Monitoring and dispersion modelling of emissions from the fluidised bed combustion of poultry litter

Gaseous emissions from the fluidised bed combustion of chickenlitter were monitored and recorded. Emission data was used tocreate a dispersion model for a proposed site on a poultry farmin Limerick, Ireland. Variables within the combustion unit notonly influenced combustion but also emission levels ofpollutants such as SO₂ and NO_x. CO emissions decreased withuse of the correct ratio between fluidising and secondary air,the staging of secondary air and the degree of turbulence withwhich the secondary air is introduced. Dispersion modelling ofactual combustion at a proposed poultry unit predicted thatground level concentrations for the set of emissions data wouldbe below the limits and guidelines set by air quality standards.This was true for both and line source. Line sourceconcentration levels were less than those for point source.     

鼎湖山主要森林生态系统地表N_2O通量

利用静态箱-气相色谱法对鼎湖山3 种处于演替不同阶段的森林类型(季风常绿阔叶林、针阔叶混交林和马尾松林)的地表N2O 通量进行了 1 年的原位观测和研究.结果表明,3 种林型地表 N2O 通量按从大到小的顺序为:季风林>混交林>松林;不同林型间的 N2O 通量差异与森林土壤的性质有密切关系,C/N 比值较低的季风林凋落叶对土壤中产生N2O 的微生物过程有较为明显的促进作用;从全年来看,松林地表N2O 通量的季节变化不明显,而季风林和混交林的地表 N2O 通量在雨季存在明显的降雨驱动效应,统计分析显示在该地区影响森林地表N2O 通量的主要因子是土壤湿度.     

光和微生物降解对芦苇落叶溶解有机物与铅相互作用的影响

溶解有机物（DOM）是决定水环境中铅（Pb）的形态、环境行为和生态风险的重要因子.然而,落叶DOM与Pb（II）络合作用的调控机制尚不清楚.光和微生物降解是调控DOM含量、组成与活性的两个关键过程.本研究运用降解培养实验、光谱学表征和荧光猝灭滴定,考察光和微生物降解单独作用和共同作用对芦苇落叶DOM的改造及其对DOM与Pb（II）相互作用的影响.激发-发射三维荧光光谱-平行因子分析共识别出4个类腐殖质组分（C1~C4）和1个类蛋白质组分（C5）.类腐殖质组分更容易被光降解,类蛋白质组分则被微生物优先利用,光降解在短期的光-微生物降解过程中起主导作用.对于原始落叶DOM,Pb（II）主要与类腐殖质组分C1、C2和C4络合,C3组分只在光-微生物降解后的样品呈现显著荧光猝灭,类蛋白质组分C5在光和光-微生物降解后开始参与络合.类腐殖质C1与Pb（II）络合的条件稳定常数logK_M在光降解后升高而在光-微生物降解后下降,C2和C4的logK_M值经过各降解过程后均升高.降解后这3个组分参与络合的比例f和络合容量F_max·f均显著降低,且光降解的影响显著高于微生物降解.这些结果表明,光降解和微生物降解对DOM丰度、组成和结构的改造将显著影响其与金属离子的络合稳定性和络合容量.     

Redistribution of zinc, cadmium, and lead among soil fractions in a sandy calcareous soil due to application of poultry litter

This study was conducted to evaluate, using soil columns, the mobilization and redistribution of heavy metals (Zn, Cd, and Pb) among different soil fractions by soluble organic ligands within poultry litter. Uncontaminated soil was amended with Zn, Cd, and Pb to achieve concentration levels of 400, 8, and 200 mg kg⁻¹ soil, respectively. Columns repacked with this amended soil were leached with distilled water, 0.01 M EDTA, 0.01 M CaCl₂, or poultry litter extract (PLE) solutions. After leaching, the soil samples in the columns were sequentially extracted for exchangeable (EXC), carbonate (CARB) organic matter (OM), Mn oxide (MNO), Fe oxide (FEO), and residual (RES) fractions. Considerable mobilization of Zn, Cd, and Pb occurred in soil during EDTA leaching. Leaching with PLE and CaCl₂ solutions significantly decreased Zn and Cd concentrations in the EXC, CARB, and OM fractions. These solutions significantly decreased Pb concentration in the EXC fraction, while PLE solubilized more Pb from EXC fraction than CaCl₂. Thus, the applied poultry litter may change Zn, Cd, and Pb fractions in metal-amended soil and possibly enhance metal mobility.     

