"Ni-struvite" - a new biomineral formed by a nickel resistant Streptomyces acidiscabies

Biomineralization dependent on bacterial activity has been described for struvite which is formed in soils, guano, putrescent matter and sediments. A new biomineral containing nickel instead of magnesium, Ni(NH4)(PO4) . 6H2O, has been identified. It was formed by nickel resistant Streptomyces acidiscabies E13, and putatively named nickel struvite. The mineral formation is dependent on biological activity since non-viable bacterial cells are not capable to induce formation of Ni-struvite under identical conditions. Formation of Ni-struvite was observed on colony surfaces upon prolonged incubation of solid minimal or complex media containing elevated concentrations of 8-15mM NiCl2. The formation of magnesium containing crystals was not observed although Mg2+ is present in the medium. However, the process was not depending on desiccation since small crystals attached to the mycelial biomass of the bacteria were observed microscopically also in liquid cultures of nickel supplemented minimal and complex media after two weeks of incubation. The capacity to induce biomineralization of a nickel containing mineral is postulated to constitute a resistance factor, allowing the soil bacterium to withstand high nickel concentrations. The strain shows nickel resistance as an adaption to its habitat, since this bacterium was isolated from a former uranium mining site in Eastern Thuringia, Germany, where nickel concentrations of up to 2000ppm (translating to appr. 30mM) occur as a result of former mining activities.     

Stability of Tylosin A in manure containing test systems determined by high performance liquid chromatography

Tylosin is a widely used antibiotic for the treatment of infections in swine. Tylosin consists of a mixture of Tylosin A, Tylosin B, Tylosin C and Tylosin D. All components contribute to the potency of tylosin but Tylosin A is by far the major component (usually about 90% and not less than 80%). A fast, robust and easily performed HPLC method has been developed for determination of Tylosin A in the presence of tylosin residues; Tylosin B, Tylosin C and Tylosin D in manure containing incubation media. The separation was performed using a YMC-Pack ODS-AQ column (250 x 4.6 mm i.d., 5 microns particle size) operated at 35 degrees C. The mobile phase consisted of 2.25% (w/v) sodium perchlorate pH 2.5-acetonitrile (60:40 v/v). Detection was performed by measuring the UV absorption at a wavelength of 290 nm. Calibration curves of tylosin made in the incubation medium containing 6.4% manure were linear in the range from 0.375 to 128.0 mg/l (R2 = 0.999). The limit of quantitation (at the RSD 20% level) for Tylosin A was found to be 0.4 mg/l in incubation media containing 6.4% manure. The recovery of Tylosin A was in the range from 100% to 108% depending on the concentration of manure. The reproducibility was good as the relative standard deviation (n = 4) in each matrix tested was in the range from 0.7 to 1.9 at the 25 mg/l level. The stability of Tylosin A was studied under methanogenic conditions and the half-life was found to be less than two days. Studies under aerobic conditions showed that the degradation rate was found to increase with increasing concentrations of manure particles in the incubation medium. It is, however, not clear whether the decrease in the concentration of Tylosin A is caused by sorption, abiotic or biotic chemical degradation. The major degradation product of Tylosin A in methanogenic as well as aerobic incubation media has a UV-spectrum and a retention time corresponding to Tylosin B. Furthermore, Tylosin D is believed to be a minor degradation product.     

Salting our landscape: an integrated catchment model using readily accessible data to assess emerging road salt contamination to streams

A new integrated catchment model for salinity has been developed to assess the transport of road salt from upland areas in watersheds to streams using readily accessible landscape, hydrologic, and meteorological data together with reported salt applications. We used Fishkill Creek (NY) as a representative watershed to test the model. Results showed good agreement between modeled and measured stream water chloride concentrations. These results suggest that a dominant mode of catchment simulation that does not entail complex deterministic modeling is an appropriate method to model salinization and to assess effects of future applications of road salt to streams. We heuristically increased and decreased salt applications by 100% and results showed that stream chloride concentrations increased by 13% and decreased by 7%, respectively. The model suggests that future management of salt application can reduce environmental concentrations, albeit over some time.     

