Problems in predicting <Superscript>137</Superscript>Cs levels in lake waters of eastern Fennoscandia

With regard to data on two-year exposure of Chernobyl-derived ¹³⁷Cs in lakes with average depths ranging from 2 to 15 m, contamination of lake waters has been estimated using a sorption-diffusion model with ¹³⁷Cs distribution and diffusion coefficients of 4000 l/kg and 1.0 × 10⁻⁷ cm², respectively.     

Long-term dynamics of radioactive <Superscript>90</Superscript>Sr and <Superscript>137</Superscript>Cs contamination of small mammals in the Chernobyl zone

Between 1986 and 1994, a decrease in nonalimentary ⁹⁰Sr and ¹³⁷Cs intake and changes in the accessibility of radionuclides in the soil-plant link of their cycle resulted in a 10-to 100-fold decrease in their specific activity (SA) in the bodies of small mammals inhabiting the Chernobyl zone, and a similar decrease was observed in the radionuclide transition factor (TF) in the soil-animal chain. Between 1995 and 2005, no consistent increase or decrease in SA or TF could be revealed against the background of a combined effect of different physicochemical and ecological factors. It is suggested that subsequent changes in the level of radioactive contamination of small mammals will generally reflect only the dynamics of physical ⁹⁰Sr and ¹³⁷Cs decay, but, nevertheless, seasonal and local variations in this level will be significant.     

Spatial Distribution of Animals and Variation in Their Trophic Activity Measured Using the Bait-Lamina Test in Sod-Podzolic Soil under a Spruce Forest

The mode of spatial distribution of soil animals and their trophic activity was studied in the sod-podzolic soil under a spruce forest. At the test point level, no apparent relationship between the distribution of soil animals and physicochemical characteristics of the soil was observed. The patterns of distribution of detritophages and the trophic activity (measured using the bait-lamina test) were similar. The perforation of laminae in the bait-lamina test resulted from the trophic activity of both micro- and mesofauna.     

Migration of Heavy Metals from Polluted Soil to Plants and Lichens under Conditions of Field Experiment on the Kola Peninsula

Russian Journal of Ecology - We have carried out a field experiment to study the migration of Ni, Cu, and Co from the organic horizon of Al–Fe-humus podzols polluted with heavy metals (HMs)...     

临沂水源地水库沉积物重金属分布、来源及生态风险评价

水源地沉积物重金属对生态环境和供水具有极大的潜在危害,一直是水资源保护研究中的热点科学问题.本研究选取临沂市3个水源地水库开展8种重金属(Cr、Cu、Cd、Ni、Pb、Zn、As和T1)的监测和研究,分析其污染及空间分布特征,利用地累积指数法和潜在生态风险指数法开展污染状况评价,并利用主成分分析法(PCA)和相关分析法对沉积物重金属进行源解析.结果 表明:3个水库沉积物重金属Cr、Zn和Pb均严重超过山东省土壤环境背景值;云蒙湖Cd轻度超标;许家崖水库沉积物重金属Cu严重超标.地积累指数法与内梅罗综合指数法评估结果显示,3大水库Zn为中度污染,云蒙湖Pb为偏中度污染,其余重金属无污染或污染较轻.生态风险指数法(RI)评估结果显示,跋山水库、云蒙湖、许家崖水库总体的RI平均值分别为52.05、59.75、61.92,三大水库均处于低度风险水平.统计分析表明研究区域沉积物中重金属主要来自自然源(36.5％)、农业生产(26.1％)、水产养殖(13.7％).     

Distribution of 137Cs in the Tree Layer of Forest Ecosystems in the Zone of the Accident at the Chernobyl Nuclear Power Plant

Trends in ¹³⁷Cs distribution over the parts of coniferous (Pinus sylvestrisL.) and deciduous (Betula pendula Rocht.) trees are described. The trees have been selected in the stationary experimental plots located in southwestern Bryansk oblast, Russian Federation. The distribution of ¹³⁷Cs in the wood along the trunk height is shown to be nonuniform. The effects of ¹³⁷Cs content in the xylem sap on the accumulation of this radionuclide in the leaves and needles are assessed. The factors controlling ¹³⁷Cs accumulation in the components of woody plants are revealed, and their significance is estimated.     

