Biodegradation of the Organophosphate Insecticide Coumaphos in Highly Contaminated Soils and in Liquid Wastes

Approximately 400000 litres of cattle dip wastes containing approximately 1500 mg litre⁻¹ of the organophosphate insecticide coumaphos are generated yearly along the Mexican border from a USDA program designed to control disease-carrying cattle ticks. Use of unlined evaporation pits for the disposal of these wastes has resulted in highly contaminated soils underlying these sites. Previous work has shown that microbial consortia present in selected dip wastes can be induced to mineralize coumaphos. Our results demonstrate that similar microbial consortia are present in coumaphos-contaminated soils from eight waste sites and that these organisms are capable of mineralizing cou-maphos in these soils using soil slurries to less than 1 mg litre⁻¹ in 7–10 days at 28°C. In addition, our results show that these consortia are able to colonize pea gravel in trickling gravel filters and can be used in these filters to metabolize coumaphos from dip wastes to less than 0·1 mg litre⁻¹ in 7–10 days at 28°C. These simple systems offer potential low cost means to detoxify coumaphos-containing wastes and to bioremediate soils contaminated with this organophosphate compound.     

盐渍化土壤中土著菌的石油烃降解潜力研究

自盐渍化地区（黄河三角洲）采集4种不同石油污染程度的土壤样品,从中筛选出高效降解石油烃的4个菌系和8个单菌株。分别以原油、柴油、烷烃和多环芳烃（PAHs）为底物进行培养,测定降解菌的生物量和降解率,研究其对不同底物的耐受浓度和降解潜力。结果表明,获得的石油烃降解菌为轻度嗜盐菌;不同菌株对不同底物的耐受浓度不同,混合菌系对不同底物的降解能力强于单菌株,对单一组分底物的降解优于复杂组分的底物;单菌株I-2、3、5、7能较好地降解PAHs并且对原油的降解能力高于柴油,单菌株I-1、4、6、8能够利用烷烃且对柴油的降解能力要比原油高;降解菌对柴油和原油的最高降解率分别可达78．4％和70．7％,对正十六烷和菲的生物降解率分别高达87．7％和88．1％,表现出较强的降解能力。研究结果表明黄河三角洲盐渍化土壤中土著菌对石油烃污染土壤具有较强的牛物修复潜力。     

Phytoremediation of Vineyard Copper-Contaminated Soil and Copper Mining Waste by a High Potential Bioenergy Crop (Helianthus annus L.)

Phytoremediation is a helpful technique to remediate copper-contaminated areas. The aim of this study was to evaluate sunflower phytoremediation capacity in two vineyard copper-contaminated soils (Inceptisol and Mollisol) and a copper mining waste. Nutrient uptake, copper phytoaccumulation, translocation factor (TF), and bioaccumulation factor (BCF) of sunflower were evaluated after 57 days of growth. Plants grown in both the Mollisol and Inceptisol soils showed high plant height. Fresh biomass was high in the Mollisol in the shoots and roots and also demonstrated the highest values on the tolerance index (TI). The BCF after growth in all three of the copper contaminated soils as Inceptisol, Mollisol, and copper mining waste showed reduction of this index value to 0.19, 0.24, and 0.03, respectively against native soil (Mollisol under natural conditions (4.71). Sunflowers have some important characteristics such as high phytomass production, copper phytoaccumulation, and potential use to biofuel. Thus, sunflower is a potential candidate to phytoremediation of vineyard copper-contaminated soils.     

百菌清降解菌株H4的分离与表征及其修复污染土壤的潜能研究

A chlorothalonil(CTN)-degrading bacterial strain H4 was isolated in this study from a contaminated soil by continuous enrichment culture to identify its characteristics and to investigate its potential for remediation of CTN in contaminated soil. Based on the morphological, physiological and biochemical tests and 16 S r DNA sequence analysis, the strain was identified as Stenotrophomonas sp. After liquid culture for 7 d, 82.2% of CTN was removed by strain H4. The isolate could degrade CTN over a broad range of temperatures and p H values, and the optimum conditions for H4 degradation were p H 7.0 and 30℃. Reintroduction of the bacteria into artificially contaminated soil resulted in substantial removal of CTN( 50%) after incubation for 14 d. Soil samples treated by H4 showed significant increases(P 0.05) in soil dehydrogenase activity, soil polyphenol oxidase activity, average well-color development obtained by the Biolog Eco plate TM assay and Shannon-Weaver index, compared with the control. Strain H4 might be a promising candidate for application in the bioremediation of CTN-contaminated soils.     

