Volatile fatty acid evolution in biomass mixture composts prepared in open and closed bioreactors

In this study we observed the production of volatile fatty acids (VFAs) during the composting process of compost heaps in two different bioreactors (open and closed) at three different depths (0, 40 and 80 cm). The compost was prepared as a mixture of bio-waste, horse manure, grass and sawdust to ensure sufficient pH conditions in compost heaps. VFA contents in the composting materials were analysed weekly over 14–119 d. The degradation process was monitored, along with temperature, pH, total organic carbon, oxidizable carbon and mono- and oligosaccharides. VFA contents were evaluated with regard to the depth of the sample site in the compost heap and to conditions in the bioreactors. The maximum VFA occurrence was observed during the first 35 d; acetic and propionic acids in particular were determined to occur in each sample. Considerable variations in their formation and elimination were observed in the two bioreactors as well as at the various depths in the compost heaps. Significant correlations were found between individual VFAs, as well as between VFA concentrations and organic carbon contents.     

Survey of patterns,levels, and trends of perfluorinated compounds in aquatic organisms and bird eggs from representative German ecosystems

Purpose  

Samples from the German Environmental Specimen Bank (ESB) covering particularly the years 1994–1996, 2000–2002, and 2006–2009 were analyzed for perfluorinated compounds (PFC; mainly C4–C13 carboxylic and sulfonic acids) to gain an overview on current PFC levels and patterns in marine, limnetic, and terrestrial biota; to assess their concentrations in different trophic levels; and to investigate whether risk management measures for PFC are successful.     

纳米铜颗粒的种间毒性关系

纳米颗粒的种间毒性关系尚无明确结论,因此很难判断纳米颗粒对未进行毒性测试的物种的风险如何。本文作者将5种水蚤(Daphnia magna, Daphnia pulex, Daphnia galeata, Ceriodaphnia dubia, Chydorus sphaericus)暴露于4种不同粒径的纳米铜颗粒(CuNPs)和1种亚微米铜颗粒的悬浊液中,考察物种的形态特征与CuNPs急性毒性的关系。结果显示,杆状的CuNPs比球状的CuNPs毒性更低。纳米铜颗粒与溶出铜离子均对CuNPs的毒性有贡献,其中,当新生蚤的体长、体表面积和身体体积更小时,5种悬浊液中颗粒的毒性更大。5种蚤的身体体积与5种CuNPs的毒性显著相关(r_adj²>0.51, p < 0.001),78-nm CuNPs与蚤身体体积的相关性最好 (r_adj²?=?0.95, p < 0.001)。这个研究可以为纳米颗粒对有相似外形特征的物种进行毒性种间外推提供线索。
精选自Lan Song, Martina G. Vijver, Geert R. de Snoo and Willie J.G.M. Peijnenburg. Assessing toxicity of copper nanoparticles across five cladoceran species. Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.3000
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3000/full     

Capability of the natural microbial community in a river water ecosystem to degrade the drug naproxen

The present work aims at evaluating the ability of the River Tiber natural microbial community to degrade naproxen in water samples collected downstream from a wastewater treatment plant. For this purpose, different water microcosms were set up (microbiologically active vs sterile ones) and treated with naproxen (100 μg/L) alone or in the co-presence of gemfibrozil in order to evaluate if the co-presence of the latter had an influence on naproxen degradation. The experiment was performed in the autumn and was compared with the same experimental set performed in spring of the same year to highlight if seasonal differences in the river water influenced the naproxen degradation. Pharmaceutical concentrations and microbial analysis (total cell number, viability, and microbial community composition) were performed at different times in the degradation experiments. The overall results show that the natural microbial community in the river water had a key role in the naproxen degradation. In fact, although there was a transient negative effect on the natural microbial community in all the experiments (3 h after adding the pharmaceutical), the latter was able to degrade naproxen within about 40 days. On the contrary, no decrease in the pharmaceutical concentration was observed in the sterile river water. Moreover, the co-presence of the two drugs lengthened the naproxen lag phase. As regards the natural microbial community composition detected by Fluorescence in situ Hybridization, Alpha and Gamma-Proteobacteria increased when the pharmaceutical halved, suggesting their role in the degradation. This study shows that with the concentration studied, naproxen was degraded by the natural microbial populations collected from a river chronically contaminated by this pharmaceutical.     

Assessment of Soil Sealing Management Responses,Strategies, and Targets Toward Ecologically Sustainable Urban Land Use Management

Soil sealing has negative impacts on ecosystem services since urban green and soil get lost. Although there is political commitment to stop further sealing, no reversal of this trend can be observed in Europe. This paper raises the questions (1) which strategies can be regarded as being efficient toward ecologically sustainable management of urban soil sealing and (2) who has competences and should take responsibility to steer soil sealing? The analyses are conducted in Germany. The assessment of strategies is carried out using indicators as part of a content analysis. Legal-planning, informal-planning, economic-fiscal, co-operative, and informational strategies are analyzed. Results show that there is a sufficient basis of strategies to secure urban ecosystem services by protecting urban green and reducing urban gray where microclimate regulation is a main target. However, soil sealing management lacks a spatial strategically overview as well as the consideration of services provided by fertile soils.     