Distribution of 90Sr and 137Cs in Arctic soil profiles polluted by heavy metals

Effects of industrial pollution on the behaviour of radionuclides in spruce forest ecosystems were studied along a gradient from of a copper-nickel smelter in Monchegorsk, NW Russia. A reference site was situated in Lapland, Finland, 152 km west of Monchegorsk. Most of the total 137Cs activity in soil was in mineral (E and B) horizons, except at the reference site where the major part was still in the organic surface layer. Most of the total 90Sr activity still remaining in the soil profile was found in the surface layer, but the relative amount decreased with increasing level of industrial pollution. Pollutants from the smelter clearly affected the chemical speciation of radionuclides. Smaller amounts of exchangeable radionuclides were present in the organic surface layer at the most polluted sites. The decline of 137Cs with decreasing distance from the smelter correlated strongly with a similar depletion in exchangeable K and Mg. Total concentrations of 137Cs and 90Sr showed high correlations with exchangeable cations, particularly in the E and upper B horizon. A sudden change in behaviour of 137Cs in the lower B horizon may be associated with changes in clay mineralogy along the soil profile caused by weathering.     

Soil to plant transfer of 137Cs and 60Co in Ferralsol, Nitisol and Acrisol

In this study, soil to plant transfer factor values were determined for 137Cs and 60Co in radish (Raphanus sativus), maize (Zea mays L.) and cabbage (Brassica oleracea L. var. capitata) growing in gibbsite-, kaolinite- and iron-oxide-rich soils. After 3 years of experiment in lysimeters it was possible to identify the main soil properties able to modify the soil to plant transfer processes, e.g. exchangeable K and pH, for 137Cs, and organic matter for 60Co. Results of sequential chemical extraction were coherent with root uptake and allowed the recognition of the role of iron oxides on 137Cs behaviour and of Mn oxides on 60Co behaviour. This information should provide support for adequate choices of countermeasures to be applied on tropical soils in case of accident or for remediation purposes.     

Distribution of Fine Roots of Coniferous Trees over the Soil Profile under Conditions of Pollution by Emissions from a Copper-Smelting Plant

The distribution of fine conducting roots of Siberian spruce, Siberian fir, and Scotch pine over the soil profile was studied in the taiga ecosystems polluted with heavy metals and SO₂. Under conditions of heavy pollution, tree roots were not found in the forest litter. Regardless of the level of technogenic load, the largest amount of conducting roots concentrated in the upper layer of mineral soil.     

Ordination of Plant Communities in Forest Biogeocenoses under Conditions of Air Pollution in the Northern Kola Peninsula

The species diversity and structure of the tree, herb–dwarf shrub, and moss–lichen layers in the biogeocenoses (BGCs) of pine forests of the Kola Peninsula were analyzed in the zone affected by the Pechenganikel Combined Works. Relationships of the diversity of phytocenoses with the amount of atmospheric fallout and the concentrations of accessible compounds of polluting elements (nickel and copper) and nutrients (potassium, magnesium, and nitrogen) in forest litters were revealed.     

两种土地利用方式下土壤重金属污染特征与评价

为研究安徽铜陵某矿区耕地和人工林地两种土地利用方式下土壤重金属污染特征，应用Tomlinson污染负荷指数法和生物富集系数评价研究区土壤重金属Cd、Cu污染水平和植物重金属富集水平。结果表明：研究区耕地土壤Cd、Cu全量2.34和161.25 mg/kg，均高于林地Cd、Cu全量1.26和80.15 mg/kg，二者均超农用地土壤污染风险筛选值（GB 15618-2018，pH≤5.5）和铜陵市重金属背景值，耕地和林地污染水平分别为中度污染和轻微污染。耕地糙米Cd（0.95 mg/kg）超标严重，黄山栾树地上部Cd、Cu富集系数均低于水稻地上部。综上，黄山栾树人工林地Cd、Cu污染轻于耕地，退耕还林是研究区更佳的土地利用选择。     

Chemical availability of 137Cs and 90Sr in undisturbed lysimeter soils maintained under controlled and close-to-real conditions

Chemical availability of 137Cs and 90Sr was determined in four undisturbed soils in a lysimeter study three and four years after deposition to the soil surface. The study was part of a larger project on radionuclide soil-plant interactions under well-defined conditions. The soil types were loam, silt loam, sandy loam and loamy sand, and were representatives of important European soil and climatic conditions. The lysimeters were installed in greenhouses with climatic and hydrological control, and were contaminated with 137Cs and 90Sr in an aerosol mixture simulating fallout from a nuclear accident. Soil samples were taken from several depths in each soil in 1997 and 1998 and the samples were sequentially extracted with H2O, NH4Ac, NH2OH.HCl, H2O2 and HNO3. Extractability of 137Cs decreased in the order: HNO3 > R-esidual > or = NH4Ac > H2O2 > or = NH2OH.HCl > or = H2O. More than 80% was found in the acid digestible or residual fractions, and 11-17% in labile fractions. Soil type differences were small. Extractability of 90Sr decreased in the order: NH4Ac > NH2OH.HCl > HNO3 > H2O2 approximately H2O. 31-58% was found in easily available fractions. Differences between soil types were quite small. The results suggest that availability of 137Cs for plant uptake and migration is low, whereas availability of 90Sr is rather high.     