Isolation and identification of boron-accumulating bacteria from contaminated soils and active sludge

High levels of boron are toxic to living organisms. The removal of boron from contaminated water is an important way of dealing with this environmental problem. For this purpose, we screened for bacteria that can absorb high levels of toxic boron from the environment. A range of boron-accumulating bacteria was isolated from boron-contaminated soil in Turkey, from uncontaminated soil in Tokyo, Japan, and from active sludge in Tokyo by semi-quantifying the boron accumulation of each single-cultured bacterium. Intracellular boron concentrations ranged from 0.3 to 1.36 nmol g⁻¹ dry weight. Nineteen isolates identified by 16S rRNA gene sequence analysis were most closely related to the genera Bacillus , Variovorax , Pseudomonas , Shewanella , Mycobacterium and Rhodococcus . To our knowledge, this is the first study examining a wide range of bacterial strains in terms of boron accumulation.     

土壤PAHs污染的微生物修复

PAHs广泛分布于土壤中,是一种非环境友好型物质。综合介绍了土壤中PAHs的来源、分布与危害,论述了PAHs的致癌毒性的结构特点、土壤PAHs污染的微生物修复原理及近年来可降解PAHs的微生物筛选情况,同时列举了新发现的可降解PAHs的微生物种类,针对土壤PAHs污染的特点提出了原位修复和异位修复两种修复方法以及从土壤性质改良和提高PAHs溶解率两方面促进微生物降解PAHs。     

A highly effective polycyclic aromatic hydrocarbon-degrading bacterium, Paracoccus sp. HPD-2, shows opposite remediation potential in two soil types

Bioaugmentation is an efficient and eco-friendly strategy for the bioremediation of polycyclic aromatic hydrocarbons(PAHs). Since the degrading abilities of soils can greatly alter the abilities of PAH-degrading bacteria, illustrating the potential and mechanism of highly efficient degrading bacteria in different soil environments is of great importance for bioremediation. A PAH-degrading bacterium, Paracoccus aminovorans HPD-2, and two soil types,red and paddy soils, with distinct PAH-degrading...     

石油烃降解混合菌修复稠油污染土壤的影响因素

稠油在开采、贮运、炼制加工及使用过程中,不可避免的污染土壤环境,对人体健康和环境造成严重影响,因此有必要采取有效措施对稠油污染土壤进行修复。利用筛选获得的石油烃降解混合菌KL9-1,对稠油污染土壤进行修复研究,考察修复过程中的影响因素。结果表明：pH、接种量、土壤中N/P、表面活性剂用量、翻耕频率、浇水频率和膨松剂种类等因素对污染土壤修复有明显的影响。 在每千克稠油污染土壤体系中,控制初始pH为8.0,接种量为70.0 mL,N∶P为3∶1,表面活性剂用量为4.0 g,每2 d浇水1次,4 d翻耕1次,稻壳作为膨松剂,在此条件下经过70 d的生物修复,石油烃降解率最高可达54.07%。     

Investigating the in situ degradation of atrazine in groundwater

This study focused on whether or not atrazine could be degraded by indigenous groundwater bacteria as part of an in situ remediation approach. Groundwater was taken from an unconfined middle upper chalk site where concentrations of atrazine and nitrate were typically in the ranges 0.02-0.2 microg litre-1 and 11.6-25.1 mg NO3-N litre-1 respectively. Sacrificial batch studies were performed using this groundwater spiked with atrazine at a concentration of 10 microg litre-1 in conjunction with a minimal mineral salts liquid (Glu-MMSL) medium which contained glucose as the sole carbon source. Treatments comprised either the Glu-MMSL groundwater cultured bacteria or Pseudomonas sp. strain ADP. Results from sacrificial batches indicated the occurrence of bacterial growth and denitrification as monitored by optical density (absorbance at 600 nm) and NO3-N content. Analysis of atrazine content by solid phase extraction coupled with high-performance liquid chromatography showed no degradation of atrazine over a period of 103 days in either treatment. These results indicated that no acclimatised bacterial community featuring positive degraders to the herbicide atrazine had become established within this chalk aquifer in response to the trace levels encountered.     

环境的PAHs污染及其生物修复技术研究进展

阐述了环境中PAHs的来源、性质和分布,综述了国内外有关生物修复技术 (生物反应器 )治理受PAHs污染环境的应用现状,提出了该技术优先研究的领域