Pool of mobile and immobile phosphorus in sediments of the large, shallow Lake Peipsi over the last 100?years

Temporal variations in sediment phosphorus (P) composition and mobility were estimated in surface sediments of accumulation (core PS509 44?cm) and erosion (core PS2009 30?cm) areas of the shallow, large Lake Peipsi sensu stricto (s.s.; 2611?km(2), unregulated water level). The P pool in sediments including buried and mobile P is evaluated for the first time, which will provide baseline data for the future modelling of internal loading in L. Peipsi. Five sedimentary P fractions (including inorganic and nonreactive P) were separately quantified: loosely adsorbed and pore-water P (NaCl-P); redox-sensitive fraction P (NaBD-P); P bound to oxides of non-reducible Fe and Al (NaOH-P); calcium-bound P, mainly from apatite minerals (HCl-P) and refractory, mainly organic P (Res-P). Concentrations of P fractions varied during the 100?years with the highest values around 2007-2008 and 1923-1935. The P in "active" layers that are available for bacteria and algae or those undergoing changes and diagenetic transformations in the sediment could follow sediments with the water content of ～88%. Potentially mobile P is not decreased in the sediments deposited 50-100?years ago and makes up ca 63?mg?m(-2)?y(-1) (with range 8.3-23.7% of the total P (TP)) in the accumulation area, and ca 0.047?mg?cm(-3) (with range 1.3-22.4% of TP) in the erosion area. The result shows that 13-60% of TP contained in the surface sediment (from 34 to 398?mg P m(-2) y(-1)) has been remobilised during accumulation and could be exported to the overlying water.     

Express-phytotest for choosing conditions and following process of soil remediation

Environmental Geochemistry and Health - Phyto- and bioremediation are perspective methods for soil recultivation. In spite of resistance of plant-hyperaccumulators and degrading microorganisms to...     

The Selenga River delta: a geochemical barrier protecting Lake Baikal waters

Regional Environmental Change - The protection of Lake Baikal and the planning of water management measures in the Selenga River Basin require a comprehensive understanding of the current state and...     

乌萨盆地(俄罗斯欧洲部分东北部)的多年冻土和基础设施:全球变暖的可能影响

文章分析了位于俄罗斯欧洲部分东北部的乌萨盆地的多年冻土地区环境条件与基础设施分布的关系.规模不一的多年冻土带(从孤立碎片到连续的多年冻土)占了整个盆地的75%.这个地区的城市化和工业化发展水平很高(例如,城镇、煤矿、烃类提炼厂、铁路和管道等).GIS分析表明这个地区的60%的基础设施都位于"高危险"的多年冻土地带,这里的"高危险"的多年冻土地带是指地温达到0～-2℃且孤立的或者不连续的多年冻土区(3%～90%的覆盖度).地温监测、航空相片解译及多年冻土模拟都表明了它们对未来全球变暖响应的差异性.在未来的几十年到一百年内,大多数受多年冻土影响的地区将可能发生解冻.这将对多年冻土区的工程建设提出很大的挑战,同时要求对那些需要经过较长时间才能获得回报的基础设施方案进行远期投资.     

Comparative use of bacterial, algal and protozoan tests to study toxicity of azo- and anthraquinone dyes

Toxicity of two azo dyes (Reactive Orange 16 (RO16); Congo Red (CR)) and two anthraquinone dyes (Remazol Brilliant Blue R (RBBR); Disperse Blue 3 (DB3)) were compared using bacterium Vibrio fischeri, microalga Selenastrum capricornutum and ciliate Tetrahymena pyriformis. The following respective endpoints were involved: acute toxicity measured as bacterial luminescence inhibition, algal growth inhibition, and the effects on the protozoa including viability, growth inhibition, grazing effect and morphometric effects. In addition, mutagenicity of the dyes was determined using Ames test with bacterium Salmonella typhimurium His(-). DB3 dye was the most toxic of all dyes in the bacterial, algal and protozoan tests. In contrast to other dyes, DB3 exhibited mutagenic effects after metabolic activation in vitro in all S. typhimurium strains used. Of the methods applied, the algal test was the most sensitive to evaluate toxicity of the dyes tested.     

Degradation of chlorophenols in aqueous media using UV XeBr excilamp in a flow-through reactor

2-Chlorophenol (2-CP), 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) at initial concentrations of 10, 20, 50 and 100mg l(-1) were degraded in aqueous media by direct UV photolysis using dielectric barrier discharge XeBr( *) excilamp (283nm) in a flow-through photoreactor. The pseudo-first order rate constants were highest and half-life times were lowest for 4-CP. The rates of photolysis under the experimental conditions increased in the order: 2-CP<2,4-DCP<4-CP. The intermediates of photolysis were identified by GC-MS and HPLC. The evolution of hydroquinone and p-benzoquinone as major intermediates of 4-CP photolysis was monitored.     

The Experimental Research (In Vitro) of Carrageenans and Fucoidans to Decrease Activity of Hantavirus

The effect of carrageenans and fucoidans on the activity of Hantavirus is studied. It has been found that among carrageenans a significant antiviral effect is exerted by the ι-type, which decreases the viral titer by 2.5 log focus forming units per mL; among fucoidans, by a preparation from Laminaria cichorioides, which reduces the number of infected cells from 27.0 to 5.3 after pretreatment of both the macrophage culture and Hantavirus. The antiviral effect of fucoidan from Laminaria japonica is shown to grow in direct proportion to the increase of dose of the preparation.     

Temporal stability of WTP estimates in labeled and unlabeled choice experiment for emissions reduction options,Queensland, Australia

Environmental Economics and Policy Studies - Estimates of non-market values are valuable for policy makers. However, evidence of the stability of value estimates over long timeframes is limited....