Dose assessment for marine biota and humans from discharge of (131)I to the marine environment and uptake by algae in Sydney, Australia

Iodine-131 reaches the marine environment through its excretion to the sewer by nuclear medicine patients followed by discharge through coastal and deepwater outfalls. ¹³¹I has been detected in macroalgae, which bio-accumulate iodine, growing near the coastal outfall of Cronulla sewage treatment plant (STP) since 1995. During this study, ¹³¹I levels in liquid effluent and sludge from three Sydney STPs as well as in macroalgae (Ulva sp. and Ecklonia radiata) growing near their shoreline outfalls were measured. Concentration factors of 176 for Ulva sp. and 526 for E. radiata were derived. Radiation dose rates to marine biota from ¹³¹I discharged to coastal waters calculated using the ERICA dose assessment tool were below the ERICA screening level of 10 μGy/hr. Radiation dose rates to humans from immersion in seawater or consumption of Ulva sp. containing ¹³¹I were three and two orders of magnitude below the IAEA screening level of 10 μSv/year, respectively.     

Profenofos induced modulation in physiological indices,genomic template stability and protein banding patterns of Anabaena sp. PCC 7120

To understand the mechanism underlying organophosphate pesticide toxicity, cyanobacterium Anabaena PCC 7120 was subjected to varied concentrations (0, 5, 10, 20 and 30 mg L^?1) of profenofos and the effects were investigated in terms of changes in cellular physiology, genomic template stability and protein expression pattern. The supplementation of profenofos reduced the growth, total pigment content and photosynthetic efficiency of the test organism in a dose dependent manner with maximum toxic effect at 30 mg L^?1. The high fluorescence intensity of 2′, 7′ –dichlorofluorescin diacetate and increased production of malondialdehyde confirmed the prevalence of acute oxidative stress condition inside the cells of the cyanobacterium. Rapid amplified polymorphic DNA (RAPD) fingerprinting and SDS-PAGE analyses showed a significant alteration in the banding patterns of DNA and proteins respectively. A marked increase in superoxide dismutase, catalase, peroxidase activity and a concomitant reduction in glutathione content indicated their possible role in supporting the growth of Anabaena 7120 up to 20 mg L^?1. These findings suggest that the uncontrolled use of profenofos in the agricultural fields may not only lead to the destruction of the cyanobacterial population, but it would also disturb the nutrient dynamics and energy flow.     

Simultaneous biodegradation of bifenthrin and chlorpyrifos by Pseudomonas sp. CB2

The degradation of bifenthrin (BF) and chlorpyrifos (CP), either together or individually, by a bacterial strain (CB2) isolated from activated sludge was investigated. Strain CB2 was identified as belonging to genus Pseudomonas based on the morphological, physiological, and biochemical characteristics and a homological analysis of the 16S rDNA sequence. Strain CB2 has the potential to degrade BF and CP, either individually or in a mixture. The optimum conditions for mixture degradation were as follows: OD_600nm = 0.5; incubation temperature = 30°C; pH = 7.0; BF-CP mixture (10 mg L^?1 of each). Under these optimal conditions, the degradation rate constants (and half-lives) were 0.4308 d^?1 (1.61 d) and 0.3377 d^?1 (2.05 d) for individual BF and CP samples, respectively, and 0.3463 d^?1 (2.00 d) and 0.2931 d^?1 (2.36 d) for the BF-CP mixture. Major metabolites of BF and CP were 2-methyl-3-biphenylyl methanol and 3,5,6-trichloro-2-pyridinol, respectively. No metabolite bioaccumulation was observed. The ability of CB2 to efficiently degrade BF and CP, particularly in a mixture, may be useful in bioremediation efforts.     

石油降解菌的分离、鉴定及其降解能力的研究

从含油污泥中,筛选出能以２０ ＃ 机械润滑油为唯一碳源的３ 株石油降解菌菌株,经鉴定分别为动胶菌属（ Ｚｏｏｇｌｏｅａ ｓｐ ．） 、氮单胞菌属（ Ａｚｏｍｏｎａｓｓｐ ．） 和假单胞菌属（ Ｐｓｅｕｄｏｍｏｎａｓ ｓｐ ．） ．通过其降解能力的测试,以动胶菌 Ｄ２ 菌株对２０ ＃ 机油的降解能力最强：在含油浓度ρ＝ ５００ ～１ ５００ ｍｇ／ Ｌ 的摇瓶试验中,其除油率为２０ ．８ ％ ～２５ ％ ．利用动胶菌 Ｄ２ 菌株进行生物接触氧化法处理含油废水模拟试验,当入流浓度为１ ０００ ｍｇ／ Ｌ 时,除油率可达９０ ．５ ％ ～１００ ％ ．这一结果表明,动胶菌 Ｄ２ 菌株生物接触氧化法处理含油废水具有很好的应用前景     

20种水溶性有机溶剂对发光菌的毒性效应

以新型淡水发光菌——青海弧菌Q67(Vibrio-qinghaiensis sp.Q67)为检测生物,应用VeritasTM微孔板光度计测定了甲醇等20种常见水溶性有机溶剂对Q67的毒性效应.结果表明,乙腈、甲醇、乙醇、丙酮、乙醚、四氢呋喃和异丙醇7种有机溶剂具有非单调J型剂量-效应关系,其他13种为典型S型剂量-效应关系.分别采用Biphasic、Logit和Weibull等非线性函数进行曲线模拟,利用模拟函数可有效估算有机溶剂的各个效应浓度Ecx值.不同组成和结构的有机溶剂对淡水发光菌的毒性效应不同,官能团相同的直链溶剂含碳数越多毒性越大.     

