溶解氧对晚期垃圾渗滤液短程硝化及微生物群落结构变化的影响

以上海老港垃圾填埋场配套污水处理设施中的污泥为菌种源,在序批式活性污泥反应器(SBR)中对晚期垃圾渗滤液进行短程硝化处理,调节SBR中溶解氧浓度,考察溶解氧对渗滤液短程硝化的影响,分析不同溶解氧条件下污泥微生物群落结构的变化.结果表明,低溶解氧(0.2～0.5 mg/L)条件下,SBR可以获得较高的短程硝化效率,反应17h后,SBR内亚硝态氮/氨氮(质量比)为1.05,氨氮负荷可达到1.5 kg/(kg·d)(以每千克污泥悬浮固体每天承担的氨氮计),出水可以满足后续厌氧氨氧化处理的要求.从污泥变形梯度凝胶电泳(DGGE)图谱中可以看出,SBR微生物群落结构中主要优势种有uncultured Bacteroidetes bacterium、uncultured bacterium、uncultured Candidatus Amoebophilus sp.等.随着溶解氧含量的升高,SBR内微生物群落结构的多样性有所升高,但溶解氧对微生物群落结构影响有限.     

HRT和SRT对AO工艺去除四环素及耐药菌的影响

研究了不同水力停留时间(HRT)和污泥龄(SRT)条件下四环素(TC)和四环素耐药菌(tetracycline resistant bacteria,TRB)在AO工艺各池中的变化情况,并在最优工况下,用宏基因组16s DNA技术测定了各池微生物群落特征。结果表明,HRT的延长对TC的去除率影响不大,在90%左右。SRT从5 d延长到20 d时,TC的去除率从81.8%升高到90.9%。适当的延长HRT和SRT有利于减少TRB的数量。AO各池的四环素耐药菌优势菌属于Proteobacteria(变形菌门)和Bacteroidetes(拟杆菌门)。     

16S rDNA克隆文库分析含硫污水生物反应器中生物群落

利用生物脱硫技术处理炼油厂含硫污水,硫化物选择性地氧化成单质硫。在进水硫化物605.3 mg·L~(-1)的条件下,硫化物去除率90.7%,单质硫生成率达到80.8%。提取反应器中的DNA样本,构建16S rDNA克隆文库对反应器中的生物群落进行分析。对51个阳性克隆子(长度约为1 400 bp)进行测序,测序结果在NCBI数据库利用Blast比对并构建系统发育树。测序结果表明,生物脱硫反应器细菌种群可分为10个类群,数量最多的是γ-变形菌(γ-Proteobacteria)占76.6%,其余类群共占23.4%。γ-Proteobacteria类群中数量最多的是具有脱硫功能的Halothiobacillus sp.(66.7%)、Thiovirga sp.(25.6%)以及Pseudomonas sp.(7.7%)。系统发育树分析结果表明,生物脱硫系统中形成了以化能自养型脱硫菌为主的微生物群落结构,异养菌数量较少。     

A2/O工艺缺氧池中反硝化聚磷菌的比例、特性研究及菌株鉴定

用释磷/聚磷装置和微生物筛选、分离方法研究A2/O工艺缺氧池污泥,确定缺氧池中反硝化聚磷菌(DPB)的比例,筛选、分离得反硝化聚磷单菌株且对单菌株聚磷特性进行研究.结果表明,缺氧池中DPB占聚磷菌(PAO)的比例约为21.5%.从缺氧池分离得到的肠杆菌科、气单胞菌属和假单胞菌属都是DPB,而不动杆菌属仅是好氧PAO,葡萄球菌属和微球菌属仅是一种专职的反硝化菌.反应过程中同时存在O2和NO3时,肠杆菌科优先利用水中的O2进行聚磷;在缺氧环境中,肠杆菌科在COD为30mg/L时的聚磷效果优于COD为180 mg/L时的聚磷效果.可见DPB的反硝化和聚磷的特性与电子受体的存在形式和COD有密切关系.因此,改良传统A2/O工艺和研发同步反硝化聚磷装置时,必须控制缺氧反硝化聚磷单元中混合液的DO和COD.     

土霉素生产废水生物处理装置中微生物群落结构特征解析

抗生素对细菌具有强抑制作用,从而会影响废水生物处理系统中的微生物群落结构。在用定量PCR方法对土霉素生产废水处理装置(进水中土霉素浓度为1 662.1±248.6μg/L)中的细菌16S rRNA基因和真菌18S rRNA基因的含量进行比较的基础上,利用16S rRNA基因克隆文库方法对污泥中的细菌群落结构进行了详细解析。定量PCR结果显示,土霉素废水活性污泥中真菌(18S rRNA)/细菌(16S rRNA)基因的拷贝数比例高达1.2,明显较高于非抗生素肌苷废水活性污泥中的比例1.52×10-6,表明真菌对于土霉素废水中有机物的去除可能发挥重要作用。细菌克隆文库分析结果显示,Alpha变形菌和Beta变形菌是主要的优势菌,比例分别为23.7%和22.0%,其次是酸杆菌(17.0%)和拟杆菌(11.9%)。     