南昌市街道灰尘重金属时空分布特征及健康风险评估

分析了南昌市夏季和冬季街道104个灰尘样品中的V、Cr、Co、Ni、Cu、Zn、As、Cd和Pb含量,并利用地积累指数（Igeo）计算其污染程度,并参考美国国家环保局(US EPA)推荐的健康风险模型评价灰尘重金属暴露的人体致癌和非致癌风险,通过主成分和相关分析识别南昌市灰尘重金属的可能来源。结果表明：南昌市街道灰尘中重金属Cr、Ni、Cu、Zn、Cd和Pb含量均显著高于江西省土壤背景值,而V、Co和As含量与江西省土壤背景值含量相近。重金属V、Co和As含量无显著季节差异,但冬夏季节含量的空间异质性较高,而Cu在季节和空间分布上均表现出显著的季节差异,其它重金属的高值区均分布在南昌市中心及老工业园附近;Igeo结果表明Cd、Cu、Zn和Cr的污染程度相对较高,而V、As和Co污染程度较轻;重金属3种暴露途径的风险排序为手-口暴露>皮肤接触暴露>呼吸暴露,其中儿童会遭受更大的非致癌风险。除了灰尘As和Cr对儿童的暴露在局部区域HQ和HI值大于1,其它重金属对不同人群的HQ和HI值均小于1。总体而言,南昌市灰尘重金属的致癌风险CR均在安全阈值范围内,大小排序为Cr > As > Co > Ni > Cd。南昌市灰尘重金属的来源广泛,其中As、Co和V主要来源于岩石风化,其它重金属元素主要来源于交通和工业等人类活动。 关键词： 街道灰尘;重金属;时空分布;健康风险;南昌市     

Accumulation of (137)Cs in Brazilian soils and its transfer to plants under different climatic conditions

The spatial distribution and behaviour of the global fallout (137)Cs in the tropical, subtropical and equatorial soil-plant systems were investigated at several upland sites in Brazil selected according to their climate characteristics, and to the agricultural importance. To determine the (137)Cs deposition density, undisturbed soil profiles were taken from 23 environments situated between the latitudes of 02 degrees N and 30 degrees S. Sampling sites located along to the equator exhibited (137)Cs deposition densities with an average value of 219Bqm(-2). Extremely low deposition densities of 1.3Bqm(-2) were found in the Amazon region. In contrast, the southern part of Brazil, located between latitudes of 20 degrees S and 34 degrees S, exhibited considerably higher deposition densities ranging from 140Bqm(-2) to 1620Bqm(-2). To examine the (137)Cs soil-to-plant transfer in the Brazilian agricultural products, 29 mainly tropical plant species, and corresponding soil samples were collected at 43 sampling locations in nine federal states of Brazil. Values of the (137)Cs concentration factor plant/soil exhibited a large range from 0.020 (beans) to 6.2 (cassava). Samples of some plant species originated from different collecting areas showed different concentration factors. The (137)Cs content of some plants collected was not measurable due to a very low (137)Cs concentration level found in the upper layers of the incremental soils. Globally, the soil-to-plant transfer of (137)Cs can be described by a logarithmic normal distribution with a geometric mean of 0.3 and a geometric standard deviation of 3.9.     

Effects of Soil Hydrothermal Conditions on the Complexes of Soil Invertebrates in Coniferous and Deciduous Forest Cultures

The effects of hydrothermal conditions on the complexes of soil invertebrates in 20-year-old cultures of Siberian stone pine, larch, Scotch pine, spruce, birch, and aspen are considered. The role of soil temperature and moisture content in determining the density of pedobionts and their vertical distribution is revealed. Seasonal fluctuations of hydrothermal parameters are shown to affect the vertical migrations of soil invertebrates and the dynamics of trophic structure of their complexes under forest cultures during the growing season.