Deterioration of bioplastic carrier bags in the environment and assessment of a new recycling alternative

Increasing environmental concerns and the introduction of technologies based on renewable resources have stimulated the replacement of persistent petroleum-derived plastics with biodegradable plastics from biopolymers. As a consequence, a variety of products are currently manufactured from bioplastic, including carrier bags. This series of studies investigated the deterioration of carrier bags made with Mater-Bi (MB), a starch-based bioplastic, in soil, compost and two aquatic ecosystems, a littoral marsh and seawater. Results from the laboratory study indicated that bioplastic carrier bags were rapidly deteriorated in soil and compost. After three months of incubation, weight loss of specimens was of 37% and 43% in soil and compost, respectively. Conversely, little deterioration was observed in specimens buried in soil under field conditions or exposed to water of a littoral marsh and of the Adriatic Sea. These findings were consistent with the greater number of bacteria and especially fungi capable of degrading MB that were recovered from soil and compost with respect to the two aquatic ecosystems. Considering that a variety of microbial isolates are capable of using MB as a source of carbon, a new alternative to recycle these MB-based carrier bags was explored. More specifically, starchy residues from bags were fermented by the fungus Rhizopus oryzae to produce up to 35 mg of lactic acid per g of bag residues.     

The functional and physiological status of Gammarus fossarum (Crustacea; Amphipoda) exposed to secondary treated wastewater

Climate change scenarios predict lower flow rates during summer that may lead to higher proportions of wastewater in small and medium sized streams. Moreover, micropollutants (e.g. pharmaceuticals and other contaminants) continuously enter aquatic environments via treated wastewater. However, there is a paucity of knowledge, whether extended exposure to secondary treated wastewater disrupts important ecosystem functions, e.g. leaf breakdown. Therefore, the amphipod shredder Gammarus fossarum was exposed to natural stream water (n = 34) and secondary treated wastewater (n = 32) for four weeks in a semi-static test system under laboratory conditions. G. fossarum exposed to wastewater showed significant reductions in feeding rate (25%), absolute consumption (35%), food assimilation (50%), dry weight (18%) and lipid content (22%). Thus, high proportions of wastewater in the stream flow may affect both the breakdown rates of leaf material and thus the availability of energy for the aquatic food web as well as the energy budget of G. fossarum.     

Identification of various laccases induced by anthracene and contribution to its degradation in a Mediterranean coastal pine litter

Mediterranean coastal ecosystems are known to be highly subject to natural and anthropic environmental stress. In this study, we examine the effects of anthracene as a common pollutant on the total microbial communities from a Pinus halepensis litter of a typical Mediterranean coastal site (Les Calanques, Marseille). The main objective was to identify the microbial factors leading the resilience of this ecosystem. Two questions were addressed: (i) how lignin-degrading enzymes (Laccase, Lignin-peroxidase and Mn-peroxidase) are affected by the presence of this molecule, (ii) whether the indigenous consortia are involved in its degradation in mesocosms under favorable incubation conditions (25 °C, 60% WHC) and after different time intervals (1 and 3 month(s)). We found a strong increase in laccase production in the presence of anthracene after 3 months, together with anthracene degradation (28% ± 5). Moreover 9,10-anthraquinone is detected as the product of anthracene oxidation after 3 months. However neither lignin-peroxidase activity nor Mn-peroxidase activity is detected. Laccase proteins directly extracted from litter were sequenced via Nano-LC-MS/MS and reveal twelve different peptide sequences induced by the presence of anthracene in the mesocoms. Our study confirms the major detoxification role of this enzymatic system and highlights the high degradation potential of fungal species inhabiting P. halepensis litter, a factor in the resilience of Mediterranean ecosystems.     