苯并[a]芘降解菌的分离筛选及其降解条件的研究

从被石油污染的土壤样品中,以苯并[a]芘为唯一碳源反复驯化,分离筛选出1株高效降解苯并[a]芘的菌株JL 14 .经形态及生理生化特征分析,初步鉴定属于氮单胞菌属(Azomonas) .菌株JL 14在苯并[a]芘浓度为5mg·L- 1 ,2 8℃振荡培养10d ,苯并[a]芘的降解率达到48. 9% .培养基初始pH值分别为4、6、8、10时,2 8℃振荡培养10d ,苯并[a]芘的降解率分别为7 1% ,2 4 8% ,49 6%和2 5 9% .JL 14在苯并[a]芘浓度分别为10mg·L- 1 与2 0mg·L- 1 的条件下,2 8℃振荡培养10d ,苯并[a]芘的降解率分别为3 8. 2 %与2 7. 6% .Zn2 + (2 0 0mg·L- 1 )、Cd2 + (5 0mg·L- 1 )与Pb2 + (2 0 0mg·L- 1 )不影响JL 14对苯并[a]芘的降解作用,但Cu2 + (5 0mg·L- 1 )、Cr2 + (5 0mg·L- 1 )对JL 14有毒性;菲和蔗糖均可促进菌株JL 14对苯并[a]芘的降解作用.     

Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China

Spatial variations in phytoplankton community within a large mesotrophic reservoir （Miyun reservoir, North China） were investigated in relation to variations in physico-chemical properties, nutrient concentrations, temperature and light conditions over a 5 month period in 2009. The dynamics of phytoplankton community was represented by the dominance of cyanobacteria through summer and fall, following with a short term dominance of chlorophyta in late fall, and a relatively high abundance of diatom in October; on the other hand, maximum phytoplankton biomass was recorded in the north shallow region of Miyun reservoir with a higher nutrients level. Particular attention was paid to the impacts of environmental conditions on the growth of two cyanobacteria genera, the toxin-producing Microcystis and the taste ＆ odor-producing Oscillatoria. Microcystis biomass was in general greatly affected by water temperature and mixing depth/local water depth ratio in this reservoir, while the Oscillatoria biomass in the surface and middle layers was greatly affected by total dissolved phosphorus, and that in the bottom layer was related with the Secchi depth/local water depth ratio. Abundant Oscillatoria biomass was observed only in late September when Microcystis biomass decreased and allowed sufficient light go through.     

Mineralization of p-nitrophenol by a new isolate Arthrobacter sp. Y1

Arthrobacter sp. Y1, capable of metabolizing p-nitrophenol (PNP) as the sole carbon, nitrogen and energy source was isolated from activated sludge. The bacterium could tolerate concentrations of PNP up to 600 mg L^{? 1}, and degradation of PNP was achieved within 120 h of incubation. PNP and its metabolites were analyzed by high performance liquid chromatography (HPLC). The metabolite formed indicated that the organism followed the 4-nitrocathechol (4-NC) pathway for metabolism of this compound. The relevant degrading-enzyme was extracellular. Addition of other carbon source (glucose 0～ 30 g L^{? 1}) led to accelerated degradation. If the glucose concentration exceeded 30 g L^{? 1}, however, degradation was repressed. Spectrophotometry assay of the nitrite and genotoxic study showed that strain Y1 could detoxify PNP. Therefore, the present study may provide a basis for the development of the bioremediation strategies to remedy the pollutants in the environment.     

Isolation, identification and characterization of an algicidal bacterium from Lake Taihu and preliminary studies on its algicidal compounds

In an effort to identify a bio-agent capable of controlling cyanobacterial blooms, we isolated a bacterial strain, A27, which exhibited strong algicidal activity against the dominant bloom-forming species of Microcystis aeruginosa in Lake Taihu. Based on 16S rRNA gene sequence analysis, this strain belongs to the genus Exiguobacterium. This is the first report of an algicidal bacterial strain belonging to the genus Exiguobacterium. Strain A27 exhibited algicidal activity against a broad range of cyanobacteria, but elicited little or no algicidal activity against the two green algal strains tested. The algicidal activity of strain A27 was shown to be dependent on the density of the bacteria and to have a threshold density of 1.5× 10⁶ CFU/mL. Our data also showed that the algicidal activity of strain A27 depended on different growth stages of Microcystis aeruginosa (exponential ≈ lag phase > early stationary) rather than that of the bacterium itself. Our results also suggested the algicidal activity of strain A27 occurred via the production of extracellular algicidal compounds. Investigation of the algicidal compounds revealed that there were at least two different algicidal compounds produced by strain A27. These results indicated that strain A27 has great potential for use in the control of outbreaks of cyanobacterial blooms in Lake Taihu.     

喹啉降解菌Ochrobactrum sp.的好氧降解特性及其在焦化废水中的生物强化作用

喹啉是焦化废水中的难降解有机物之一,以喹啉为唯一碳氮源从某焦化废水处理厂活性污泥中分离出1株喹啉降解菌KDQ3,16S r DNA序列分析表明KDQ3为Ochrobactrum sp.,其对喹啉降解的最适条件为37℃和初始pH 7.0~8.0,喹啉降解动力学符合Haldane模型.KDQ3能在10.4 mg·L~(-1)Cr(Ⅵ)存在时降解200 mg·L~(-1)喹啉.此外,KDQ3能在实际好氧池焦化废水环境中降解喹啉和提高COD去除率,说明该菌具有生物强化焦化废水的应用潜力.