共基质和无机盐对原油降解菌株降解原油效果的影响

从大港油田石油污染土壤中分离筛选出1株原油降解菌X3,对原油的降解率达72．6％,经鉴定X3菌株属于假单胞菌属（Psedomonas）。利用生物摇床对X3菌株降解原油的实验发现,共代谢基质α-乳糖对X3菌株降解原油有促进作用,可使原油降解率提高到80．3％;而葡萄糖和蔗糖对X3菌株降解原油有抑制作用。Fe2＋对X3菌株的降解原油也有促进作用,在α-乳糖和Fe2＋的共同作用下,X3菌株对原油的降解率可达82．3％;K＋和Mg2＋对X3菌株降解原油则有抑制作用。在FeSO4质量浓度为0．2～0．3mg／L时,X3菌株对原油的降解率最高,FeSO4质量浓度继续增加,X3菌株对原油的降解率下降。     

活性艳蓝X-BR降解菌的筛选

从某印染厂废水排放出口的污泥中分离到一株活性艳蓝X-BR染料高效降解菌LPY68-14,经生理生化鉴定,该菌为埃希氏菌(Escherichia sp.).研究了影响菌株LPY68-14降解效果的因素,实验结果表明:在缺氧、质量分数为0.2%葡萄糖为外加碳源、温度37℃、接种量4 mL、pH 7的最佳条件下,质量浓度为30 mg/L的活性艳蓝X-BR经菌株LPY68-14处理24 h后的降解率可达80%;当活性艳蓝X-BR质量浓度为100～400 mg/L时,该菌处理48 h后的降解率可稳定在70%左右.     

高效石油烃降解菌的筛选及其对原油污染土壤的修复

从陕北原油污染土壤中筛选出7株高效石油烃降解菌,其中黄杆菌属CC-2、不动细菌属SC-5、假单胞菌属SC-6表现出较强的石油烃降解能力。通过单因素试验和正交试验考察总石油烃(TPH)降解效果的影响因素,得出各因素对TPH降解率影响程度的大小次序为:溶液p H降解温度降解菌接种量摇床转速,且在降解菌接种量为7%(φ)、溶液p H为7、降解温度为30℃、摇床转速为150 r/min的最适处理条件下,菌株SC-6的TPH降解率可达61.23%。原油污染土壤生物修复实验结果表明:高效石油烃降解菌的投加有利于土壤TPH降解率和酶活性的提高;"菌株SC-6+营养剂"组修复处理42 d后的TPH降解率可达57.59%。     

石油污染土壤的生物修复技术研究

通过实验室选择性富集培养,从大庆石油污染土壤中获得了能以大庆原油为碳源快速生长的石油降解菌。采用该降解菌对原油污染土壤进行了原位生物联合修复实验。接入降解菌的处理单元分别种植大豆、碱草或加入蓬松剂,与空白试样作对比。各处理单元石油污染土壤中石油烃含量初始值为2228．25mg／kg（以1kg干土计）。经过135d的生物联合修复,石油烃降解率达63．65％-83．26％。     

4株正十六烷降解菌的降解能力及代谢动力学特性

从处理采油废水的活性污泥中分离出4株产生物表面活性剂的正十六烷高效降解菌。菌株A14和B45为非脱羧勒克菌（Leclercia adecarboxylata）,菌株C28和A27为肠杆菌（Enterobacter sp.）。在NaCl质量浓度15~25 g/L、pH 6.0~7.0、接种量10%（φ）,培养温度37 ℃,摇床转速160 r/min、正十六烷体积分数0.30%的条件下降解16 d后,菌株A14、B45、C28和A27的正十六烷降解率分别为93.7%,87.8%,73.3%,65.7%。4株菌所产生的生物表面活性剂均为磷脂类表面活性剂。菌体生长满足逻辑斯蒂模型,正十六烷的降解满足一级反应动力学模型。菌株C28、A27的生长速率快于菌株A14、B45,菌株A14、B45的正十六烷降解速率快于菌株C28、A27。     

微生物降解重油的初步研究

丛石油污染的土壤中筛选出一株假单胞菌,考察了其对重油的降解效果。降解18d,重油的降解率达到42．8％,饱和烃、芳香烃、胶质、沥青质的降解率分别为42．95％,43．85％,44．5％,5．55％;质量浓度2．5g／L的表面活性剂Tween-80可使重油的18d降解率达到51．0％;弱碱性条件有利于重油的生物降解;生物泥浆法处理重油污染的土壤,1kg土壤中重油质量100g,降解45d,重油的降解率达到38．85％。     

对苯二甲酸降解菌固定化生物流化床处理精对苯二甲酸废水

采用微生物筛选、纯化技术,获得了降解对苯二甲酸（TA）的YPC—TA1,YPC—TA2,YPC-TA3,YPC—TA44株菌株。将筛选出的TA降解菌固定化,处理初始TA质量浓度为2650mg／L的模拟废水,降解36h后TA去除率达100％。用TA降解芮在生物流化床反应器中处理PTA废水,最佳容积负荷为6.7kg／（m^3·d）。生物流化床反应器可在容积负荷为6．0～6．5kg／（m^3·d）的较佳条件下长周期稳定运行,COD去除率保持在91％左右,TA去除率保持在94％左右。低pH废水冲击和高容积负荷废水冲击时COD,TA去除率均明显下降,恢复正常讲水后3～4d,COD,TA去除率均恢复正常。     

