Plutonium, 137Cs and 90Sr in selected invertebrates from some areas around Chernobyl nuclear power plant

Results are presented for ¹³⁷Cs, ⁹⁰Sr and plutonium activity concentrations in more than 20 samples of terrestrial invertebrates, including species of beetles, ants, spiders and millipedes, collected in the highly contaminated area of the Chernobyl exclusion zone. The majority of samples were collected in Belarus, with some also collected in the Ukraine. Three other samples were collected in an area of lower contamination. Results show that seven samples exceed an activity concentration of 100 kBq/kg (ash weight - a.w.) for ¹³⁷Cs. The maximum activity concentration for this isotope was 1.52 ± 0.08 MBq/kg (a.w.) determined in ants (Formica cynerea). Seven results for ⁹⁰Sr exceeded 100 kBq/kg (a.w.), mostly for millipedes. Relatively high plutonium activity concentrations were found in some ants and earth-boring dung beetles. Analyses of activity ratios showed differences in transfer of radionuclides between species. To reveal the correlation structure of the multivariate data set, the Partial Least-Squares method (PLS) was used. Results of the PLS model suggest that high radiocesium activity concentrations in animal bodies can be expected mainly for relatively small creatures living on the litter surface. In contrast, high strontium activity concentrations can be expected for creatures which conduct their lives within litter, having mixed trophic habits and a moderate lifespan. No clear conclusions could be made for plutonium.     

有机污染土壤通风去污技术优化设计

有机污染土壤通风去污技术（SVE）是一种经济,安全的场内治理技术,SVE优化设计包括建立污染土壤通风去污模型和抽排去污流场模型,并以此为基础算工程费用,用一虚拟工况对提出的模型及计算公式进行了验证。     

Investigating incorporation and distribution of radionuclides in trinitite

Most of the surface explosions in nuclear tests have released radioactivity to the environment in the form of bulk glassy materials originating from the melting of sandy soil in the neighbourhood of ground zero. In view of clarifying issues concerning the mechanism of formation and the radiological impact of these materials, we investigated incorporation and volume distribution of radionuclides in a typical fragment of trinitite, the glassy substance generated following the first nuclear test (Trinity Site, New Mexico, 1945). Specific activities were determined by γ-spectrometry for the most significant fission and activation products. In particular, ¹⁵²Eu activity was used to estimate the original point of collection of the sample with respect to ground zero. After embedding in an epoxy resin, the sample was then sliced to perform cross-sectional β- and α-autoradiograph. α-spectrometry was also carried out on a fine powder obtained by surface abrasion. In the β-autoradiography, hot spots were distinguishable in the proximity of the blast side, over a 1000 times less intense background of sand activation products. Also α-contamination (from ^239+240Pu and ²⁴¹Am) was mostly concentrated within the superficial layer, in a fraction of only 20% of the overall volume of the sample, exhibiting a discontinuous, droplet-like distribution. This evidence would partially support a recent hypothesis on trinitite formation according to which most of the glass layer was formed not on the ground but by a rain of material injected into the fireball that melted, fell back, and collected on a bed of already fused sand.     

The Future of Baltic Sea Populations: Local Extinction or Evolutionary Rescue?

Environmental change challenges local and global survival of populations and species. In a species-poor environment like the Baltic Sea this is particularly critical as major ecosystem functions may be upheld by single species. A complex interplay between demographic and genetic characteristics of species and populations determines risks of local extinction, chances of re-establishment of lost populations, and tolerance to environmental changes by evolution of new adaptations. Recent studies show that Baltic populations of dominant marine species are locally adapted, have lost genetic variation and are relatively isolated. In addition, some have evolved unusually high degrees of clonality and others are representatives of endemic (unique) evolutionary lineages. We here suggest that a consequence of local adaptation, isolation and genetic endemism is an increased risk of failure in restoring extinct Baltic populations. Additionally, restricted availability of genetic variation owing to lost variation and isolation may negatively impact the potential for evolutionary rescue following environmental change.     

Determination of U, Pu and Am isotopes in Irish Sea sediment by a combination of AMS and radiometric methods

Samples from a marine sediment core from the Irish Sea (54.416 N, 3.563 W) were analyzed for the isotopic composition of uranium, plutonium and americium by a combination of radiometric methods and AMS. The radiochemical procedure consisted of a Pu separation step by anion exchange, subsequent U separation by extraction chromatography using UTEVA^® and finally Am separation with TRU^® Resin.Additionally to radiometric determination of these isotopes by alpha spectrometry, the separated samples were also used for the determination of ²³⁶U/²³⁸U and plutonium isotope ratios by Accelerator Mass Spectrometry (AMS) at the VERA facility.     

Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands

In the context of the European Water Framework Directive, controlled flooding of lowlands is considered as a potential water management strategy to minimise the risk of flooding of inhabited areas. However, due to historical pollution and overbank sedimentation, metal levels are elevated in most wetlands, which can cause adverse effects on the ecosystem's dynamics. Additionally, salinity affects the bioavailability of metals present or imported into these systems. The effect of different flooding regimes and salinity exposure scenarios (fresh- and brackish water conditions) on Cu and Zn accumulation in the oligochaete Tubifex tubifex (Müller, 1774) was examined. Metal mobility was closely linked to redox potential, which is directly related to the prevalent hydrological regime. Flooded, and thus more reduced, conditions minimized the availability of metals, while oxidation of the substrates during a drier period was associated with a rapid increase of metal availability and accumulation in the oligochaetes.     

宁夏入黄排水沟中药物和个人护理品的污染特征与生态风险评价

药物和个人护理品（PPCPs）是一类新污染物,对水生生物具有潜在危害.为探究宁夏入黄排水沟中PPCPs的污染特征与生态风险,利用固相萃取-超高效液相色谱-质谱联用仪对21种PPCPs进行检测分析．结果表明,宁夏入黄排水沟中目标PPCPs的总浓度范围在47.52~1 700.96 ng·L^-1之间.其中,环丙沙星、对乙酰氨基酚、二苯甲酮-3和避蚊胺的检出率大于80%;检出浓度最大的5种化合物分别为对乙酰氨基酚、避蚊胺、咖啡因、二苯甲酮-3和左氧氟沙星,浓度最大值分别为597.21、563.23、559.00、477.28和473.07 ng·L^-1.空间分布上,排水沟中PPCPs的污染程度呈现出银川市>石嘴山市>吴忠市>中卫市的分布特征,入黄口采样点PPCPs总浓度范围为124.82~1 046.61 ng·L^-1.来源分析表明,宁夏入黄排水沟中磺胺嘧啶和土霉素主要来自于畜禽养殖,左氧氟沙星和环丙沙星主要来源于医疗废水,三氯卡班和三氯生来自于生活污水和工业废水,咖啡因和避蚊胺主要来自于生活污水.入黄排水沟中双氯芬酸、西咪替丁、三氯卡班和三氯生的污染程度与区域人口数量和经济发展水平呈正相关.生态风险评价结果显示,宁夏入黄排水沟中左氧氟沙星、双氯芬酸、吉非罗齐、二苯甲酮-3和三氯卡班表现为高风险;值得关注的是,大多数采样点PPCPs的综合生态风险表现为高风险.     

引水调控改善太湖湖湾水环境及其效果预测

在总结太湖水污染问题的基础上,分析得出水流缓慢、动力掺混能力弱、水流交换不畅、水体自净能力差、纳污能力小、入湖污染负荷量大且远超过湖湾的纳污能力是梅梁湖湾水污染严重的主要原因,提出区域水污染综合治理、入湖污染物总量控制、引水调控等水污染防治策略及其关键控制技术,利用数值模拟技术给出了太湖梅梁湖湾入湖污染物排放总量控制定额,并结合引江济太调水试验,采用平面二维水流水质数学模型模拟预测引水调控对梅梁湖湾的水环境改善效果及大流量集中调水和小流量维持性调水的水环境     

Winter survival of microbial contaminants in soil: An in situ verification

The aim of the research was to evaluate, at site scale, the influence of freezing and freeze/ thaw cycles on the survival of faecal coliforms and faecal enterococci in soil, in a climate change perspective. Before the winter period and during grazing, viable cells of faecal coliforms and faecal enterococci were detected only in the first 10 cm below ground, while, after the winter period and before the new seasonal grazing, a lower number of viable cells of both faecal indicators was detected only in some of the investigated soil profiles, and within the first 5 cm. Taking into consideration the results of specific investigations, we hypothesise that the non-uniform spatial distribution of grass roots within the studied soil can play an important role in influencing this phenomenon, while several abiotic factors do not play any significant role. Taking into account the local trend in the increase of air temperature, a different distribution of microbial pollution over time is expected in spring waters, in future climate scenarios. The progressive increase in air temperature will cause a progressive decrease in freeze/thaw cycles at higher altitudes, minimising cold shocks on microbial cells, and causing spring water pollution also during winter.     

Degradation of Soil Environment in the Post‐Flooding Area: Content of Polycyclic Aromatic Hydrocarbons (PAHs) and S‐Triazine Herbicides

Impacts of flooding on the soil environment with regard to soil pollution with polycyclic aromatic hydrocarbons and s‐triazine (cyanazine, simazine, atriazine, propazine, prometryn) herbicides have been evaluated. No clear differences in the sum of the PAHs content were observed in the present studies. Only changes in the levels of individual PAHs were noted. In soils covered with flooding both at a depth of 0–20 and 20–40 high molecular weight PAHs were predominant (especially mutagenic and carcinogenic 5‐rings PAHs) whereas in non‐flooded areas, 2‐ and 3‐rings PAHs constituted over 80%. In the case of s‐triazine herbicides, no influence of flooding on the changes in their content in agriculturally used soils was noted. On the other hand, clearly lower levels of cyanazine, simazine and atriazine were not in the flooded forest soil as compared to the non‐flooded forest soil.