双氧水协同生化法处理实际印染废水

研究了双氧水协同水解酸化-接触氧化系统对实际印染废水的处理效果,并与完全生化处理系统进行对比。将100.0 m L经稀释的浓度为3 m L·L-1的双氧水溶液,用蠕动泵以1.67 m L·min-1的速度投加至正常运行的水解酸化体系底部,投加频率1次·d-1。结果表明,水解酸化体系对COD的去除率为23%~46%,氨氮去除率在-93%~+8.5%之间波动,出水色度为125~150倍;而接触氧化体系COD去除率提高至39%~59%,氨氮去除率接近100%,出水色度为100~125倍。采用16S r DNA宏基因组高通量测序技术,对比分析了双氧水协同生化处理系统和完全生化处理系统内的微生物菌群结构差异,发现双氧水可洗脱水解酸化污泥中的部分厌氧菌,促进优势菌门Proteobacteria(变形菌)和Bacteroidetes(拟杆菌)的富集,有助于脱色,并有助于洗脱接触氧化体系中的部分非优势菌,刺激Nitrospirae(硝化螺旋菌)的生长,促进脱氮作用。     

斑石鲷循环水养殖系统生物滤池微生物群落对水质变化的动态响应

为了解斑石鲷循环水养殖系统生物滤池内部细菌群落组成及其净水机制,通过高通量测序方法,研究了不同时期各级生物滤池的细菌群落结构,分析了各级生物滤池的水质参数及水处理效果。结果表明:实验筛选出37个门和513个细菌属,第3级生物滤池整体微生物群落丰富度和多样性均高于第1级和第2级生物滤池,第2级和第3级生物滤池微生物群落相似性最高。在门水平上,优势菌为变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes);在属水平上,发现了起硝化作用的亚硝化单胞菌属Nitrosomonas和硝化螺菌属Nitrospira;实验还发现该系统生物滤池可能存在功能上的浪费现象。该系统的细菌群落结构有稳定的演替模式,生物膜微生物群落变化对水质有一定程度的动态响应,Muricauda、Maribacter等反硝化细菌对硝态氮浓度的变化作用不明显。     

京杭运河杭州段水体污染和细菌群落结构特征

为了解人类活动对城市河道水体污染和细菌群落的影响,选取京杭运河杭州段进行了分季节采样研究。测定了水体的环境与水质参数,分析了细菌丰度、胞外酶活性和群落结构变化。结果显示,从上游到下游,水体中高锰酸盐指数、氨氮、总氮以及细菌丰度和β-葡萄糖苷酶活性大体呈递增趋势,冬季水体总体污染水平及细菌丰度均显著高于其他季节。水体中细菌的主要种类集中在变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacterioidetes)、厚壁菌门(Firmicutes)和蓝藻门(Cyanobacteria),所占比例分别为37.8%、24.3%、18.9%、10.8%和8.1%,属于黄杆菌(Flavobacterium)、厚壁菌(Firmicutes bacterium)和放线菌(Actinobacterium)的细菌是水体中大多数时间的优势细菌。限制性排序分析显示,水体细菌群落结构从上游到下游差异明显,高锰酸盐指数和总氮是关键影响因子。杭州市区由人类活动产生的污染物输入是京杭运河杭州段的主要污染源,水体细菌群落对水体污染物的变化有着明显的响应。     

3DBER-S阴极nirS型反硝化菌群的分析

为探究低碳氮比条件下3DBER-S(三维电极生物膜与硫自养耦合脱氮工艺)阴极反硝化菌群特征、强化脱氮机制,在TOC/TN=0.36的进水条件下稳定运行反应器,运用nir S基因克隆文库方法,分析了3DBER-S阴极生物膜反硝化菌群结构。结果表明,在3DBER-S阴极生物膜上反硝化菌中,β变形菌(β-proteobacteria)是优势菌种,占细菌总数的59.22%。其中,所占比例最大的是异养菌,包括与固氮弧菌属(Azoarcus tolulyticus)和趋磁螺菌(Magnetospirillum magneticum)类似的细菌,分别占44.74%和21.05%。能够分别利用硫单质或氢气作为电子供体进行反硝化脱氮的Sulfuricella denitrifican、高氯酸盐降解菌(Dechlorospirillum sp.)和陶厄氏菌属(Thauera)三者所占比例之和达到了17.11%。表明系统中氮的去除是由异养反硝化、氢自养反硝化和硫自养反硝化共同作用的结果,既有效减少了脱氮过程中有机碳源的消耗,又维持了系统酸碱度的平衡,从而能够在低碳氮比条件下维持稳定高效的脱氮效果。     

AO工艺处理淀粉污水效能及微生物群落解析

对某淀粉污水厂与实验室的AO处理工艺进行比较研究,通过常规水质监测及Miseq测序技术解析水质处理效果、进水成分差异与AO工艺菌群结构的相关性。结果表明,当进水COD和NH_(3-)N浓度分别为500和450.0 mg·L~(-1),污水厂稳定运行出水COD和NH_(3-)-N浓度分别为83和1.3 mg·L~(-1),其去除率分别达到96.52%和99.66%;实验室AO处理工艺调试45 d后出水COD和NH_(3-)-N浓度分别为78.8和49.9 mg·L~(-1),其去除率分别达到90.83%和88.50%。Miseq测序结果表明,Proteobacteria、Bacteroidetes、Chloroflexi、Firmicutes、Actinobacteria和Candidate division TM7在各样本中为主要菌门。污水厂与实验室AO处理工艺各样品菌属表现出相同的变化趋势,当AO系统运行良好时,其优势菌属为Anaerolineaceae、Saprospiraceae和Betoaproteobacteria等,三者总相对丰度比例为30%。污水厂与实验室AO处理工艺菌群也存在一定差异,其中较显著的有Firmicutes、Saprospiraceae和Betaproteobactenria等。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Observations on the influence of water and soil pH on the persistence of insecticides

Abstract

The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

Radionuclides in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.