链霉菌(Streptomyces sp.)对吡啶的降解特性

从焦化废水的活性污泥中分离出对溶液中吡啶具有降解效果的链霉菌（Streptomyces sp．）,考察了吡啶初始质量浓度、初始pH、降解温度、振荡速度等对吡啶降解效果的影响,初步探讨了该菌降解吡啶的动力学与机理。实验结果表明,该菌对吡啶有很强的耐受力,能以吡啶为惟一碳源和氮源生长。链霉菌在初始pH=8、降解温度30℃、振荡速度100r／min的条件下培养7d后,吡啶的质量浓度从250mg/L降至6．6mg/L,吡啶降解率达97．4％。该菌对吡啶的降解反应符合一级动力学方程,初始质量浓度为100mg／L时的吡啶降解速率常数为0．4011d^-1。紫外一可见光谱分析表明,吡啶经该菌降解后的特征环被破坏。     

黄孢原毛平革菌的生长及降解石油条件的优化

在限氮振荡的条件下研究了藜芦醇、Tween-80、草酸、H2O2对黄孢原毛平革菌(P.C.菌)的生长量和石油降解性能的影响。实验结果表明:藜芦醇质量浓度低于0.05 g/L时促进P.C.菌的生长,高质量浓度时抑制P.C.菌的生长,石油降解率随藜芦醇质量浓度增加先升高后下降;Tween-80质量浓度低于7 mg/L时,P.C.菌生长量和石油降解率均随Tween-80质量浓度增大而增加,Tween-80质量浓度大于其临界胶束浓度时,P.C.菌生长量和石油降解率均低于未加Tween-80时;添加草酸抑制P.C.菌的生长,草酸质量浓度为35 mg/L时石油降解率最高,草酸质量浓度为350 mg/L时石油降解率低于未加草酸时;加入H2O2的体系中,石油降解率明显高于无H2O2体系。     

混合菌修复石油污染土壤

选取4种从石油污染土壤中分离出的石油降解菌(包括根瘤菌(A)、节细菌(B)、嗜盐菌(C)和芽孢杆菌(D)),对模拟石油污染土壤进行了微生物修复实验。考察了4种菌单独使用时的石油降解率,确定了混合菌的最佳配比和菌群的最优培养条件,并对比了微生物修复前后土壤的各项性质。实验结果表明:4种菌均可提高微生物修复石油污染土壤的修复效果,使用D菌时石油降解率最高;当混合菌的w(A)∶w(B)∶w(C)∶w(D)=12∶2∶21∶65时,在培养条件为混合菌接种量122.0 mL/kg、土壤含水率14%(w)、鸡粪加入量90 g/kg、麦糠加入量150 g/kg和表面活性剂加入量22 mL/kg的情况下,土壤的修复效果最好,40 d后石油降解率达66.95%;经混合菌修复的石油污染土壤,其肥力明显升高,脱氢酶、过氧化酶和脲酶的活性均升高,微生物数量也有明显增加。     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

四氮唑废水处理工艺设计

高浓度、高盐分的四氮唑生产废水通过三效蒸发浓缩,馏出液经铁炭氧微电解和混凝预处理,再采用水解酸化一接触氧化一反应二沉主体组合工艺进行处理。研究了该工艺所需构筑物和设备的设计与选型。该工艺在正常运行条件下,处理后出水pH6～9,COD 302mg／L,BOD5 108mg／L,SS30mg／L,色度36倍,水质达到GB8978--1996（污水综合排放标准》三级标准。     

Application of Cellulose Microfibrils in Polymer Nanocomposites

Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were added at low concentrations (2–10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young’s modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. Addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch–pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.     

Effects of Nitrogen Deposition on Bryophyte Species Composition of Calcareous Grasslands

Regular additions of NH₄NO₃ (35–140 kg N ha⁻¹ yr⁻¹) and (NH₄)₂SO₄ (140 kg N ha⁻¹ yr⁻¹) to a calcareous grassland in northern England over a period of 12 years have resulted in a decline in the frequency of the indigenous bryophyte species and the establishment of non-indigenous calcifuge species, with implications for the structure and composition of this calcareous bryophyte community. The lowest NH₄NO₃ additions of 35 kg N ha⁻¹ yr⁻¹ produced significant declines in frequency of Hypnum cupressiforme, Campylium chrysophyllum, and Calliergon cuspidatum. Significant reductions in frequency at higher NH₄NO₃ application rates were recorded for Pseudoscleropodium purum, Ctenidum molluscum, and Dicranum scoparium. The highest NH₄NO₃ and (NH₄)₂SO₄ additions provided conditions conducive for the establishment of two typical calcifuges – Polytrichum spp. and Campylopus introflexus, respectively. Substrate-surface pH measurements showed a dose-related reduction in pH with increasing NH₄NO₃ deposition rates of 1.6 pH units between the control and highest deposition rate, and a further significant fall in pH, of >1 pH unit, between the NH₄NO₃ and (NH₄)₂SO₄ treatments. These results suggest that indigenous bryophyte composition may be at risk from nitrogen deposition rates of 35 kg N ha⁻¹ yr⁻¹ or less. These effects are of particular concern for rare or endangered species of low frequency.