Characterisation and optimisation of three potential aerobic bacterial strains for kraft lignin degradation from pulp paper waste

Eight aerobic bacterial strains were isolated from pulp paper mill effluent sludge. Out of eight through nutrient enrichment technique three potential aerobic bacterial strains ITRC S(6), ITRC S(7) and ITRC S(8) were found capable to effectively degrade the kraft lignin (KL), a major byproduct of the chemical pulping process and main contributor to the colour and toxicity of effluent. Further, these potential strains (ITRC S(6), ITRC S(7) and ITRC S(8)) were biochemically characterised as Gram variable small rod, Gram negative rod and Gram positive rod respectively. Subsequently, 16S rRNA sequencing showed 95% base sequence homology and it was identified as Paenibacillus sp. (AY952466), Aneurinibacillus aneurinilyticus (AY856831), Bacillus sp. (AY952465) for ITRC S(6), IITRC S(7) and ITRC S(8), respectively. In batch decolourization experiments Bacillus sp. ITRC S(8) reduced the colour of lignin amended mineral salt medium, pH 7.6 by 65% after 6th d, at 30 degrees C, A. aneurinilyticus ITRC S(7) by 56% and Paenibacillus ITRC S(6) 43%. Under these conditions the three strains degraded the KL by 37%, 33% and 30%, respectively while the mixed culture of these three bacteria reduced colour by 69%, lignin by 40% and total substrate by 50% under same conditions. Biodegradation of the KL was not affected by low (<0.2 mg l(-1)) dissolved oxygen content; thus oxygen inhibition is more likely to be a metabolism-dependent event. Initially with 48 h incubation the decolourization was slow with decreased pH. Further incubation there was rapid decolourization with slight increase in pH at 6d compared with initial pH by increasing culture optical density. The lignin analysis from medium with HPLC indicated complete degradation rather than biotransformation with complete loss of absorbance peak at 280 nm.     

Anaerobic biotransformation of explosives in aquifer slurries amended with ethanol and propylene glycol

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 2,4,6-trinitrotoluene (TNT) are explosives that are frequently found as environmental contaminants on military installations. Hydrogen has been shown to support the anaerobic transformation of these explosives. We investigated ethanol and propylene glycol as electron donors for providing syntrophically produced H2 for stimulating the anaerobic biodegradation of explosives in contaminated soil. The study was conducted using anoxic microcosms constructed with slurries of the contaminated soil and groundwater. The addition of 5mM ethanol and propylene glycol enhanced the biodegradation of RDX and HMX relative to the control bottles. Ethanol was depleted within about 20 days, resulting in the transient formation of hydrogen, acetate, and methane. The hydrogen headspace concentration increased from 8 ppm to 1838 ppm before decreasing to background concentrations. Propylene glycol was completely degraded after 15 days, forming hydrogen, propionate, and acetate as end-products. The hydrogen headspace concentrations increased from 56 ppm to 628 ppm before decreasing to background concentrations. No methane formation was observed during the incubation period of 48 days. Our findings indicate the addition of ethanol and propylene to the aquifer slurries increased the hydrogen concentrations and enhanced the biotransformation of RDX and HMX in the explosive-contaminated soil.     

Sea salt concentrations across the European continent

The oceans are a major source for particles that play an important role in many atmospheric processes. In Europe sea salt may contribute significantly to particulate matter concentrations. We have compiled sodium concentration data as a tracer for sea salt for 89 sites in Europe to provide more insight in the distribution of sea salt across Europe. The annual average sea salt concentrations above land were estimated to range between 0.3 and almost 13 μg m^?3. Maximum concentrations are found at the Irish coast. At coastal sites along the Atlantic and North Sea coast concentrations tend to be around 5 μg m^?3. More inland locations up to about 300 km away from the coast tend to show concentrations between 2 and 5 μg m^?3, whereas sites further away from the coast are characterized by lower concentrations. An analysis of the representativity of the data with respect to a long term average showed that the long average is associated with a standard deviation of around 15%. The compilation of observations provides an improved overview of sea salt concentrations in Europe as well as an improved basis for model validation. Verification of the results of the LOTOS-EUROS model learned that the model represents well the spatial variability of the observed sea salt concentrations very well. However, the absolute concentrations are significantly overestimated due to large uncertainties in the emission and dry deposition parameterizations. Using the high explained variability in the gradients across Europe, the bias-corrected modelled distribution serves as a best estimate of the sea salt distribution across Europe for 2005.     

