Availability and plant uptake of heavy metals from contaminated dredged material placed in flooded and upland disposal environments

The availability and plant uptake of heavy metals was evaluated from contaminated dredged material placed in flooded and upland disposal environments using a solid-phase plant bioassay. The objective of the study was to verify previous dredged material research results and to develop a plant bioassay procedure that could indicate phytotoxicity and bioaccumulation of heavy metals in contaminated dredged material. The plant bioassay indicated more uptake and bioaccumulations of cadmium and, to a lesser extent, zinc when contaminated dredged material was placed in an upland environment where the sediment was allowed to air-dry. Placing the contaminated dredged material in a flooded (reduced) environment lowered the availability and plant uptake of cadmium and, to a lesser extent, zinc. Factors that influenced the availability and plant uptake of heavy metals from contaminated sediments included sediment oxidation-reduction potential, organic matter content, total sulfur content, and pH. The plant bioassay showed phytotoxicity and bioaccumulation of arsenic under a flooded environment. Placing the arsenic-contaminated sediment in an upland environment reduced both the phytotoxicity and bioaccumulation of arsenic in the freshwater marsh plant Cyperus esculentus.     

Hyperaccumulation of Pb, Zn and Cd in herbaceous grown on lead-zinc mining area in Yunnan, China

A field survey of herbaceous growing on lead-zinc mining area in Yunnan, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Zn and Cd in shoots. In total, 220 plant samples of 129 species of 50 families and 220 soil samples in which the plants were growing were collected. According to accumulation concentration in plant shoots and the concentration time levels compared to plants from non-polluted environments, 21 plant samples of 16 species were chosen as best-performing specimens, 11 plant samples of 10 species for Pb, 5 plant samples of 4 species for Zn and 5 plant samples of 5 species for Cd. Sonchus asper (L.) Hill in Qilinkeng had hyperaccumulation capacity to Pb and Zn. Corydalis pterygopetala Franch in Paomaping had hyperaccumulation capacity to Zn and Cd. All 5 Cd hyperaccumulators came from Lanping lead-zinc mining area. Out of 11 Pb hyperaccumulators, 7 came from Minbingying of Huice lead-zinc mining area. The average of the concentration time levels compared to plants from non-polluted environments were higher than 10 times in all plant samples, the concentration time levels changed from 203 times to 620 times for Pb, from 50 times to 70 times for Zn and from 145 times to 330 times for Cd. Out of 21 plant samples, translocation factor changed from 0.35 to 1.90, only translocation factor of 7 plant samples were higher than 1. Enrichment coefficients of all samples were lower than 1. These plant species were primarily heavy metal hyperaccumulator, and will be used in phytoremediation of the metallic pollutants in soils after further research in accumulation mechanism.     

气候变暖等因素对山东省种植业产出的影响

通过建立引入气候因素的种植业生产函数模型,利用1990-2009年山东省40个县市种植业生产及气象面板数据,运用产出增长分解法,实证分析气候因素和非气候因素对山东省种植业产出的影响并对产出增长的各要素贡献进行分解。结果表明:气候变暖对山东省种植业带来明显的负面影响。1990-2009年间气候因素对山东省40个县市的总体产出增长的影响为-11.03%,在其他条件不变的情况下,平均温度每升高1℃,总体种植业总产值减少2.2%,总体产值增长下降1.48%;温度升高对鲁西北地区、鲁南地区种植业产出的影响最为明显;同时,降水对种植业产出影响显著,降水因素使得山东省种植业产出增长减少16.86%;物质投入中化肥和农药对种植业产出增长贡献最大,但农业劳动力减少,特别是种植业劳动力的减少,开始显著地影响种植业产出,使得种植业产出增长减少5.90%;技术进步的影响作用在下降。     

