低温微生物环境污染修复技术研究进展

生物修复技术由于成本低、效果好、对环境负面影响小,且无二次污染等优点,受到普遍的关注,已成为环境治理的重要方法和技术.目前微生物修复技术多以常温微生物为主,而在自然环境中,占地表绝大部分的极地、海洋、湖泊以及高山和高纬地区的土壤等,其全年平均温度大多在15℃或以下,恰恰是低温微生物的最适生长温度.因此,以低温微生物为主的生物修复技术,在常年低温的极地、海洋、高山或高纬区域以及若干地区冬季进行污染物的生物降解方面有独到的优势.目前,以低温微生物为主体的低温生物修复技术已成了生物修复技术研究领域的热点.从4个方面讨论目前利用低温微生物所开展的低温生物修复技术的最新发展动态.     

重金属的生物吸附技术研究

利用生物包括发酵工业的菌丝体废渣或海洋微生物对重金属的吸附作用，来治理重金属造成的污染，其具有原料丰富，成本低，处理效率高等优点，是目前国外研究较多的一种处理重金属污染的方法。本文从生物吸附的概念、机理、吸附剂的性能，以及生物吸附剂的固定化等诸方面进行了综述。同时阐述了生物对重金属吸附技术研究的发展趋势和应用前景。     

生物表面活性剂及其在环境修复中的研究进展

生物表面活性剂是由微生物分泌的天然产物，由于其物理性质和化学结构与许多人工合成的表面活性剂相似，并且对土壤、淡水、海洋等生态系统毒性较低，因而在环境污染治理方面，特别是在重金属和石油等有机溶剂污染的原位和异位生物修复方面具有极大的应用潜力。主要综述了近年国内外生物表面活性剂在廉价制备、作用机理、环境修复中的研究进展。     

水产养殖自身污染及其生物修复技术

介绍了生物修复的概念、水产养殖存在的自身污染问题及其主要生物修复技术。营养物污染、药物污染和底泥富集污染是水产养殖存在的主要自身污染问题；微生物修复、水生植物修复和水生动物修复是污染养殖水域生物修复的3种主要形式；微生物的有效性、生物入侵、二次污染、修复生物的季节性和非水生植物的利用等方面是实施生物修复应注意的主要方面。最后指出，推行清洁生产、实行生态养殖是水产养殖业可持续发展的出路。     

砷污染土壤微生物修复机制及其研究进展

土壤砷污染是一个全球性问题。越来越多的研究表明,自然界中的微生物在砷的迁移转化过程中发挥了重要作用。微生物修复是目前研究的热点,也是治理砷污染土壤的主要手段之一。综述了土壤中砷污染现状及其赋存形式,重点分析讨论了砷污染土壤的微生物修复机制以及提高微生物修复效率的方法。土壤砷污染修复是一项复杂的系统工程,单一的修复技术很难实现显著的效果。只有建立在以微生物修复为主的基础上,辅之以物理化学、植物及农业生态等措施,才能大大提高微生物修复效率。总结了近年来国内外微生物修复砷污染土壤技术的研究进展,以期为深入研究微生物代谢砷的机制及其在砷污染治理中的应用提供参考。     

生物表面活性剂及其在环境修复中的研究进展

生物表面活性剂是由微生物分泌的天然产物,由于其物理性质和化学结构与许多人工合成的表面活性剂相似,并且对土壤、淡水、海洋等生态系统毒性较低,因而在环境污染治理方面,特别是在重金属和石油等有机溶剂污染的原位和异位生物修复方面具有极大的应用潜力.主要综述了近年国内外生物表面活性剂在廉价制备、作用机理、环境修复中的研究进展.     

原位生物修复治理汞害的机制及作用

概述植物、微生物在去除水、土壤中汞污染方面的有效性。介绍微生物固定、转化汞及其化合物的机制以及原位生物修复技术在治理汞害方面的作用     

低温硝基苯降解菌选育及在土壤修复中的应用

从硝基苯污染地下水中筛选出一株以硝基苯为唯一碳源和氮源的低温、高效降解菌,命名为XJ菌;初步鉴定XJ菌为革兰氏阴性微小短杆细菌、恶臭假单胞菌属,降解硝基苯遵循部分还原降解途径;在10℃下培养96 h,XJ菌对硝基苯的降解去除率达到91.1%,其中约有67.1%的硝基氮素转变成了氨氮。在10℃下利用XJ菌修复硝基苯污染土壤,修复时间为96 h时,硝基苯去除率达到85.7%,XJ菌密度及微生物脱氢酶活性保持较高的水平。本研究可为低温下硝基苯污染土壤的生物修复提供参考。     

水产养殖自身污染及其生物修复技术

介绍了生物修复的概念、水产养殖存在的自身污染问题及其主要生物修复技术.营养物污染、药物污染和底泥富集污染是水产养殖存在的主要自身污染问题;微生物修复、水生植物修复和水生动物修复是污染养殖水域生物修复的3种主要形式;微生物的有效性、生物入侵、二次污染、修复生物的季节性和非水生植物的利用等方面是实施生物修复应注意的主要方面.最后指出,推行清洁生产、实行生态养殖是水产养殖业可持续发展的出路.     

生物修复高氯酸盐污染的研究进展

生物修复技术是目前高氯酸盐污染环境整治的最具潜力的修复技术之一,具有成本低、无二次污染的特点,是国内外一个新的研究热点,亦是仅见的污染控制及修复的环境友好技术。介绍了环境中高氯酸盐污染的来源与分布,阐述了生物修复(主要包括植物修复和微生物修复)的特点及作用机制,认识到2种类型修复技术各有其优劣势;重点综述了生物修复高氯酸盐污染的国内外研究现状,得出植物根际降解对植物修复高氯酸盐起着十分重要作用,而微生物修复是目前最有希望获得大规模应用的高氯酸盐污染修复技术;最后提出了植物-微生物联合强化修复高氯酸盐污染的技术将更具应用前景。     

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.