不同镉污染农田土壤上秸秆和炭化秸秆分解动态及其对土壤镉的吸附特征

通过温室土壤培养实验,研究不同镉污染农田土壤上不同的作物秸秆和炭化作物秸秆还田后的分解动态和还田秸秆材料对污染土壤中镉的吸附特征,探讨秸秆和炭化秸秆还田做为重金属镉污染农田土壤修复剂的可行性。实验结果表明,还田的油菜秸秆和玉米秸秆在2种镉污染水稻土壤上6个月分解了43％-65％,秸秆炭化后还田则很稳定,2种镉污染土壤上还田6个月时累计分解量小于5％。2种镉污染土壤上还田的秸秆和炭化秸秆随还田时间延长镉含量逐渐增加。模拟镉污染土壤上,相同时期油菜秸秆中镉含量显著高于玉米秸秆,油菜秸秆炭中镉含量显著高于玉米秸秆炭。在镉污染土壤上,还田的玉米秸秆、油菜秸秆、玉米秸秆炭和油菜秸秆炭对土壤镉的净吸附量相近,均小于1．1μg／g。在模拟镉污染土壤上还田的油菜秸秆和油莱秸秆炭对土壤镉净吸附量最高分别达到2．74μg／g和7．03μg／g,分别是玉米秸秆和玉米秸秆炭的2倍,且显著高于其在镉污染土壤上的净吸附量,具有高的吸附能力。     

A comparison of phytoremediation capability of selected plant species for given trace elements

In our experiment, As, Cd, Pb, and Zn remediation possibilities on medium contaminated soil were investigated. Seven plant species with a different trace element accumulation capacity and remediation potential were compared. We found good accumulation capabilities and remediation effectiveness of Salix dasyclados similar to studied hyperaccumulators (Arabidopsis halleri and Thlaspi caerulescens). We have noticed better remediation capability in willow compared to poplar for most of the elements considered in this experiment. On the contrary, poplar species were able to remove a larger portion of Pb as opposed to other species. Nevertheless, the removed volume was very small. The elements found in plant biomass depend substantially on the availability of these elements in the soil. Different element concentrations were determined in natural soil solution and by inorganic salt solution extraction (0.01 molL(-1) CaCl(2)). Extracted content almost exceeded the element concentration in the soil solution. Element concentrations in soil solution were not significantly affected by sampling time.     

Efficacy of forming biofilms by <Emphasis Type="Italic">Pseudomonas migulae</Emphasis> AN-1 toward in situ bioremediation of aniline-contaminated aquifer by groundwater circulation wells

The formation and activity of aniline-degrading biofilms developed by the psychrotrophic Pseudomonas migulae AN-1 were studied for the in situ remediation of contaminated aquifer using in-well bioreactor of groundwater circulating wells (GCWs). Biofilms grown in mineral salt medium with aniline exhibited tolerance to high concentrations of aniline. In aniline degradation rate, AN-1 biofilms exhibited slight differences compared with planktonic cells. The effectiveness and bio-implication of AN-1 biofilms in GCWs were investigated to treat aniline-contaminated aquifer. The results demonstrate that AN-1 biofilms survived the GCWs treatment process with high aniline-degrading efficiency. This system provides a novel environmentally friendly technology for the in situ bioremediation of low-volatile contaminants.     

Effect of salt and urban water samples on bacterivory by the ciliate, Tetrahymena thermophila

The effect of road salt on the eating of bacteria or bacterivory by the ciliate, Tetrahymena thermophila, was followed in non-nutrient Osterhout's solution with Escherichia coli expressing green fluorescent protein. Bacterivory was impaired at between 0.025 and 0.050% w/v but the ciliates appeared to have normal morphologies and motilities, whereas at above 0.1%, bacterivory was blocked and many ciliates died. By contrast, E. coli remained viable, suggesting salt could alter predator-prey relationships in microbial communities. In nutrient medium, salt was not toxic and the ciliates grew. After growth in salt, ciliates consumed bacteria in 0.2% salt, indicating the salt acclimation of bacterivory. Bacteria and ciliates were added to urban creek samples to compare their capacity to support exogenous bacterivory. Even though samples were collected weekly for a year and be expected to have fluctuating salt levels as a result of deicing, all creek samples supported a similar level of bacterivory.     