滇池人工湿地的植物群落学特征研究

用植物群落生态学方法,研究了滇池小河口的天然湿地以及表流和潜流两种人工湿地的植被群落学特征。研究区内调查发现有12种植物群落,包含有植物17种。结果表明：表流人工湿地的群落多样性大于潜流人工湿地,甚至也大于天然湿地;在两种人工湿地中,植物群落中的层次数比较接近;从植被群落结构来看,在物种多样性和shannon wiener指数方面表现为潜流人工湿地大于表流人工湿地,天然湿地居中。从天然湿地到表流湿地,再到潜流湿地,随着湿地环境水文条件的变化,植物群落组成与分布状况也在变化,表现出从湿地植物向陆生植物演替的趋势。研究表明两种人工湿地中的芦苇（Phragmites australis）群落长势不同。在人工湿地中适宜构建芦苇群落,在表面流人工湿地植物选择中可以考虑水芹菜（Oenanthe stolonifera）和慈菇（Sagittaria sagittifolia）。人工湿地的水文条件与湿地植物之间的相互关系是人工湿地进一步研究的重要方面。     

长江上游玉龙雪山植物物种多样性形成的探讨

玉龙雪山位于云南省西北部的丽江市,是界于澜沧江和金沙江之间云岭山脉的主峰。南临丽江坝,东、西、北三面均为金沙江环绕,处于中国三大植物多样性中心之一的横断山区的核心地带,具有很高的植物物种多样性。该区有藻类植物31科72属196种,地衣植物17科20余种,在苔藓植物中有苔类45种、藓类130种,蕨类植物约有220 多种,种子植物有171科804属2 646种(不含栽培种及种下等级),其中中国特有种1 631种,占本区种子植物总数的61.46%。对玉龙雪山植物物种多样性的形成进行了探讨,认为玉龙雪山丰富的植物物种多样性主要来源于3个第三纪古植物区系成分即古北大陆、古地中海以及古南大陆成分,其中以古北大陆成分为主。之后的新构造运动及第四纪冰期冰川的反复作用,形成了玉龙雪山复杂多样的生态环境。来源于以上3个古植物区系成分的植物物种在以后的进化过程中经过不断分化、发展以及与临近区域的交流,形成了现在丰富的植物物种多样性格局。     

Predictive model for the (14)C radioactivity in a plant following an exposure to airborne (14)CO(2) gas

This paper provides details of a dynamic compartment model for estimating the (14)C radioactivity in an agricultural plant exposed to an amount of airborne (14)CO(2) gas. The plant, in the model, is divided into two compartments, the plant body (shoot and root) and ears, to predict the radioactivity of different parts of a plant. The carbon transports from, to and between the compartments are described by the processes of a photosynthesis, respiration, and translocation. The carbon transport fluxes of these processes are determined from the growth rates of a plant, which are usually easily attained. The model predictions showed that the present model could converge to a region where the specific activity model is applicable when the elapsed exposure time was extended up to the harvest time of a plant. The (14)C activity of a plant was greatly affected by the elapsed exposure time, the developmental stages of a plant at an exposure time, and the airborne (14)C activity during an exposure. It was expected that the peak of the ears' (14)C activity appeared when the exposure time was close to the ears-maturity date. The model predictions agreed reasonably well with the measured (14)C radioactivity of the rice plants that were artificially exposed to (14)CO(2) of a high (14)C source for a short period of time in an exposure box.     

Indicatory aspect of the geographic analysis of plant communities with respect to floristic composition on mountain slopes differing in exposure (the Polar Urals)

Latitudinal geographic groups of vascular plant, moss, and lichen species included in tundra communities and lower vegetation layers of larch forest and open forest have been analyzed with respect to their distribution according to different altitudinal levels and slopes differing in exposure. Prevailing plant groups have been identified. The results were compared with corresponding data on the composition of plant communities in the neighboring flatland area (Kharp Research Station).     

Analysis of priority pollutants at a primary aluminum production facility

This paper investigated the source of priority pollutants, assessment of the wastewater treatment plant, and priority pollutant removal efficiency for a single Soderberg-type primary aluminum plant.Forty-eight hour composite samples were collected from the following streams: (1) plant intake water; (2) wastewater from the primary air pollution control system (gas stream cooling water and wet ESPs); (3) secondary air pollution control system (room ventilation wet scrubber liquor); (4) paste plant briquette cooling water; and (5) final effluent after the wastewater treatment plant.Wastewater from the primary air pollution control system entered a conventional chemical coagulation (using slacked lime) — clarification plant. Clarified water from the clarifier was combined with the other three wastewater streams and flowed into a settling lagoon with a 20-h hydraulic retention time. Clarified lagoon water was finally discharged to the river.The principal source of organic compounds in the wastewater was from the primary and secondary air pollution control systems and results from the volatilization of petroleum coke and pitch in the Soderberg anode. Wastewater treatment plant removal efficiencies of greater than 85% were achieved for the majority of the organic priority pollutant species detected.     