Microscale Spatial Variation in Forest Litter Phytotoxicity

The spatial variation (within a 100 × 100 m plot) in the pollution of forest litter with heavy metals (Cu, Cd, Pb, and Zn), its acidity, and phytotoxicity (measured by the results of the root test using seedlings from a genetically homogeneous sample of common dandelion (Taraxacum officinale s.l.) have been estimated. Forest litter has been sampled in three zones differing in the toxic impact of long-term polymetal pollution by emissions from a copper-smelting plant emissions in the Middle Urals. The phytotoxicity variation is maximum in a moderately polluted plot, where both very high and very low pollution levels were observed, which determines a substantially nonlinear dose–effect relationship. The litter phytotoxicity is mainly accounted for by exchangeable forms of metals. Biological testing of samples from the most polluted plot has demonstrated marked antagonism between heavy metals and acidity.     

模拟酸雨对亚热带三个树种凋落叶分解速率及分解酶活性的影响

利用凋落物袋法研究了模拟酸雨对中国亚热带地区3个典型树种杉木(Cunninghamia lanceolata)、香樟(Cinnamomum camphora)、银杏(Ginkgo biloba)凋落叶分解速率及酶活性的影响.酸雨分别设置为重度酸雨(pH=2.5)、中度酸雨(pH=4.0)、对照处理(pH =5.6)3个梯度.试验结果表明:酸雨胁迫会抑制凋落叶的分解,且随着酸雨强度的增强,抑制作用更明显.杉木、香樟、银杏3个树种对照处理下周转期分别比中度酸雨短33％、43％、14％,比重度酸雨短44％、52％、17％.3种分解酶对酸雨胁迫的表现不同,脲酶和纤维素酶表现为一定的抑制作用,基本呈现为对照处理(pH=5.6)＞中度酸雨(pH=4.0)＞重度酸雨(pH=2.5),与凋落物的分解速率排列情况一致,蔗糖酶在酸雨胁迫下反而有激活的趋势,表现为重度酸雨(pH=2.5)＞中度酸雨(pH =4.0)＞对照处理(pH=5.6).不同树种对酸雨胁迫的影响有一定的差异性,针叶树种杉木受影响最大,阔叶树种香樟和银杏受影响较小,银杏的抗酸性较强,且针叶树种的分解速率比阔叶树种慢.脲酶和纤维素酶对凋落叶的分解贡献较大,而蔗糖酶的影响相对较小.酶活性与季节有较大的关系,夏季活性相对偏高,冬季活性相对偏低.     

三峡库区城市富营养化河流凋落物的混合分解效应

以三峡库区重庆市主城段清水溪为典型的城市富营养化河流代表,选取河岸带3种常见凋落叶为分解对象,设计了7种凋落物组合（3个单种和4个混合物种）和3种孔径的分解袋（50μm、250μm和2mm）,开展原位实验,探讨混合凋落物的性状、功能多样性与底栖分解者类群及其交互作用对叶片质量损失和混合效应的影响.结果表明,仅有50%的处理表现为显著非加和效应（且均为负值）,这与凋落物的性状密切相关.随着混合凋落物功能离散度的增加,尤其组合中含高木质素等难分解物质的凋落物时,分解变慢.微生物在富营养化河流混合凋落物的分解中占主导作用,小型和大型底栖动物均抑制了混合凋落物的分解过程.在富营养化河流的修复过程中,需重视河流凋落物分解功能,注重调整河岸带植物的配置,以及提升底栖动物的生物多样性并恢复底栖动物在凋落物分解中的正面效应.