Removal of low concentrations of carbon tetrachloride in compost-based biofilters operated under methanogenic conditions.

Research was performed to demonstrate the removal of carbon tetrachloride (CT) using compost biofilters operated under methanogenic conditions. Biofilters were operated at an empty-bed residence time of 2.8 minutes using nitrogen as the atmosphere. Hydrogen and carbon dioxide were supplied as an electron donor and carbon source, respectively, during acclimation of the bed medium microbes. Once methanogenesis was demonstrated, CT flow to the biofilter was established. Biofilters were operated over a CT concentration range from 20 to 700 ppbv for 6 months. Bed medium microbes were able to remove up to 75% of the inlet CT. At excessively high CT concentrations (> 500 ppmv), methane production and hydrogen utilization by the bed medium microbes appeared to be inhibited. CT removal by the biofilter decreased when the hydrogen supply was removed from the biofilter inlet, indicating that hydrogen acted as the electron donor for reductive dechlorination. The removal efficiency and relatively low empty bed residence times demonstrated by these laboratory-scale biofilters indicate that anaerobic biofiltration of CT may be a feasible full-scale process.     

Studies on biodegradation of nicotine by Arthrobacter sp. strain HF-2

A nicotine-degrading bacterium, strain HF-2, was isolated from tobacco waste-contaminated soil and identified as a member of Arthrobacter sp. based on morphology, physiological tests, 16S rDNA sequence and phylogenetic characteristics. At thermal denaturation test indicated that the G + C mol% of strain HF-1 was 63.5. The relationship between the growth of the isolate and the nicotine degradation suggested that strain HF-2 could utilize nicotine as sole sources of carbon, nitrogen and energy. Blue pigment was observed during the nicotine degradation by strain HF-2. The isolate grew well at 20 to 33 degrees C, initial pH 6.5 to 8.0 and 0.5 to 2.0 g L-1 of nicotine concentration in the nicotine inorganic salt media. The maximum growth and nicotine degradation occurred at 30 degrees C, initial pH 7.0 and 0.7 g.L-1 of nicotine concentration in media under natural incubation condition. Strain HF-2 could degrade 100% of nicotine under the optimized incubation conditions for 43 h. The concentrations of nicotine were monitored by high performance liquid chromatography. This study demonstrates Arthrobacter sp. strain HF-2 had a great ability to degrade nicotine, and it may be available for the application to the bioremediation of environments contaminated by tobacco waste.     

Influence of ciprofloxacin on the microbial catabolic diversity in soil

In this study, the effect of ciprofloxacin (CIP) on the catabolic diversity of soil microbial communities was evaluated. Soil samples were spiked with ciprofloxacin (0, 1, 5 and 50 mg?kg^?1) and were incubated for 1, 3, 9, 22 and 40 days. Untreated controls received only water. The functional diversity of the microbial community studied was characterized using a catabolic response profile (CRP). Six substrate groups were tested: carbohydrates, amino acids, carboxylic acids, aromatic chemicals, alcohols and polymers. After 40 days, the CIP concentrations in the soil samples ranged from 25% to 58% of the initial concentrations. Soil respiratory responses to the individual substrates D-glucose, lactose, D-mannose, L-glutamic, Na-citrate, malic acid and inosine were inhibited at the high CIP concentrations (5 and 50 mg·kg^?1) in the soils and were increased at the lowest CIP concentration (1 mg·kg^?1). Soil respiration was inhibited at all of the CIP concentrations after the addition of D-galactose and glycerol. The CIP concentration and incubation time explained 45.3% of the variance of the catabolic responses. The CRP analysis clearly discriminated among the different CIP concentrations. The results suggest that CIP strongly affects the catabolic diversities of soil microbial communities and that its effect is more significant than that of incubation time.     