论贵州岩溶山区植物物种多样性的保护

论述了植物物种多样性的概念及保护意义，针对贵州岩溶山区生态环境和植物资源现状，认为植物资源的开发和利用必须重视对植物物种多样性的保护，并提出了保护植物物种多样性的几点建议。     

Selenium bioavailability and uptake as affected by four different plants in a loamy clay soil with particular attention to mycorrhizae inoculated ryegrass

The aim of this study was to investigate the influence of plant species, especially of their rhizosphere soil, and of inoculation with an arbuscular mycorrhizal (AM) fungus on the bioavailability of selenium and its transfer in soil-plant systems. A pot experiment was performed with a loamy clay soil and four plant species: maize, lettuce, radish and ryegrass, the last one being inoculated or not with an arbuscular mycorrhizal fungus (Glomus mosseae). Plant biomass and Se concentration in shoots and roots were estimated at harvest. Se bioavailability in rhizosphere and unplanted soil was evaluated using sequential extractions. Plant biomass and selenium uptake varied with plant species. The quantity of rhizosphere soil also differed between plants and was not proportional to plant biomass. The highest plant biomass, Se concentration in plants, and soil to plant transfer factor were obtained with radish. The lowest Se transfer factors were obtained with ryegrass. For the latter, mycorrhizal inoculation did not significantly affect plant growth, but reduced selenium transfer from soil to plant by 30%. In unplanted soil after 65 days aging, more than 90% of added Se was water-extractable. On the contrary, Se concentration in water extracts of rhizosphere soil represented less than 1% and 20% of added Se for ryegrass and maize, respectively. No correlation was found between the water-extractable fraction and Se concentration in plants. The speciation of selenium in the water extracts indicated that selenate was reduced, may be under organic forms, in the rhizosphere soil.     

Microbial ecology of soils surrounding nuclear and thermal power plants in Taiwan

This paper reports a study of the effect of three nuclear and one thermal power plants on the microbial ecology of soils. Populations of bacteria, actinomycetes, fungi, cellulolytic microbes, phosphate-solubilizing microbes and nitrogen-fixing microbes in the soil in the vicinity of each plant were studied. Soils were acidic at three sites, and moisture contents of the power plant soils were lower than those of the surrounding areas. Microbial populations of the topsoils (0-20 cm deep) were higher than the subsoils (21-40 cm deep), and only 10-15% of them showed significant difference (P < .05). Thirty-three percent of the samples from the surrounding areas had higher microbial population than those from the power plant areas, but 19% was the reverse. Populations of cellulolytic, phosphate-solubilizing and nitrogen-fixing microbes varied with sampling locations, season and environmental conditions. Ratios of cellulolytic, phosphate-solubilizing and nitrogen-fixing microbes to total viable counts in some samples of the surrounding areas were significantly higher than in the power plant areas. Although the microbial populations of power plant soil and its surrounding area were somewhat different, it cannot be attributed as an effect of power plant operation, as the differences were not consistent.     

Growth, yield and elements content of wheat (Triticum aestivum) grown in composted municipal solid wastes amended soil

A commercial formulation of composted municipal solid wastes (MSW) was used for amending soil at 0, 50, 100, 150, 200 and 250 kg ha⁻¹ in which wheat had been grown (field experiments) and element residues of amended soil and plant parts were enumerated. MSW amendment caused a significant improvement in soil quality. Growth (shoot length, leaf number, leaf area, tiller number, plant dry weight and chlorophyll contents of leaves) and yield (length of panicle, number of panicles per plant and grain yield per plant) of wheat increased gradually up to the MSW-amendment level of 200 kg ha⁻¹. Elements, Ni, Zn, Cu, Cd, Cr, and Pb accumulated in plants from MSW amended soil, but the degree of metal accumulation was the least in seeds in comparison to other plant parts (root, stem and leaf). Moreover, Ni, Zn, Cd and Pb, were in high concentration in all plant parts. It is recorded that the level of 200 kg ha⁻¹ MSW amendment caused better growth and yield of wheat, but progressive levels of metal accumulation in plant parts were recorded due to increase in amendment levels. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

