living in them, especially at certain times of the year, e.g. snowmelt.     

Analysis of PCDD/Fs and dioxin-like PCBs in atmospheric deposition samples from the Flemish measurement network: correlation between the CALUX bioassay and GC-HRMS

Since the CALUX (Chemically Activated LUciferase gene eXpression) bioassay is a fast, sensitive and inexpensive tool for the analysis of a high number of samples, the use of this technique in routine analysis of atmospheric deposition samples may be a valuable alternative for GC-HRMS. In this study, a validated CALUX method was used for the analysis of PCDD/Fs and dioxin-like PCBs in more than 90 atmospheric deposition samples for different locations in Flanders. The samples were taken in residential and agricultural areas, where a threshold limit of 21 pg WHO-TEQ m⁻² d⁻¹ for the sum of PCDD/Fs and dioxin-like PCBs was set, and in industrial zones and natural reserves, where no official threshold limit is available. The results from the Flemish measurement program showed correlation between CALUX and GC-HRMS for all the samples, originating from the different areas (R² of 0.81, 0.53 and 0.64 for dl-PCBs, PCDD/Fs and sum of both fractions, respectively). Median CALUX/GC-HRMS ratios of 2.0, 0.9 and 1.3 were reported for the PCDD/Fs, dioxin-like PCBs and the sum of both fractions, respectively. The results show that the CALUX bioassay is a valuable alternative tool for the classic GC-HRMS analysis of atmospheric deposition samples in the Flemish measurement network.     

Effects of dry deposition on the concentration-distributions of atmospheric pollutants within land- and sea-breeze circulations

In a land- and sea-breeze situation, effects of dry deposition on the dynamics of the concentrations of chemically reacting air pollutants are investigated using a transport/transformation/removal model with diurnally varying deposition velocities modeled in terms of the aerodynamic, surface, and residual resistances. The results show that the diurnally varying flows and eddy diffusivities, which are characteristic of the landand sea-breeze system, transfer the effects of dry deposition on the concentrations quickly to the upper layer over the land and sea surfaces. The dry deposition effect on one species can be transmitted to others through the network of chemical reactions, e.g. inclusion of dry deposition into the simulation resulted in the increase of hydrocarbon concentrations. It is also predicted that the dry deposition processes could remove a considerable part of emitted NO_x, and SO₂ from the local circulations, e.g. for 2 days about 40% of the emitted NO_x was removed by the dry deposition of NO, NO₂, HNO₃ and PAN and in the case of SO₂, 25 % by that of SO₂ and SO₄²⁻.     

中国SO_2排放对日本SO_2浓度及硫沉降的影响

利用相关文献及来自酸沉降网的中、日两国各观测站点的SO2监测资料,分析了近十年来中国SO2的污染现状、趋势及排放量对下风向日本各观测站点SO2浓度及硫沉降量的影响。结果表明,通过文献分析可知,2001—2009中国的SO2年均质量浓度分布在40~50μg/m3,总体呈下降趋势;中国部分城市的SO2年均浓度与中国SO2排放量的相关性总体高于日本各观测站点的SO2年均浓度与中国SO2排放量的相关性,中国的SO2排放对日本各观测站点的SO2年均浓度影响总体较小;情景模拟分析发现,中国SO2排放量对日本各观测站点SO2年均浓度的贡献率在7.5%~44.0%,平均贡献率为22.6%;中国SO2排放量对日本各观测站点硫沉降的贡献率在8%~41%,平均贡献率为22.1%。     

Influence of major African dust intrusions on the 137Cs and 40K activities in the lower atmosphere at the Island of Tenerife

The influence of two intensive low-altitude atmospheric-dust intrusions on the activity levels of ¹³⁷Cs and ⁴⁰K as well as atmospheric particle matter (PM10) concentrations in the lower atmosphere of the Canary Islands are analysed here. These two events took place at the beginning of January 2002 and March 2004, respectively. 3D atmospheric back-trajectories indicated that the main source of dust material involved in the considered atmospheric intrusions came from NW Africa. A consequence of these dust intrusions was the major increase of PM10 concentrations in the lower atmosphere. Both episodes were characterised by having weekly averages of PM10 concentration surpassing 150 μg m⁻³, higher than the daily PM10 limit value established by the EC/1999/30 directive for PM10 from 2005. Similarly, during these two events, both ¹³⁷Cs and ⁴⁰K activities increased by a factor of 6 and 13 as well as 13 and 14, respectively, over the basal values calculated for each radionuclide and time period (0.59±0.02 and 0.88±0.07 μBq m⁻³ as well as 12±6 and 24±8 μBq m⁻³).