Determining metal origins and availability in fluvial deposits by analysis of geochemical baselines and solid-solution partitioning measurements and modelling

Metals in floodplain soils and sediments (deposits) can originate from lithogenic and anthropogenic sources, and their availability for uptake in biota is hypothesized to depend on both origin and local sediment conditions. In criteria-based environmental risk assessments, these issues are often neglected, implying local risks to be often over-estimated. Current problem definitions in river basin management tend to require a refined, site-specific focus, resulting in a need to address both aspects. This paper focuses on the determination of local environmental availabilities of metals in fluvial deposits by addressing both the origins of the metals and their partitioning over the solid and solution phases. The environmental availability of metals is assumed to be a key force influencing exposure levels in field soils and sediments. Anthropogenic enrichments of Cu, Zn and Pb in top layers could be distinguished from lithogenic background concentrations and described using an aluminium-proxy. Cd in top layers was attributed to anthropogenic enrichment almost fully. Anthropogenic enrichments for Cu and Zn appeared further to be also represented by cold 2 M HNO₃ extraction of site samples. For Pb the extractions over-estimated the enrichments. Metal partitioning was measured, and measurements were compared to predictions generated by an empirical regression model and by a mechanistic-kinetic model. The partitioning models predicted metal partitioning in floodplain deposits within about one order of magnitude, though a large inter-sample variability was found for Pb.     

Metal accumulation in earthworms inhabiting floodplain soils

The main factors contributing to variation in metal concentrations in earthworms inhabiting floodplain soils were investigated in three floodplains differing in inundation frequency and vegetation type. Metal concentrations in epigeic earthworms showed larger seasonal variations than endogeic earthworms. Variation in internal levels between sampling intervals were largest in earthworms from floodplain sites frequently inundated. High and low frequency flooding did not result in consistent changes in internal metal concentrations. Vegetation types of the floodplains did not affect metal levels in Lumbricus rubellus, except for internal Cd levels, which were positively related to the presence of organic litter. Internal levels of most essential metals were higher in spring. In general, no clear patterns in metal uptake were found and repetition of the sampling campaign will probably yield different results.     

The effect of ryegrass (Lolium perenne) on decrease of PAH content in long term contaminated soil

The biodegradation of polycyclic aromatic hydrocarbons in microecosystems containing long-term contaminated soil was investigated. Soil was contaminated by different chemicals, including PAHs since World War II. Aging of the soil was expected to act as a principal factor limiting biodegradation. Half of the microecosystems contained ryegrass (Lolium perenne) and long-term selected natural soil microflora originally present in contaminated soil. The others contained contaminated soil with natural microflora only. Half of the microecosystems in each parallel experiment was fertilised with N-P-K fertiliser. Cultivation was carried out at 12 and 18 months in a greenhouse with a natural photoperiod and the ability to degrade 15 chosen PAH was investigated. For analysis, the soil from each pot was divided into three horizontal layers for mutual comparison among layers and each layer was further divided into four equal samples. Soil extracts were analysed using HPLC. After a one-year-cultivation period the content of the monitored PAHs declined to 50%. Mostly, there were no significant differences between the microecosystems. Best degraded were fluoranthene and pyrene, which were the major contaminants present in original soil. Also, other compounds were successfully degraded, even benzo[a]pyrene and benzo[ghi]perylene. Dibenz[a,h]anthracene and indeno[1,2,3-cd]pyrene were the only PAHs, examined that showed no significant degradation. Although some differences between the soil layers were detected, no conclusive trends could be found. However, significantly lower concentrations of PAHs were determined mostly in the bottom layer of the analysed profiles. In vegetated microecosystems the decline of PAHs concentrations was more remarkable after 18 months cultivation.     

Organometals of tin, lead and mercury compounds in landfill gases and leachates from Bavaria, Germany

Organo-Sn, -Pb and -Hg compounds were monitored in gases and leachates of 11 municipal waste landfills and one hazardous waste landfill from Bavaria, Germany, with the objectives to estimate the methylation of Sn, Pb and Hg and to assess the risk of their release into the adjacent environment. In the gases, tetramethyl Sn predominated (>80% of total gaseous Sn) with concentrations up to 160mug Sn m(-3). Dimethyl-Hg and tetramethyl-Pb were only occasionally detected with concentrations up to 2.9 and 2.1mugm(-3) as Hg or Pb, respectively. In all leachates, trimethyl-Sn dominated with a maximum concentration of 2100ng Sn L(-1). No organo-Pb compounds were found, and monomethyl-Hg was detected in only one leachate. The concentrations of trimethyl-Sn were up to 100-fold higher in the condensate water than in leachates, and the concentrations of organo-Sn compounds were lower in the adjacent groundwater than in the corresponding leachates. The high abundance of methylated Sn species in the gases and leachates indicates Sn methylation, suggesting the landfill as a source for organo-Sn compounds. In comparison, methylation of Hg and Pb was of little importance, probably due to low Hg concentrations and low rates of Pb methylation in the landfill. The risks of organo-Sn compounds release to the adjacent air is low due to flaring of landfill gases. However, there is probable release of organo-Sn compounds, especially trimethyl-Sn, to the adjacent groundwater.