三峡水库忠县至秭归县段消落带植被群落特征研究

为了研究三峡水库周期性的水位调节对消落带植被群落特征的影响，选择重庆忠县至宜昌秭归段的消落带植被群落进行研究，运用重要值和多样性指数分析不同高程的植物种类组成、生活型分布特征及物种多样性。结果表明：（1）研究区域统计植物共32科70属73种，禾本科、菊科和豆科是3个优势科，单种、属现象明显；狗牙根、苍耳、鬼针草、苘麻、鳢肠、酸模叶蓼、莲子草是3个高程的共存种，其中，狗牙根和苍耳在3个高程均为优势物种。（2）研究区域共统计11种植物生活型，在消落带下部和中部，一年生草本植物占绝对优势；在消落带上部，多年生草本植物成为优势生活型，生活型类型多样化，蕨类、藤本、灌木以及乔木植物开始出现。（3）消落带植物群落的丰富度、多样性、均匀度指数均随海拔变化表现出显著差异，并且随海拔升高呈现上升趋势。由此可见，水位变化对植物群落结构和物种多样性产生很大影响，在低海拔区段，消落带物种组成简单化，耐水淹和繁衍能力强的植物成为优势物种；随着海拔上升，水淹胁迫减弱，出现更多适应水位变化的植物种类，使植物群落沿海拔变化形成不同的分布特征。这些研究结果对三峡库区消落带生态修复植物的筛选，以及物种多样性的提高具有参考价值。     

巢湖迎风面直立堤岸生态修复技术研究

针对巢湖直立堤岸生态系统受损的现状,研发了适合于巢湖迎风面的直立堤岸基底改善与生态修复技术。考虑到直立堤岸迎风面风浪较大且淘蚀严重的特点,首先对传统的生态混凝土配方进行改良,从而较大程度地提高了生态混凝土的物化性能,使其具备高透水性、高稳固性、植生性等诸多优点。同时,以巢湖湖滨带现场调查与野外模拟实验结果为依据,确定巢湖湖滨带最适的基底类型为灰壤（植入深度10 cm）,并适当添加铁盐和铝盐;确定最适的植被类型为飞蓬草。在此基础上,确定生态混凝土最适配比为江砂〖DK〗∶碎石〖DK〗∶水泥=10〖DK〗∶3〖DK〗∶2,进而集成研发了生态混凝土 原位土壤 植被混合护坡技术。该技术应用到迎风面的直立堤岸后,植被覆盖率超过70%,土壤中有效磷削减67%以上     

Altitude dependent 137Cs concentrations in different plant species in alpine agricultural areas

The Gastein valley in the Central Part of the Austrian Alps was one of the regions most heavily affected by fallout of the Chernobyl nuclear catastrophe, depositing (137)Cs inventory up to 70 kBq/m(2) in May 1986. In many studies dealing with the uptake of (137)Cs by vegetation used for farming, a significant correlation between (137)Cs concentration in the plants and altitude a.s.l. has been observed. In order to quantify the influence of the composition of plant communities on the average (137)Cs concentration in vegetation on farmland, plant-specific activity concentrations in plant species have been determined. Alongside a transect from valley sites at 850 m a.s.l. to alpine pastures at 1660 m, the aggregated transfer factors C(ag) (m(2)/kg) have been measured for plant communities and plant species. C(ag) values for mixed vegetation are more or less similar in valley sites, but they increase exponentially with a doubling height of 122+/-22 m above appr. 1200 m altitude a.s.l. On average all species are affected by this increase in a similar way. C(ag) values of ubiquitous plant indicate that the composition of plant communities is of minor importance for the contamination of mixed vegetation.     

Plant matter decomposition in the upper timberline ecotone of the Polar Urals

A relatively high biological activity of soils has been revealed at the upper timberline in the Polar Urals. The role of the altitudinal gradient as a factor of destruction process has distinctly manifested itself upon comparing decomposition rates of flowering plant foliage and herbaceous plant roots in the forest and in the tundra. The qualitative composition of decomposing plant matter has also proved to play a significant role. The soil moisture regime of the ecotope is the leading factor of the destruction process.     