Effects of incubation on solubility and mobility of trace metals in two contaminated soils

Much research has focused on changes in solubility and mobility of trace metals in soils under incubation. In this experiment, changes in solubility and mobility of trace metals (Pb, Cu and As) and Fe in two contaminated soils from Tampa, Florida and Montreal, Canada were examined. Soils of 30 g were packed in columns and were incubated for 3-80 days under water-flooding incubation. Following incubation, metal concentrations in pore water (water soluble) and in 0.01 M CaCl2 leachates (exchangeable+water soluble) were determined. While both soils were contaminated with Pb (1600-2500 mg kg(-1)), Tampa soil was also contaminated with As (230 mg kg(-1)). Contrast to the low pH (3.8) of Tampa soil, Montreal soil had an alkaline pH of 7.7 and high Ca of 1.6%. Concentrations of Fe(II) increased with incubation time in the Tampa soil mainly due to reductive Fe dissolution, but decreased in the Montreal soil possibly due to formation of FeCO3. The inverse relationship between concentrations of Pb and Fe(II) in pore water coupled with the fact that Fe(II) concentrations were much greater than those of Pb in pore water may suggest the importance of Fe(II) in controlling Pb solubility in soils. However, changes in concentrations of Fe(II), Pb, Cu and As in pore water with incubation time were similar to those in leachate, i.e. water soluble metals were positively related to exchangeable metals in the two contaminated soils. This research suggests the importance of Fe in controlling metal solubility and mobility in soils under water-flooded incubation.     

Biodegradation of chlorpyrifos by either single or combined cultures of some soilborne plant pathogenic fungi

Abstract

Biodegradation of chlorpyrifos was studied in liquid culture media amended with either single or combined eight different plant pathogenic fungi isolated from the continuous cropping wheat fields. The average recovery of chlorpyrifos from the liquid media was found to be 86.1%. The detection limit of chlorpyrifos by the analytical method used was 19 ppb. Data showed that the growth of mixed fungi at concentrations up to 200 ppm of chlorpyrifos was higher than in the control treatment. Chlorpyrifos concentrations declined in the medium of combined fungi more than it did in the medium of any single fungus with increase in the incubation period. The amount of chlorpyrifos recovered was 79.8 ppm (39.9%) in the combined fungal cultures after 21 days. However, those recovered from the media of Fusarium graminearum, F. oxysporum, Rhizoctonia solani, Cladosporhim cladosporiodes, Cephalosporium sp., Trichoderma viridi, Alternaria alternata, and Cladorrhinum brunnescens, ranged from 48.0 to 74.8%. The half‐life value (T_1/2) for chlorpynfos was 15.8 day in the medium amended with mixed fungi. However, for the single cultures it ranged from 19.3 to 33.0 day.     

Microbial degradation of arsenobetaine, the major water soluble organoarsenic compound occurring in marine animals

The conversion of arsenobetaine into other arsenic compounds by microorganisms occurring in the bottom sediments from coastal waters was demonstrated for the first time. Three arsenic metabolites were observed on high performance liquid chromatogram during incubation at 25 °C for 80 days in 2 kinds of media, 1/5 ZoBell 2216E and a medium composed of inorganic salts. The time course pattern of arsenic metabolites during incubation was fairly different between these 2 media.     

Removal of Low Concentrations of Carbon Tetrachloride in Compost-Based Biofilters Operated under Methanogenic Conditions

ABSTRACT

Research was performed to demonstrate the removal of carbon tetrachloride (CT) using compost biofilters operated under methanogenic conditions. Biofilters were operated at an empty-bed residence time of 2.8 minutes using nitrogen as the atmosphere. Hydrogen and carbon dioxide were supplied as an electron donor and carbon source, respectively, during acclimation of the bed medium microbes. Once methanogenesis was demonstrated, CT flow to the biofilter was established. Biofilters were operated over a CT concentration range from 20 to 700 ppbv for 6 months. Bed medium microbes were able to remove up to 75% of the inlet CT. At excessively high CT concentrations (>500 ppmv), methane production and hydrogen utilization by the bed medium microbes appeared to be inhibited. CT removal by the biofilter decreased when the hydrogen supply was removed from the biofilter inlet, indicating that hydrogen acted as the electron donor for reductive dechlorination. The removal efficiency and relatively low empty bed residence times demonstrated by these laboratory-scale biofilters indicate that anaerobic biofiltration of CT may be a feasible full-scale process.     