Climate change driven plant–metal–microbe interactions

Various biotic and abiotic stress factors affect the growth and productivity of crop plants. Particularly, the climatic and/or heavy metal stress influence various processes including growth, physiology, biochemistry, and yield of crops. Climatic changes particularly the elevated atmospheric CO₂ enhance the biomass production and metal accumulation in plants and help plants to support greater microbial populations and/or protect the microorganisms against the impacts of heavy metals. Besides, the indirect effects of climatic change (e.g., changes in the function and structure of plant roots and diversity and activity of rhizosphere microbes) would lead to altered metal bioavailability in soils and concomitantly affect plant growth. However, the effects of warming, drought or combined climatic stress on plant growth and metal accumulation vary substantially across physico–chemico–biological properties of the environment (e.g., soil pH, heavy metal type and its bio-available concentrations, microbial diversity, and interactive effects of climatic factors) and plant used. Overall, direct and/or indirect effects of climate change on heavy metal mobility in soils may further hinder the ability of plants to adapt and make them more susceptible to stress. Here, we review and discuss how the climatic parameters including atmospheric CO₂, temperature and drought influence the plant–metal interaction in polluted soils. Other aspects including the effects of climate change and heavy metals on plant–microbe interaction, heavy metal phytoremediation and safety of food and feed are also discussed. This review shows that predicting how plant–metal interaction responds to altering climatic change is critical to select suitable crop plants that would be able to produce more yields and tolerate multi-stress conditions without accumulating toxic heavy metals for future food security.     

Post-deposition transport of radionuclides in fruit

This paper considers two main pathways for contamination of fruit by radionuclides: (i) absorption after deposition directly to exposed fruit surfaces, and (ii) absorption after deposition to other exposed plant surfaces followed by translocation to fruit. The aim is to collect the available information on fruit from temperate regions, identify the factors affecting post deposition processes in fruit plant systems, identify gaps in knowledge and give recommendations for future work. The majority of information available on above-ground absorption and further translocation to fruit concerns 134Cs and 85Sr in soluble form in apple, strawberry and grapevine. In general, 85Sr is absorbed and translocated to a lesser extent than is 134Cs. The rate of absorption and translocation depends on the physiological stage and age of the plant, and varies between different plant species and varieties.     

Selection of an effective sludge dewatering system for a small wastewater treatment plant

The Jahra Plant was commissioned in 1981 as a secondary treatment plant employing the extended aeration process. The plant has been upgraded since that time by constructing additional tertiary filtration units to improve effluent quality. The plant has a design capacity of 66 000 m³/d. At present, the daily inflow to the plant is about 47 000 m³/d of domestic sewage. The sludge produced at the Jahra Plant can be classified as excess activated sludge which combines the primary and secondary solids. At present, there are 30 drying beds receiving about 100 m³ of sludge dally. Sewage-sludge production represents about 0.5% of the total flow treated at the plant and is increasing yearly with increases in population and water consumption. Present dewatering systems are not adequate to cope with expansion in sewage treatment. Increasing the capacity of the existing plant would require more drying beds that could exacerbate existing odor problems. Some dewatering systems, such as the belt filter press and the centrifuge, have been tested to determine the most effective one under local conditions. Appropriate polymer doses for thickening have been determined. This paper describes present sludge dewatering units and operating techniques which have been developed during the operation of this facility.     

水位变动下三峡库区消落带植物群落特征

水位变动是湿地的基本特征之一,对湿地生态系统意义重大。为了解水位变动对三峡库区消落带植物群落的影响,于2010年8月对白夹溪消落带植物群落进行调查,采用TWINSPAN分类法对植物群落进行分类。结果表明:共发现维管植物85种,隶属34科70属;植物群落可划分为18个类型,狗牙根等5种群落为白夹溪消落带代表性植物群落;随着淹水程度的加深,群落组成呈现出由旱生植物到湿生植物的过渡趋势;植物群落香农指数、均匀度指数、丰富度指数和生物量指数随水位梯度呈“∧”型变化趋势,辛普森指数呈“∨”型变化趋势。与156 m蓄水周期相比,植物物种数量、群落类型及组成、多样性均发生改变。水位变动是消落带新生湿地植物群落变化的主要驱动因子