Effects of pH on the mortality and accumulation of copper in tissues of Oreochromis niloticus

In the present study, effect of pH on the mortality and accumulation of copper in various tissue and organs of Oreochromis niloticus were tested at varying concentrations of copper in the medium and over different periods of time. Experimental animals were exposed to pH 5.5, 7.8 and 9.5 and 0.1, 0.5, 1.0 and 5.0 ppm copper over periods of 7, 15 and 30 days in liver, gills and muscle were determined using atomic absorption spectrophotometric techniques. The rate of mortality at 1.0 and 5.0 ppm Cu was 100% after 7 days of exposure at pH 5.5 while at 5.0 ppm Cu was 66% after 30 days of exposure at pH 7.8. No mortality was observed in any of the copper concentrations tested at pH 9.5. In all pH levels, tissue accumulation of copper increased with increasing concentrations of copper in the medium at a given exposure period. In all pH values tested, highest levels of copper were found in the liver of O. niloticus, followed by the gills and muscle tissues. Accumulation of copper in all tissues were higher at pH 5.5 compared with the other pH values in all the conditions tested.     

Geochemical behavior of metals and metalloids in an estuary affected by acid mine drainage (AMD)

The Tinto and Odiel rivers in southwest Spain drain the world’s largest sulfide mineral formation: the Iberian Pyrite Belt which has been worked since 2,500 BC. The Tinto and Odiel estuarine zones include both an extensive area of salt marsh and an intensively industrialized urban area. As a consequence of pyrite oxidation, the Tinto and Odiel rivers are strongly acidic (pH?<?3) with unusually high and quite variable metal concentrations. In this study, seasonally varying concentrations of dissolved major and trace elements were determined in the acid mine drainage affected estuary of the Ría de Huelva. During estuarine mixing, ore-derived metal concentrations exhibit excellent correlations with pH as the main controlling parameter. As pH increases, concentrations of dissolved ore-associated elements are attenuated, and this process is enhanced during the summer months. The decrease in Fe and Al concentrations ranged from 80 to 100 % as these elements are converted from dissolved to sediment-associated forms in the estuary. Coprecipitation/adsorption processes also removed between 60 and 90 % of the originally dissolved Co, Cu, Mn, Pb, Zn, and Th; however, Cd and Ni exhibited a greater propensity to remain in solution, with an average removal of approximately 60 %. On the other hand, As and U exhibited a different behavior; it is likely that these elements remain in dissolved forms because of the formation of U carbonates and soluble As species. Concentrations of As remain at elevated levels in the outer estuary (average?=?48 μg L^?1) which exceeds concentrations present in the Tinto River. Nevertheless, the estuary has recently witnessed improvements in water quality, as compared to results of several previous studies reported in the 1990s.     

Dynamic chemical characteristics of soil solution after pig manure application: a column study

When manures from intensive livestock operations are applied to agricultural or vegetable fields at a high rate, large amounts of salts and metals will be introduced into soils. Using a column leaching experiment, this study assessed the leaching potential of the downward movement of Cu and Zn as well as some salt ions after an intensive farm pig manure at rates of 0%, 5% and 10% (w/w) were applied to the top 20 cm of two different textured soils (G soil -sandy loam soil; H soil-silty clay loam soil), and investigated the growth of amaranth and Cu and Zn transfer from soil to amaranth (Amaranthus tricolor). Soil solutions were obtained at 20, 40 and 60 cm depth of the packed column and analyzed for pH, electrical conductivity (EC), dissolved organic matter (DOC) and Cu and Zn concentrations. The results indicated that application of pig manure containing Cu and Zn to sandy loam soil might cause higher leaching and uptake risk than silty clay loam soil, especially at high application rates. And manure amendment at 5% and 10% significantly decreased the biomass of amaranth, in which the salt impact rather than Cu and Zn toxicity from manures played more important role in amaranth growth. Thus the farmer should avoid application the high rate of pig manure containing metal and salt to soil at a time, especially in sandy soil.